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BoP Lab / Classes / STU

STU vs FB vs T2 vs FP pace at every track

Lap times across years say as much about the weather as the class. % of STU is each class's best lap as a share of STU's on the same day, so the conditions drop out: 100% is level, less is quicker, and a move in it is the class getting faster or slower against the field.

Class · click a class to switch, + to compare alongside (up to 4: remove one to add another)
Series
Reference class · the yardstick the % column and chart are measured against
Tracks · untick to narrow

Quickest here: STU 1:19.234 Franklin Church, Runoffs 2018 qualifying · FB 1:19.886 Alex Mayer, Runoffs 2016 qualifying · T2 1:31.563 Preston Calvert, Runoffs 2016 qualifying · FP 1:35.938 John Walker, Runoffs 2016 qualifying

1:201:402:002:202:4054 rule changes between Runoffs 2018 and Runoffs 201954 ▾66 rule changes between Runoffs 2019 and Runoffs 202066 ▾63 rule changes between Runoffs 2020 and Runoffs 202163 ▾66 rule changes between Runoffs 2021 and Runoffs 202266 ▾26 rule changes between Runoffs 2022 and Runoffs 202326 ▾56 rule changes between Runoffs 2023 and Runoffs 202456 ▾64 rule changes between Runoffs 2024 and Runoffs 202564 ▾75 rule changes between Runoffs 2025 and Runoffs 202675 ▾STU race best at Runoffs 2015: 2:06.756 (Eric Heinrich)STU race best at Runoffs 2016: 1:34.597 (Cameron Maugeri)STU race best at Runoffs 2017: 1:49.387 (Rob Huffmaster)STU race best at Runoffs 2018: 1:46.514 (Kevin Boehm)STU race best at Runoffs 2019: 2:00.483 (Kevin Boehm)STU race best at Runoffs 2020: 2:28.410 (Anthony Geraci)STU race best at Runoffs 2021: 1:47.441 (Joe Moser)STU race best at Runoffs 2022: 2:32.357 (Mark Liller)STU race best at Runoffs 2023: 2:02.302 (Mark Liller)STU race best at Runoffs 2024: 2:25.824 (Thomas Noble)STU race best at Runoffs 2025: 2:24.497 (Chip Herr)STU race best at Runoffs 2026: 2:26.416 (Richard Astacio)STU qualifying best at Runoffs 2015: 2:05.494 (Eric Heinrich)STU qualifying best at Runoffs 2016: 1:32.738 (Joe Moser)STU qualifying best at Runoffs 2017: 1:48.921 (Rob Huffmaster)STU qualifying best at Runoffs 2018: 1:19.234 (Franklin Church)STU qualifying best at Runoffs 2019: 1:59.948 (Kevin Boehm)STU qualifying best at Runoffs 2020: 2:27.883 (David Fiorelli)STU qualifying best at Runoffs 2021: 1:47.078 (Joe Moser)STU qualifying best at Runoffs 2022: 2:00.615 (Johan Schwartz)STU qualifying best at Runoffs 2023: 2:00.389 (Johan Schwartz)STU qualifying best at Runoffs 2024: 2:26.227 (Thomas Noble)STU qualifying best at Runoffs 2025: 2:23.083 (Peter Cunningham)STU qualifying best at Runoffs 2026: 2:24.912 (Richard Astacio)FB race best at Runoffs 2015: 1:51.616 (J R Osborne)FB race best at Runoffs 2016: 1:21.015 (Jeremy Hill)FB race best at Runoffs 2017: 1:33.702 (Alex Mayer)FB race best at Runoffs 2018: 1:31.189 (J R Osborne)FB race best at Runoffs 2019: 1:57.688 (Pete Frost)FB qualifying best at Runoffs 2015: 1:50.711 (J R Osborne)FB qualifying best at Runoffs 2016: 1:19.886 (Alex Mayer)FB qualifying best at Runoffs 2017: 1:33.746 (Gary Hickman)FB qualifying best at Runoffs 2018: 1:28.612 (J R Osborne)FB qualifying best at Runoffs 2019: 1:54.469 (Pete Frost)T2 race best at Runoffs 2015: 2:01.077 (Kurt Rezzetano)T2 race best at Runoffs 2016: 1:32.691 (John M Buttermore)T2 race best at Runoffs 2017: 1:48.769 (John M Buttermore)T2 race best at Runoffs 2018: 1:45.999 (John Kachadurian)T2 race best at Runoffs 2019: 1:58.551 (Cooper I MacNeil)T2 race best at Runoffs 2020: 2:26.803 (Kurt Rezzetano)T2 race best at Runoffs 2021: 1:48.474 (Kurt Rezzetano)T2 race best at Runoffs 2022: 2:04.756 (Kurt Rezzetano)T2 race best at Runoffs 2023: 2:01.201 (Kurt Rezzetano)T2 race best at Runoffs 2024: 2:23.261 (Kurt Rezzetano)T2 race best at Runoffs 2025: 2:23.483 (Kurt Rezzetano)T2 race best at Runoffs 2026: 2:23.141 (Scotty B White)T2 qualifying best at Runoffs 2015: 2:00.172 (Kurt Rezzetano)T2 qualifying best at Runoffs 2016: 1:31.563 (Preston Calvert)T2 qualifying best at Runoffs 2017: 1:48.618 (John M Buttermore)T2 qualifying best at Runoffs 2018: 1:45.032 (John Kachadurian)T2 qualifying best at Runoffs 2019: 1:57.537 (Cooper I MacNeil)T2 qualifying best at Runoffs 2020: 2:24.195 (Alan Kossof)T2 qualifying best at Runoffs 2021: 1:47.509 (Kurt Rezzetano)T2 qualifying best at Runoffs 2022: 2:00.276 (Kurt Rezzetano)T2 qualifying best at Runoffs 2023: 1:59.504 (Kurt Rezzetano)T2 qualifying best at Runoffs 2024: 2:22.117 (Kurt Rezzetano)T2 qualifying best at Runoffs 2025: 2:23.351 (Kurt Rezzetano)T2 qualifying best at Runoffs 2026: 2:23.977 (Scotty B White)FP race best at Runoffs 2015: 2:12.419 (Kevin Ruck)FP race best at Runoffs 2016: 1:36.399 (John Walker)FP race best at Runoffs 2017: 1:53.007 (Eric Prill)FP race best at Runoffs 2018: 1:48.481 (Joe Huffaker)FP race best at Runoffs 2019: 2:08.076 (Eric Prill)FP race best at Runoffs 2020: 2:34.033 (Kevin Ruck)FP race best at Runoffs 2021: 1:59.933 (Cliff Ira)FP race best at Runoffs 2022: 2:17.641 (Mason Workman)FP race best at Runoffs 2023: 2:07.787 (Cliff Ira)FP race best at Runoffs 2024: 2:33.246 (Kevin Ruck)FP race best at Runoffs 2025: 2:34.271 (Chris Bovis)FP race best at Runoffs 2026: 2:33.240 (David Strittmatter)FP qualifying best at Runoffs 2015: 2:11.009 (Kevin Ruck)FP qualifying best at Runoffs 2016: 1:35.938 (John Walker)FP qualifying best at Runoffs 2017: 1:52.091 (Eric Prill)FP qualifying best at Runoffs 2018: 1:47.588 (Joe Huffaker)FP qualifying best at Runoffs 2019: 2:07.436 (Eric Prill)FP qualifying best at Runoffs 2020: 2:31.414 (Ethan Shippert)FP qualifying best at Runoffs 2021: 1:51.082 (Craig Chima)FP qualifying best at Runoffs 2022: 2:06.217 (Eric Prill)FP qualifying best at Runoffs 2023: 2:08.248 (Cliff Ira)FP qualifying best at Runoffs 2024: 2:32.327 (Cliff Ira)FP qualifying best at Runoffs 2025: 2:32.395 (David Strittmatter)FP qualifying best at Runoffs 2026: 2:33.275 (Stephen Simonds)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2025R2025Road America · Runoffs 2026R2026
STUFBT2FPsolid race · dashed qualifying · slower is lower
90%100%110%54 rule changes between Runoffs 2018 and Runoffs 201954 ▾66 rule changes between Runoffs 2019 and Runoffs 202066 ▾63 rule changes between Runoffs 2020 and Runoffs 202163 ▾66 rule changes between Runoffs 2021 and Runoffs 202266 ▾26 rule changes between Runoffs 2022 and Runoffs 202326 ▾56 rule changes between Runoffs 2023 and Runoffs 202456 ▾64 rule changes between Runoffs 2024 and Runoffs 202564 ▾75 rule changes between Runoffs 2025 and Runoffs 202675 ▾STU race best at Runoffs 2015: 100.0% of STU's (Eric Heinrich)STU race best at Runoffs 2016: 100.0% of STU's (Cameron Maugeri)STU race best at Runoffs 2017: 100.0% of STU's (Rob Huffmaster)STU race best at Runoffs 2018: 100.0% of STU's (Kevin Boehm)STU race best at Runoffs 2019: 100.0% of STU's (Kevin Boehm)STU race best at Runoffs 2020: 100.0% of STU's (Anthony Geraci)STU race best at Runoffs 2021: 100.0% of STU's (Joe Moser)STU race best at Runoffs 2022: 100.0% of STU's (Mark Liller)STU race best at Runoffs 2023: 100.0% of STU's (Mark Liller)STU race best at Runoffs 2024: 100.0% of STU's (Thomas Noble)STU race best at Runoffs 2025: 100.0% of STU's (Chip Herr)STU race best at Runoffs 2026: 100.0% of STU's (Richard Astacio)STU qualifying best at Runoffs 2015: 100.0% of STU's (Eric Heinrich)STU qualifying best at Runoffs 2016: 100.0% of STU's (Joe Moser)STU qualifying best at Runoffs 2017: 100.0% of STU's (Rob Huffmaster)STU qualifying best at Runoffs 2018: 100.0% of STU's (Franklin Church)STU qualifying best at Runoffs 2019: 100.0% of STU's (Kevin Boehm)STU qualifying best at Runoffs 2020: 100.0% of STU's (David Fiorelli)STU qualifying best at Runoffs 2021: 100.0% of STU's (Joe Moser)STU qualifying best at Runoffs 2022: 100.0% of STU's (Johan Schwartz)STU qualifying best at Runoffs 2023: 100.0% of STU's (Johan Schwartz)STU qualifying best at Runoffs 2024: 100.0% of STU's (Thomas Noble)STU qualifying best at Runoffs 2025: 100.0% of STU's (Peter Cunningham)STU qualifying best at Runoffs 2026: 100.0% of STU's (Richard Astacio)FB race best at Runoffs 2015: 88.1% of STU's (J R Osborne)FB race best at Runoffs 2016: 85.6% of STU's (Jeremy Hill)FB race best at Runoffs 2017: 85.7% of STU's (Alex Mayer)FB race best at Runoffs 2018: 85.6% of STU's (J R Osborne)FB race best at Runoffs 2019: 97.7% of STU's (Pete Frost)FB qualifying best at Runoffs 2015: 88.2% of STU's (J R Osborne)FB qualifying best at Runoffs 2016: 86.1% of STU's (Alex Mayer)FB qualifying best at Runoffs 2017: 86.1% of STU's (Gary Hickman)FB qualifying best at Runoffs 2018: 111.8% of STU's (J R Osborne)FB qualifying best at Runoffs 2019: 95.4% of STU's (Pete Frost)T2 race best at Runoffs 2015: 95.5% of STU's (Kurt Rezzetano)T2 race best at Runoffs 2016: 98.0% of STU's (John M Buttermore)T2 race best at Runoffs 2017: 99.4% of STU's (John M Buttermore)T2 race best at Runoffs 2018: 99.5% of STU's (John Kachadurian)T2 race best at Runoffs 2019: 98.4% of STU's (Cooper I MacNeil)T2 race best at Runoffs 2020: 98.9% of STU's (Kurt Rezzetano)T2 race best at Runoffs 2021: 101.0% of STU's (Kurt Rezzetano)Off the chart: T2 race best at Runoffs 2022: 81.9% of STU's (Kurt Rezzetano)T2 race best at Runoffs 2023: 99.1% of STU's (Kurt Rezzetano)T2 race best at Runoffs 2024: 98.2% of STU's (Kurt Rezzetano)T2 race best at Runoffs 2025: 99.3% of STU's (Kurt Rezzetano)T2 race best at Runoffs 2026: 97.8% of STU's (Scotty B White)T2 qualifying best at Runoffs 2015: 95.8% of STU's (Kurt Rezzetano)T2 qualifying best at Runoffs 2016: 98.7% of STU's (Preston Calvert)T2 qualifying best at Runoffs 2017: 99.7% of STU's (John M Buttermore)Off the chart: T2 qualifying best at Runoffs 2018: 132.6% of STU's (John Kachadurian)T2 qualifying best at Runoffs 2019: 98.0% of STU's (Cooper I MacNeil)T2 qualifying best at Runoffs 2020: 97.5% of STU's (Alan Kossof)T2 qualifying best at Runoffs 2021: 100.4% of STU's (Kurt Rezzetano)T2 qualifying best at Runoffs 2022: 99.7% of STU's (Kurt Rezzetano)T2 qualifying best at Runoffs 2023: 99.3% of STU's (Kurt Rezzetano)T2 qualifying best at Runoffs 2024: 97.2% of STU's (Kurt Rezzetano)T2 qualifying best at Runoffs 2025: 100.2% of STU's (Kurt Rezzetano)T2 qualifying best at Runoffs 2026: 99.4% of STU's (Scotty B White)FP race best at Runoffs 2015: 104.5% of STU's (Kevin Ruck)FP race best at Runoffs 2016: 101.9% of STU's (John Walker)FP race best at Runoffs 2017: 103.3% of STU's (Eric Prill)FP race best at Runoffs 2018: 101.8% of STU's (Joe Huffaker)FP race best at Runoffs 2019: 106.3% of STU's (Eric Prill)FP race best at Runoffs 2020: 103.8% of STU's (Kevin Ruck)FP race best at Runoffs 2021: 111.6% of STU's (Cliff Ira)FP race best at Runoffs 2022: 90.3% of STU's (Mason Workman)FP race best at Runoffs 2023: 104.5% of STU's (Cliff Ira)FP race best at Runoffs 2024: 105.1% of STU's (Kevin Ruck)FP race best at Runoffs 2025: 106.8% of STU's (Chris Bovis)FP race best at Runoffs 2026: 104.7% of STU's (David Strittmatter)FP qualifying best at Runoffs 2015: 104.4% of STU's (Kevin Ruck)FP qualifying best at Runoffs 2016: 103.5% of STU's (John Walker)FP qualifying best at Runoffs 2017: 102.9% of STU's (Eric Prill)Off the chart: FP qualifying best at Runoffs 2018: 135.8% of STU's (Joe Huffaker)FP qualifying best at Runoffs 2019: 106.2% of STU's (Eric Prill)FP qualifying best at Runoffs 2020: 102.4% of STU's (Ethan Shippert)FP qualifying best at Runoffs 2021: 103.7% of STU's (Craig Chima)FP qualifying best at Runoffs 2022: 104.6% of STU's (Eric Prill)FP qualifying best at Runoffs 2023: 106.5% of STU's (Cliff Ira)FP qualifying best at Runoffs 2024: 104.2% of STU's (Cliff Ira)FP qualifying best at Runoffs 2025: 106.5% of STU's (David Strittmatter)FP qualifying best at Runoffs 2026: 105.8% of STU's (Stephen Simonds)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2025R2025Road America · Runoffs 2026R2026
STUFBT2FPsolid race · dashed qualifying · each class's best lap as a share of STU's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
EventSTUFBT2FP
Qual bestRace bestTrapQual bestRace bestTrapvs STU% of STUQual bestRace bestTrapvs STU% of STUQual bestRace bestTrapvs STU% of STU
Road America Runoffs 20262026-09-282:24.912Richard Astacio · fastest of 17 · top 5 within 2.6s+1.829s (+1.28%)2:26.416Richard Astacio · fastest of 16 · top 5 within 1.5s+1.919s (+1.33%)145.1Hugh Stewart+0.8 mph (+0.5%)2:23.977Scotty B White · fastest of 22 · top 5 within 2.5s+0.626s (+0.44%)2:23.141Scotty B White · fastest of 18 · top 5 within 2.7s-0.342s (-0.24%)147.2Ami Wilson-6.9 mph (-4.5%)-3.275squal -0.935s97.8%qual 99.4%2:33.275Stephen Simonds · fastest of 26 · top 5 within 1.0s+0.880s (+0.58%)2:33.240David Strittmatter · fastest of 25 · top 5 within 1.7s-1.031s (-0.67%)132.4David Strittmatter±0.0 mph (±0.0%)+6.824squal +8.363s104.7%qual 105.8%
75 rule changes (STU: 15, T2: 26, FP: 34)15 weight · 14 cars added · 9 induction · 7 engine · 3 aero · 3 tyres & wheels · 2 suspension & brakes · 1 removed · 16 wording · 5 other · GT3U wheel and tyre options clarified: 15x7 with 225 section at +275 lbs; 15x9 with 245 section at +275 lbs plus 1.5%; 16–18x9 with 245 section at +275 lbs plus 3.0%. · T2-TCR all models gain 300 lbs minimum weight; splitter ride height 3.50 inches, chassis 4.0 inches. · HP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1. · 1996-2000 Honda Civic CX/DX/LX with D16Y7 engine newly classified in HP. · HP 1275 Midget/Sprite alternate intake manifold from MG-B now permitted; balance tube shortening and flange modification allowed. · HP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs. · STU cars at or under 2,825 lbs minimum weight limited to 8-inch wheels; over 2,825 lbs limited to 9-inch wheels. · STU GT3U minimum weight increases from GT3 race weight plus 225 to plus 275 pounds; 2.0L unrestricted engines add 75 lbs. · T2-TCR adds 2023 Hyundai Veloster N TCR and Elantra N TCR, both SEQ transmission, 90% power level, 3000 lbs minimum weight. · STU adds BMW M50B20TU engine, 1991 cc, minimum weight per chart, must meet all STU engine regulations. · STL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. · T2 2015–2023 Ecoboost Mustang restrictor removed, tyres to 315, weight cut 100 lbs to 3300. · T2 Chevrolet Corvette C6 Coupe/Grand Sport gains permission for OEM C6 ZR1 and Z06 carbon splitter and spoiler dimensions. · T2-TCR Mazda 3 tyres capped at 275 section width; splitter, valance, ride height rules removed; TCR regulations source simplified. · EP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm. · FP Volkswagen Jetta 82-84 carburation option 2 comma removed; all five models' carb specs clarified or confirmed. · FP Spec Line Volkswagen Rabbit and Scirocco 1789cc base weight corrected to 1803 lbs. · EP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm. · BMW E21 320i/is (80–83) newly classified in HP Spec Lines effective 2026-05-01. · HP BMW 318is 84-85 displacement corrected to 1767 cc, 89.0 x 71.0 mm bore and stroke. · STU Honda K20C1 Turbo I4 turbo restrictor increases from 35mm to 36mm TIR. · STU GT86 Cup car must meet 2022 Toyota GR Cup rules, tires maximum 245 section width. · STU Mazda Renesis Street Port added to Table B with 2450 lbs minimum weight and 70mm throttle body options. · STU eliminates 33 and 34 mm inlet restrictor options, removing minimum weights of 2380 and 2525 lbs. · T2 BMW 435i brakes increased to 370mm front and 345mm rear from 340mm and 330mm. · T2 Porsche Cayman S year ranges and displacement specs adjusted for 2026 Atlanta HST. · T2 TCR cars must conform to 2024 TCR Technical Regulations; wheel size capped at 10" x 18", tyres at 275 max width. · FP Fiat X-1/9 1300 and 1500 intake and exhaust valve sizes corrected to 36.3/(1.43) and 31.2-33.3/(1.23-1.31). · FP Fiat X-1/9 & Bertone dual carburetors choke size increases from 28mm to 30mm on intake runner manifold. · STU Mazda MZR engines may now use Fab 9 Elite NC MX5 Performance Intake manifold as alternative option. · T2 BMW M235iR removes alternative tune permission. · FP adds Toyota 5E 1497cc DOHC engine, 1900 lbs, 23mm restrictor, SIR fuel induction. · FP class adds Toyota 4E DOHC 1331 cc engine, 1900 lbs minimum weight, unrestricted fuel induction. · FP Fiat X1/9 fuel injection carburetors simplified to one 36 or 40 DCNF option; exhaust valve enlarged to 33.0/1.30. · BMW 435i 2014–2017 added to T2 at 2979 cc, 40mm restrictor, 3400 lbs minimum weight. BMW M235i restrictor clarified to 40mm TIR. · Nissan Z including Nismo added to T2 with 2997cc, 38mm restrictor, 19in wheels, 3600–3650 lbs, 355–381mm brakes. · T2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously only spherical bearings permitted. · T2-TCR adds Link & Co 03 TCR and MG6 TCR at 3000 lbs, 90% power, sequential, 275 max tyre width. · STU Mazda MZR (LF, L3, L5) Turbo added; Goodwin intake removed, Jack Spania Racing 70 mm intake and Fab9 Tuning bottom-mount turbo kit approved. · T2, T3, T4 now allow under-dash electronics relocation for access after roll cage installation. · T2 Cadillac CT4-V Blackwing minimum weight drops 50 lbs to 3750. · T2 C6 Corvette LS2 restrictor increases from 67mm to 80mm FPR. · T2 Dodge Viper SRT10 coupe 03-06 minimum weight cut 25 lbs to 3650. · T2 Mustang GT 5.0L gains Ford Track/Performance Package rear spoiler aero parts. · T4 Performance clarified: 1-piece alternative rotors permitted only at sizes listed in spec line; alternate brake kits may use matching 1-piece rotors. · EP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted. · EP BMW Z3 2.5L and other models get smaller restrictors, 50mm to 55mm, and Z3 2.5L weight rises 50 to 78 lbs. · FP Lancia Scorpion minimum weight cut to 1950 lbs from 2030 lbs. · FP VW Rabbit Convertible no longer required to remove factory roll bar. · FP Acura Integra and Honda Civic models gain 50–79 lbs minimum weight; Mazda Miata and Mercury Capri compression ratio to 11.0:1 and valve lift to .425". · FP Honda D15, D16, B16A, B18 engines gain 105–120 lbs minimum weight across seven configurations. · STU 36mm restrictor revised to 2830 cc, 37mm to 2980 cc. · STU removes 275 tire option and 2% weight adder for cars over 3150 lbs; maximum section width now 245. · STU Honda K20 and K24 engines lose 2% weight penalty; minimum weight now per chart only. · T2 Ford Mustang Boss 302 restrictor opens 56mm to 63mm; Mustang GT 5.0L opens 60mm to 65mm. · T2 Chevrolet Camaro SS/1LE (10-15) minimum weight cut 50 lbs to 3575. · T2 Ford Mustang Challenge Dark Horse R gains 81cc to 5038, weighs 50 lbs more at 3825, runs 315 tyres instead of 295. · EP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **. · EP Mazda MX-5 1.8L 90-97 minimum weight reduced to 2125 lbs. · HP Spec Lines Austin-Healey Sprite/Midget 1098cc minimum weight drops to 1550 lbs. · HP Volvo 142 P-1800 engine gains compression ratio limit 12.0:1 and valve lift limit .425 inch. · HP Mini DOHC 1.6 valve lift limit drops to .390" from .450". · FP Scirocco 83–88 classified Prep Level 1: 1733–1803 lbs, 1715–1780 cc, iron block, aluminium head, carburetted or fuel injected. · FP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion. · EP, FP, HP: rear drum-to-disc brake conversion clarified; rotors solid, diameter limited to largest front rotor permitted. · EP Ford Mustang 94-98 fuel injected throttle body inside diameter set to 60. · FP Volkswagen Scirocco: remove two weight tiers at 1733 and 1803 lbs, two engine options, and 13-inch wheel option; allow 15-inch wheels. · STU Honda K24 engine swap weight increases by 2 percent, effective November 1, 2025. · T3 and T4 Mazda MX-5 Miata add permitted gearset kit PT#0000-02-6100 to Notes. · T4 MX-5 Miata 19-24 and 16-18, T3 MX-5 16-18 and Global Cup ND1/ND: discontinued DG Motorsports hardtop part #0000-07-5901 removed from permitted list. · T2 Spec Corvette rev limit set to 7100 rpm. · HP Plymouth Arrow gains 4 or 5 speed transmission option specification. · Appendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'. · EP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock.showhide
  • STU Wheel and tire requirements for GT3U #40679wordingwordingGT3U wheel and tyre options clarified: 15x7 with 225 section at +275 lbs; 15x9 with 245 section at +275 lbs plus 1.5%; 16–18x9 with 245 section at +275 lbs plus 3.0%.
