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BoP Lab / Classes / T1

T1 vs SM vs AS vs T4 pace at every track

Lap times across years say as much about the weather as the class. % of T1 is each class's best lap as a share of T1'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: T1 1:28.656 Ross Murray, Runoffs 2016 qualifying · SM 1:40.514 Justin Hille, Runoffs 2016 qualifying · AS 1:30.651 Tom Sloe, Runoffs 2016 qualifying · T4 1:38.813 Jonathan Yanca, Runoffs 2016 qualifying

1:402:002:202:4042 rule changes between Runoffs 2018 and Runoffs 201942 ▾56 rule changes between Runoffs 2019 and Runoffs 202056 ▾53 rule changes between Runoffs 2020 and Runoffs 202153 ▾50 rule changes between Runoffs 2021 and Runoffs 202250 ▾44 rule changes between Runoffs 2022 and Runoffs 202344 ▾56 rule changes between Runoffs 2023 and Runoffs 202456 ▾63 rule changes between Runoffs 2024 and Runoffs 202563 ▾53 rule changes between Runoffs 2025 and Runoffs 202653 ▾T1 race best at Runoffs 2015: 1:55.494 (Andrew Aquilante)T1 race best at Runoffs 2016: 1:29.309 (Ross Murray)T1 race best at Runoffs 2017: 1:42.871 (Andrew Aquilante)T1 race best at Runoffs 2018: 1:41.125 (Kristofer Olson)T1 race best at Runoffs 2019: 2:14.413 (Andrew Aquilante)T1 race best at Runoffs 2020: 2:18.701 (Mark Boden)T1 race best at Runoffs 2021: 1:43.752 (Mark Boden)T1 race best at Runoffs 2022: 2:16.067 (Andrew Aquilante)T1 race best at Runoffs 2023: 1:55.488 (Andrew Aquilante)T1 race best at Runoffs 2024: 2:16.131 (Andrew Aquilante)T1 race best at Runoffs 2025: 2:21.612 (Drew Delmonico)T1 qualifying best at Runoffs 2015: 1:53.562 (Andrew Aquilante)T1 qualifying best at Runoffs 2016: 1:28.656 (Ross Murray)T1 qualifying best at Runoffs 2017: 1:41.793 (Andrew Aquilante)T1 qualifying best at Runoffs 2018: 1:39.970 (Kristofer Olson)T1 qualifying best at Runoffs 2019: 1:54.771 (Andrew Aquilante)T1 qualifying best at Runoffs 2020: 2:17.646 (Andrew Aquilante)T1 qualifying best at Runoffs 2021: 1:42.292 (Andrew Aquilante)T1 qualifying best at Runoffs 2022: 1:54.890 (Andrew Aquilante)T1 qualifying best at Runoffs 2023: 1:54.520 (Andrew Aquilante)T1 qualifying best at Runoffs 2024: 2:16.578 (Andrew Aquilante)T1 qualifying best at Runoffs 2025: 2:20.677 (James Candelaria)SM race best at Runoffs 2015: 2:24.067 (Todd Lamb)SM race best at Runoffs 2016: 1:40.764 (Michael Carter)SM race best at Runoffs 2017: 1:59.100 (Michael Gagliardo)SM race best at Runoffs 2018: 1:55.278 (Michael Carter)SM race best at Runoffs 2019: 2:16.459 (Elivan Goulart)SM race best at Runoffs 2020: 2:43.748 (Preston Pardus)SM race best at Runoffs 2021: 1:58.837 (Brian Henderson)SM race best at Runoffs 2022: 2:19.107 (Travis Wiley)SM race best at Runoffs 2023: 2:16.229 (Julian DaCosta)SM race best at Runoffs 2024: 2:41.486 (Brett Kowalski)SM race best at Runoffs 2025: 2:44.430 (Kyle Greenhill)SM race best at Runoffs 2026: 2:42.725 (Francisco Barroso)SM qualifying best at Runoffs 2015: 2:18.661 (Andrew Carbonell)SM qualifying best at Runoffs 2016: 1:40.514 (Justin Hille)SM qualifying best at Runoffs 2017: 1:58.306 (Chris Haldeman)SM qualifying best at Runoffs 2018: 1:54.355 (Ken Sutherland)SM qualifying best at Runoffs 2019: 2:14.552 (Todd Buras)SM qualifying best at Runoffs 2020: 2:42.209 (Kyle Greenhill)SM qualifying best at Runoffs 2021: 1:57.695 (Brian Henderson)SM qualifying best at Runoffs 2022: 2:14.664 (Danny Steyn)SM qualifying best at Runoffs 2023: 2:14.986 (Danny Steyn)SM qualifying best at Runoffs 2024: 2:41.106 (Ethan Goulart)SM qualifying best at Runoffs 2025: 2:43.111 (Bobby Gossett)SM qualifying best at Runoffs 2026: 2:42.173 (Brett Kowalski)AS race best at Runoffs 2015: 2:02.922 (Andy McDermid)AS race best at Runoffs 2016: 1:33.424 (Edward Hosni)AS race best at Runoffs 2017: 1:51.507 (Bryan Long)AS race best at Runoffs 2018: 1:50.345 (John Heinricy)AS race best at Runoffs 2019: 2:03.900 (James Jost)AS race best at Runoffs 2020: 2:27.668 (Gregory Eaton)AS race best at Runoffs 2021: 1:50.606 (Gregory Eaton)AS race best at Runoffs 2022: 2:04.578 (Gregory Eaton)AS race best at Runoffs 2023: 2:04.120 (Gregory Eaton)AS race best at Runoffs 2024: 2:26.429 (Gregory Eaton)AS race best at Runoffs 2025: 2:29.232 (Gregory Eaton)AS race best at Runoffs 2026: 2:28.471 (Andrew McDermid)AS qualifying best at Runoffs 2015: 2:01.746 (Tom Sloe)AS qualifying best at Runoffs 2016: 1:30.651 (Tom Sloe)AS qualifying best at Runoffs 2017: 1:45.220 (James Jost)AS qualifying best at Runoffs 2018: 1:47.782 (Andrew McDermid)AS qualifying best at Runoffs 2019: 2:02.938 (Gregory Eaton)AS qualifying best at Runoffs 2020: 2:27.045 (Gregory Eaton)AS qualifying best at Runoffs 2021: 1:50.427 (Drew Cattell)AS qualifying best at Runoffs 2022: 2:02.162 (Kurt Rezzetano)AS qualifying best at Runoffs 2023: 2:03.082 (Daniel Richardson)AS qualifying best at Runoffs 2024: 2:26.578 (Gregory Eaton)AS qualifying best at Runoffs 2025: 2:26.792 (Andrew McDermid)AS qualifying best at Runoffs 2026: 2:26.911 (Andrew McDermid)T4 race best at Runoffs 2015: 2:15.994 (Philip Royle)T4 race best at Runoffs 2016: 1:40.397 (Oscar Jackson)T4 race best at Runoffs 2017: 1:56.923 (Oscar Jackson)T4 race best at Runoffs 2018: 1:54.030 (John Heinricy)T4 race best at Runoffs 2019: 2:10.959 (Nick Leverone)T4 race best at Runoffs 2020: 2:37.881 (Chi Ho)T4 race best at Runoffs 2021: 1:55.929 (John Heinricy)T4 race best at Runoffs 2022: 2:25.443 (John Heinricy)T4 race best at Runoffs 2023: 2:11.962 (Devin Anderson)T4 race best at Runoffs 2024: 2:34.208 (Alex Lozano)T4 race best at Runoffs 2025: 2:32.633 (Alex Lozano)T4 race best at Runoffs 2026: 2:35.757 (Matt Spicuzzi)T4 qualifying best at Runoffs 2015: 2:15.886 (Philip Royle)T4 qualifying best at Runoffs 2016: 1:38.813 (Jonathan Yanca)T4 qualifying best at Runoffs 2017: 1:56.566 (Oscar Jackson)T4 qualifying best at Runoffs 2018: 1:52.339 (Gresham Wagner)T4 qualifying best at Runoffs 2019: 2:11.257 (John Heinricy)T4 qualifying best at Runoffs 2020: 2:37.403 (John Heinricy)T4 qualifying best at Runoffs 2021: 1:54.397 (Stephen Blethen)T4 qualifying best at Runoffs 2022: 2:09.577 (John Heinricy)T4 qualifying best at Runoffs 2023: 2:10.514 (Devin Anderson)T4 qualifying best at Runoffs 2024: 2:34.430 (Matt Spicuzzi)T4 qualifying best at Runoffs 2025: 2:32.956 (Matt Spicuzzi)T4 qualifying best at Runoffs 2026: 2:35.876 (Matt Spicuzzi)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
T1SMAST4solid race · dashed qualifying · slower is lower
100%105%110%115%120%42 rule changes between Runoffs 2018 and Runoffs 201942 ▾56 rule changes between Runoffs 2019 and Runoffs 202056 ▾53 rule changes between Runoffs 2020 and Runoffs 202153 ▾50 rule changes between Runoffs 2021 and Runoffs 202250 ▾44 rule changes between Runoffs 2022 and Runoffs 202344 ▾56 rule changes between Runoffs 2023 and Runoffs 202456 ▾63 rule changes between Runoffs 2024 and Runoffs 202563 ▾53 rule changes between Runoffs 2025 and Runoffs 202653 ▾T1 race best at Runoffs 2015: 100.0% of T1's (Andrew Aquilante)T1 race best at Runoffs 2016: 100.0% of T1's (Ross Murray)T1 race best at Runoffs 2017: 100.0% of T1's (Andrew Aquilante)T1 race best at Runoffs 2018: 100.0% of T1's (Kristofer Olson)T1 race best at Runoffs 2019: 100.0% of T1's (Andrew Aquilante)T1 race best at Runoffs 2020: 100.0% of T1's (Mark Boden)T1 race best at Runoffs 2021: 100.0% of T1's (Mark Boden)T1 race best at Runoffs 2022: 100.0% of T1's (Andrew Aquilante)T1 race best at Runoffs 2023: 100.0% of T1's (Andrew Aquilante)T1 race best at Runoffs 2024: 100.0% of T1's (Andrew Aquilante)T1 race best at Runoffs 2025: 100.0% of T1's (Drew Delmonico)T1 qualifying best at Runoffs 2015: 100.0% of T1's (Andrew Aquilante)T1 qualifying best at Runoffs 2016: 100.0% of T1's (Ross Murray)T1 qualifying best at Runoffs 2017: 100.0% of T1's (Andrew Aquilante)T1 qualifying best at Runoffs 2018: 100.0% of T1's (Kristofer Olson)T1 qualifying best at Runoffs 2019: 100.0% of T1's (Andrew Aquilante)T1 qualifying best at Runoffs 2020: 100.0% of T1's (Andrew Aquilante)T1 qualifying best at Runoffs 2021: 100.0% of T1's (Andrew Aquilante)T1 qualifying best at Runoffs 2022: 100.0% of T1's (Andrew Aquilante)T1 qualifying best at Runoffs 2023: 100.0% of T1's (Andrew Aquilante)T1 qualifying best at Runoffs 2024: 100.0% of T1's (Andrew Aquilante)T1 qualifying best at Runoffs 2025: 100.0% of T1's (James Candelaria)Off the chart: SM race best at Runoffs 2015: 124.7% of T1's (Todd Lamb)SM race best at Runoffs 2016: 112.8% of T1's (Michael Carter)SM race best at Runoffs 2017: 115.8% of T1's (Michael Gagliardo)SM race best at Runoffs 2018: 114.0% of T1's (Michael Carter)SM race best at Runoffs 2019: 101.5% of T1's (Elivan Goulart)SM race best at Runoffs 2020: 118.1% of T1's (Preston Pardus)SM race best at Runoffs 2021: 114.5% of T1's (Brian Henderson)SM race best at Runoffs 2022: 102.2% of T1's (Travis Wiley)SM race best at Runoffs 2023: 118.0% of T1's (Julian DaCosta)SM race best at Runoffs 2024: 118.6% of T1's (Brett Kowalski)SM race best at Runoffs 2025: 116.1% of T1's (Kyle Greenhill)Off the chart: SM qualifying best at Runoffs 2015: 122.1% of T1's (Andrew Carbonell)SM qualifying best at Runoffs 2016: 113.4% of T1's (Justin Hille)SM qualifying best at Runoffs 2017: 116.2% of T1's (Chris Haldeman)SM qualifying best at Runoffs 2018: 114.4% of T1's (Ken Sutherland)SM qualifying best at Runoffs 2019: 117.2% of T1's (Todd Buras)SM qualifying best at Runoffs 2020: 117.8% of T1's (Kyle Greenhill)SM qualifying best at Runoffs 2021: 115.1% of T1's (Brian Henderson)SM qualifying best at Runoffs 2022: 117.2% of T1's (Danny Steyn)SM qualifying best at Runoffs 2023: 117.9% of T1's (Danny Steyn)SM qualifying best at Runoffs 2024: 118.0% of T1's (Ethan Goulart)SM qualifying best at Runoffs 2025: 115.9% of T1's (Bobby Gossett)AS race best at Runoffs 2015: 106.4% of T1's (Andy McDermid)AS race best at Runoffs 2016: 104.6% of T1's (Edward Hosni)AS race best at Runoffs 2017: 108.4% of T1's (Bryan Long)AS race best at Runoffs 2018: 109.1% of T1's (John Heinricy)Off the chart: AS race best at Runoffs 2019: 92.2% of T1's (James Jost)AS race best at Runoffs 2020: 106.5% of T1's (Gregory Eaton)AS race best at Runoffs 2021: 106.6% of T1's (Gregory Eaton)Off the chart: AS race best at Runoffs 2022: 91.6% of T1's (Gregory Eaton)AS race best at Runoffs 2023: 107.5% of T1's (Gregory Eaton)AS race best at Runoffs 2024: 107.6% of T1's (Gregory Eaton)AS race best at Runoffs 2025: 105.4% of T1's (Gregory Eaton)AS qualifying best at Runoffs 2015: 107.2% of T1's (Tom Sloe)AS qualifying best at Runoffs 2016: 102.3% of T1's (Tom Sloe)AS qualifying best at Runoffs 2017: 103.4% of T1's (James Jost)AS qualifying best at Runoffs 2018: 107.8% of T1's (Andrew McDermid)AS qualifying best at Runoffs 2019: 107.1% of T1's (Gregory Eaton)AS qualifying best at Runoffs 2020: 106.8% of T1's (Gregory Eaton)AS qualifying best at Runoffs 2021: 108.0% of T1's (Drew Cattell)AS qualifying best at Runoffs 2022: 106.3% of T1's (Kurt Rezzetano)AS qualifying best at Runoffs 2023: 107.5% of T1's (Daniel Richardson)AS qualifying best at Runoffs 2024: 107.3% of T1's (Gregory Eaton)AS qualifying best at Runoffs 2025: 104.3% of T1's (Andrew McDermid)T4 race best at Runoffs 2015: 117.7% of T1's (Philip Royle)T4 race best at Runoffs 2016: 112.4% of T1's (Oscar Jackson)T4 race best at Runoffs 2017: 113.7% of T1's (Oscar Jackson)T4 