  • T2 TCR Data Points - BoP #40508weight +300 lbsslower · weightT2-TCR all models gain 300 lbs minimum weight; splitter ride height 3.50 inches, chassis 4.0 inches.
  • FP Mini Cooper Compression Ratio #40517enginefaster · engineHP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1.
  • FP 1996-2000 Honda Civic (CX, DX, VP, LX) with Engine Code D16Y7 #40322cars addedadded1996-2000 Honda Civic CX/DX/LX with D16Y7 engine newly classified in HP.
  • FP 1275 Midget/Sprit Alternate intake manifold E/O #40370inductionadded · inductionHP 1275 Midget/Sprite alternate intake manifold from MG-B now permitted; balance tube shortening and flange modification allowed.
  • FP HP Honda Civic (92-95) #40464weight -70 lbsfaster · weightHP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs.
  • STU 9” Wheels #40433tyres & wheelsslower · tyres & wheelsSTU cars at or under 2,825 lbs minimum weight limited to 8-inch wheels; over 2,825 lbs limited to 9-inch wheels.
  • STU Weight adjustment to former GT3U cars #40474weightslower · weightSTU GT3U minimum weight increases from GT3 race weight plus 225 to plus 275 pounds; 2.0L unrestricted engines add 75 lbs.
  • T2 2023 TCR Hyundais #40278cars addedaddedT2-TCR adds 2023 Hyundai Veloster N TCR and Elantra N TCR, both SEQ transmission, 90% power level, 3000 lbs minimum weight.
  • STU Request to allow BMW M50B20TU engine in STU #40202cars addedaddedSTU adds BMW M50B20TU engine, 1991 cc, minimum weight per chart, must meet all STU engine regulations.
  • STU Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied.
  • T2 2015+ Ecoboost Mustang #40005weight -100 lbsfaster · weightT2 2015–2023 Ecoboost Mustang restrictor removed, tyres to 315, weight cut 100 lbs to 3300.
  • T2 C6 Corvette - All Body Trims Requested #40174aeroadded · aeroT2 Chevrolet Corvette C6 Coupe/Grand Sport gains permission for OEM C6 ZR1 and Z06 carbon splitter and spoiler dimensions.
  • T2 T2-TCR Table Mazda 3 #40209tyres & wheelstyres & wheelsT2-TCR Mazda 3 tyres capped at 275 section width; splitter, valance, ride height rules removed; TCR regulations source simplified.
  • FP Miata track width - errors and omissions #39976aerofaster · aeroEP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm.
  • FP GCR Spec Line Correction #39977wordingwordingFP Volkswagen Jetta 82-84 carburation option 2 comma removed; all five models' carb specs clarified or confirmed.
  • FP CGR Spec Line Weight Correction #39978wordingwordingFP Spec Line Volkswagen Rabbit and Scirocco 1789cc base weight corrected to 1803 lbs.
  • FP Triumph GT6 Spec Change. #40098inductionfaster · inductionEP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm.
  • FP Request to Classify BMW E21 320i #40110cars addedaddedBMW E21 320i/is (80–83) newly classified in HP Spec Lines effective 2026-05-01.
  • FP BMW 318is 84-85 engine displacement correction #40116wordingwordingHP BMW 318is 84-85 displacement corrected to 1767 cc, 89.0 x 71.0 mm bore and stroke.
  • STU Turbo Restrictor Size Increase Request #40008inductionfaster · inductionSTU Honda K20C1 Turbo I4 turbo restrictor increases from 35mm to 36mm TIR.
  • STU GT86 Cups Car in STU #40028wordingwordingSTU GT86 Cup car must meet 2022 Toyota GR Cup rules, tires maximum 245 section width.
  • STU Mazda Rx-8 Renesis - Streetported Variant & Added Weight #39785cars addedaddedSTU Mazda Renesis Street Port added to Table B with 2450 lbs minimum weight and 70mm throttle body options.
  • STU Eliminate 33 and 34 mm TIRs #39872inductionremoved · inductionSTU eliminates 33 and 34 mm inlet restrictor options, removing minimum weights of 2380 and 2525 lbs.
  • T2 14-17 BMW 435i Brake Approval Request #39910suspension & brakessuspension & brakesT2 BMW 435i brakes increased to 370mm front and 345mm rear from 340mm and 330mm.
  • T2 Porsche Cayman S Spec Lines Needed for Atlanta HST #39947wordingwordingT2 Porsche Cayman S year ranges and displacement specs adjusted for 2026 Atlanta HST.
  • T2 Please address loopholes in T2 TCR #40002wordingwordingT2 TCR cars must conform to 2024 TCR Technical Regulations; wheel size capped at 10" x 18", tyres at 275 max width.
  • FP Correct Valve Sizes on FP Fiat x19 1300 and 1500 #39850otherotherFP Fiat X-1/9 1300 and 1500 intake and exhaust valve sizes corrected to 36.3/(1.43) and 31.2-33.3/(1.23-1.31).
  • FP Dual Carburetor Adjustments #39851inductionfaster · inductionFP Fiat X-1/9 & Bertone dual carburetors choke size increases from 28mm to 30mm on intake runner manifold.
  • STU Fab 9 Racing Intake Manifold in STU #39767cars addedaddedSTU Mazda MZR engines may now use Fab 9 Elite NC MX5 Performance Intake manifold as alternative option.
  • T2 BMW 240i Permitted Tune #39861wordingremovedT2 BMW M235iR removes alternative tune permission.
  • FP Request Toyota 5E Series Engines #38208otheraddedFP adds Toyota 5E 1497cc DOHC engine, 1900 lbs, 23mm restrictor, SIR fuel induction.
  • FP Request for Toyota 4E Series Engines #38209cars addedaddedFP class adds Toyota 4E DOHC 1331 cc engine, 1900 lbs minimum weight, unrestricted fuel induction.
  • FP Dual Carbs for the Fiat X1/9 #39593enginefaster · engineFP Fiat X1/9 fuel injection carburetors simplified to one 36 or 40 DCNF option; exhaust valve enlarged to 33.0/1.30.
  • T2 Request to Add 2014-2017 435i to T2 #38991cars addedaddedBMW 435i 2014–2017 added to T2 at 2979 cc, 40mm restrictor, 3400 lbs minimum weight. BMW M235i restrictor clarified to 40mm TIR.
  • T2 Consideration for Nissan Z & NISMO Z to Touring 2 Class #39296cars addedaddedNissan Z including Nismo added to T2 with 2997cc, 38mm restrictor, 19in wheels, 3600–3650 lbs, 355–381mm brakes.
  • T2 Allow Alt Bushing Material in Toe Links #39607suspension & brakesadded · suspension & brakesT2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously only spherical bearings permitted.
  • T2 Request for Classification of MG6 TCR in T2-TCR Class #39702cars addedaddedT2-TCR adds Link & Co 03 TCR and MG6 TCR at 3000 lbs, 90% power, sequential, 275 max tyre width.
  • STU Request for Permission on Aftermarket Turbo Kit and Intake #39529cars addedaddedSTU Mazda MZR (LF, L3, L5) Turbo added; Goodwin intake removed, Jack Spania Racing 70 mm intake and Fab9 Tuning bottom-mount turbo kit approved.
  • T2 Alternate Placement of Fuse Panel and Electronics Request #39370otheraddedT2, T3, T4 now allow under-dash electronics relocation for access after roll cage installation.
  • T2 Rebalance Blackwing Cadillac T2 for 2026 #39426weight -50 lbsfaster · weightT2 Cadillac CT4-V Blackwing minimum weight drops 50 lbs to 3750.
  • T2 C6 LS2 Corvette Parity Request #39472inductionfaster · inductionT2 C6 Corvette LS2 restrictor increases from 67mm to 80mm FPR.
  • T2 T2 Tire Sizing #39490weight -25 lbsfaster · weightT2 Dodge Viper SRT10 coupe 03-06 minimum weight cut 25 lbs to 3650.
  • T2 Rear Spoiler for Mustang GT S550 (15-23) #39499aeroadded · aeroT2 Mustang GT 5.0L gains Ford Track/Performance Package rear spoiler aero parts.
  • T2 Clarify T4 Brake Rotor Allowance #39503wordingwordingT4 Performance clarified: 1-piece alternative rotors permitted only at sizes listed in spec line; alternate brake kits may use matching 1-piece rotors.
  • FP TR2 Notes E&O #39180wordingwordingEP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted.
  • FP Balance of Power #39187induction +50 lbsslower · inductionEP BMW Z3 2.5L and other models get smaller restrictors, 50mm to 55mm, and Z3 2.5L weight rises 50 to 78 lbs.
  • FP Competition Adjustment Request #39259weight -80 lbsfaster · weightFP Lancia Scorpion minimum weight cut to 1950 lbs from 2030 lbs.
  • FP Factory Roll Bar Removal on VW Convertible #39268wordingwordingFP VW Rabbit Convertible no longer required to remove factory roll bar.
  • FP FP Parity Request #39325weight +50 lbsslower · weightFP Acura Integra and Honda Civic models gain 50–79 lbs minimum weight; Mazda Miata and Mercury Capri compression ratio to 11.0:1 and valve lift to .425".
  • FP Adjust former-GTL Honda's with B/D-Series Engines #39374weightslower · weightFP Honda D15, D16, B16A, B18 engines gain 105–120 lbs minimum weight across seven configurations.
  • STU Turbo Inlet Restrictor Table #38961wordingwordingSTU 36mm restrictor revised to 2830 cc, 37mm to 2980 cc.
  • STU 275 Tire Rule #38983tyres & wheelsslower · tyres & wheelsSTU removes 275 tire option and 2% weight adder for cars over 3150 lbs; maximum section width now 245.
  • STU STU Honda Engine weight penalty #39375weightfaster · weightSTU Honda K20 and K24 engines lose 2% weight penalty; minimum weight now per chart only.
  • T2 Help the 2011-2014 s197Mustang GT and Boss302 Less Restriction #38523enginefaster · engineT2 Ford Mustang Boss 302 restrictor opens 56mm to 63mm; Mustang GT 5.0L opens 60mm to 65mm.
  • T2 Improving Competitiveness of Gen 5 Camaro SS #39021weight -50 lbsfaster · weightT2 Chevrolet Camaro SS/1LE (10-15) minimum weight cut 50 lbs to 3575.
  • T2 Adjust T2 Darkhorse R #39346engineslower · engineT2 Ford Mustang Challenge Dark Horse R gains 81cc to 5038, weighs 50 lbs more at 3825, runs 315 tyres instead of 295.
  • FP Please Lower Weight of 280Z #38871weight -160 lbsfaster · weightEP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **.
  • FP Miata Weight Adjustment Follow Up #38949weight -25 lbsfaster · weightEP Mazda MX-5 1.8L 90-97 minimum weight reduced to 2125 lbs.
  • FP Weight Break for 1098 Midget / Sprite #38970weight -80 lbsfaster · weightHP Spec Lines Austin-Healey Sprite/Midget 1098cc minimum weight drops to 1550 lbs.
  • FP HP Volvo 142 spec omission #38994engineslower · engineHP Volvo 142 P-1800 engine gains compression ratio limit 12.0:1 and valve lift limit .425 inch.
  • FP HP Mini DOHC 1.6 #38996engineslower · engineHP Mini DOHC 1.6 valve lift limit drops to .390" from .450".
  • FP 83-88 FP Scirocco Spec Line Creation #38997cars addedaddedFP Scirocco 83–88 classified Prep Level 1: 1733–1803 lbs, 1715–1780 cc, iron block, aluminium head, carburetted or fuel injected.
  • FP Add to Rabbit description #39019wordingwordingFP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion.
  • FP Clean-up 9.1.5.E.7e #39025otherotherEP, FP, HP: rear drum-to-disc brake conversion clarified; rotors solid, diameter limited to largest front rotor permitted.
  • FP Add TB size to Ford Mustang (94-98) Spec Line #39130inductionadded · inductionEP Ford Mustang 94-98 fuel injected throttle body inside diameter set to 60.
  • FP Correct Existing VW Scirocco Spec Line #39140cars addedremoved · cars addedFP Volkswagen Scirocco: remove two weight tiers at 1733 and 1803 lbs, two engine options, and 13-inch wheel option; allow 15-inch wheels.
  • STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ #38746weightslower · weightSTU Honda K24 engine swap weight increases by 2 percent, effective November 1, 2025.
  • T2 ND Gearset Request for T4 #39166otheraddedT3 and T4 Mazda MX-5 Miata add permitted gearset kit PT#0000-02-6100 to Notes.
  • T2 ND Spec Lines Wrong PT#'s #39170removedremovedT4 MX-5 Miata 19-24 and 16-18, T3 MX-5 16-18 and Global Cup ND1/ND: discontinued DG Motorsports hardtop part #0000-07-5901 removed from permitted list.
  • T2 Touring 2 Post-Runoffs BOP Adjustments and Changes #39274induction -50 lbs
  • T2 Adjust rev limit on Spec Corvette in T2 #39282engineslower · engineT2 Spec Corvette rev limit set to 7100 rpm.
  • FP HP Plymouth Arrow spec omission #38995cars addedaddedHP Plymouth Arrow gains 4 or 5 speed transmission option specification.
  • FP Add Wheel Diameter to Appendix G #39008wordingwordingAppendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'.
  • FP Add TB ID tolerance to general Prod rules #39009wordingaddedEP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock.