race best at Runoffs 2018: 112.8% of T1's (John Heinricy)Off the chart: T4 race best at Runoffs 2019: 97.4% of T1's (Nick Leverone)T4 race best at Runoffs 2020: 113.8% of T1's (Chi Ho)T4 race best at Runoffs 2021: 111.7% of T1's (John Heinricy)T4 race best at Runoffs 2022: 106.9% of T1's (John Heinricy)T4 race best at Runoffs 2023: 114.3% of T1's (Devin Anderson)T4 race best at Runoffs 2024: 113.3% of T1's (Alex Lozano)T4 race best at Runoffs 2025: 107.8% of T1's (Alex Lozano)T4 qualifying best at Runoffs 2015: 119.7% of T1's (Philip Royle)T4 qualifying best at Runoffs 2016: 111.5% of T1's (Jonathan Yanca)T4 qualifying best at Runoffs 2017: 114.5% of T1's (Oscar Jackson)T4 qualifying best at Runoffs 2018: 112.4% of T1's (Gresham Wagner)T4 qualifying best at Runoffs 2019: 114.4% of T1's (John Heinricy)T4 qualifying best at Runoffs 2020: 114.4% of T1's (John Heinricy)T4 qualifying best at Runoffs 2021: 111.8% of T1's (Stephen Blethen)T4 qualifying best at Runoffs 2022: 112.8% of T1's (John Heinricy)T4 qualifying best at Runoffs 2023: 114.0% of T1's (Devin Anderson)T4 qualifying best at Runoffs 2024: 113.1% of T1's (Matt Spicuzzi)T4 qualifying best at Runoffs 2025: 108.7% of T1's (Matt Spicuzzi)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
T1SMAST4solid race · dashed qualifying · each class's best lap as a share of T1's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
EventT1SMAST4
Qual bestRace bestTrapQual bestRace bestTrapvs T1% of T1Qual bestRace bestTrapvs T1% of T1Qual bestRace bestTrapvs T1% of T1
Road America Runoffs 20262026-09-282:42.173Brett Kowalski · fastest of 34 · top 5 within 0.3s-0.938s (-0.58%)2:42.725Francisco Barroso · fastest of 35 · top 5 within 0.2s-1.705s (-1.04%)119.6Wyatt Couch+0.3 mph (+0.3%)2:26.911Andrew McDermid · fastest of 8 · top 5 within 3.4s+0.119s (+0.08%)2:28.471Andrew McDermid · fastest of 8 · top 5 within 2.4s-0.761s (-0.51%)151.0Andrew McDermid-0.6 mph (-0.4%)2:35.876Matt Spicuzzi · fastest of 12 · top 5 within 2.4s+2.920s (+1.91%)2:35.757Matt Spicuzzi · fastest of 12 · top 5 within 2.7s+3.124s (+2.05%)127.6Matt Spicuzzi-6.0 mph (-4.5%)
53 rule changes (T1: 12, SM: 2, AS: 13, T4: 26)8 cars added · 7 weight · 5 induction · 5 suspension & brakes · 4 engine · 4 tyres & wheels · 3 removed · 1 aero · 8 wording · 8 other · AS Camaro 16+ Spec Line: 1LE front splitter kit permitted, belt tensioner and motor mount parts allowed, spark plug position defined. · AS class adds Pirelli P Zero Trofeo Track as permitted tyre option for competition. · AS class rear trailing arms no longer required to maintain stock length, only to locate rear axle. · AS Ford Mustang GT 4.6L 4-valve regains allowance, minimum weight 3200 lbs. · AS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs. · SM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. · T1 classes now require U-rated or better DOT tires; re-grooving DOT tires banned; shaving and truing only allowed. · AS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776. · T1 trunk lid and wing mounting wording clarified; no performance change. · T1 LS1, LS6 removes OEM designation; 70mm restrictor requirement deleted. · T1 Spec Line Coyote Boss 302 production years corrected to 11–14, displacement 4957 cc unchanged. · AS EFI engine build sheets add dry sump, header, camshaft, and timing chain tensioner options for LS, LT1, Ford, and Mopar engines. · AS LT1 Camaro engine build sheet added with full specs; LT1 weight 3200 lbs, GTO tire to 275, Mustang weight to 3525 lbs, oil catch tanks now required. · SM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. · T1 restrictor requirement removed entirely; no replacement specified. · AS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets. · T1 GT4 Spec Line 4030- permits Wagner Tuning #200001124 intercooler as replacement for OEM heat exchanger. · AS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line. · T1 Chevrolet Corvette C6 LS1/LS6 spec line reinstated: 3200 lbs minimum, 70mm restrictor. · T2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously only spherical bearings permitted. · AS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm. · T1 Spec Line removes 70mm flat plate restrictor option. · T2, T3, T4 now allow under-dash electronics relocation for access after roll cage installation. · T4 Performance clarified: 1-piece alternative rotors permitted only at sizes listed in spec line; alternate brake kits may use matching 1-piece rotors. · AS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft. · unclear · T1 non-GT4 cars: multiple restrictor increases 61–80mm range, one weight raise to 3600 lbs, L76 engine clarified, throttle body permission removed. · T1 BMW M3 E92 (08-13) Spec Line 1090 removed entirely. · AS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs. · 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.showhide
  • AS 2016+ Camaro Spec Line Full Prep #39646otheraddedAS Camaro 16+ Spec Line: 1LE front splitter kit permitted, belt tensioner and motor mount parts allowed, spark plug position defined.
  • AS Consideration of Pirelli P Zero Trofeo Track for AS Competition #40495tyres & wheelsadded · tyres & wheelsAS class adds Pirelli P Zero Trofeo Track as permitted tyre option for competition.
  • T4 02-06 R53 Mini Cooper Hotchkins Rear Camber Arms #40677suspension & brakes
  • AS Change in 9.1.6.D.4.d.5 in Suspension Mounting Points #40094suspension & brakesfaster · suspension & brakesAS class rear trailing arms no longer required to maintain stock length, only to locate rear axle.
  • AS Re-Add 4.6L 4v 96-04 Mustang Cobra #40239cars addedaddedAS Ford Mustang GT 4.6L 4-valve regains allowance, minimum weight 3200 lbs.