Road America Runoffs 20252025-09-292:23.083Peter Cunningham · fastest of 16 · top 5 within 2.6s-3.144s (-2.15%)2:24.497Chip Herr · fastest of 15 · top 5 within 3.8s-1.327s (-0.91%)144.3Chip Herr-1.0 mph (-0.7%)2:23.351Kurt Rezzetano · fastest of 11 · top 5 within 3.1s+1.234s (+0.87%)2:23.483Kurt Rezzetano · fastest of 10 · top 5 within 2.9s+0.222s (+0.15%)154.1John Heinricy+4.8 mph (+3.2%)-1.014squal +0.268s99.3%qual 100.2%2:32.395David Strittmatter · fastest of 20 · top 5 within 2.9s+0.068s (+0.04%)2:34.271Chris Bovis · fastest of 19 · top 5 within 1.8s+1.025s (+0.67%)132.4David Strittmatter-1.1 mph (-0.8%)+9.774squal +9.312s106.8%qual 106.5%
64 rule changes (STU: 18, T2: 29, FP: 17)14 weight · 12 cars added · 9 engine · 7 induction · 7 tyres & wheels · 1 removed · 9 wording · 5 other · STU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs. · STU-TCR gains GT3 TCR spec lines; 275 tyre option now costs 150 lb adder, up from 100 lb. · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · T2, T3, T4 spec table header changed from T2 to ET. · BMW M2 CS Cup 2020-2021 in T2 Spec must run Red power stick part #8324085, not Purple #8324089. · T2 Corvette C5 Z06 and C6 brake allowances simplified to stock specifications only. · T2 Chevrolet Corvette C5 LS1 restrictor reduced from 59mm to 58mm FPR. · EP BMW Z4 03-05 gains 52mm flat plate intake restrictor. · EP Fiat 124 Spider Competition 1600 and 2000 minimum weight drops 50 lbs to 2000; carburetors now allow 36mm chokes instead of 34mm. · STU 2.8–3.2L N/A engines now permit 245 max tyre width; over 3150 lbs cars may run 275 with 2% weight penalty. · STU Mazda MZR intake manifold now allows Goodwin 61-2510 or Gato Performance 31972. · STU Honda JDM H23a added, 2259 cc, minimum weight per chart, must meet ST engine regulations. · HP Fiat X-1/9 and Bertone 1500 minimum weights reduced to 1740 lbs, 1784 lbs, 1827 lbs; 1300 models to 1600, 1640, 1680 lbs; additional 1300 and 1500 specs to 2010, 1900 lbs. · STU wheels capped at 18 inches diameter; under 2,850 lbs max 8 inches wide, over 2,850 lbs max 9 inches wide. · STU-GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tyre options clarified with weight adjustments. · T2 C6 Corvette LS2 requires 67mm FPR restrictor, up from 63mm. · T2 Nissan 370Z max wheel size increases from 19×10 to 19×10.5 inches. · T2 Cadillac CT4-V Blackwing tire size maximum increases from 295 to 315. · Chevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs. · HP Ford Festiva 88-93 minimum weight lowered to 1600 lbs, competition weight to 1640, prepared weight to 1680; compression ratio raised to 11.0:1. · Ford Mustang Challenge Darkhorse R added to T2 with 4957cc engine, 58mm restrictor, 3650 lbs minimum weight. · T2 350Z Spec Line eliminates detailed part numbers and consolidates allowances into cleaner performance criteria. · EP BMW Z3 2.5L, Z3 2.8L, 328i E36/E46, 325i E36/E46 intake restrictors reduced 4mm each, to 52–58mm. · FP Acura Integra and Honda Civic models restricted from 55mm to 51mm intake; Del Sol VTEC weight raised to 2290, 2347, 2405 lbs. · EP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36. · EP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450. · EP Mazda MX-5 Miata 99-05 minimum weight reduced to 2100 lbs, 2153 lbs with power, 2205 lbs modified. · FP Volkswagen Jetta Mark IV 4dr FWD added to GTL-FP Cars classification with 98.2 in wheelbase. · FP adds optional induction chokes as alternative to SIR, same size as listed restrictor. · STU BMW N54/N55 3.0 classified at chart plus 3% minimum weight; N54 twin turbo not allowed. · STU Mini Cooper S SC pulley diameter reduced to 2.185 inches. · STU Honda K20C1 Turbo I4 exempted from 3% direct injection weight adder. · STU GT3U minimum weight increases 150 pounds to 250 pounds. · EP BMW models now require flat plate intake restrictors: Z3 2.5L 52mm, Z3 2.8L 55mm, 328i E36 58mm, 328i/ci E46 58mm, 325i E46 56mm, 325i E36 56mm, 325is M-Technic 56mm. · T2 Ford Mustang GT 5.0L (15-23) combined with separate restrictors: 63mm for Gen 2, 60mm for Gen 3; 100 lb weight break removed. · T2 Chevrolet Camaro 1LE 1LE gains 100 lbs to 3600, restrictor opens 58mm to 62mm. · T2 BMW M235iR permitted oil cooler, radiator per touring rules, and silicone charge pipe. · Ford SCCA Club Spec Mustang added to T3 at 3350 lbs; Mazda SCCA Club Spec MX-5 added to T4 at 2500 lbs. · EP BMW 325i/is E30 84-91 weight reduced to 2150 lbs base, 2204 lbs with turbo, 2258 lbs supercharged. · FP Sprite and Midget 1275cc and 1500cc bore, stroke, displacement, and valve specifications corrected to factory dimensions. · F Production now permits GT-Lite cars meeting Appendix N specs to compete, governed by Appendix N not PCS 9.1.5. · STU Audi 1.8T Wagon removed; Porsche 944 1800cc weight to Chart, turbo inlet restrictor deleted. · STU-GT3 reclassified as STU-GT3U, effective 1 January 2026. · STU GT3 TCR may run 275-wide DOT tires with 100 lb weight penalty; A compound prohibited at 275. · T2, T3, T4: nine, nine, and thirty-seven expired spec lines removed effective 2025-01-01. · T2 Ford Mustang GT 5.0L 11-14 minimum weight drops 50 lbs to 3525. · T2 Spec Corvette: SC-3200, SC+-3300; Nankang NS-2R or 295 R compound or any 200tw 315 tire; radiator shroud, brakes, shocks, dry sump, battery, differential, springs now permitted. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · STU BMW N54/N55 turbo inlet restrictors now required per GCR definition; twin turbo conversion to single turbo clarified. · T2, T3 Mustang spec lines remove redundant driveshaft allowance notes across six model year ranges. · T2 Chevrolet Corvette C6 LS3 restrictor increased from 53mm to 56mm flat plate. · T2, T3, T4 fuel cell installations may omit charcoal canisters, emissions valves, and sensors. · T2, T3, T4 brake specifications clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter. · T2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors. · Porsche Spec Boxster moves to T4, minimum weight 2750 lbs, ineligible for Runoffs until 3 Super Tour events. · T2 Corvette C6 front wheel width increases to 11 inches, rear to 11 or 13 inches. · T4 BMW 320i Spec Line: Turner Motorsports intercooler #024703TMS02 now allowed. · 2005 Cadillac CTS 3.6L 6-speed manual classified in T3 Spec. · T2 C5 Corvette restrictors now engine-specific: LS1 59mm, LS2 63mm, LS3 56mm FPR. · T2 Chevrolet Corvette Z06 (06-12) Spec Line deleted entirely. · HP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1. · STU Mini Cooper S SC: 1900 stock pulley spec to 2.565 diameter; 2100 now permits 2.285 diameter pulley. · T2 Spec Corvette now allows 295 R compound DOT tire alternative to required Nankang NS-2R.showhide
  • STU Lotus Weight Reduction E&O #38919weightfaster · weightSTU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs.
  • STU STU-TCR Adjustments #38723weightslower · weightSTU-TCR gains GT3 TCR spec lines; 275 tyre option now costs 150 lb adder, up from 100 lb.
  • STU Lotus Weight Reduction #38772weight -50 lbsfaster · weightLotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs.
  • T2 Incorrect Touring Heading #38451wordingwordingT2, T3, T4 spec table header changed from T2 to ET.
  • T2 Clarifications needed to BMW M2 CS cup line #38536wordingwordingBMW M2 CS Cup 2020-2021 in T2 Spec must run Red power stick part #8324085, not Purple #8324089.
  • T2 Fix brake allowance supersessions. #38554otherotherT2 Corvette C5 Z06 and C6 brake allowances simplified to stock specifications only.
  • T2 C5 Corvette correction #38782engineslower · engineT2 Chevrolet Corvette C5 LS1 restrictor reduced from 59mm to 58mm FPR.
  • FP BMW Z4 update #38490inductionslower · inductionEP BMW Z4 03-05 gains 52mm flat plate intake restrictor.
  • FP EP Fiat 124 Spider Competition Adjustment Request #38498weight -50 lbsfaster · weightEP Fiat 124 Spider Competition 1600 and 2000 minimum weight drops 50 lbs to 2000; carburetors now allow 36mm chokes instead of 34mm.
  • STU 2.8-3.2L N/A Engine Allowances #38007tyres & wheelsfaster · tyres & wheelsSTU 2.8–3.2L N/A engines now permit 245 max tyre width; over 3150 lbs cars may run 275 with 2% weight penalty.
  • STU 2006-2015 Mazda Miata Intake Manifold #38422engineadded · engineSTU Mazda MZR intake manifold now allows Goodwin 61-2510 or Gato Performance 31972.
  • STU Requesting Approval of the JDM Honda h23a #38489cars addedaddedSTU Honda JDM H23a added, 2259 cc, minimum weight per chart, must meet ST engine regulations.
  • FP Base Weight Adjustment for H-Production X1/9 Spec Lines #38255weight -50 lbsfaster · weightHP Fiat X-1/9 and Bertone 1500 minimum weights reduced to 1740 lbs, 1784 lbs, 1827 lbs; 1300 models to 1600, 1640, 1680 lbs; additional 1300 and 1500 specs to 2010, 1900 lbs.
  • STU Wheel Size Inconsistency #38018tyres & wheelstyres & wheelsSTU wheels capped at 18 inches diameter; under 2,850 lbs max 8 inches wide, over 2,850 lbs max 9 inches wide.
  • STU Table C: STU-GT3U Clarification #38268weightfaster · weightSTU-GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tyre options clarified with weight adjustments.
  • T2 C6 T-2 Corvette 6 Liter Engine Restrictor #37490enginefaster · engineT2 C6 Corvette LS2 requires 67mm FPR restrictor, up from 63mm.
  • T2 370Z Mid link Replacement for True Coil Overs and OEM Wheel Size #38014tyres & wheelsfaster · tyres & wheelsT2 Nissan 370Z max wheel size increases from 19×10 to 19×10.5 inches.
  • T2 T2 Cadillac tire #38210tyres & wheelsfaster · tyres & wheelsT2 Cadillac CT4-V Blackwing tire size maximum increases from 295 to 315.
  • FP Request for Classification of Chevrolet Spark #37755cars addedaddedChevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs.
  • FP Request to Lower Ford Festiva Minimum Weight to 1600 LBS #37939weight -100 lbsfaster · weightHP Ford Festiva 88-93 minimum weight lowered to 1600 lbs, competition weight to 1640, prepared weight to 1680; compression ratio raised to 11.0:1.
  • T2 Please class the Darkhorse R in T2 #37295cars addedaddedFord Mustang Challenge Darkhorse R added to T2 with 4957cc engine, 58mm restrictor, 3650 lbs minimum weight.
  • T2 T2 350Z Spec Line Cleanup #37603wordingwordingT2 350Z Spec Line eliminates detailed part numbers and consolidates allowances into cleaner performance criteria.
  • FP Request Competition Adjustment to BMW Z3 2.5L #37120inductionslower · inductionEP BMW Z3 2.5L, Z3 2.8L, 328i E36/E46, 325i E36/E46 intake restrictors reduced 4mm each, to 52–58mm.
  • FP FP Class Adjustments #37458inductionslower · inductionFP Acura Integra and Honda Civic models restricted from 55mm to 51mm intake; Del Sol VTEC weight raised to 2290, 2347, 2405 lbs.
  • FP Interpretation of Production Rules on Mirrors #37235wordingaddedEP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36.
  • FP Weight Reduction for Honda S2000 #37466weightfaster · weightEP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450.
  • FP Mazda 1999 Miata 1.8L #37488weight -50 lbsfaster · weightEP Mazda MX-5 Miata 99-05 minimum weight reduced to 2100 lbs, 2153 lbs with power, 2205 lbs modified.
  • FP Errors & Omissions #37648cars addedaddedFP Volkswagen Jetta Mark IV 4dr FWD added to GTL-FP Cars classification with 98.2 in wheelbase.
  • FP GTL/FP consolidation 2025 Rules #37659inductionadded · inductionFP adds optional induction chokes as alternative to SIR, same size as listed restrictor.
  • STU BMW N54/N55 Engine Allowance Follow Up #37447cars addedaddedSTU BMW N54/N55 3.0 classified at chart plus 3% minimum weight; N54 twin turbo not allowed.
  • STU STU Mini Cooper pulley size clarification re: letter #36980 #37717inductionfaster · inductionSTU Mini Cooper S SC pulley diameter reduced to 2.185 inches.
  • STU Question About a Weight Modifier #37782weightfaster · weightSTU Honda K20C1 Turbo I4 exempted from 3% direct injection weight adder.
  • STU Increase Minimum Weight #37919weight +100 lbsslower · weightSTU GT3U minimum weight increases 150 pounds to 250 pounds.
  • T2 T2 BOP #37312induction
  • FP Effective date for Jan 2025 GCR updates #37654inductionslower · inductionEP BMW models now require flat plate intake restrictors: Z3 2.5L 52mm, Z3 2.8L 55mm, 328i E36 58mm, 328i/ci E46 58mm, 325i E46 56mm, 325i E36 56mm, 325is M-Technic 56mm.
  • T2 Mustang Update backdate #37275enginefaster · engineT2 Ford Mustang GT 5.0L (15-23) combined with separate restrictors: 63mm for Gen 2, 60mm for Gen 3; 100 lb weight break removed.
  • T2 BOP Adjustment for 2016 - Camaro SS/1LE #37434weight +100 lbsfaster · weightT2 Chevrolet Camaro 1LE 1LE gains 100 lbs to 3600, restrictor opens 58mm to 62mm.
  • T2 BMW M235iR TCS CHANGE REQUEST #37470otheraddedT2 BMW M235iR permitted oil cooler, radiator per touring rules, and silicone charge pipe.
  • T2 Request to Classify Club Spec in Appropriate Touring Classes #37523cars addedaddedFord SCCA Club Spec Mustang added to T3 at 3350 lbs; Mazda SCCA Club Spec MX-5 added to T4 at 2500 lbs.
  • FP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line #37119weight -50 lbsfaster · weightEP BMW 325i/is E30 84-91 weight reduced to 2150 lbs base, 2204 lbs with turbo, 2258 lbs supercharged.
  • FP Fix Error in Spridget Spec Line #37437wordingwordingFP Sprite and Midget 1275cc and 1500cc bore, stroke, displacement, and valve specifications corrected to factory dimensions.
  • FP Create ruleset that allows GTL cars to run in FP #37485cars addedaddedF Production now permits GT-Lite cars meeting Appendix N specs to compete, governed by Appendix N not PCS 9.1.5.
  • STU Audi 1.8t Wagon STU Table B #36685cars addedremoved · cars addedSTU Audi 1.8T Wagon removed; Porsche 944 1800cc weight to Chart, turbo inlet restrictor deleted.
  • STU Merger GT3 to STU #37486wordingunclearSTU-GT3 reclassified as STU-GT3U, effective 1 January 2026.
  • STU GT3 TCR Tire allowance #37494tyres & wheelsadded · tyres & wheelsSTU GT3 TCR may run 275-wide DOT tires with 100 lb weight penalty; A compound prohibited at 275.
  • T2 Remove spec lines that have expired #37269removedremovedT2, T3, T4: nine, nine, and thirty-seven expired spec lines removed effective 2025-01-01.
  • T2 BoP for the Various Mustangs #37185weight -50 lbsfaster · weightT2 Ford Mustang GT 5.0L 11-14 minimum weight drops 50 lbs to 3525.
  • T2 Spec Corvette Line Clarification. #37441otheraddedT2 Spec Corvette: SC-3200, SC+-3300; Nankang NS-2R or 295 R compound or any 200tw 315 tire; radiator shroud, brakes, shocks, dry sump, battery, differential, springs now permitted.
  • STU Request to Remove Miata Hubs from General category #37138cars addedaddedSTL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved.
  • STU BMW N54/N55 Engine Allowance #37146wordingwordingSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; twin turbo conversion to single turbo clarified.
  • T2 Redundant Verbiage Regarding Mustang Spec Lines for Driveshaft #36484wordingwordingT2, T3 Mustang spec lines remove redundant driveshaft allowance notes across six model year ranges.
  • T2 Request Less Restriction for Ls-3 Engined C6 Corvette #36810enginefaster · engineT2 Chevrolet Corvette C6 LS3 restrictor increased from 53mm to 56mm flat plate.
  • T2 Fuel Emissions Components #37076otheraddedT2, T3, T4 fuel cell installations may omit charcoal canisters, emissions valves, and sensors.
  • T2 fix brake wording #37129wordingwordingT2, T3, T4 brake specifications clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter.
  • T2 Evaporative emissions systems #37130otheraddedT2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors.
  • T2 Move Spec Boxster to T4 #37158cars addedaddedPorsche Spec Boxster moves to T4, minimum weight 2750 lbs, ineligible for Runoffs until 3 Super Tour events.
  • T2 Corvette Wheels #37169tyres & wheelsfaster · tyres & wheelsT2 Corvette C6 front wheel width increases to 11 inches, rear to 11 or 13 inches.
  • T2 BMW 320i Spec Line #37204engineadded · engineT4 BMW 320i Spec Line: Turner Motorsports intercooler #024703TMS02 now allowed.
  • T2 Classification for a 2005 Cadillac CTS 3.6 liter 6 speed manual #37224cars addedadded2005 Cadillac CTS 3.6L 6-speed manual classified in T3 Spec.
  • T2 Please Consider Allowing Update to the C5 Corvette #37298engineunclearT2 C5 Corvette restrictors now engine-specific: LS1 59mm, LS2 63mm, LS3 56mm FPR.
  • T2 Major error in lane, but nobody ran it. #37302cars addedremoved · cars addedT2 Chevrolet Corvette Z06 (06-12) Spec Line deleted entirely.
  • FP 1275 HP Spridget Level 2 Only #36518enginefaster · engineHP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1.
  • STU R53 15% Pulley Request #36980enginefaster · engineSTU Mini Cooper S SC: 1900 stock pulley spec to 2.565 diameter; 2100 now permits 2.285 diameter pulley.
  • T2 Spec Corvette Change for T2 #37127tyres & wheelsadded · tyres & wheelsT2 Spec Corvette now allows 295 R compound DOT tire alternative to required Nankang NS-2R.
Road America Runoffs 20242024-10-012:26.227Thomas Noble · fastest of 18 · top 5 within 2.3s-1.656s (-1.12%)2:25.824Thomas Noble · fastest of 17 · top 5 within 2.4s-2.586s (-1.74%)145.3Thomas Noble+1.1 mph (+0.8%)2:22.117Kurt Rezzetano · fastest of 8 · top 5 within 2.7s-2.078s (-1.44%)2:23.261Kurt Rezzetano · fastest of 7 · top 5 within 3.0s-3.542s (-2.41%)149.3Scotty B White+2.0 mph (+1.3%)-2.563squal -4.110s98.2%qual 97.2%2:32.327Cliff Ira · fastest of 26 · top 5 within 2.1s+0.913s (+0.60%)2:33.246Kevin Ruck · fastest of 24 · top 5 within 1.4s-0.787s (-0.51%)133.5David Strittmatter+0.3 mph (+0.2%)+7.422squal +6.100s105.1%qual 104.2%
56 rule changes (STU: 4, T2: 31, FP: 21)18 weight · 10 cars added · 4 induction · 4 suspension & brakes · 3 aero · 3 engine · 3 tyres & wheels · 1 removed · 8 wording · 2 other · FP Honda CRX/CRX Si 84-87 block material changes from iron to aluminium. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.). · STU RWD turbo cars no longer required to reduce inlet restrictor by 1 mm from table minimum. · T2 Subaru Impreza WRX STi (03-07) and (08-11) expiry notes removed, appeal deadline lifted. · T2 Ford Mustang S550 5.0L gains 100 lb weight allowance with 4-piston stock or Brembo 355mm brakes; Ecoboost 2.3 brake weight allowance removed. · T2 Mustang GT 5.0L 15-17 and 2018- now permit Track/Performance Package parts; T3 V6 15-17 clarified to allow Track/Performance package. · T2 Ford Mustang S550 5.0 Gen2/Gen3 loses 100 lbs with 4-piston stock or Brembo brakes, 355mm rotors. · T2-T4 Ford Mustangs: remove 25 lb penalty for non-OEM driveshaft, clarify alternate driveshaft allowance. · T2 Camaro SS, Camaro 1LE, Corvette C5, C6, Z06, Firebird, Solstice GXP now allow four or six piston front calipers. · Audi S4 (2000–2002) classified in T3 with 2671cc, 3400 lbs minimum weight, 38mm restrictor, allowing 800lb springs and intercooler. · Nissan 300ZX 84–89 added to EP, 2550–2678 lbs, 2960 cc SOHC, fuel injection, 12.0:1 compression, 0.500" valve lift limit. · Mazda RX-7 92-97 added to EP Prep as Level 2 rotary 13B 6-port, 2200–2310 lbs, carb or fuel injection, 42 mm choke. · EP Mazda RX-8 (04-11) alternate spec line removed; single spec line retained. · FP Honda CRX 84-87 plastic front header nose panel, rocker skirts, door caps can now be replica alternate material stock appearance. · FP Acura Integra 90-01 and Honda Civic Del Sol VTEC, Civic Si 99-00 require 55mm flat plate intake restrictor. · T3 and T4 Mazda RX-8 may remove or disable factory oil injection system. · T2 BMW M3 01-06 maximum wheel size increases from 18 x 9 to 18 x 10 inches. · T2, T3, T4 driveshafts may use carbon fiber, aluminum, or steel; two-piece replaced with one-piece; non-OEM adds 25 lbs. · T2 Porsche Cayman S 06-09 adds StopTech ST60/ST40 brake kit option with 50 lb weight penalty. · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588. · FP Mazda Protégé ES (01-03) renamed to Mazda Protégé ES/5 (01-03). · STU Mini Cooper S SC gains alternate LEAP OMICRON hood scoop part LEP-OMICRON3 as permitted option. · STU BMW S54 B32 OEM dry sump oiling system now permitted. · T2, T3, T4 Spec Lines remove wheelbase requirement, add Required Restrictor specification. · T2 and T3 Nissan 370Z front brake rotors increase to 355×32 mm, rears to 350×20 mm. · T2 2018+ Mustang GT 5.0L gains BMR rear upper control arm camber links part #UTCA064. · HP Honda Civic 1.5 1988-91 minimum weight drops 70 lbs to 2175; also 2-speed and 3-speed minimums cut 72 and 73 lbs. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. · T2 Ford Mustang GT 5.0L 15-17 permits BMR rear upper control arm camber links part #UTCA064. · T2 Camaro SS, 1LE, Corvette C5, C6, Z06, Firebird, Solstice GXP now allow four or six piston front calipers. · T2 Cadillac CT4-V Blackwing Runoffs eligibility requirement removed. · T2, T3, T4 battery replacement no longer allows alternate manufacturer batteries within 10% OEM weight. · T4 now allows C-Spec touring cars to compete, in addition to existing B-Spec eligibility. · T2, T3, T4 spec lines expire 12/31/24; submit to appeal or cars are removed from class. · T2 Chevrolet Camaro 1LE minimum weight rises to 3575 lbs; restrictor grows to 60mm flat plate. · EP BMW Z3 2.5L minimum weight increased to 2500 lbs, 2563 lbs with power adder, 2625 lbs with two power adders. · FP Honda throttle body inside diameters corrected across seven models: Civic 1.5 to 42", Civic Si to 55", CRX 1.5 to 42", CRX 84-87 to 33/42", CRX Si 88-91 to 55". · EP Mazda MX-5 1.8L (90-97) minimum weight cut to 2150 lbs; (94-97) variants to 2000, 2050, 2100 lbs. · EP Triumph GT6 dual 1.75-inch carburetors weight rises to 1940 lbs; triple Weber 40 DCOE option added at 1990 lbs. · EP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm. · EP Triumph TR8 dry sump allowance moved from Carburetor line to Notes. · EP Porsche 944/924S 2.5L and 2.7L minimum weights corrected: 2479cc to 2306–2363 lbs, 2681cc to 2358–2415 lbs. · T2 Cadillac CT4-V Blackwing rear wheels widen from 18 x 10 to 18 x 11; sway bars now allowed 35mm front, 30mm rear. · T2 BMW M2 CS Cup minimum weight cut 50 lbs to 3550; M235iR cut 50 lbs to 3300. · T2 Spec Corvette weight drops 175 lbs to 3200; restrictor and ride height requirements removed; Nankang NS-2R tyres now mandatory. · T2 Dodge Viper SRT-10 rear tyre shrinks to 335/30 from 345/30. · T2 Ford Mustang GT 5.0L (11-14) gains 75 lbs to 3575; (15-17) gains 50 lbs to 3650; (18+) gains 50 lbs to 3650. Restrictors enlarged. · T2 Chevrolet Camaro 1LE minimum weight drops to 3500 lbs, restrictor plate increases to 58mm flat. · T2 C5 Z06 gains 56mm restrictor spec; C6 LS2 restrictor opens to 63mm, LS3 to 53mm. · T3 Nissan 370Z now includes model years 2009–2022 with Nismo editions. · EP Porsche 944/924S combines 2.5L and 2.7L variants (83-89), raises weight to 2250–2415 lbs, allows 2681cc displacement. · FP Toyota Corolla 2TC loses 43 lbs to 1810; HP Corolla loses 50–52 lbs to 1910–2006. · EP Triumph GT6 minimum weight drops to 1800 lbs. · T2 BMW M2 CS Cup 2020- gains permission for hood vents conforming to 9.1.9.2.D.8.a.7.showhide
  • FP Errors/emissions Honda Civic/CRX #36700enginefaster · engineFP Honda CRX/CRX Si 84-87 block material changes from iron to aluminium.