  • AS Errors and Omissions #40532weightslower · weightAS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs.
  • T4 Is it time? #40653cars added
  • T4 Combine T4 BRZ/86/FRS generations #40656weight
  • SM Rear Toe Link #40271wordingwordingSM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361.
  • T1 Tire Equality #40342tyres & wheelstyres & wheelsT1 classes now require U-rated or better DOT tires; re-grooving DOT tires banned; shaving and truing only allowed.
  • T4 Dodge Neon DOHC Weight #40329weight
  • AS Clarification for LM7 Holley Carburetor #40167wordingwordingAS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776.
  • T1 Trunk Lid Wording #40177wordingwordingT1 trunk lid and wing mounting wording clarified; no performance change.
  • T4 SPB In T4 #39973other
  • T4 02-06 Mini Cooper S #40106weight -50 lbs
  • T4 02-06 Mini Cooper S Fuel #40107other
  • T4 Shock error #40176suspension & brakes
  • T4 Max Tire Sizes #40183tyres & wheels
  • T1 Clarification on Request #39716 T1 (Spec Line #1139) #39924wordingunclearT1 LS1, LS6 removes OEM designation; 70mm restrictor requirement deleted.
  • T1 Mistake in Line 1430 #39958wordingwordingT1 Spec Line Coyote Boss 302 production years corrected to 11–14, displacement 4957 cc unchanged.
  • T4 2003 Honda Civic Si Classification #39999cars added
  • AS Header Information Update for EFI Engine Build Sheets #39886engineadded · engineAS EFI engine build sheets add dry sump, header, camshaft, and timing chain tensioner options for LS, LT1, Ford, and Mopar engines.
  • AS Errors and Omissions #39933otherfasterAS LT1 Camaro engine build sheet added with full specs; LT1 weight 3200 lbs, GTO tire to 275, Mustang weight to 3525 lbs, oil catch tanks now required.
  • SM Part Number Change Request #39914otherunclearSM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c.
  • T1 Spec line #1139 Restrictor Change Request #39922enginefaster · engineT1 restrictor requirement removed entirely; no replacement specified.
  • T4 16-24 ND MX5 T4 #39934suspension & brakes
  • AS Re-Organization of AS Spec lines for 2026 #39887wordingwordingAS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets.
  • T1 Replace OEM Heat Exchanger (Intercooler) With Aftermarket #39542aeroadded · aeroT1 GT4 Spec Line 4030- permits Wagner Tuning #200001124 intercooler as replacement for OEM heat exchanger.
  • T4 ND MX-5 Spec Line Rewrite Request #39802weight -100 lbs
  • T4 4.0 Mustang spec line cleanup #39831induction
  • AS Edelbrock manifold (& timing kit) to Chevy LS Spec Lines Request #39055cars addedaddedAS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line.
  • T1 LS1 into Corvette C6 Spec Line Request #39716cars addedaddedT1 Chevrolet Corvette C6 LS1/LS6 spec line reinstated: 3200 lbs minimum, 70mm restrictor.
  • T4 T4 and T3 Feedback #39230removed
  • T4 T4 Mustang 4.0 #39489induction
  • T4 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.
  • AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501inductionslower · inductionAS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm.
  • T1 additional T1 adjustment #39520engineremoved · engineT1 Spec Line removes 70mm flat plate restrictor option.
  • T4 Alternate Placement of Fuse Panel and Electronics Request #39370otheraddedT2, T3, T4 now allow under-dash electronics relocation for access after roll cage installation.
  • T4 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.
  • AS 1994 Mustang Spec Line Request #39104engineadded · engineAS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft.
  • T1 Keep S2000 Classification #39344wordingunclearunclear
  • T1 Correcting and updating T1 GT4 spec lines #39394weight
  • T1 BOP adjustments to non GT4 T1 cars #39406induction +100 lbsfaster · inductionT1 non-GT4 cars: multiple restrictor increases 61–80mm range, one weight raise to 3600 lbs, L76 engine clarified, throttle body permission removed.
  • T1 Remove T1 Spec Line #39407removedremovedT1 BMW M3 E92 (08-13) Spec Line 1090 removed entirely.
  • T4 Classing 1995-99 Dodge Neon SOHC #39285cars added
  • AS Cadillac CTS-V BOP Weight Change #38640weight -50 lbsfaster · weightAS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs.
  • T4 02-06 Mini Cooper Gear Ratios #38966other
  • T4 Reinstatement of the 2005-2010 Cobalt into T4 #38987cars added
  • T4 Request to Classify Mercedes C230K #39080cars added
  • T4 ND Gearset Request for T4 #39166otheraddedT3 and T4 Mazda MX-5 Miata add permitted gearset kit PT#0000-02-6100 to Notes.
  • T4 E&O wheel size on ND #39168tyres & wheels
  • T4 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.
  • T4 Touring 4 Post-Runoffs BOP Adjustments and Changes #39251induction -100 lbs
Road America Runoffs 20252025-09-292:20.677James Candelaria · fastest of 5 · top 5 within 5.9s+4.099s (+3.00%)2:21.612Drew Delmonico · fastest of 5 · top 5 within 11.8s+5.481s (+4.03%)163.6Drew Delmonico+5.7 mph (+3.6%)2:43.111Bobby Gossett · fastest of 32 · top 5 within 0.3s+2.005s (+1.24%)2:44.430Kyle Greenhill · fastest of 28 · top 5 within 0.3s+2.944s (+1.82%)119.3Francisco Barroso-0.6 mph (-0.5%)+22.818squal +22.434s116.1%qual 115.9%2:26.792Andrew McDermid · fastest of 11 · top 5 within 3.9s+0.214s (+0.15%)2:29.232Gregory Eaton · fastest of 10 · top 5 within 4.0s+2.803s (+1.91%)151.5Andrew McDermid+1.9 mph (+1.3%)+7.620squal +6.115s105.4%qual 104.3%2:32.956Matt Spicuzzi · fastest of 10 · top 5 within 3.8s-1.474s (-0.95%)2:32.633Alex Lozano · fastest of 10 · top 5 within 4.3s-1.575s (-1.02%)133.7Alex Lozano+4.4 mph (+3.4%)+11.021squal +12.279s107.8%qual 108.7%
63 rule changes (T1: 19, SM: 4, AS: 11, T4: 29)12 weight · 11 cars added · 9 engine · 7 tyres & wheels · 2 aero · 1 induction · 1 removed · 10 wording · 10 other · T2, T3, T4 spec table header changed from T2 to ET. · AS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs. · AS Ford Mustang GT 05-14 Restricted Prep Engine gains additional gear ratio option: 3.66, 2.43, 1.69, 1.32, 1.00, .65. · SMX drivers must submit data acquisition files on time or face suspension and $250 fine. · SMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fines, level 2 and 4 may carry $500 fines. · AS Ford Mustang GT 5.0L 15-17 flat plate restrictor reduces from 67mm to 64mm. · AS LS1/LS6 intakes added for 5.3L truck engine: part numbers 12561269 and 88894095. · SM tire marking rules clarified: one Hoosier SM 7.5 P205/50/ZR17 set per Super Tour weekend, impound after first dry session, damaged tires may be replaced with used tires only. · Porsche 981 GT4 Clubsport added to T1 as Spec Line 4085, minimum weight 3100 lbs, 265/645 front and 305/680 rear tires. · T1 Honda S2000 Spec Line 1530 minimum weight drops 50 lbs to 2900. · T1 BMW E46 M3 permits BMW #GS7D36SG sequential transmission as aftermarket option in SL# 1060 and 1070. · T1 BMW M3 E92 minimum weight reduced to 3300 lbs. · T1 Mustang Darkhorse R tyres widen to 315 front and rear, weight set to 3600 lbs with driver, Runoffs eligibility requires 3 Super Tour events. · AS Flotek head value seat cutting dimensions figure updated for consistency. · AS class notes cleaned: fuel cell and ECM specifications removed from multiple Camaro, Firebird, Challenger and Mustang variants. · T1 Cadillac CT4-V Blackwing added: 3564cc, 3750 lbs minimum, OEM ECU with reprogramming allowed. · AS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models. · T1 Mustang Spec 1430 restrictor opens 60mm to 65mm; Spec 1460 weight up to 3500 lbs, restrictor 70mm; Corvette 1190 restrictor 67mm to 70mm; BMW 1090 restrictor tightens 40mm to 35mm, expires 12/31/25; BMW 1100 weight up to 3350 lbs. · T1 Mustang weight to 3600 lbs, restrictor to 60mm; Corvette weight to 3500 lbs, restrictor to 67mm; BMW deleted. · T1 E46 M3 Spec Line 1050 throttle body changed from Dinan D760-3400 to VAC Motorsports VAC-TB-S54 on 3.250L engine. · T1 Chevrolet Corvette C8 (2020-2023) minimum weight drops to 3500 lbs. · T1 Chevrolet Camaro Gen 5 required restrictor increases from 75mm to 80mm flat plate. · T1 Audi R8 GT4 Spec Line #4020 max tire size changes to 315 DOT, 305/645, or 30/65-18 (f), 33/68-18 (r) Non-DOT. · Ford SCCA Club Spec Mustang added to T3 at 3350 lbs; Mazda SCCA Club Spec MX-5 added to T4 at 2500 lbs. · AS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm. · AS Mustang GT 05-14 Restricted loses 300 lbs engine; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively. · AS class: multiple American muscle cars gain additional allowed gear ratio options across model years and prep levels. · AS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM. · T2, T3, T4: nine, nine, and thirty-seven expired spec lines removed effective 2025-01-01. · SMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation. · T1 GT4 tire sizes standardized: most cars 315 DOT with 305/660 or 305/645 Non-DOT; Camaro 305/680, Mustang 315/680 Non-DOT. · BMW M4 GT4 (G82) added to T1 as spec line 4031, 3525 lbs minimum, red power stick; F82 model switched to red power stick. · T1 now permits 5.5 inch clutch as engine option. · T1 GT4 Spec Line 4020 restrictor opens to 45mm and minimum weight drops to 3400 lbs with driver. · T1 adds Mustang Darkhorse R homologated car, 305/315 tyres, 10.5/11 in wheels, minimum weight TBD. · T1 Corvette may roll or flatten wheel opening lips, remove composite fender lips and liners, and add fender vents for tire clearance. · T1 E46 M3 S54 now allows Dinan Throttle Body #D760-3400 on the 3.250L engine. · T2, T3 Mustang spec lines remove redundant driveshaft allowance notes across six model year ranges. · 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. · T4 BMW 320i Spec Line: Turner Motorsports intercooler #024703TMS02 now allowed. · 2005 Cadillac CTS 3.6L 6-speed manual classified in T3 Spec.showhide
  • T4 Incorrect Touring Heading #38451wordingwordingT2, T3, T4 spec table header changed from T2 to ET.
  • AS RE: Previous Letter 37695 Update #38245weight -75 lbsfaster · weightAS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs.
  • T4 Allow B-Spec cars to run in T4 #38439other
  • AS Errors and Omissions #38234otheraddedAS Ford Mustang GT 05-14 Restricted Prep Engine gains additional gear ratio option: 3.66, 2.43, 1.69, 1.32, 1.00, .65.
  • SM SMX Data Submission - Penalties #38248otheraddedSMX drivers must submit data acquisition files on time or face suspension and $250 fine.
  • SM Committee) SMX Penaly Clarification updated language #38337wordingwordingSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fines, level 2 and 4 may carry $500 fines.
  • T4 T4 Mustang #38059weight -100 lbs
  • T4 SSC tire allowance #38216tyres & wheels
  • AS Errors and Omission #38055inductionslower · inductionAS Ford Mustang GT 5.0L 15-17 flat plate restrictor reduces from 67mm to 64mm.
  • AS Request to Add LS1/LS6 Intakes for 5.3L Truck Engine EnO #38197cars addedaddedAS LS1/LS6 intakes added for 5.3L truck engine: part numbers 12561269 and 88894095.
  • SM Clarify Tire Marking Regs #38005wordingwordingSM tire marking rules clarified: one Hoosier SM 7.5 P205/50/ZR17 set per Super Tour weekend, impound after first dry session, damaged tires may be replaced with used tires only.
  • T1 Acceptance of Porsche 981 GT4 Clubsport into T1 #36664cars addedaddedPorsche 981 GT4 Clubsport added to T1 as Spec Line 4085, minimum weight 3100 lbs, 265/645 front and 305/680 rear tires.
  • T1 Request to Restore T1 Honda S2000 to Proper Weights #37644weight -50 lbsfaster · weightT1 Honda S2000 Spec Line 1530 minimum weight drops 50 lbs to 2900.
  • T1 DCT Transmission in E46 #37964cars addedaddedT1 BMW E46 M3 permits BMW #GS7D36SG sequential transmission as aftermarket option in SL# 1060 and 1070.
  • T1 Reduce E92 M3 Minimum Weight to 3050 #38092weightfaster · weightT1 BMW M3 E92 minimum weight reduced to 3300 lbs.
  • T1 Finalize Spec Line for T1 Darkhorse #38106tyres & wheelsfaster · tyres & wheelsT1 Mustang Darkhorse R tyres widen to 315 front and rear, weight set to 3600 lbs with driver, Runoffs eligibility requires 3 Super Tour events.
  • T4 Correct Ring and Pinion Ratio to T3, Sorry I Mean T4 3.7 V6 Stang #38041wording
  • T4 T4 Mustang #38058aero
  • AS Flotek Head Plunge Cut Inconsistencies #37502wordingwordingAS Flotek head value seat cutting dimensions figure updated for consistency.
  • AS Notes clean up #37693wordingwordingAS class notes cleaned: fuel cell and ECM specifications removed from multiple Camaro, Firebird, Challenger and Mustang variants.
  • T1 Cadillac CT4-V Blackwing #38003cars addedaddedT1 Cadillac CT4-V Blackwing added: 3564cc, 3750 lbs minimum, OEM ECU with reprogramming allowed.
  • AS Race memo #37902wordingwordingAS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models.
  • T1 Correct and make new T1 BOP adjustments. #37737weight +75 lbsslower · weightT1 Mustang Spec 1430 restrictor opens 60mm to 65mm; Spec 1460 weight up to 3500 lbs, restrictor 70mm; Corvette 1190 restrictor 67mm to 70mm; BMW 1090 restrictor tightens 40mm to 35mm, expires 12/31/25; BMW 1100 weight up to 3350 lbs.