  • FP Errant entry in HP production line item #36231wordingwordingHP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.).
  • STU RWD Turbo Disadvantage #36255inductionfaster · inductionSTU RWD turbo cars no longer required to reduce inlet restrictor by 1 mm from table minimum.
  • T2 Errors #36214induction -75 lbs
  • T2 Subaru Appeal #36258wordingwordingT2 Subaru Impreza WRX STi (03-07) and (08-11) expiry notes removed, appeal deadline lifted.
  • T2 S550 Brakes #36571weightslower · weightT2 Ford Mustang S550 5.0L gains 100 lb weight allowance with 4-piston stock or Brembo 355mm brakes; Ecoboost 2.3 brake weight allowance removed.
  • T2 Mustang T2/T3 #35877cars addedaddedT2 Mustang GT 5.0L 15-17 and 2018- now permit Track/Performance Package parts; T3 V6 15-17 clarified to allow Track/Performance package.
  • T2 S550 Brakes #35926weightfaster · weightT2 Ford Mustang S550 5.0 Gen2/Gen3 loses 100 lbs with 4-piston stock or Brembo brakes, 355mm rotors.
  • T2 T2-T4 Driveshaft Mistake...? #36050weightfaster · weightT2-T4 Ford Mustangs: remove 25 lb penalty for non-OEM driveshaft, clarify alternate driveshaft allowance.
  • T2 request for allowance of 6 piston calipers for T2 C5 corvettes #36126suspension & brakesadded · suspension & brakesT2 Camaro SS, Camaro 1LE, Corvette C5, C6, Z06, Firebird, Solstice GXP now allow four or six piston front calipers.
  • T2 B8/8.5 Audi S4 T3 and T2 #36195cars addedaddedAudi S4 (2000–2002) classified in T3 with 2671cc, 3400 lbs minimum weight, 38mm restrictor, allowing 800lb springs and intercooler.
  • FP NIssan 300ZX Z31 to EP #35830cars addedaddedNissan 300ZX 84–89 added to EP, 2550–2678 lbs, 2960 cc SOHC, fuel injection, 12.0:1 compression, 0.500" valve lift limit.
  • FP RX7 1993 and Up Request In EP Spec Lines, classify #36031cars addedaddedMazda RX-7 92-97 added to EP Prep as Level 2 rotary 13B 6-port, 2200–2310 lbs, carb or fuel injection, 42 mm choke.
  • FP Clean-up Multiple EP RX-8 Spec Lines In EP #36156cars addedremoved · cars addedEP Mazda RX-8 (04-11) alternate spec line removed; single spec line retained.
  • FP Request to Replace CRX Plastic Panels #35876cars addedaddedFP Honda CRX 84-87 plastic front header nose panel, rocker skirts, door caps can now be replica alternate material stock appearance.
  • FP FP data and parity #35896inductionadded · inductionFP Acura Integra 90-01 and Honda Civic Del Sol VTEC, Civic Si 99-00 require 55mm flat plate intake restrictor.
  • T2 Allow T4 and T3 RX8 to Disable/Remove Factory Oil Inj. #35761engineadded · engineT3 and T4 Mazda RX-8 may remove or disable factory oil injection system.
  • T2 Competition Adjustment Request/Wheel Size of E46 #35895tyres & wheelsfaster · tyres & wheelsT2 BMW M3 01-06 maximum wheel size increases from 18 x 9 to 18 x 10 inches.
  • T2 Driveshafts #35916weightslower · weightT2, T3, T4 driveshafts may use carbon fiber, aluminum, or steel; two-piece replaced with one-piece; non-OEM adds 25 lbs.
  • T2 Brake Request for 2009 Porsche Cayman #35723cars addedaddedT2 Porsche Cayman S 06-09 adds StopTech ST60/ST40 brake kit option with 50 lb weight penalty.
  • FP GCR Correction - Redundant HP Spec Lines #35623removedremovedHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588.
  • FP Update FP Protege (01-03) Model Info #35715wordingwordingFP Mazda Protégé ES (01-03) renamed to Mazda Protégé ES/5 (01-03).
  • STU Letter #35397 addendum #35453aeroadded · aeroSTU Mini Cooper S SC gains alternate LEAP OMICRON hood scoop part LEP-OMICRON3 as permitted option.
  • STU S54 Drysump #35464otheraddedSTU BMW S54 B32 OEM dry sump oiling system now permitted.
  • T2 Reorganize Spec Lines #35375otheraddedT2, T3, T4 Spec Lines remove wheelbase requirement, add Required Restrictor specification.
  • T2 370Z Brake Rotor Size Correction #35487suspension & brakessuspension & brakesT2 and T3 Nissan 370Z front brake rotors increase to 355×32 mm, rears to 350×20 mm.
  • T2 Letter #35154 2018+ Mustang GT Expansion #35488suspension & brakesadded · suspension & brakesT2 2018+ Mustang GT 5.0L gains BMR rear upper control arm camber links part #UTCA064.
  • FP Update 1988-1991 Civic to Match 1988-1991 CRX #35399weightfaster · weightHP Honda Civic 1.5 1988-91 minimum weight drops 70 lbs to 2175; also 2-speed and 3-speed minimums cut 72 and 73 lbs.
  • STU ST Electric-Assisted Steering Systems #35066aeroadded · aeroSTL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems.
  • T2 2015+ Mustang Sway Bar and A-Arm Request #35154suspension & brakesadded · suspension & brakesT2 Ford Mustang GT 5.0L 15-17 permits BMR rear upper control arm camber links part #UTCA064.
  • T2 Brake Kits #35245cars addedaddedT2 Camaro SS, 1LE, Corvette C5, C6, Z06, Firebird, Solstice GXP now allow four or six piston front calipers.
  • T2 Runoffs wording on Caddy in T2 #35377wordingaddedT2 Cadillac CT4-V Blackwing Runoffs eligibility requirement removed.
  • T2 More Car Lightening Stuff #35319wordingremovedT2, T3, T4 battery replacement no longer allows alternate manufacturer batteries within 10% OEM weight.
  • T2 Inclusion of B-C spec cars in T4 #35374cars addedaddedT4 now allows C-Spec touring cars to compete, in addition to existing B-Spec eligibility.
  • T2 T2-T4 Set expiration dates on spec lines #35378wordingremovedT2, T3, T4 spec lines expire 12/31/24; submit to appeal or cars are removed from class.
  • T2 Reply to letter #35161 and #31661 #35384weight +75 lbsslower · weightT2 Chevrolet Camaro 1LE minimum weight rises to 3575 lbs; restrictor grows to 60mm flat plate.
  • FP FP data #35060weight +25 lbs
  • FP Request to Review Z3 2.5 Spec Line #35073weight +50 lbsslower · weightEP BMW Z3 2.5L minimum weight increased to 2500 lbs, 2563 lbs with power adder, 2625 lbs with two power adders.
  • FP Corrections to Honda Spec Lines in FP #35250wordingunclearFP Honda throttle body inside diameters corrected across seven models: Civic 1.5 to 42", Civic Si to 55", CRX 1.5 to 42", CRX 84-87 to 33/42", CRX Si 88-91 to 55".
  • FP Miata Alternate Head #35253weight -50 lbsfaster · weightEP Mazda MX-5 1.8L (90-97) minimum weight cut to 2150 lbs; (94-97) variants to 2000, 2050, 2100 lbs.
  • FP Triumph GT6 Adjustments #35255weightslower · weightEP Triumph GT6 dual 1.75-inch carburetors weight rises to 1940 lbs; triple Weber 40 DCOE option added at 1990 lbs.
  • FP Honda S2000 throttle body #35272inductionfaster · inductionEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
  • FP Correction within Triumph TR8 Spec Line #35315wordingwordingEP Triumph TR8 dry sump allowance moved from Carburetor line to Notes.
  • FP Correction to EP 924S/944 Spec Line #35317weightweightEP Porsche 944/924S 2.5L and 2.7L minimum weights corrected: 2479cc to 2306–2363 lbs, 2681cc to 2358–2415 lbs.
  • T2 Rebalance Blackwing Cadillac T2 #35079tyres & wheelsfaster · tyres & wheelsT2 Cadillac CT4-V Blackwing rear wheels widen from 18 x 10 to 18 x 11; sway bars now allowed 35mm front, 30mm rear.
  • T2 M2 CS RACING #35130weight -50 lbsfaster · weightT2 BMW M2 CS Cup minimum weight cut 50 lbs to 3550; M235iR cut 50 lbs to 3300.
  • T2 Spec Corvette in T2 #35139weight -175 lbsfaster · weightT2 Spec Corvette weight drops 175 lbs to 3200; restrictor and ride height requirements removed; Nankang NS-2R tyres now mandatory.
  • T2 T2 Viper BoP #35155tyres & wheelsslower · tyres & wheelsT2 Dodge Viper SRT-10 rear tyre shrinks to 335/30 from 345/30.
  • T2 BOP Adjustment for 5.0L Mustangs #35156weight +75 lbsslower · weightT2 Ford Mustang GT 5.0L (11-14) gains 75 lbs to 3575; (15-17) gains 50 lbs to 3650; (18+) gains 50 lbs to 3650. Restrictors enlarged.
  • T2 Take at Look at T-2 BOP #35161weight -50 lbsfaster · weightT2 Chevrolet Camaro 1LE minimum weight drops to 3500 lbs, restrictor plate increases to 58mm flat.
  • T2 C5 Corvette Spec Line Oversight #35169enginefaster · engineT2 C5 Z06 gains 56mm restrictor spec; C6 LS2 restrictor opens to 63mm, LS3 to 53mm.
  • T2 Requested Update of Model Years of 370Z #35231cars addedaddedT3 Nissan 370Z now includes model years 2009–2022 with Nismo editions.
  • FP Porsche 944/924S Rule Change Request #35002weightslower · weightEP Porsche 944/924S combines 2.5L and 2.7L variants (83-89), raises weight to 2250–2415 lbs, allows 2681cc displacement.
  • FP FP and HP Toyota Corolla #35030weight -43 lbsfaster · weightFP Toyota Corolla 2TC loses 43 lbs to 1810; HP Corolla loses 50–52 lbs to 1910–2006.
  • FP Triumph GT6 Adjustments #35054weight -30 lbsfaster · weightEP Triumph GT6 minimum weight drops to 1800 lbs.
  • T2 M2 CS RACING #35122aeroadded · aeroT2 BMW M2 CS Cup 2020- gains permission for hood vents conforming to 9.1.9.2.D.8.a.7.
Virginia International Raceway Runoffs 20232023-09-232:00.389Johan Schwartz · fastest of 13 · top 5 within 2.3s-0.226s (-0.19%)2:02.302Mark Liller · fastest of 14 · top 5 within 1.6s-30.055s (-19.73%)144.0Mark Liller+0.1 mph (+0.1%)1:59.504Kurt Rezzetano · fastest of 13 · top 5 within 2.1s-0.772s (-0.64%)2:01.201Kurt Rezzetano · fastest of 13 · top 5 within 1.6s-3.555s (-2.85%)150.7Scotty B White-1.9 mph (-1.2%)-1.101squal -0.885s99.1%qual 99.3%2:08.248Cliff Ira · fastest of 21 · top 5 within 1.0s+2.031s (+1.61%)2:07.787Cliff Ira · fastest of 20 · top 5 within 0.8s-9.854s (-7.16%)133.7Cliff Ira+1.1 mph (+0.9%)+5.485squal +7.859s104.5%qual 106.5%
26 rule changes (STU: 3, T2: 17, FP: 6)7 cars added · 5 suspension & brakes · 3 engine · 3 weight · 1 aero · 1 tyres & wheels · 4 wording · 2 other · T2 Chevrolet Corvette C6 LS2 restrictor plate increases from 58mm to 60mm flat plate. · T2 Cadillac CT4-V Blackwing permitted to use Radium fuel surge tank with fireproof bulkhead requirement. · Mazda RX-8 T3 and T4 transmission and final drive pairing requirement removed; T4 gains Mazdaspeed radiator, spring kit, restrictor, spoiler, air dam. · T3 BMW 320i 14–15 gains aftermarket intercooler; T4 BMW 320i 14–15 loses it. · T3 and T2 Pontiac Solstice GXP 07-09 minimum ride height set to 3 inches. · FP and HP Sprite and Spitfire 1500 intake valve size corrected to 36.6 mm, removing prior decimal specifications. · HP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with year and body-type clarifications. · STU adds 2022 Toyota GR Cup and GR86 Cup, both 2387cc, 2700 lbs, 18-inch wheels, 245/620R18 slicks. · 370Z T2 suspension notes clarified: sway bars now 35mm front/29mm rear, SPL rear toe arms removed, NISMO alternatives added to camber/traction arms and mid-link. · Ford Fiesta HP model years change to 11-19; Chevrolet Sonic FP model years change to 12-19. · T2 Porsche Cayman S year range extended from 06-08 to 06-09. · Toyota Celica 78-80 classified FP Prep level 2, 2100–2205 lbs, 2190 cc SOHC four-cylinder, stock carburetion, 11.0:1 compression limit, .450" valve lift limit. · T2 C5 Z06 with 56mm restrictor weighs 3425 lbs; 58mm restrictor option removed. · STU Mazda BP5A now classified at 1839 cc displacement, 2510 lbs minimum weight, alternate intake manifold permitted. · T2 upper and lower control arm bushings can now use polyurethane, delrin, or alternate synthetic material. · T2 Cadillac CT4-V Blackwing now permits adjustable sway bar end links. · STU minimum weights adjusted: 2450 cc to 2595 lbs, 2600 cc to 2710 lbs. · T2 Honda Civic Type-R tire width increases from 275 to 295. · FP Mazda Protégé ES (01-03) renamed to Protégé ES/5 (01-03) to include P5 model variant. · T2 C5 Corvette gains GM Motorsports T1 suspension package and SpecCorvette SCT-1 swaybars. · T2 and T3 Mustang 11-14 may remove upper grille fog lights, replace with mesh or screen. · EP, FP, HP port matching limited to 1 inch depth from mating surface. · T2 BMW M235iR minimum weight drops 50 lbs to 3350; aftermarket T2 compliant shocks now allowed. · T5 touring class added; T2-T5 cars may race one class up; T5 maximum tyre width 225 with minimum aspect ratio 45. · T2-T5 Touring front and rear suspension maximum negative camber clarified to 3.5 degrees. · T2 Dodge Viper SRT-10 rear wheel widens to 19 x 13, weight increases to 3675 lbs, throttle restrictor hole enlarged to 44mm convertible or 42mm hardtop.showhide
  • T2 Corvette LS2 Restrictor Plate Adjustment #34456enginefaster · engineT2 Chevrolet Corvette C6 LS2 restrictor plate increases from 58mm to 60mm flat plate.
  • T2 Blacking Cadillac Fuel Capacity #34624otheraddedT2 Cadillac CT4-V Blackwing permitted to use Radium fuel surge tank with fireproof bulkhead requirement.
  • T2 Rules Clarification for Mazda RX8 Spec Line #34395wordingwordingMazda RX-8 T3 and T4 transmission and final drive pairing requirement removed; T4 gains Mazdaspeed radiator, spring kit, restrictor, spoiler, air dam.
  • T2 rule book corrections #34437otheraddedT3 BMW 320i 14–15 gains aftermarket intercooler; T4 BMW 320i 14–15 loses it.
  • T2 Ride Height Correction for the T3 Solstice. #34615suspension & brakessuspension & brakesT3 and T2 Pontiac Solstice GXP 07-09 minimum ride height set to 3 inches.
  • FP Correct Intake Valve Size on 1500cc Midget/Spitfire #34419wordingwordingFP and HP Sprite and Spitfire 1500 intake valve size corrected to 36.6 mm, removing prior decimal specifications.
  • FP ITC to FP? #34286cars addedremoved · cars addedHP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with year and body-type clarifications.
  • STU 2022 Toyota GR Cup for STU #34449cars addedaddedSTU adds 2022 Toyota GR Cup and GR86 Cup, both 2387cc, 2700 lbs, 18-inch wheels, 245/620R18 slicks.
  • T2 370Z Obsolete Parts & NISMO Alternatives to SPL Parts #34297suspension & brakessuspension & brakes370Z T2 suspension notes clarified: sway bars now 35mm front/29mm rear, SPL rear toe arms removed, NISMO alternatives added to camber/traction arms and mid-link.
  • FP Request to Classify Sonic and Fiesta in HP #34264cars addedaddedFord Fiesta HP model years change to 11-19; Chevrolet Sonic FP model years change to 12-19.
  • T2 2009 Porsche Cayman Classing Request #34147cars addedaddedT2 Porsche Cayman S year range extended from 06-08 to 06-09.