  • T1 T1 Parity Compared to GT4 #37170weight +125 lbsslower · weightT1 Mustang weight to 3600 lbs, restrictor to 60mm; Corvette weight to 3500 lbs, restrictor to 67mm; BMW deleted.
  • T1 Clarification of Request Approval #37273 #37399engineengineT1 E46 M3 Spec Line 1050 throttle body changed from Dinan D760-3400 to VAC Motorsports VAC-TB-S54 on 3.250L engine.
  • T1 C8 Corvette Facts #37400weight -100 lbsfaster · weightT1 Chevrolet Corvette C8 (2020-2023) minimum weight drops to 3500 lbs.
  • T1 Camaro Gen 5 Competitive Disadvantage #37440enginefaster · engineT1 Chevrolet Camaro Gen 5 required restrictor increases from 75mm to 80mm flat plate.
  • T1 Tire Changes in the Rules for GT4 #37497tyres & wheelstyres & wheelsT1 Audi R8 GT4 Spec Line #4020 max tire size changes to 315 DOT, 305/645, or 30/65-18 (f), 33/68-18 (r) Non-DOT.
  • T4 Ford Mustang V6 (05-14) #37516other
  • T4 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.
  • AS Increase Coyote Engine Restrictor to 80mm #36177enginefaster · engineAS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm.
  • AS Performance Pack for 2015+ Mustang #36867enginefaster · engineAS Mustang GT 05-14 Restricted loses 300 lbs engine; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively.
  • AS Gear Ratios #37131otheraddedAS class: multiple American muscle cars gain additional allowed gear ratio options across model years and prep levels.
  • AS ECU specs for LS engine #37208engineadded · engineAS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM.
  • T4 Remove spec lines that have expired #37269removedremovedT2, T3, T4: nine, nine, and thirty-seven expired spec lines removed effective 2025-01-01.
  • T4 2016-2018 Mazda Miata MX5 #37085weight -75 lbs
  • SM E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingwordingSMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation.
  • T1 Changes to T1 Tires for GT4 and Other Cars #35383tyres & wheelsunclearT1 GT4 tire sizes standardized: most cars 315 DOT with 305/660 or 305/645 Non-DOT; Camaro 305/680, Mustang 315/680 Non-DOT.
  • T1 G82 M4 GT4 inclusion in T1 #35864cars addedaddedBMW M4 GT4 (G82) added to T1 as spec line 4031, 3525 lbs minimum, red power stick; F82 model switched to red power stick.
  • T1 Alt. Clutch Allowance #36606engineadded · engineT1 now permits 5.5 inch clutch as engine option.
  • T1 BOP Changes Need Updates #36667engine -150 lbsfaster · engineT1 GT4 Spec Line 4020 restrictor opens to 45mm and minimum weight drops to 3400 lbs with driver.
  • T1 Request Ford Performance Darkhorse R in T1 #37136cars addedaddedT1 adds Mustang Darkhorse R homologated car, 305/315 tyres, 10.5/11 in wheels, minimum weight TBD.
  • T1 Car Mods for T1 Corvette under line item 1150 #37173aeroadded · aeroT1 Corvette may roll or flatten wheel opening lips, remove composite fender lips and liners, and add fender vents for tire clearance.
  • T1 Increased Bore Throttle Bodies for E46 M3 S54 Engine #37273engineadded · engineT1 E46 M3 S54 now allows Dinan Throttle Body #D760-3400 on the 3.250L engine.
  • T4 Redundant Verbiage Regarding Mustang Spec Lines for Driveshaft #36484wordingwordingT2, T3 Mustang spec lines remove redundant driveshaft allowance notes across six model year ranges.
  • T4 R53 Mini Cooper S Weight Reduction Request #36612weight
  • T4 Allowable Wheel Offset #36855tyres & wheels
  • T4 Fuel Emissions Components #37076otheraddedT2, T3, T4 fuel cell installations may omit charcoal canisters, emissions valves, and sensors.
  • T4 2019-2024 Mazda 3 for T4 #37077cars added
  • T4 fix brake wording #37129wordingwordingT2, T3, T4 brake specifications clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter.
  • T4 Evaporative emissions systems #37130otheraddedT2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors.
  • T4 Allow Spec MX5 upgrade kit for 2009-11 RX8 S2 Transmision #37140other
  • T4 Move Spec Boxster to T4 #37158cars addedaddedPorsche Spec Boxster moves to T4, minimum weight 2750 lbs, ineligible for Runoffs until 3 Super Tour events.
  • T4 3.7 Mustangs to T4 #37188cars added
  • T4 BMW 320i Spec Line #37204engineadded · engineT4 BMW 320i Spec Line: Turner Motorsports intercooler #024703TMS02 now allowed.
  • T4 MX5 2006-2015 NC Help #37221other
  • T4 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.
  • T4 Civic SI in T4 #37248weight -50 lbs
  • T4 2006-2015 T4 NC Mx5 spec line #37278weight
  • T4 ND MX-5 wheel allowance #37279tyres & wheels
  • T4 T4 BOP #37281weight +75 lbs
  • T4 Allow 7.5 #37286tyres & wheels
  • T4 Bop Request 06-11 Honda Civic Si #37013other
Road America Runoffs 20242024-10-012:16.578Andrew Aquilante · fastest of 8 · top 5 within 4.8s-1.068s (-0.78%)2:16.131Andrew Aquilante · fastest of 7 · top 5 within 4.0s-2.570s (-1.85%)157.9Andrew Aquilante-0.8 mph (-0.5%)2:41.106Ethan Goulart · fastest of 49 · top 5 within 0.5s-1.103s (-0.68%)2:41.486Brett Kowalski · fastest of 43 · top 5 within 0.3s-2.262s (-1.38%)119.9Alex Bertagnoli-1.4 mph (-1.2%)+25.355squal +24.528s118.6%qual 118.0%2:26.578Gregory Eaton · fastest of 18 · top 5 within 2.6s-0.467s (-0.32%)2:26.429Gregory Eaton · fastest of 18 · top 5 within 2.5s-1.239s (-0.84%)149.6Gregory Eaton+0.4 mph (+0.3%)+10.298squal +10.000s107.6%qual 107.3%2:34.430Matt Spicuzzi · fastest of 15 · top 5 within 1.8s-2.973s (-1.89%)2:34.208Alex Lozano · fastest of 14 · top 5 within 2.2s-3.673s (-2.33%)129.3Alex Lozano-0.9 mph (-0.7%)+18.077squal +17.852s113.3%qual 113.1%
56 rule changes (T1: 13, SM: 4, AS: 11, T4: 28)19 cars added · 9 weight · 5 suspension & brakes · 4 engine · 3 removed · 2 aero · 1 induction · 1 tyres & wheels · 4 wording · 8 other · AS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options. · SMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification. · SM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01. · SMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only. · SM and SMX now allow an alternate shifter bushing at the bottom of the shift lever. · 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-T4 Ford Mustangs: remove 25 lb penalty for non-OEM driveshaft, clarify alternate driveshaft allowance. · Audi S4 (2000–2002) classified in T3 with 2671cc, 3400 lbs minimum weight, 38mm restrictor, allowing 800lb springs and intercooler. · AS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes. · AS Chevrolet Camaro 1LE (2016-) added with 3600 lbs minimum weight, 275 tires, 60mm restrictor, 345/338mm