  • FP Classification Request for 1978 Toyota Celica #34097cars addedaddedToyota Celica 78-80 classified FP Prep level 2, 2100–2205 lbs, 2190 cc SOHC four-cylinder, stock carburetion, 11.0:1 compression limit, .450" valve lift limit.
  • T2 C5 Z06 Straight Line Speed #33575weightslower · weightT2 C5 Z06 with 56mm restrictor weighs 3425 lbs; 58mm restrictor option removed.
  • STU Alternate OEM Miata Intake Manifold #33827engineadded · engineSTU Mazda BP5A now classified at 1839 cc displacement, 2510 lbs minimum weight, alternate intake manifold permitted.
  • T2 Allowance of any nonmetallic bushing material in T2 #33833suspension & brakesadded · suspension & brakesT2 upper and lower control arm bushings can now use polyurethane, delrin, or alternate synthetic material.
  • T2 Allow Adjustable stabilizer bar links #33861suspension & brakesadded · suspension & brakesT2 Cadillac CT4-V Blackwing now permits adjustable sway bar end links.
  • STU E&O STU NA Weight Chart. #33737weightfaster · weightSTU minimum weights adjusted: 2450 cc to 2595 lbs, 2600 cc to 2710 lbs.
  • T2 Honda Civic Type R Tire Size Increase #33672tyres & wheelsfaster · tyres & wheelsT2 Honda Civic Type-R tire width increases from 275 to 295.
  • FP Request to Add Mazda Protege P5 to FP #33664cars addedaddedFP Mazda Protégé ES (01-03) renamed to Protégé ES/5 (01-03) to include P5 model variant.
  • T2 C5 Corvette Swaybars #33269suspension & brakesadded · suspension & brakesT2 C5 Corvette gains GM Motorsports T1 suspension package and SpecCorvette SCT-1 swaybars.
  • T2 Mustang OEM Grill Request #33333aeroadded · aeroT2 and T3 Mustang 11-14 may remove upper grille fog lights, replace with mesh or screen.
  • FP Review Limited Prep Port Matching Rules #33600wordingwordingEP, FP, HP port matching limited to 1 inch depth from mating surface.
  • T2 BMW M235iR/M240iR Aftermarket 2WNR Shocks Allowed - Touring 2 #33464weight -50 lbsfaster · weightT2 BMW M235iR minimum weight drops 50 lbs to 3350; aftermarket T2 compliant shocks now allowed.
  • T2 Touring (T2-T5) Category #33617cars addedaddedT5 touring class added; T2-T5 cars may race one class up; T5 maximum tyre width 225 with minimum aspect ratio 45.
  • T2 ENO 9.1.9.2.D.1.e.1.a. #33651wordingwordingT2-T5 Touring front and rear suspension maximum negative camber clarified to 3.5 degrees.
  • T2 Heavy Cars #33345engine +125 lbsfaster · engineT2 Dodge Viper SRT-10 rear wheel widens to 19 x 13, weight increases to 3675 lbs, throttle restrictor hole enlarged to 44mm convertible or 42mm hardtop.
Virginia International Raceway Runoffs 20222022-09-242:00.615Johan Schwartz · fastest of 21 · top 5 within 2.6s+0.667s (+0.56%)2:32.357Mark Liller · fastest of 19 · top 5 within 4.3s+31.874s (+26.46%)143.9Johan Schwartz+0.1 mph (+0.1%)2:00.276Kurt Rezzetano · fastest of 14 · top 5 within 1.7s+2.739s (+2.33%)2:04.756Kurt Rezzetano · fastest of 14 · top 5 within 2.0s+6.205s (+5.23%)152.5Aaron Kaplan+3.2 mph (+2.1%)-27.601squal -0.339s81.9%qual 99.7%2:06.217Eric Prill · fastest of 18 · top 5 within 1.5s-1.219s (-0.96%)2:17.641Mason Workman · fastest of 15 · top 5 within 3.2s+9.565s (+7.47%)132.5Cliff Ira+1.2 mph (+0.9%)-14.716squal +5.602s90.3%qual 104.6%
66 rule changes (STU: 21, T2: 20, FP: 25)12 weight · 11 cars added · 11 engine · 4 aero · 4 induction · 4 suspension & brakes · 3 tyres & wheels · 15 wording · 2 other · Volkswagen New Beetle 2.5L 5-cyl DOHC classified in EP at 2400–2520 lbs with fuel injection. · EP Mazda RX-7 12A/13B and 13B now permit 2 bbl fuel injected throttle body with 42mm chokes on dual-y manifold. · EP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc. · STU Mazda 13B Turbo added as Chart Limited displacement, streetport only, alternative turbos only. · STU OEM louver vents no longer count against vent allowance or 200 square inch limit. · STU non-4-valve engines gain 9% base engine weight reduction allowance; 2400cc minimum weight drops 1 lb to 2595. · STU normally-aspirated engines 2976cc–3200cc with single throttle body lose 10% base engine weight reduction allowance. · ST removes redundant language about engine balance shaft removal and alternate pulley installation. · EP Subaru BRZ title updated to include model years 13–20; Toyota 86/Scion FR-S title likewise updated to 13–20. · T2 BMW M235iR/M240iR: 240iR/Evo package penalty removed, EVO package specification clarified. · T2 BMW E92 M3 (08-14) now permits Fall Line Suspension arms for G8X/F8x/E9x M3, E9x M3/E82 1M. · FP Lotus Super Seven 91.7 ci minimum weight increases 50 lbs, to 1580. · EP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with 150 lbs penalty. · BMW 128i (08-13) classified in EP at 2700 lbs minimum with 2996 cc engine, stock throttle body, 11.0:1 compression and 0.400" valve lift limits. · EP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles. · Mazda Protégé ES 99-00 classified FP, 2150–2258 lbs, 1839 cc DOHC, fuel injection, 11.0:1 compression, 0.450" valve lift. · STU cars that qualified for 9 inch wheels in 2021 may continue running them through 2022 only. · STU splitter definition clarified: must attach to lowest point of front, have no vertical deviations. · T2-T4 Touring cars with alternative springs now permitted to use performance top hats with spherical bearings on shocks and struts. · T2 BMW E92 M3 (08-14) notes changed from 77 to 78. · Cadillac CT4-V Blackwing added to T2, 3564 cc, 3800 lbs minimum, 18×10/11 wheels, 295 MT tyres, 380/339 mm brakes. · EP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection. · EP, FP, HP Production clarify idle control valve options: stock original allowed, removable with blocked ports, or mechanical replaced with electronic stock type. · FP BMW 325e/es displacement corrected to 2693 cc. · STU BMW E36 M3 (95-99) S52B32 minimum weight cut to 3110 lbs from 3200, displacement to 3152 cc. · STU BMW S50B32 Euro maximum displacement 3201 cc, minimum weight 3300 lbs, permits 0.040 overbore and 0.5 compression increase. · ST engine swap origin rule narrowed: North America changed to United States only for case-by-case approval. · STU Honda CRX 84-91 and Civic Del Sol 93-97 both ineligible for front-wheel-drive weight reductions. · STU wheel width rule clarified: under 2950 lbs uses max 8.0 inches, 2950 lbs and over uses max 9.0 inches. · STU single-throttle body cars get lower minimum weights: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs. · T2-T4 touring cars model year 2018+ may use aftermarket ECU with 75 lb weight penalty via spec line adjustment. · T2 BMW M2 CS Cup 2020- now allows exhaust part #18302459928 and hot country package parts. · Cadillac CT4-V Blackwing 2022+ added to T2 with 3564 cc engine, 3800 lbs minimum weight, 18×10 front and 18×11 rear wheels, 295 MT tyres. · EP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate. · Ford Mustang 94-98 weight reduced to 2550/2614/2678 lbs; 99-03 3.8L classified EP at 2700/2768/2835 lbs. · EP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45. · FP VW Golf III/Jetta III 93-98 intake valve shrinks to 39.5 mm (1.56 in), exhaust to 32.9 mm (1.30 in). · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STU Audi A4 1.8T minimum weight fixed to 3050 lbs, K04 turbo removed, VF30 with 35mm restrictor required; Porsche 944 1800 weight fixed to 3050 lbs, VW/Audi 1.8L engine removed, 35mm inlet restrictor required. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · T2-T4 grill opening removal for cooling permitted without 16 square inch limit; mesh shape must match factory. · T2 Chevrolet Corvette C6 LS2 restrictor increases from 56 mm to 58 mm. · EP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked. · STU engines may delete balance shafts and plug openings; alternate pulleys or gears allowed only for timing belt or chain operation. · STU hood vents now allow louvers within 200 square inches. · T2 BMW Z4M 06-08 minimum weight reduced 50 lbs to 3100. · EP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width. · EP, FP, HP front-wheel-drive cars may alter body and subframes to install alternate axle shaft, matching RWD freedom. · EP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400. · FP Honda Civic Del Sol VTEC compression ratio limited to 11.0:1, valve lift to .425", removes dry sump and internal engine prep allowances. · FP Honda Prelude 84-87 and Mazda GLC/323 86-88 valve lift measurement method clarified, Level 1 parts list removed. · STU adds Honda K23 with 2354 cc displacement and chart minimum weight, K24 block allowed with K23 internals and head. · STU Honda K23 relaxes internal engine requirement, now needs only K23 crankshaft. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · T2 Dodge Viper SRT-10 coupe weight drops to 3550 lbs, throttle restrictor hole shrinks to 41mm. · T2, T3, T4 clarify grill opening removal limited to 16 square inches for radiator cooling; mesh shape must be retained. · T2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted. · T2, T3, T4: clarified that 'permitted' or 'allowed' parts in spec lines are alternatives to category rule allowances, not replacements. · T2 Spec Mustang model designation changed to Ford Spec Mustang. · EP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; compression ratio 12.0:1 max, valve lift 0.500" max, dry sump allowed. · Toyota Corolla GTS RWD (84-87) and FX16 FWD (87-88) added to HP; old Corolla (84-87) removed. · T2 BMW M2 CS Cup 2020 rear brake rotor minimum thickness reduced from 390 mm to 380 mm. · T4 adds 2014 VW Jetta 1.8T TSI to Spec Lines. · T2 adds 2017+ BMW M2 with 2979cc engine, 10.5x18 wheels, 295 tyres, 3650 lbs minimum weight. · Porsche 911 997.2 GTS (09-12) added to T2 with 60mm flat plate restrictor, 3400 lbs minimum, PDK option at +100 lbs. · Toyota MR-2 1.6L 85-89 HP track width corrected to 15×47 / 15×47 inches; stock track baseline now 103% plus 2.5 inches.showhide
  • FP Request to classify VW New Beetle 2.5L in EP #32725cars addedaddedVolkswagen New Beetle 2.5L 5-cyl DOHC classified in EP at 2400–2520 lbs with fuel injection.
  • FP Request Rotary Injection on Dual Y manifold #32775inductionadded · inductionEP Mazda RX-7 12A/13B and 13B now permit 2 bbl fuel injected throttle body with 42mm chokes on dual-y manifold.
  • FP Request for Corrado Stroke & Displacement Correction #32985wordingwordingEP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc.
  • STU Request Mazda 13 B turbo #32668cars addedaddedSTU Mazda 13B Turbo added as Chart Limited displacement, streetport only, alternative turbos only.
  • STU Hood Vents and Intercooler Scoops #32733aeroadded · aeroSTU OEM louver vents no longer count against vent allowance or 200 square inch limit.
  • STU Non 4 valve weight reduction removed #32808weightfaster · weightSTU non-4-valve engines gain 9% base engine weight reduction allowance; 2400cc minimum weight drops 1 lb to 2595.
  • STU Error in new minimum weight table when combined with other text #32711engineslower · engineSTU normally-aspirated engines 2976cc–3200cc with single throttle body lose 10% base engine weight reduction allowance.
  • STU Redundant Language in May GCR #32713wordingwordingST removes redundant language about engine balance shaft removal and alternate pulley installation.
  • FP Subaru BRZ Model Years #32500wordingwordingEP Subaru BRZ title updated to include model years 13–20; Toyota 86/Scion FR-S title likewise updated to 13–20.
  • T2 BMW M235iR/M240iR Min Weight Clarification #32430weightfaster · weightT2 BMW M235iR/M240iR: 240iR/Evo package penalty removed, EVO package specification clarified.
  • T2 Follow up to Letter 30888 #32477suspension & brakesadded · suspension & brakesT2 BMW E92 M3 (08-14) now permits Fall Line Suspension arms for G8X/F8x/E9x M3, E9x M3/E82 1M.
  • FP Weight Adjustment of Lotus 7 #32213weight +50 lbsslower · weightFP Lotus Super Seven 91.7 ci minimum weight increases 50 lbs, to 1580.
  • FP EP MX-5 Global Cup Car #32218weightweightEP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with 150 lbs penalty.
  • FP Please Class BMW 128i in EP #32370cars addedaddedBMW 128i (08-13) classified in EP at 2700 lbs minimum with 2996 cc engine, stock throttle body, 11.0:1 compression and 0.400" valve lift limits.
  • FP Inconsistency in Body Work Descriptions #32396aeroadded · aeroEP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles.
  • FP Request to classify the 1999-2000 Mazda Protege in FP #32398cars addedaddedMazda Protégé ES 99-00 classified FP, 2150–2258 lbs, 1839 cc DOHC, fuel injection, 11.0:1 compression, 0.450" valve lift.
  • STU Opposed to the Proposed STU Weight Chart #32381tyres & wheelsadded · tyres & wheelsSTU cars that qualified for 9 inch wheels in 2021 may continue running them through 2022 only.
  • STU Clarification request for GCR 9.1.4.D.3.a Splitter Definition #32414wordingwordingSTU splitter definition clarified: must attach to lowest point of front, have no vertical deviations.
  • T2 Request Alternate Front & Rear Strut/Shock Top Hats #32452suspension & brakesadded · suspension & brakesT2-T4 Touring cars with alternative springs now permitted to use performance top hats with spherical bearings on shocks and struts.
  • T2 Request BoP E92 torque #32456wordingwordingT2 BMW E92 M3 (08-14) notes changed from 77 to 78.
  • T2 Classify Cadillac Blackwing #32535cars addedaddedCadillac CT4-V Blackwing added to T2, 3564 cc, 3800 lbs minimum, 18×10/11 wheels, 295 MT tyres, 380/339 mm brakes.
  • FP Mazda RX8 with 13b Rotary #32170engineengineEP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection.
  • FP Request Idle control valve clarification #32178wordingwordingEP, FP, HP Production clarify idle control valve options: stock original allowed, removable with blocked ports, or mechanical replaced with electronic stock type.
  • FP Correct FP BMW 325e/es Displacement #32394wordingunclearFP BMW 325e/es displacement corrected to 2693 cc.
  • STU Request Adjustment to Min Weight for STU BMW E36 M3 (95-99) #31535weight -90 lbsfaster · weightSTU BMW E36 M3 (95-99) S52B32 minimum weight cut to 3110 lbs from 3200, displacement to 3152 cc.
  • STU BMW E36 M3 Canadian (North American) S50B32 engine #31866engineadded · engineSTU BMW S50B32 Euro maximum displacement 3201 cc, minimum weight 3300 lbs, permits 0.040 overbore and 0.5 compression increase.
  • STU Engine Swap Origin Country #32209wordingwordingST engine swap origin rule narrowed: North America changed to United States only for case-by-case approval.
  • STU CRX/Civic Del Sol #32214weightslower · weightSTU Honda CRX 84-91 and Civic Del Sol 93-97 both ineligible for front-wheel-drive weight reductions.
  • STU Error correction #32383wordingwordingSTU wheel width rule clarified: under 2950 lbs uses max 8.0 inches, 2950 lbs and over uses max 9.0 inches.
  • STU Single TB Weight Modifiers Add to Chart #32393weightfaster · weightSTU single-throttle body cars get lower minimum weights: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs.
  • T2 Request to Allow the Use of Aftermarket ECU's in Touring #31067engineadded · engineT2-T4 touring cars model year 2018+ may use aftermarket ECU with 75 lb weight penalty via spec line adjustment.
  • T2 BMW M2 CS Cup 2020- Exhaust #32243engineadded · engineT2 BMW M2 CS Cup 2020- now allows exhaust part #18302459928 and hot country package parts.
  • T2 RequestT2 classification- 2022 Cadillac CT4-V Blackwing #32263cars addedaddedCadillac CT4-V Blackwing 2022+ added to T2 with 3564 cc engine, 3800 lbs minimum weight, 18×10 front and 18×11 rear wheels, 295 MT tyres.
  • FP EP Adjustments #31858inductionslower · inductionEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
  • FP 1999 3.8L Ford Mustang to EP? #31635weightfaster · weightFord Mustang 94-98 weight reduced to 2550/2614/2678 lbs; 99-03 3.8L classified EP at 2700/2768/2835 lbs.
  • FP Improved Touring Tires #32064tyres & wheelsadded · tyres & wheelsEP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45.
  • FP VW Golf Jetta 2.0L intake and exhaust size correction. #32173engineslower · engineFP VW Golf III/Jetta III 93-98 intake valve shrinks to 39.5 mm (1.56 in), exhaust to 32.9 mm (1.30 in).
  • STU Single TB Weight Modifiers #31449weightfaster · weightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs.
  • STU Request to Remove A4 1.8t from STU Spec Line Tables #31465weightslower · weightSTU Audi A4 1.8T minimum weight fixed to 3050 lbs, K04 turbo removed, VF30 with 35mm restrictor required; Porsche 944 1800 weight fixed to 3050 lbs, VW/Audi 1.8L engine removed, 35mm inlet restrictor required.
  • STU Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels.
  • T2 Reply to letter #31486/29879 T2-T4 Grill openings #31935aerofaster · aeroT2-T4 grill opening removal for cooling permitted without 16 square inch limit; mesh shape must match factory.
  • T2 C6 Restrictor Help #31995inductionfaster · inductionT2 Chevrolet Corvette C6 LS2 restrictor increases from 56 mm to 58 mm.
  • FP Throttle Body and Idle Air #31800wordingwordingEP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked.
  • STU Request Allowance for Balance Shaft Delete in STU #31434enginefaster · engineSTU engines may delete balance shafts and plug openings; alternate pulleys or gears allowed only for timing belt or chain operation.
  • STU Request Louvers in hood vents #31916aeroadded · aeroSTU hood vents now allow louvers within 200 square inches.
  • T2 BMW Z4M Adjustment #31885weight -50 lbsfaster · weightT2 BMW Z4M 06-08 minimum weight reduced 50 lbs to 3100.
  • FP Porsche 968 Engine Questions #31478engineengineEP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width.
  • FP PCS E. 2. n. 4. Add Axle Shaft to Allow FWD the Same Freedom #31592otheraddedEP, FP, HP front-wheel-drive cars may alter body and subframes to install alternate axle shaft, matching RWD freedom.
  • FP BMW Z3 2.5L Spec Line #31724engineadded · engineEP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400.
  • FP FP Del Sol VTEC #31859engineslower · engineFP Honda Civic Del Sol VTEC compression ratio limited to 11.0:1, valve lift to .425", removes dry sump and internal engine prep allowances.
  • FP Standardize Level 2 Classifications in FP #31868wordingwordingFP Honda Prelude 84-87 and Mazda GLC/323 86-88 valve lift measurement method clarified, Level 1 parts list removed.
  • STU Request to Add Honda K23 Spec Line #30682cars addedaddedSTU adds Honda K23 with 2354 cc displacement and chart minimum weight, K24 block allowed with K23 internals and head.
  • STU RE: Aug FT letter 30682 #31060enginefaster · engineSTU Honda K23 relaxes internal engine requirement, now needs only K23 crankshaft.
  • STU Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed.
  • T2 Touring 2 BOP adjustments for 2022 #31480weight -50 lbsfaster · weightT2 Dodge Viper SRT-10 coupe weight drops to 3550 lbs, throttle restrictor hole shrinks to 41mm.
  • T2 Reply to letter 29879 T2-T4 Grill Openings #31486wordingwordingT2, T3, T4 clarify grill opening removal limited to 16 square inches for radiator cooling; mesh shape must be retained.
  • T2 Request to clarify radiator hoses #31682otheraddedT2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted.
  • T2 Clarify Permitted/Allowed #31743wordingwordingT2, T3, T4: clarified that 'permitted' or 'allowed' parts in spec lines are alternatives to category rule allowances, not replacements.
  • T2 SMG #31837wordingwordingT2 Spec Mustang model designation changed to Ford Spec Mustang.
  • FP 944S2 Restrictor #31396inductionslower · inductionEP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; compression ratio 12.0:1 max, valve lift 0.500" max, dry sump allowed.
  • FP Classing Clarification for 1986 Toyota Corolla FX16 #31527cars addedaddedToyota Corolla GTS RWD (84-87) and FX16 FWD (87-88) added to HP; old Corolla (84-87) removed.
  • T2 Typo for BMW M2 CS Cup 2020 #31173suspension & brakessuspension & brakesT2 BMW M2 CS Cup 2020 rear brake rotor minimum thickness reduced from 390 mm to 380 mm.
  • T2 Request to Classify 2014 VW Jetta 1.8t TSI #30436cars addedaddedT4 adds 2014 VW Jetta 1.8T TSI to Spec Lines.
  • T2 Request new car 2017 BMW M2 #30486cars addedaddedT2 adds 2017+ BMW M2 with 2979cc engine, 10.5x18 wheels, 295 tyres, 3650 lbs minimum weight.
  • T2 Request to Classify Porsche 997.2 GTS in T2 (body not = to C2S) #30686cars addedaddedPorsche 911 997.2 GTS (09-12) added to T2 with 60mm flat plate restrictor, 3400 lbs minimum, PDK option at +100 lbs.
  • FP E&O; MR2 Track #31120suspension & brakessuspension & brakesToyota MR-2 1.6L 85-89 HP track width corrected to 15×47 / 15×47 inches; stock track baseline now 103% plus 2.5 inches.
Indianapolis Motor Speedway Runoffs 20212021-09-251:47.078Joe Moser · fastest of 30 · top 5 within 2.0s-1.843s (-1.69%)1:47.441Joe Moser · fastest of 28 · top 5 within 1.8s-1.946s (-1.78%)146.9Kip VanSteenburg1:47.509Kurt Rezzetano · fastest of 26 · top 5 within 1.6s-1.109s (-1.02%)1:48.474Kurt Rezzetano · fastest of 26 · top 5 within 2.5s-0.295s (-0.27%)151.5Scotty B. White+1.033squal +0.431s101.0%qual 100.4%1:51.082Craig Chima · fastest of 39 · top 5 within 1.2s-1.009s (-0.90%)1:59.933Cliff Ira · fastest of 33 · top 5 within 5.4s+6.926s (+6.13%)131.8Cliff Ira+12.492squal +4.004s111.6%qual 103.7%
63 rule changes (STU: 12, T2: 30, FP: 21)22 cars added · 13 weight · 4 induction · 3 suspension & brakes · 2 engine · 1 aero · 1 tyres & wheels · 12 wording · 5 other · T2 BMW M2 CS Cup 2020- mandatory power stick part number assigned as #8324089. · EP Honda S2000 now allows F22c engine in 1997cc and 2157cc displacements with revised weight brackets and specifications. · EP Nissan 240-SX S13/S14 weight drops to 2400 lbs base, 2460 turbo, 2520 supercharged; comp ratio raised to 12.0:1, valve lift to 0.500 inch. · T2 Porsche 911/997.1 (06–08) now permits Cargraphics CARP97DFIFKR alternate exhaust manifold. · EP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed. · Plymouth Arrow 76–80 classified in HP Prep at 1800–1890 lbs with 1598 cc iron-block OHV four-cylinder. · BMW 318i/is E30 (84-85) reclassified from FP to HP at 2200–2310 lbs, SOHC 1797cc, fuel injection, 11.0:1 compression, .425" valve lift limit. · FP Fiat X1/9 1300 loses 50 lbs to 1665; X1/9 Bertone loses 50 lbs to 1765. · Daimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors. · STU fender flare wording clarified: flare of exterior contour may not change wheel opening size, location or shape from side view. · STU Mazda 12A Bridgeport weight reduced from 2550 lbs to 2350 lbs. · T2 BMW M2 CS Cup 2020- weight increases from 3625 to 3600 lbs; Purple power stick mandatory, hot country package allowed. · Porsche 924 Level 1 Prep moved from EP to FP classification. · EP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound. · T3 Honda Civic Type-R 2020+ allowed brake rotor #45251-TGH-A01 with 25 lb penalty. · T2 Mustang GT 5.0L 15-17 throttle body raised to 58mm, 2018- raised to 55mm. · T2 BMW Z4M 06–08 minimum weight increases 50 lbs, to 3150. · T2 BMW E92M3 weight drops 50 lbs to 3425; intake restrictor shrinks from 80mm to 77mm. · 84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lb weight, 1998cc SOHC engine, two 32mm carburetors. · FP Fiat X1/9 and Bertone 1300 brake rotors now 257 x 12 mm, 10.1 inch diameter, 0.407 inch thickness. · STU fender flare rules clarified: maximum 2 inches total, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry. · T2 Corvettes C5 Z06, C6, and Z06 gain dry sump kit options and air dam trimming allowances. · T2 Chevrolet Camaro 1LE auto trans: gear ratios and final drive 2.77 specified. · T2 BMW M3 01-06 minimum weight reduced from 3100 lbs to 3000 lbs. · T2 Chevrolet Camaro SS/1LE model years expanded to 2010-2015. · Mazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC four-cylinder, fuel injected with 55mm throttle body, comp ratio 12.0:1 max, valve lift 0.500" max. · FP Volkswagen Golf and Jetta III and IV intake valves increase to 40.0 mm, exhaust to 33.0 mm. · STU Honda S2000 now allows F20/F22 K24 crankshaft with chart weight for achieved displacement. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · T2-T4 clutch discs and pressure plates must be at least 95% of factory OEM weight, bolted to unmodified stock flywheel. · Spec Corvette added to T2 with 3375 cc, 295 DOT tires, 53 mm restrictor, 3.75 in minimum ride height, 3200 lbs minimum weight. · T2 BMW E92 M3 front and rear spring rate limit raised from 800 to 1000 #/in. · T2 Toyota Supra 2020+ spring rates limited to 800 lb/in front, 1000 lb/in rear. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · T2 BMW M2 CS Cup 2020- permitted to remove door glass and mechanism. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STU Porsche PDK automatic transmission limited to 8 forward speeds; sequential DCT systems require 3.5% minimum weight increase. · STU Mazda 13B Street Port 2400 removes choke location rule, allows auto-type 2bbl with any dual-Y manifold. · STU driveshaft and half-shafts now explicitly permitted in steel or aluminum, removing OEM material requirement. · T2 BMW M235iR gains M240iR/Evo package option with 50 lb penalty and DOT tyre requirement. · Toyota Supra 2020- added to T2 with 2998 cc engine, 3450 lbs minimum weight, 19×10 wheels, 295 tyres. · T2 Honda Civic Type-R gains allowance for PRL cold air intake #PRL PRL-HCR-INT-HVI. · T2 Porsche Carrera S 997.2 (06-08) weight reduced 50 lbs to 3225. · T2 Ford Mustang GT 5.0L 15-17 gear ratios changed to 3.66, 2.43, 1.69, 1.32, 1.00, 0.65 or 4.17, 2.34, 1.52, 1.14, 0.87, 0.69. · T2 BMW Z4M 06-08 maximum wheel size increases from 18×9 to 18×10 inches. · T2 BMW M2 CS Cup 2020- and M235iR (-2016) clarify homologation and touring rule allowances in Notes. · EP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate. · FP Volkswagen Golf 1.8, Jetta, Rabbit and Scirocco gain 50 lb weight breaks, minimum weights to 1900–1733 lbs. · STU Mazda 13B Spec and Bridge Port removed; Street Port added at 2400 lbs minimum weight. · T2 BMW M2 CS Cup 2020+ classified at 2979 cc, 3625 lbs, 295 tires, 10.5×18 wheels, 380/390 mm brakes. · T2 and T3 Nissan 350Z and 370Z permit 44011-RC350 rear caliper kit and SZ350 rotors; T2 350Z also permits Stillen 400338. · T4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.55 final drive, plus 25 lb penalty. · T3 Scion FR-S/Toyota 86 and Subaru BRZ capped to 2021 model year; T4 models capped to 2021. · FP Mk2 Golf and Jetta 1.8 lose 50 lbs to 1900; HP Jetta GLI engine code removed. · EP, FP, HP Level 1 and Level 2 induction systems: carburettor jets, needles, metering rods allowed; throttle body porting permitted; wording clarified. · EP Nissan Datsun SRL 311U Roadster minimum weight reduced 75 lbs to 1925. · EP Triumph TR8 78-81 minimum weight drops to 2500 lbs. · Honda Civic EX 96-00 classified FP2 at 1975 lbs, SOHC 1590cc, fuel injection, 56mm throttle body, comp ratio 12.0:1 max, valve lift 0.450" max. · FP adds FAJS to permitted Weber-type and auto-type carburetor substitutes in two sections. · ST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion. · T2 BMW E92 M3 (08-14) minimum weight reduced 50 lbs to 3475; brake, suspension, restrictor and transmission specs clarified with duplicate AP Racing line removed. · T2 Corvette C5 Z06 restrictor sizes increase to 53mm and 58mm; C6 LS2 to 56mm, LS3 to 50mm; Camaro SS/1LE weight drops 75 lbs to 3625; Camaro 1LE restrictor to 56mm; Mustang GT 11-14 to 58mm; 15-17 to 55mm; 2018- to 53mm; Viper restrictor … · T3 Alfa Romeo 4C Launch Edition variant now allowed.showhide
  • T2 BMW M2 CS Power Stick Part Number #31087wordingwordingT2 BMW M2 CS Cup 2020- mandatory power stick part number assigned as #8324089.
  • FP Request to Allow F22c Engine for 2000-2003 Honda S2000 #30548cars addedaddedEP Honda S2000 now allows F22c engine in 1997cc and 2157cc displacements with revised weight brackets and specifications.
  • FP Request a review of the S14 240SX in EP. #30873weight -200 lbsfaster · weightEP Nissan 240-SX S13/S14 weight drops to 2400 lbs base, 2460 turbo, 2520 supercharged; comp ratio raised to 12.0:1, valve lift to 0.500 inch.
  • T2 997.1 EO #30933cars addedaddedT2 Porsche 911/997.1 (06–08) now permits Cargraphics CARP97DFIFKR alternate exhaust manifold.
  • FP Lotus/Caterham 7 America Request #30392wordingwordingEP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed.
  • FP Request to classify ITC Plymouth Arrow #30588cars addedaddedPlymouth Arrow 76–80 classified in HP Prep at 1800–1890 lbs with 1598 cc iron-block OHV four-cylinder.
  • FP Reclassification of the 1984/85 BMW 318i from FP to HP #30661cars addedaddedBMW 318i/is E30 (84-85) reclassified from FP to HP at 2200–2310 lbs, SOHC 1797cc, fuel injection, 11.0:1 compression, .425" valve lift limit.
  • FP Fiat x1/9 Competition Adjustments #30711weight -50 lbsfaster · weightFP Fiat X1/9 1300 loses 50 lbs to 1665; X1/9 Bertone loses 50 lbs to 1765.
  • FP Reclassify Daimler SP 250 #30721cars addedaddedDaimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors.
  • STU STU Fender flares #30696wordingwordingSTU fender flare wording clarified: flare of exterior contour may not change wheel opening size, location or shape from side view.
  • STU Request weight reduction for 12A bridgeport motor in Miata #30751weight -200 lbsfaster · weightSTU Mazda 12A Bridgeport weight reduced from 2550 lbs to 2350 lbs.
  • T2 Request #30406wordingunclearT2 BMW M2 CS Cup 2020- weight increases from 3625 to 3600 lbs; Purple power stick mandatory, hot country package allowed.
  • FP Move Porsche 924 in Level 1 Prep From EP to FP #30135cars addedaddedPorsche 924 Level 1 Prep moved from EP to FP classification.
  • FP Clarify Application of Percentage Based Weight Penalties #30669wordingwordingEP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound.
  • T2 Civic Type R Brake Rotors #29817weightslower · weightT3 Honda Civic Type-R 2020+ allowed brake rotor #45251-TGH-A01 with 25 lb penalty.
  • T2 Mustang S550 Parity in T2 #29925inductionfaster · inductionT2 Mustang GT 5.0L 15-17 throttle body raised to 58mm, 2018- raised to 55mm.
  • T2 Request BOP on BMW Z4 T2 car #30597weight +50 lbsslower · weightT2 BMW Z4M 06–08 minimum weight increases 50 lbs, to 3150.
  • T2 E92 #30639weight -50 lbsfaster · weightT2 BMW E92M3 weight drops 50 lbs to 3425; intake restrictor shrinks from 80mm to 77mm.
  • FP Change Classification of 84-87 Mazda 626 from FP to HP #30350cars addedadded84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lb weight, 1998cc SOHC engine, two 32mm carburetors.
  • FP Fiat X1/9 brake rotors #30423otherotherFP Fiat X1/9 and Bertone 1300 brake rotors now 257 x 12 mm, 10.1 inch diameter, 0.407 inch thickness.
  • STU Request for Fender Flare Clarification #30375wordingwordingSTU fender flare rules clarified: maximum 2 inches total, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry.
  • T2 C5/6 Corvette in T1, T1-LP and T2 Dry Sump Standardization #29046otheraddedT2 Corvettes C5 Z06, C6, and Z06 gain dry sump kit options and air dam trimming allowances.
  • T2 Request for Chevrolet Camaro 1LE (2016-) Auto Trans #29067cars addedaddedT2 Chevrolet Camaro 1LE auto trans: gear ratios and final drive 2.77 specified.
  • T2 Request E46 M3 Minimum Competition Weight #29429weight -100 lbsfaster · weightT2 BMW M3 01-06 minimum weight reduced from 3100 lbs to 3000 lbs.
  • T2 Request to add 2015 to Chevrolet Camaro SS/1LE 2010-2014 #29736cars addedaddedT2 Chevrolet Camaro SS/1LE model years expanded to 2010-2015.
  • FP Please Classify Mazda3 in FP #30165cars addedaddedMazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC four-cylinder, fuel injected with 55mm throttle body, comp ratio 12.0:1 max, valve lift 0.500" max.
  • FP Golf MkIII Valve Size Request #30268enginefaster · engineFP Volkswagen Golf and Jetta III and IV intake valves increase to 40.0 mm, exhaust to 33.0 mm.
  • STU Provision for Interchangeable Engine Components Already Allowed #30342engineadded · engineSTU Honda S2000 now allows F20/F22 K24 crankshaft with chart weight for achieved displacement.
  • STU ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingwordingST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section.
  • T2 Request consistency review in GCR #30263wordingwordingT2-T4 clutch discs and pressure plates must be at least 95% of factory OEM weight, bolted to unmodified stock flywheel.
  • T2 Class Spec Corvette in T2? #30297cars addedaddedSpec Corvette added to T2 with 3375 cc, 295 DOT tires, 53 mm restrictor, 3.75 in minimum ride height, 3200 lbs minimum weight.
  • T2 E92 BMW Spring Rate Request #30391suspension & brakesfaster · suspension & brakesT2 BMW E92 M3 front and rear spring rate limit raised from 800 to 1000 #/in.
  • T2 Please correct recent T2 Spec Line #30401suspension & brakessuspension & brakesT2 Toyota Supra 2020+ spring rates limited to 800 lb/in front, 1000 lb/in rear.
  • STU Super Touring Alternate Miata Hubs #30345cars addedaddedST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1.
  • T2 Request BMW M2CS door glass removal #30254cars addedaddedT2 BMW M2 CS Cup 2020- permitted to remove door glass and mechanism.
  • STU Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment.
  • STU Porsche PDK #30081wordingwordingSTU Porsche PDK automatic transmission limited to 8 forward speeds; sequential DCT systems require 3.5% minimum weight increase.
  • STU Reference Letter #29333 Proposed STU 13B Spec Line Changes #30086wordingwordingSTU Mazda 13B Street Port 2400 removes choke location rule, allows auto-type 2bbl with any dual-Y manifold.
  • STU Drive Shaft Request #30087otherotherSTU driveshaft and half-shafts now explicitly permitted in steel or aluminum, removing OEM material requirement.
  • T2 Request Addition of BMW M240iR #29503cars addedaddedT2 BMW M235iR gains M240iR/Evo package option with 50 lb penalty and DOT tyre requirement.
  • T2 2021 Toyota Supra #29567cars addedaddedToyota Supra 2020- added to T2 with 2998 cc engine, 3450 lbs minimum weight, 19×10 wheels, 295 tyres.
  • T2 Request Cold Air Intake for Honda Civic Type R #29942inductionadded · inductionT2 Honda Civic Type-R gains allowance for PRL cold air intake #PRL PRL-HCR-INT-HVI.
  • T2 Adjust T2 spec line that was missed in T2 BOP #30055weight -50 lbsfaster · weightT2 Porsche Carrera S 997.2 (06-08) weight reduced 50 lbs to 3225.
  • T2 Fix T2 Mustang spec line #30106otherunclearT2 Ford Mustang GT 5.0L 15-17 gear ratios changed to 3.66, 2.43, 1.69, 1.32, 1.00, 0.65 or 4.17, 2.34, 1.52, 1.14, 0.87, 0.69.
  • T2 Z4 Wheel Size #30113tyres & wheelsfaster · tyres & wheelsT2 BMW Z4M 06-08 maximum wheel size increases from 18×9 to 18×10 inches.
  • T2 Clarify T2 Spec lines #30194wordingwordingT2 BMW M2 CS Cup 2020- and M235iR (-2016) clarify homologation and touring rule allowances in Notes.
  • FP Alternate Front Brake Rotors and Calipers for EP AH 3000 #29893otherotherEP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate.
  • FP Request VW weight break #29963weight -50 lbsfaster · weightFP Volkswagen Golf 1.8, Jetta, Rabbit and Scirocco gain 50 lb weight breaks, minimum weights to 1900–1733 lbs.
  • STU 13B Rules Adjustment #29333cars addedremoved · cars addedSTU Mazda 13B Spec and Bridge Port removed; Street Port added at 2400 lbs minimum weight.
  • T2 Request to Classify BMW M2 CS #29523cars addedaddedT2 BMW M2 CS Cup 2020+ classified at 2979 cc, 3625 lbs, 295 tires, 10.5×18 wheels, 380/390 mm brakes.
  • T2 350Z Rear Caliper Replacement #29710cars addedaddedT2 and T3 Nissan 350Z and 370Z permit 44011-RC350 rear caliper kit and SZ350 rotors; T2 350Z also permits Stillen 400338.
  • T2 Request Mustang 8.8” rear axle replacement #29860cars addedaddedT4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.55 final drive, plus 25 lb penalty.
  • T2 Cap year range on all 86s #29908wordingwordingT3 Scion FR-S/Toyota 86 and Subaru BRZ capped to 2021 model year; T4 models capped to 2021.
  • FP Mk2 VW Consistency and Cleanup of FP and HP Spec Lines #29195weight -50 lbsfaster · weightFP Mk2 Golf and Jetta 1.8 lose 50 lbs to 1900; HP Jetta GLI engine code removed.
  • FP Correct Wording for Level 1 and Level 2 Induction Systems #29406inductionfaster · inductionEP, FP, HP Level 1 and Level 2 induction systems: carburettor jets, needles, metering rods allowed; throttle body porting permitted; wording clarified.
  • FP Weight Reduction for Datsun Roadster #29409weight -75 lbsfaster · weightEP Nissan Datsun SRL 311U Roadster minimum weight reduced 75 lbs to 1925.
  • FP EP TR8 Adjustment #29512weight -100 lbsfaster · weightEP Triumph TR8 78-81 minimum weight drops to 2500 lbs.
  • FP Request to Classify 1996-2000 Honda Civic EX #29515cars addedaddedHonda Civic EX 96-00 classified FP2 at 1975 lbs, SOHC 1590cc, fuel injection, 56mm throttle body, comp ratio 12.0:1 max, valve lift 0.450" max.
  • FP FAJS Carburetor #29576cars addedaddedFP adds FAJS to permitted Weber-type and auto-type carburetor substitutes in two sections.
  • STU Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
  • T2 Request to Reevaluate T2 Spec Line for E92 M3 #28266weight -50 lbsfaster · weightT2 BMW E92 M3 (08-14) minimum weight reduced 50 lbs to 3475; brake, suspension, restrictor and transmission specs clarified with duplicate AP Racing line removed.