brakes. · AS Chevrolet/Pontiac Camaro & Firebird 82–92 5.7L LS1 classified: 3200 lbs, 13.1×1.27 disc brakes, 17 in max wheel, 65 mm restrictor, SLP intake lid permitted. · AS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations. · Mercedes AMG-C63 S 2023 added to T1 with 4000 cc, 3700 lb minimum weight, no restrictor. · T3 and T4 Mazda RX-8 may remove or disable factory oil injection system. · T2, T3, T4 driveshafts may use carbon fiber, aluminum, or steel; two-piece replaced with one-piece; non-OEM adds 25 lbs. · AS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes. · AS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25. · T1 Honda S2000 classified: 1530 cc max, 2950 lbs minimum, 4.75" supercharger pulley, 6.75" crank pulley. · Chevrolet Camaro, Pontiac Firebird 70–81 Full Prep classified in AS at 3400–3600 lbs with 108.0 wheelbase, specific head castings, and suspension modifications permitted. · AS class adds fuel cell location notes to multiple Cadillac, Chevrolet, Dodge and Ford models: cells within 24 inches of standard tank. · Chevrolet Camaro 6th gen Full Prep added to AS class at 3400 lbs base or 3600 lbs with built engine. · AS class: Ford Mustang GT 05-14 Restricted prep added; Cadillac CTS-V 04-07 to 3450 lbs; Camaro/Firebird variants reconfigured with weight and notes changes; Dodge Challenger 08-20 restrictor 76mm to 80mm; Ford Mustang variants updated wei… · T1 adds Pontiac GTO 2006-2009 LS1 5700cc, 3400 lbs minimum, engine repositioning allowed. · 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. · T1 Chevrolet Corvette C8 (2020–23) restrictor plate increases from 70mm to 72mm flat plate. · T1 category removes 23 car spec lines including NSX, Viper, Ferrari, Mazda, Nissan, Porsche, Subaru, Toyota; Porsche 997 spec line 1680 expiration 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. · T1 GT4 cars gain Runoffs eligibility; weights and power maps adjusted across six models; tire rules now allow IMSA or SRO GT4 slicks. · T1 removes 27 spec line numbers entirely, including engine, suspension, brake and aero specifications. · T3 Nissan 370Z now includes model years 2009–2022 with Nismo editions. · T1 Chevrolet Corvette C5 LS2 added: 6000 cc, 3300 lbs minimum, 72mm restrictor, carbon aero option −50 lbs. · T1 adds Chevrolet Corvette C7 (14–19) including Z51, Grandsport as homologated car. · T1 Gen 5 Camaro minimum weight cut 75 lbs to 3475; restrictor opens from 70mm to 75mm flat plate. · T1 Aston Martin Vantage gains OEM Sportshift II transmission as permitted option. · Pontiac GTO 2006-2009 re-integrated to T1 with LS2 at 3400 lbs, 72mm restrictor, or LS3 at 3500 lbs, 61mm restrictor. · T1 Porsche 997-1 GT3 Cup added as spec line 4210, minimum weight 3050 lbs, 996 spec line 1670 removed.showhide
  • AS Mustang transmission ratios #36662otheraddedAS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options.
  • SM SMX Camera Rule Correction #36496wordingwordingSMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification.
  • SM Committee) AIM ECU Protocol #36556engineadded · engineSM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01.
  • SM Committee) OE versus OEM Definitons #36608wordingwordingSMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only.
  • SM Committee) Shifter Bushing #36611otheraddedSM and SMX now allow an alternate shifter bushing at the bottom of the shift lever.
  • T4 T4 Camaro V6 weight reduction #36232weight
  • T4 BOP adjustment for ND MX5s #36345weight -50 lbs
  • T4 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.
  • T4 Homologation of car to T4 #36030cars added
  • T4 T2-T4 Driveshaft Mistake...? #36050weightfaster · weightT2-T4 Ford Mustangs: remove 25 lb penalty for non-OEM driveshaft, clarify alternate driveshaft allowance.
  • T4 MINI Cooper S Spec Lines Corrections. #36086removed
  • T4 Allow Removal of Sound Tubes #36130induction
  • T4 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.
  • AS Request for Classification of 2018-2023 mustang In #35764cars addedaddedAS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes.
  • T4 Allow OEM Front Spoiler 06-08 Miata in T4 #35941aero
  • T4 T4 Mustang Weight Reduction In T4 Spec #36051weight -50 lbs
  • T4 R53 Mini Cooper S spec line request In #36056suspension & brakes
  • AS 6th gen Camaro limited prep #35733cars addedaddedAS Chevrolet Camaro 1LE (2016-) added with 3600 lbs minimum weight, 275 tires, 60mm restrictor, 345/338mm brakes.
  • AS Chevrolet/Pontiac Camaro & Firebird (82-92) 5.7L V8 LS1 Alum BLK #35825cars addedaddedAS Chevrolet/Pontiac Camaro & Firebird 82–92 5.7L LS1 classified: 3200 lbs, 13.1×1.27 disc brakes, 17 in max wheel, 65 mm restrictor, SLP intake lid permitted.
  • AS Full Prep Head #35891engineadded · engineAS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations.
  • T1 Please Expedite classing the C63 Mercedes #35987cars addedaddedMercedes AMG-C63 S 2023 added to T1 with 4000 cc, 3700 lb minimum weight, no restrictor.
  • T4 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.
  • T4 2023 ND2 Miata Classification and Allowances #35837weight
  • T4 Errors and Omissions for 06-09 VW Rabbit Rotor #35851suspension & brakes
  • T4 Driveshafts #35916weightslower · weightT2, T3, T4 driveshafts may use carbon fiber, aluminum, or steel; two-piece replaced with one-piece; non-OEM adds 25 lbs.
  • T4 GCR ERROR - letter not properly applied to GCR #35999weight
  • AS Restricted Prep Aftermarket Parts Request #35682otheraddedAS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes.
  • AS Allowance of 11 #35824tyres & wheelsfaster · tyres & wheelsAS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25.
  • T1 Honda S2000 #35582cars addedaddedT1 Honda S2000 classified: 1530 cc max, 2950 lbs minimum, 4.75" supercharger pulley, 6.75" crank pulley.
  • T4 Corrections to T4 RX8 Spec line #35767aero
  • AS Request to Classify 1970-1981 Camaro and Firebird in AS #33659cars addedaddedChevrolet Camaro, Pontiac Firebird 70–81 Full Prep classified in AS at 3400–3600 lbs with 108.0 wheelbase, specific head castings, and suspension modifications permitted.
  • AS Fuel Cell 12 #34194otheraddedAS class adds fuel cell location notes to multiple Cadillac, Chevrolet, Dodge and Ford models: cells within 24 inches of standard tank.
  • AS Please Classify the 6th Gen Into AS. #35448cars addedaddedChevrolet Camaro 6th gen Full Prep added to AS class at 3400 lbs base or 3600 lbs with built engine.