  • T2 Request for Parity Among Vehicles Including S550 Mustang #29486induction -75 lbsfaster · inductionT2 Corvette C5 Z06 restrictor sizes increase to 53mm and 58mm; C6 LS2 to 56mm, LS3 to 50mm; Camaro SS/1LE weight drops 75 lbs to 3625; Camaro 1LE restrictor to 56mm; Mustang GT 11-14 to 58mm; 15-17 to 55mm; 2018- to 53mm; Viper restrictor …
  • T2 Alfa Romeo 4C Launch Edition #29531cars addedaddedT3 Alfa Romeo 4C Launch Edition variant now allowed.
Road America Runoffs 20202020-10-022:27.883David Fiorelli · fastest of 14 · top 5 within 4.1s2:28.410Anthony Geraci · fastest of 14 · top 5 within 3.1s144.2David Fiorelli2:24.195Alan Kossof · fastest of 15 · top 5 within 2.5s2:26.803Kurt Rezzetano · fastest of 14 · top 5 within 2.2s147.3Mark Boden-1.607squal -3.688s98.9%qual 97.5%2:31.414Ethan Shippert · fastest of 23 · top 5 within 2.2s2:34.033Kevin Ruck · fastest of 21 · top 5 within 2.3s133.2Sam Henry+5.623squal +3.531s103.8%qual 102.4%
66 rule changes (STU: 17, T2: 30, FP: 19)15 cars added · 10 weight · 6 engine · 6 suspension & brakes · 1 aero · 1 induction · 1 tyres & wheels · 18 wording · 8 other · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · T2 Ford Mustang GT 5.0L and Ecoboost 2.3 sway bar part numbers added to notes: M-FR3A-M8 kit, bars M5490-E or M5490-G. · STU fender flare rule reworded: now per-corner up to 2" total, 1% weight penalty applies to entire modification. · T2 stock replacement brake rotors now allow 2-piece ferrous disks with aluminum hats, within 5% of OE diameter. · T2 Porsche Cayman S, Spyder 10-12 gains cooler ducting, springs to 800#/in front and 1000#/in rear, rotor ducting, and specific Stop Tech calipers with 343 mm front rotor. · EP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566. · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds. · STL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules. · T2 Ford Mustang EcoBoost and GT 5.0L gain three optional gear ratio sets for competition. · Porsche 911 S 67-68 classified in EP at 1800–1890 lbs, 1991cc opposed 6-cylinder SOHC with 36mm carburetors. · FP Mazda 626 84-87 carburetor spec clarified to two auto-type sidedraft 32mm choke or fuel injection. · STU request for alternate intake manifold denied; no change to rules. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · STU large displacement turbo engines limited by GCR turbo list; no BoP change granted. · STU sequential shifters referred to Board of Directors for approval; no rule change effective. · Request to add vehicle to T2, T3, T4 roster; refer to letter #27663 in June 2020 Fastrack for decision. · T2 Porsche Cayman S, Spyder 10-12 gains brake, suspension, steering, and aero upgrades including StopTech calipers, 800#/in front and 1000#/in rear springs, and free sway bars. · EP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed. · FP Volkswagen Scirocco E&O adds four engine variants with weights 1520–1853 lbs and displacements 1471–1780 cc. · STU Mazda 13B Bridge Port and Street Port added with 2550 lbs and 2250 lbs minimum weight respectively. · 2004 Mercedes Benz CLK 320 Coupe classified in T4 at 3200 lbs with 3299cc engine, 17-inch wheels, 245 tyres, EIBACH PN# 2563.140 springs allowed. · T1 and T2 Corvettes now allow coilover suspension with 800 lb max coil springs; T1 Z06 conversion no longer T1-only. · FP Pre: 1990–1994 Mazda Protégé classified at 2150–2258 lbs, 1839cc DOHC, fuel injection, 11.0:1 compression, .450" valve lift limit. · HP Mini Cooper 02-06 and 07-13 convertible model years corrected to 05-08 and 09-15 respectively. · T2 BMW E92 M3 08-14 adds AP Racing brake kit front 13.01.10038, rear 13.01.10053 to allowed list. · T2 Corvette C5 Z06 weight drops 50 lbs to 3175 with 45mm restrictor, 50 lbs to 3350 with 55mm. · T3 BMW Z3 M & Coupe 98-99 minimum weight reduced to 3150 lbs. · EP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch. · 1989-90 Nissan 240-SX SOHC added to FP Pre L2 at 2400–2520 lbs, 2389 cc, fuel injection, 11.0:1 compression, .450" valve lift limit. · STU Honda S2000 gains HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed options. · STU Lotus Elise Cup R and SC Exige SC gain 100 lbs minimum weight to 2300, 2500. · STU Volkswagen GTI/GLI MK5 and Jetta Mk4 may now install turbo inlet restrictor in OEM housing, per TIR spec. · STU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates to original. · T2 Porsche 911 997 and 997.2 Carrera S require OEM rear deck lid; GT3 Cup front fascia allowed with 75 lb penalty, GT3 Cup splitter banned. · T2 Ford Mustang GT 5.0L 15-17 transmission gear ratios corrected to 3.66, 2.43, 1.69, 1.32, 1.00, 0.65 or 4.69, 2.98, 2.14, 1.76, 1.52, 1.27, 1.00, 0.85, 0.68, 0.63. · FP Volkswagen Jetta, Rabbit, Scirocco reclassified with weights 1520–1853 lbs, intake valves 40.0 mm, exhaust 33.0 mm, throttle 35/52 mm. · HP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure. · Porsche 914-4 2.0L classified in FP Prep 2 at 2030–2132 lbs with 1968cc OHV engine, Solex/Weber/Dellorto carbs or fuel injection, 11.0:1 compression limit, .450" valve lift limit. · FP Ford Fiesta 78-80 minimum weight reduced 130 lbs, to 1660. · STU vehicles over 2951 lbs base weight may use 9 inch wide wheels, changed from 2950 lbs. · STU turbocharged engines now use base weight instead of minimum weight; DFI cars add 3% to base weight. · T2 Porsche 911/997 (06-08), 997.2 (09-12), Carrera S (06-08): spoiler, bumper, airdams, rear wing height rules removed. · HP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF. · Pontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18x9.5, Sky weight drops to 3200 lbs. · T2 ferrous metal two-piece brake rotors allowed, must be within 5% of OE diameter. · Mazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01. · T2 Nissan 370Z gains StopTech brake kit allowance with 50 lb penalty. · T2 Ford Mustang Ecoboost 2.3 loses 100 lbs to 3400, wheels widen to 19 x 11, intercooler and suspension parts allowed. · T2 Mustang GT5.0L (15-17) wheels change to 19 x 11; Brembo BBK 380mm rotors now permitted at no weight penalty instead of +50 lbs. · Mazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed. · FP Mazda Protégé ES 2001–2003 newly classified at 2350–2468 lbs with 1991 cc DOHC four-cylinder, fuel injection, 11.0:1 compression, .450 in. valve lift limit. · T2 must have fire system installed; T3 and T4 may have one per GCR 9.3. · T3 Ford Mustang EcoBoost gains three transmission gear ratio options. · T2 Chevrolet Camaro SS 10-14 adds 1LE-SS Track Pack with dry sump, suspension and brake options permitted. · T2 Camaro SS/1LE (10-14) permits 1LE-SS Track Pack, specific suspension, brake, dry sump, and driveshaft parts. · T2 Chevrolet Camaro 1LE 2016- minimum weight cut to 3550 lbs from 3600 lbs. · T2 Honda Civic Type-R 2017- minimum weight drops 50 lbs to 3000; tire TIR spec increases to 51mm. · T3 and T4 Mazda RX-8 Base/R3 (04-12) reclassified to include Sport and GT variants. · Toyota 86 GT variant (2017–) added to T3 and T4 spec lines. · FP and HP: 1988–91 Honda Civic and CRX track widths corrected to 61.3 / 61.7 inches across multiple levels. · EP, FP, HP cylinder head rules reorganized for clarity; no performance change. · STU allows OEM electronic throttle bodies, manual conversion, cam changes, and manual-to-electronic conversion with same inner diameter.showhide
  • FP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458otherfasterHP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches.
  • T2 Request 2018+ mustang swaybar update #28659suspension & brakesadded · suspension & brakesT2 Ford Mustang GT 5.0L and Ecoboost 2.3 sway bar part numbers added to notes: M-FR3A-M8 kit, bars M5490-E or M5490-G.
  • STU Request for Advanced Aero Rule Wording Clarification. #29124wordingwordingSTU fender flare rule reworded: now per-corner up to 2" total, 1% weight penalty applies to entire modification.
  • T2 Request to Clarify New 2-piece Brake Rotor Rule #29106otherotherT2 stock replacement brake rotors now allow 2-piece ferrous disks with aluminum hats, within 5% of OE diameter.
  • T2 please consider BoP for the following cars in T2 #29266weight -50 lbs
  • T2 Request clarification on most recent approval by the Board #29284otheraddedT2 Porsche Cayman S, Spyder 10-12 gains cooler ducting, springs to 800#/in front and 1000#/in rear, rotor ducting, and specific Stop Tech calipers with 343 mm front rotor.
  • FP EP BMW Z3 Rule Clarification #28998wordingwordingEP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566.
  • STU Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds.
  • STU ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules.
  • T2 Request to correct GCR for 2018+ FORD Mustang GT & Ecoboost #28803otheraddedT2 Ford Mustang EcoBoost and GT 5.0L gain three optional gear ratio sets for competition.
  • FP Request to Classify Porsche 911 2.0L #28456cars addedaddedPorsche 911 S 67-68 classified in EP at 1800–1890 lbs, 1991cc opposed 6-cylinder SOHC with 36mm carburetors.
  • FP Request to change to Carburetor Spec Line 84-87 Mazda 626 #28926wordingwordingFP Mazda 626 84-87 carburetor spec clarified to two auto-type sidedraft 32mm choke or fuel injection.
  • STU Request for Alternate Intake Manifold #26514wordingunclearSTU request for alternate intake manifold denied; no change to rules.
  • STU Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
  • STU Request BoP for my Car #29004wordingunclearSTU large displacement turbo engines limited by GCR turbo list; no BoP change granted.
  • STU Sequential Shifters in STU #29031wordingunclearSTU sequential shifters referred to Board of Directors for approval; no rule change effective.
  • T2 Request to Add a Vehicle to the Roster (contd.) #27698wordingunclearRequest to add vehicle to T2, T3, T4 roster; refer to letter #27663 in June 2020 Fastrack for decision.
  • T2 Request brake upgrade and electric power steering pump #28946suspension & brakesfaster · suspension & brakesT2 Porsche Cayman S, Spyder 10-12 gains brake, suspension, steering, and aero upgrades including StopTech calipers, 800#/in front and 1000#/in rear springs, and free sway bars.
  • FP BMW Cylinder Head Casting and Part Numbers #28708engineslower · engineEP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed.
  • FP Correct Scirocco Spec line E&O #28892cars addedaddedFP Volkswagen Scirocco E&O adds four engine variants with weights 1520–1853 lbs and displacements 1471–1780 cc.
  • STU Rotary Help #27833cars addedaddedSTU Mazda 13B Bridge Port and Street Port added with 2550 lbs and 2250 lbs minimum weight respectively.
  • T2 Request to Classify 2004 Mercedes Benz 320 CLK #27663cars addedadded2004 Mercedes Benz CLK 320 Coupe classified in T4 at 3200 lbs with 3299cc engine, 17-inch wheels, 245 tyres, EIBACH PN# 2563.140 springs allowed.
  • T2 Consider coil spring conversion Corvette in T2 #28824suspension & brakesadded · suspension & brakesT1 and T2 Corvettes now allow coilover suspension with 800 lb max coil springs; T1 Z06 conversion no longer T1-only.
  • FP Request to Classify 1990-1994 Mazda Protege #28381cars addedaddedFP Pre: 1990–1994 Mazda Protégé classified at 2150–2258 lbs, 1839cc DOHC, fuel injection, 11.0:1 compression, .450" valve lift limit.
  • FP Error in Mini Cooper Spec Line #28713wordingwordingHP Mini Cooper 02-06 and 07-13 convertible model years corrected to 05-08 and 09-15 respectively.
  • T2 Please Add the Following BBK to Allowed List for E92 M3 #28421suspension & brakesadded · suspension & brakesT2 BMW E92 M3 08-14 adds AP Racing brake kit front 13.01.10038, rear 13.01.10053 to allowed list.
  • T2 C5 Weight Adjustment #28433weight -50 lbsfaster · weightT2 Corvette C5 Z06 weight drops 50 lbs to 3175 with 45mm restrictor, 50 lbs to 3350 with 55mm.
  • T2 Z3M Roadster Weight #28437weightfaster · weightT3 BMW Z3 M & Coupe 98-99 minimum weight reduced to 3150 lbs.
  • FP Caterham 7 Spec Line #28498wordingwordingEP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch.
  • FP Request to classify SOHC 1989-90 240SX in F prod L2 #28553cars addedadded1989-90 Nissan 240-SX SOHC added to FP Pre L2 at 2400–2520 lbs, 2389 cc, fuel injection, 11.0:1 compression, .450" valve lift limit.
  • STU Request to approve Honda S2000 HKS supercharger #27281otheraddedSTU Honda S2000 gains HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed options.
  • STU Request BoP on the Lotus #27637weight +100 lbsslower · weightSTU Lotus Elise Cup R and SC Exige SC gain 100 lbs minimum weight to 2300, 2500.
  • STU Turbo Inlet Restrictor On MK5 Volkswagen #27704otherslowerSTU Volkswagen GTI/GLI MK5 and Jetta Mk4 may now install turbo inlet restrictor in OEM housing, per TIR spec.
  • STU Honda K20C1 removal #27732engineslower · engineSTU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm.
  • STU Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineadded · engineSTU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs.
  • STU Alternate Engine for Porsche 944 #28259engineadded · engineSTU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates to original.
  • T2 Limit Changes to the 997.2 Porsche #28242aeroslower · aeroT2 Porsche 911 997 and 997.2 Carrera S require OEM rear deck lid; GT3 Cup front fascia allowed with 75 lb penalty, GT3 Cup splitter banned.
  • T2 Correct T2 Mustang Transmission #28732wordingunclearT2 Ford Mustang GT 5.0L 15-17 transmission gear ratios corrected to 3.66, 2.43, 1.69, 1.32, 1.00, 0.65 or 4.69, 2.98, 2.14, 1.76, 1.52, 1.27, 1.00, 0.85, 0.68, 0.63.
  • FP VW Weight and Valve Size Request #27886wordingwordingFP Volkswagen Jetta, Rabbit, Scirocco reclassified with weights 1520–1853 lbs, intake valves 40.0 mm, exhaust 33.0 mm, throttle 35/52 mm.
  • FP Request to allow 40 DCOE carb for the Datsun 510 #28195engineadded · engineHP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure.
  • FP Request to classify Porsche 914 2L in LPrep FProd #28231cars addedaddedPorsche 914-4 2.0L classified in FP Prep 2 at 2030–2132 lbs with 1968cc OHV engine, Solex/Weber/Dellorto carbs or fuel injection, 11.0:1 compression limit, .450" valve lift limit.
  • FP Request Ford Fiesta Weight Adjustment #28336weightfaster · weightFP Ford Fiesta 78-80 minimum weight reduced 130 lbs, to 1660.
  • STU Please Modify the STU Wheel Size Rule for Clarity #27694weightfaster · weightSTU vehicles over 2951 lbs base weight may use 9 inch wide wheels, changed from 2950 lbs.
  • STU Turbo Engine Cars Base Weight #28032wordingwordingSTU turbocharged engines now use base weight instead of minimum weight; DFI cars add 3% to base weight.
  • T2 Request to Readjust the T2 Porsches #27746wordingwordingT2 Porsche 911/997 (06-08), 997.2 (09-12), Carrera S (06-08): spoiler, bumper, airdams, rear wing height rules removed.
  • FP Request for Help for Datsun 1200 #27934inductionfaster · inductionHP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF.
  • T2 Please Switch the Solstice GXP as Specified in T2, to T3 #27413cars added -50 lbsfaster · cars addedPontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18x9.5, Sky weight drops to 3200 lbs.
  • T2 Request for Two Piece Stop Tech Brake Rotors #27582suspension & brakessuspension & brakesT2 ferrous metal two-piece brake rotors allowed, must be within 5% of OE diameter.
  • T2 Request to Classify all Mazda RX8 Models in T3/T4 #27606cars addedaddedMazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01.
  • T2 Request for Alternative Brake Kit on Nissan 370Z #27912suspension & brakesslower · suspension & brakesT2 Nissan 370Z gains StopTech brake kit allowance with 50 lb penalty.
  • T2 2015- Current Ecoboost Mustang #27971weight -100 lbsfaster · weightT2 Ford Mustang Ecoboost 2.3 loses 100 lbs to 3400, wheels widen to 19 x 11, intercooler and suspension parts allowed.
  • T2 T2 Mustang #28022tyres & wheelsfaster · tyres & wheelsT2 Mustang GT5.0L (15-17) wheels change to 19 x 11; Brembo BBK 380mm rotors now permitted at no weight penalty instead of +50 lbs.
  • FP Request to List Mazda Miata Throttle Body Size #27907wordingwordingMazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed.
  • FP Request to Classify 2001-2003 Mazda Protege ES in FP #27922cars addedaddedFP Mazda Protégé ES 2001–2003 newly classified at 2350–2468 lbs with 1991 cc DOHC four-cylinder, fuel injection, 11.0:1 compression, .450 in. valve lift limit.
  • T2 Clarification of On-Board Fire System for T2 #27183wordingwordingT2 must have fire system installed; T3 and T4 may have one per GCR 9.3.
  • T2 Mustang Ecoboost and GT Transmission #27439cars addedaddedT3 Ford Mustang EcoBoost gains three transmission gear ratio options.
  • T2 Request for Dailey Engineering Dry Sump on 2010 Camaro SS #27514cars addedaddedT2 Chevrolet Camaro SS 10-14 adds 1LE-SS Track Pack with dry sump, suspension and brake options permitted.
  • T2 Request for Half Shafts - 2014 Camaro SS 1LE #27584otheraddedT2 Camaro SS/1LE (10-14) permits 1LE-SS Track Pack, specific suspension, brake, dry sump, and driveshaft parts.
  • T2 Request for Parity Among Vehicles #27665weight -50 lbs
  • T2 Request for 2016-2020 Camaro SS Help #27776weight -50 lbsfaster · weightT2 Chevrolet Camaro 1LE 2016- minimum weight cut to 3550 lbs from 3600 lbs.
  • T2 Request for Competitive Adjustments to Honda Civic Type R #27839weight -50 lbsfaster · weightT2 Honda Civic Type-R 2017- minimum weight drops 50 lbs to 3000; tire TIR spec increases to 51mm.
  • T2 T4 RX8 Classification Error #27902cars addedaddedT3 and T4 Mazda RX-8 Base/R3 (04-12) reclassified to include Sport and GT variants.
  • T2 Request to add Toyota 86 GT to Spec Line #27910cars addedaddedToyota 86 GT variant (2017–) added to T3 and T4 spec lines.
  • FP Request to Correct Track of 1988-91 Honda Civic #27487otherotherFP and HP: 1988–91 Honda Civic and CRX track widths corrected to 61.3 / 61.7 inches across multiple levels.
  • FP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingwordingEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
  • STU Request for an electronic throttle body #27342engineadded · engineSTU allows OEM electronic throttle bodies, manual conversion, cam changes, and manual-to-electronic conversion with same inner diameter.
Virginia International Raceway Runoffs 20192019-10-051:59.948Kevin Boehm · fastest of 25 · top 5 within 3.5s2:00.483Kevin Boehm · fastest of 25 · top 5 within 2.5s143.8Kevin Boehm1:54.469Pete Frost · only car1:57.688Pete Frost · only car145.9Pete Frost-2.795squal -5.479s97.7%qual 95.4%1:57.537Cooper I MacNeil · fastest of 19 · top 5 within 3.4s1:58.551Cooper I MacNeil · fastest of 18 · top 5 within 2.4s149.4James Leithauser-1.932squal -2.411s98.4%qual 98.0%2:07.436Eric Prill · fastest of 19 · top 5 within 0.6s2:08.076Eric Prill · fastest of 18 · top 5 within 0.8s131.4Ken Kannard+7.593squal +7.488s106.3%qual 106.2%
54 rule changes (STU: 22, T2: 23, FP: 9)13 cars added · 7 suspension & brakes · 6 aero · 5 engine · 5 induction · 3 weight · 1 tyres & wheels · 13 wording · 1 other · FP and HP Austin-Healey Sprite Mk I / MG Midget may replace rear bodywork aft of cockpit with alternate material stock-appearing components. · EP Mazda MX-5 Global Cup classification updated to include 2019 model year. · Production classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted. · Production carburetor and fuel injection rules clarified: permitted optional carburetors listed, Weber and auto-type substitutions specified, fuel injection throttle body and butterfly dimensions detailed, intake manifold port extension pr… · EP, FP, HP carburetors: jets, needles, metering rods, needle valves unrestricted; choke parts removable; stock or optional Weber 40 DCN permitted; Weber types, auto types listed. · STU wing assembly wording corrected: no part may be higher than roof height. · T2, T3, T4 spare tire and cover removal wording clarified; removable covers now explicitly allowable to remove. · EP Mazda MX-5/Miata model years expand from 1999-2002 to 1999-2005. · STU Nissan SR20DET removes -2mm penalty from Table B. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · T2 Cadillac CTS-V classification expanded from 2006-07 model years to include 2004-05 models. · T2 Cadillac CTS-V 06-07 gains allowance for Hotchkiss sway bars up to 36mm front, 25mm rear. · T2 Cadillac CTS-V 06-07 requires 57mm flat plate restrictor. · T2 Ford Mustang GT 5.0L tire width reduced from 315 to 295. · STU aftermarket side skirts now allowed if they meet 3-inch ride height, lack ducts except jacks or exhaust, don't exceed fascia width, stay below door bottom, and don't reinforce chassis. · STU wheel flare wording clarified: each fender may be flared to 2" with 1% weight penalty, maintaining OEM profile. · T2 Audi TT RS 2018+ gains front sway bar to 30mm, rear to 28mm, springs to 1200 lb/in, aftermarket intercooler. · T2 Honda Civic Type-R 2017+ minimum weight rises 150 lbs to 3050, TIR turbo restrictor enlarges 38mm to 50mm. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · EP, FP, HP: clarified that tapered holes in ball joints can be reamed for bolt conversion, and wheel bearings and hubs unrestricted on all axles. · EP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant. · STU Mazda 13B Bridge Port now permits ELITE ROTARY SHOP FD V2.0 intake manifold; stock throttle body requirement removed. · STU Mazda MZR gains alternate Goodwin intake manifold option with stock or Acura throttle body. · STU alternate suspension components rule moved from section E to section D. · STU Honda/Acura B20 now permits B16 or B18 VTEC cylinder head and matching intake manifold. · STU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero. · STU Honda Civic Si TCA 2017- requires 37mm TIR throttle as of June 1, 2019. · STU BMW S54B32 OEM classified separately from E46, displacement 3246 cc, minimum weight 3300 lbs, OEM engine mandatory. · T2 Mustang GT rear anti-roll bar may now be removed or disconnected. · FP Dodge Daytona/Chrysler Laser 84-85 added at 2100 lbs; Shelby Charger/Omni 024 83-84 weight cut to 2100 lbs. · Honda Civic Si 2017- added to STU with 1500cc displacement, 2800 lbs minimum weight, OEM engine and bodywork, specific HPD parts allowed. · STU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum; no Super Touring allowances, OEM intake and cams, 1mm overbore, compression +0.5 permitted. · STU Mazda 13B and 13B Bridge Port may use 13B RE or REW housings and intake with turbo removed. · STU Honda K24 may use intake part numbers 17100-RRB-A00 or 17100-PRB-A10. · STU Mazda 12A Bridge Port added, minimum weight 2550 lbs, Nikki or Auto-type carburettor with specified modifications. · STU World Challenge car weight rule deleted; no replacement specified. · STU AWD/RWD cars no longer must reduce restrictor 1 mm from table. · STU rear wing maximum 12" cord, 72 sq in end plates each, roof height max, body width limit. · T1-LP Ford Mustang GT 5.0L 2018- classified at 3400 lbs with 65mm restrictor, T2 and T3 Mustangs limited to 2015-2017. · T2 Audi TT RS (2018-) newly classified: 2480cc, 3400 lbs minimum, 19-inch wheels, 275 tires, 371/310mm brakes, 40mm TIR required. · T2 2017+ Civic Type R sway bar rules relaxed: any front/rear up to 30mm allowed, specific HPD parts no longer required. · T4 and T3 Mazda MX-5 hardtop rules clarified: any OEM or aftermarket top permitted if retaining OEM silhouette; specific part numbers listed. · T2, T3, T4 now allow any thermostat serving original equipment intent only. · T2 Ford Mustang Boss 302 (12-13) minimum weight drops to 3500 lbs. · T2 Corvette C6 Coupe/Grand Sport 05-13 front camber maximum 3.0 degrees removed. · T2 Pontiac Firebird and Chevrolet Camaro SS 98-02 permit spring relocation to shock. · T3 and T4 Mazda MX-5 Miata eligibility capped at 2016–2018 model years. · Ford Mustang GT 5.0L 2018+ classified in T2 at 3600 lbs minimum with 50mm restrictor, 19×11 wheels, 315 tyres, specific Ford Performance parts permitted. · STU adds Honda K20C1 Turbo I4, 1996 cc, 3025 lbs minimum weight, 36mm TIR required. · T4 Celica GT wheelbase 2600 and 15x7 wheels added; Forte years narrowed; Fiesta ST starts 2014; Fiat 124 years 16-18 added; battery rule clarified. · T2 Porsche Cayman S/GTS years extended from 13-14 to 13-15, adding 2015 GTS model. · T2 Honda Civic Type-R 2017- allowed Cuztom Tuning FG-CIV16-V3-TR-BK alternate grill. · T1–T4 spec car classifications clarified with permitted parts, rule conformance versions, and exclusions of other touring modifications. · T2–T4 subframe bushings now permitted to be replaced with non-spherical bushings of any material.showhide
  • FP Request bodywork for Austin Healey Bugeye Sprite MK1 #27106aeroadded · aeroFP and HP Austin-Healey Sprite Mk I / MG Midget may replace rear bodywork aft of cockpit with alternate material stock-appearing components.
  • FP Request to classify the GMX5 2019 #27263cars addedaddedEP Mazda MX-5 Global Cup classification updated to include 2019 model year.
  • FP level one susp. component rule #27270wordingwordingProduction classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted.
  • FP Clarification of Carb Rules - Prep 1 #27300wordingwordingProduction carburetor and fuel injection rules clarified: permitted optional carburetors listed, Weber and auto-type substitutions specified, fuel injection throttle body and butterfly dimensions detailed, intake manifold port extension pr…
  • FP Clarification of Carb Rules - Prep 2 #27301inductioninductionEP, FP, HP carburetors: jets, needles, metering rods, needle valves unrestricted; choke parts removable; stock or optional Weber 40 DCN permitted; Weber types, auto types listed.
  • STU Request to correct E&O advanced aerodynamics #27290wordingwordingSTU wing assembly wording corrected: no part may be higher than roof height.
  • T2 Request spare tire/wheel clarification #27012wordingfasterT2, T3, T4 spare tire and cover removal wording clarified; removable covers now explicitly allowable to remove.
  • FP Request Miata Eligibility - 2003 #27121cars addedaddedEP Mazda MX-5/Miata model years expand from 1999-2002 to 1999-2005.
  • STU Remove -2mm penalty from SR20DET Nissan #26982enginefaster · engineSTU Nissan SR20DET removes -2mm penalty from Table B.
  • STU Request clarification for manifold and throttle in STU #27004wordingwordingSTU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required.
  • T2 Request to change Cadillac CTS-V years from 06-07 to 04-07 #26842cars addedaddedT2 Cadillac CTS-V classification expanded from 2006-07 model years to include 2004-05 models.
  • T2 Request to allow Hotchkiss front / rear sway bars on T2 CTS-V #26845suspension & brakesadded · suspension & brakesT2 Cadillac CTS-V 06-07 gains allowance for Hotchkiss sway bars up to 36mm front, 25mm rear.
  • T2 Consider T2 06-07 Cadillac CTS-V BoP #27022inductionslower · inductionT2 Cadillac CTS-V 06-07 requires 57mm flat plate restrictor.
  • T2 Correct T2 Mustang tire size #27024tyres & wheelsslower · tyres & wheelsT2 Ford Mustang GT 5.0L tire width reduced from 315 to 295.
  • STU Request to clarify afterrmarket side skirts exhaust exit #26814aeroadded · aeroSTU aftermarket side skirts now allowed if they meet 3-inch ride height, lack ducts except jacks or exhaust, don't exceed fascia width, stay below door bottom, and don't reinforce chassis.
  • STU Wheel Flare wording #26872wordingwordingSTU wheel flare wording clarified: each fender may be flared to 2" with 1% weight penalty, maintaining OEM profile.
  • T2 2018+ Audi TT RS Suspension Allowances #26631suspension & brakesadded · suspension & brakesT2 Audi TT RS 2018+ gains front sway bar to 30mm, rear to 28mm, springs to 1200 lb/in, aftermarket intercooler.
  • T2 Request BOP adjustment for 2018 Honda Civic Type R-TIR removal #26882weight +150 lbsfaster · weightT2 Honda Civic Type-R 2017+ minimum weight rises 150 lbs to 3050, TIR turbo restrictor enlarges 38mm to 50mm.
  • STU Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.
  • FP Rollcenter Correction Clarification #25873wordingaddedEP, FP, HP: clarified that tapered holes in ball joints can be reamed for bolt conversion, and wheel bearings and hubs unrestricted on all axles.
  • FP Hardtops #26476aeroadded · aeroEP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant.
  • STU Request to Use Japanese Mazda 13b Intake Manifold #25790engineadded · engineSTU Mazda 13B Bridge Port now permits ELITE ROTARY SHOP FD V2.0 intake manifold; stock throttle body requirement removed.
  • STU Request Alternate Intake for Mazda MZR In a Rear Wheel Drive App. #26352inductionadded · inductionSTU Mazda MZR gains alternate Goodwin intake manifold option with stock or Acura throttle body.
  • STU E&O Suspension #26424wordingwordingSTU alternate suspension components rule moved from section E to section D.
  • STU Revisit B20 VTEC #26530engineadded · engineSTU Honda/Acura B20 now permits B16 or B18 VTEC cylinder head and matching intake manifold.
  • STU Move Flared Fenders to STU Advanced Aero #26564aeroaeroSTU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero.
  • STU TCA Civic SI E&O #26606inductionslower · inductionSTU Honda Civic Si TCA 2017- requires 37mm TIR throttle as of June 1, 2019.
  • STU S54 Spec line #26620cars addedcars addedSTU BMW S54B32 OEM classified separately from E46, displacement 3246 cc, minimum weight 3300 lbs, OEM engine mandatory.
  • T2 Request for Removal of Rear Anti-roll Bar in T2 Mustang GT #26533suspension & brakesfaster · suspension & brakesT2 Mustang GT rear anti-roll bar may now be removed or disconnected.
  • FP Request Classification of Dodge Daytona in F Production #26259weight -150 lbsfaster · weightFP Dodge Daytona/Chrysler Laser 84-85 added at 2100 lbs; Shelby Charger/Omni 024 83-84 weight cut to 2100 lbs.
  • STU Request to Class Assignment for 2017 Civic #24287cars addedaddedHonda Civic Si 2017- added to STU with 1500cc displacement, 2800 lbs minimum weight, OEM engine and bodywork, specific HPD parts allowed.
  • STU Request to run E46 3246cc in STU #25126cars addedaddedSTU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum; no Super Touring allowances, OEM intake and cams, 1mm overbore, compression +0.5 permitted.
  • STU Engine Classification for Rotary #25564engineadded · engineSTU Mazda 13B and 13B Bridge Port may use 13B RE or REW housings and intake with turbo removed.
  • STU K24/K20 Head Swap Clarification/Amendment #25899otheraddedSTU Honda K24 may use intake part numbers 17100-RRB-A00 or 17100-PRB-A10.
  • STU Request to Classify 12a Bridge Ported Rotary Engine #25985cars addedaddedSTU Mazda 12A Bridge Port added, minimum weight 2550 lbs, Nikki or Auto-type carburettor with specified modifications.
  • STU World Challenge Car Eligibility #26387wordingunclearSTU World Challenge car weight rule deleted; no replacement specified.
  • STU Request a phone call for discussion regarding weight #26398inductionfaster · inductionSTU AWD/RWD cars no longer must reduce restrictor 1 mm from table.
  • STU Advanced Aero E&O #26413aeroadded · aeroSTU rear wing maximum 12" cord, 72 sq in end plates each, roof height max, body width limit.
  • T2 Request Mustang GT Limited Prep 2018 Classification #24431cars addedaddedT1-LP Ford Mustang GT 5.0L 2018- classified at 3400 lbs with 65mm restrictor, T2 and T3 Mustangs limited to 2015-2017.
  • T2 Request to Classify 2018 Audi TT RS #25961cars addedaddedT2 Audi TT RS (2018-) newly classified: 2480cc, 3400 lbs minimum, 19-inch wheels, 275 tires, 371/310mm brakes, 40mm TIR required.
  • T2 Request for Adjustments on 2017+ Civic Type R #25969suspension & brakessuspension & brakesT2 2017+ Civic Type R sway bar rules relaxed: any front/rear up to 30mm allowed, specific HPD parts no longer required.
  • T2 Correct Mazda MX-5 Hard Top Notes #26137wordingwordingT4 and T3 Mazda MX-5 hardtop rules clarified: any OEM or aftermarket top permitted if retaining OEM silhouette; specific part numbers listed.
  • T2 Consider opening class rules to allow any thermostat #26187engineadded · engineT2, T3, T4 now allow any thermostat serving original equipment intent only.
  • T2 Ford Mustang Boss 302 (12-13) - correct weight #26287weight -50 lbsfaster · weightT2 Ford Mustang Boss 302 (12-13) minimum weight drops to 3500 lbs.
  • T2 Request camber correction 005-2013 corvette C6 #26288suspension & brakesremoved · suspension & brakesT2 Corvette C6 Coupe/Grand Sport 05-13 front camber maximum 3.0 degrees removed.
  • T2 Request 98-02 Firebird 98-02 Camaro reloacte rear spring #26291suspension & brakesadded · suspension & brakesT2 Pontiac Firebird and Chevrolet Camaro SS 98-02 permit spring relocation to shock.
  • T2 Cap 2016 Mazda Miata year at 2018 #26388cars addedremoved · cars addedT3 and T4 Mazda MX-5 Miata eligibility capped at 2016–2018 model years.
  • T2 Class Ford Mustang GT 2018+ (reference letter 24431) #26400cars addedaddedFord Mustang GT 5.0L 2018+ classified in T2 at 3600 lbs minimum with 50mm restrictor, 19×11 wheels, 315 tyres, specific Ford Performance parts permitted.
  • STU Request to Equalize Direct Injected Turbo Cars #24890cars addedaddedSTU adds Honda K20C1 Turbo I4, 1996 cc, 3025 lbs minimum weight, 36mm TIR required.
  • T2 Errors, Omissions, and Updates (Various) #22414wordingwordingT4 Celica GT wheelbase 2600 and 15x7 wheels added; Forte years narrowed; Fiesta ST starts 2014; Fiat 124 years 16-18 added; battery rule clarified.
  • T2 Request to classify 2015 Cayman GTS 3.4L in T2 #25335cars addedaddedT2 Porsche Cayman S/GTS years extended from 13-14 to 13-15, adding 2015 GTS model.
  • T2 Request for 2017-2018 Honda Civic Type R - 4 BOP Grill #25513aeroadded · aeroT2 Honda Civic Type-R 2017- allowed Cuztom Tuning FG-CIV16-V3-TR-BK alternate grill.
  • T2 Add Clarification to Spec Car Classifications Vehicle Spec #25774wordingwordingT1–T4 spec car classifications clarified with permitted parts, rule conformance versions, and exclusions of other touring modifications.
  • T2 Clarify Subframe Bushings Permitted for T2-T4 #25800suspension & brakesadded · suspension & brakesT2–T4 subframe bushings now permitted to be replaced with non-spherical bushings of any material.
Sonoma Raceway Runoffs 20182018-10-101:19.234Franklin Church · fastest of 10 · top 5 within 21.5s1:46.514Kevin Boehm · fastest of 9 · top 5 within 7.4s103.0Franklin Church1:28.612J R Osborne · fastest of 7 · top 5 within 3.3s1:31.189J R Osborne · fastest of 7 · top 5 within 3.7s140.5J R Osborne-15.325squal +9.378s85.6%qual 111.8%1:45.032John Kachadurian · fastest of 30 · top 5 within 2.4s1:45.999John Kachadurian · fastest of 28 · top 5 within 3.0s106.5John Kachadurian-0.515squal +25.798s99.5%qual 132.6%1:47.588Joe Huffaker · fastest of 15 · top 5 within 3.0s1:48.481Joe Huffaker · fastest of 14 · top 5 within 2.2s109.1Joe Huffaker+1.967squal +28.354s101.8%qual 135.8%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:48.921Rob Huffmaster · fastest of 34 · top 5 within 2.0s1:49.387Rob Huffmaster · fastest of 31 · top 5 within 2.4s1:33.746Gary Hickman · fastest of 18 · top 5 within 3.3s1:33.702Alex Mayer · fastest of 17 · top 5 within 3.0s-15.685squal -15.175s85.7%qual 86.1%1:48.618John M Buttermore · fastest of 26 · top 5 within 0.8s1:48.769John M Buttermore · fastest of 25 · top 5 within 1.2s-0.618squal -0.303s99.4%qual 99.7%1:52.091Eric Prill · fastest of 42 · top 5 within 1.2s1:53.007Eric Prill · fastest of 40 · top 5 within 0.7s+3.620squal +3.170s103.3%qual 102.9%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:32.738Joe Moser · fastest of 16 · top 5 within 2.5s1:34.597Cameron Maugeri · fastest of 16 · top 5 within 0.8s1:19.886Alex Mayer · fastest of 10 · top 5 within 1.5s1:21.015Jeremy Hill · fastest of 10 · top 5 within 1.2s-13.582squal -12.852s85.6%qual 86.1%1:31.563Preston Calvert · fastest of 22 · top 5 within 0.5s1:32.691John M Buttermore · fastest of 20 · top 5 within 1.5s-1.906squal -1.175s98.0%qual 98.7%1:35.938John Walker · fastest of 33 · top 5 within 0.4s1:36.399John Walker · fastest of 27 · top 5 within 0.3s+1.802squal +3.200s101.9%qual 103.5%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-212:05.494Eric Heinrich · fastest of 18 · top 5 within 4.6s2:06.756Eric Heinrich · fastest of 17 · top 5 within 3.5s1:50.711J R Osborne · fastest of 20 · top 5 within 1.1s1:51.616J R Osborne · fastest of 19 · top 5 within 2.1s-15.140squal -14.783s88.1%qual 88.2%2:00.172Kurt Rezzetano · fastest of 20 · top 5 within 3.2s2:01.077Kurt Rezzetano · fastest of 19 · top 5 within 2.8s-5.679squal -5.322s95.5%qual 95.8%2:11.009Kevin Ruck · fastest of 20 · top 5 within 1.6s2:12.419Kevin Ruck · fastest of 18 · top 5 within 1.1s+5.663squal +5.515s104.5%qual 104.4%

By track

TrackEventsTypical % of STUBestLatest
Road America4100.0%100.0%Runoffs 2020100.0%Runoffs 2026
Virginia International Raceway3100.0%100.0%Runoffs 2019100.0%Runoffs 2023
Indianapolis Motor Speedway2100.0%100.0%Runoffs 2017100.0%Runoffs 2021
Daytona International Speedway1100.0%100.0%Runoffs 2015100.0%Runoffs 2015
Mid-Ohio Sports Car Course1100.0%100.0%Runoffs 2016100.0%Runoffs 2016
Sonoma Raceway1100.0%100.0%Runoffs 2018100.0%Runoffs 2018
About this data
Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of STU's best on the same day: the weather, the track and its configuration cancel out, so one figure compares across tracks and years where lap times cannot. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.