  • AS spec lines #35713otherunclearAS class: Ford Mustang GT 05-14 Restricted prep added; Cadillac CTS-V 04-07 to 3450 lbs; Camaro/Firebird variants reconfigured with weight and notes changes; Dodge Challenger 08-20 restrictor 76mm to 80mm; Ford Mustang variants updated wei…
  • T1 9.1.9.1 T1 new category item/ line 26 rule to expire Jan 1 2023 #35411cars addedaddedT1 adds Pontiac GTO 2006-2009 LS1 5700cc, 3400 lbs minimum, engine repositioning allowed.
  • T4 Reorganize Spec Lines #35375otheraddedT2, T3, T4 Spec Lines remove wheelbase requirement, add Required Restrictor specification.
  • T4 Allow any 400lb rear spring in the RX8 #35433suspension & brakes
  • T4 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.
  • T1 C8 Corvette T1 Restrictor Plate Request #35213enginefaster · engineT1 Chevrolet Corvette C8 (2020–23) restrictor plate increases from 70mm to 72mm flat plate.
  • T1 The Cars Have Expired #35379removedremovedT1 category removes 23 car spec lines including NSX, Viper, Ferrari, Mazda, Nissan, Porsche, Subaru, Toyota; Porsche 997 spec line 1680 expiration removed.
  • T4 More Car Lightening Stuff #35319wordingremovedT2, T3, T4 battery replacement no longer allows alternate manufacturer batteries within 10% OEM weight.
  • T4 ND Missed Items #35352other
  • T4 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.
  • T4 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.
  • T1 GT4 batch adjustment in T1 #35162cars added -85 lbsaddedT1 GT4 cars gain Runoffs eligibility; weights and power maps adjusted across six models; tire rules now allow IMSA or SRO GT4 slicks.
  • T1 Remove T1 spec lines #35192removedremovedT1 removes 27 spec line numbers entirely, including engine, suspension, brake and aero specifications.
  • T4 Mazda MX-5 ND1 Spec Line Request #34232weight +50 lbs
  • T4 BRZ/FRS/86 Spring Allowance #35038suspension & brakes
  • T4 TSX Allowance #35219other
  • T4 Requested Update of Model Years of 370Z #35231cars addedaddedT3 Nissan 370Z now includes model years 2009–2022 with Nismo editions.
  • T1 New T1 add spec line for C5 corvette LS2 engines (Copy from C6) #33764cars addedaddedT1 Chevrolet Corvette C5 LS2 added: 6000 cc, 3300 lbs minimum, 72mm restrictor, carbon aero option −50 lbs.
  • T1 C7 Corvette Rule Change Request #34897cars addedaddedT1 adds Chevrolet Corvette C7 (14–19) including Z51, Grandsport as homologated car.
  • T1 Camaro Gen 5 Weight Reduction Due to Competitive Disadvantage #35092weight -75 lbsfaster · weightT1 Gen 5 Camaro minimum weight cut 75 lbs to 3475; restrictor opens from 70mm to 75mm flat plate.
  • T1 Addendum to Letter #35022: Drivetrain Rule #35105cars addedaddedT1 Aston Martin Vantage gains OEM Sportshift II transmission as permitted option.
  • T1 2004 - 2006 Pontiac GTO Re-Integration Back Into T1 #34403cars addedaddedPontiac GTO 2006-2009 re-integrated to T1 with LS2 at 3400 lbs, 72mm restrictor, or LS3 at 3500 lbs, 61mm restrictor.
  • T1 Request to Classify Porsche 997-1 GT3 Cup #34561cars addedaddedT1 Porsche 997-1 GT3 Cup added as spec line 4210, minimum weight 3050 lbs, 996 spec line 1670 removed.
Virginia International Raceway Runoffs 20232023-09-231:54.520Andrew Aquilante · fastest of 12 · top 5 within 3.7s-0.370s (-0.32%)1:55.488Andrew Aquilante · fastest of 12 · top 5 within 2.7s-20.579s (-15.12%)159.2James Candelaria+1.6 mph (+1.0%)2:14.986Danny Steyn · fastest of 52 · top 5 within 0.1s+0.322s (+0.24%)2:16.229Julian DaCosta · fastest of 46 · top 5 within 0.3s-2.878s (-2.07%)120.3Jim Drago+1.1 mph (+0.9%)+20.741squal +20.466s118.0%qual 117.9%2:03.082Daniel Richardson · fastest of 11 · top 5 within 2.2s+0.920s (+0.75%)2:04.120Gregory Eaton · fastest of 9 · top 5 within 3.0s-0.458s (-0.37%)154.6James Jost+3.7 mph (+2.5%)+8.632squal +8.562s107.5%qual 107.5%2:10.514Devin Anderson · fastest of 24 · top 5 within 0.5s+0.937s (+0.72%)2:11.962Devin Anderson · fastest of 23 · top 5 within 0.1s-13.481s (-9.27%)127.8Raymond Blethen+0.5 mph (+0.4%)+16.474squal +15.994s114.3%qual 114.0%
44 rule changes (T1: 19, SM: 1, AS: 4, T4: 20)8 cars added · 8 weight · 4 engine · 4 suspension & brakes · 3 tyres & wheels · 2 aero · 2 induction · 1 removed · 8 wording · 4 other · AS crate motor part number specification clarified; both CT400 P/N-19370604 and 19370604 engine assemblies permitted for GM vehicles. · AS Ford Mustang GT 5.0L (15-17) Restricted maximum wheel diameter increases to 19.0 inches. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front upper control arms; SPC-66045 spec part removed. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 now allows alternate front brake calipers with adaptor brackets for component compatibility. · Chevrolet Camaro GT4-R added to T1 GT4 Spec Line 4035, 315 tires, 3375 lbs minimum, ineligible for Runoffs. · T1 Dodge Viper ACR / SRT RT-10 and ACR/ACR-X spec lines 1350 and 1370 remove 12/23 expiration dates. · T1 GT4 McLaren 570S, Mercedes AMG GT4, and Porsche 718 Cayman GT4 CS MR now eligible for Runoffs competition. · T1 GT4 BMW M4 spec line number changed from 4050 to 4030. · T1 Chevrolet Corvette C5 rear spoiler to 5 inches above bumper allowed, plus 50 lbs; carbon aero parts permitted with 50 lb decrease. · 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. · T1 Dodge Viper ACR/ACR-X restrictor increases from 50mm to 60mm flat plate. · T1 Dodge Viper ACR/ACR-X Spec Line 1370 restrictor increases to 55mm; Spec Line 1390 decreases to 55mm flat plates. · T1 Ford Mustang S197 (05-14) must use OEM 8.8 differential housing. · T1 Chevrolet Camaro Gen 5 LS7 gains two spec lines with 70mm and 53mm restrictors, both 3450 lbs minimum. · T1 Chevrolet Camaro Gen 5, Corvette C5 and C6: resleeve restricted to stock parameters for engine repair or replacement, not LS3 bore/stroke. · T1 Ford Mustang S197 (05-14) reinstated with 5.0L Voodoo engine, 3550 lbs minimum, 75mm restrictor. · T1-GT4 minimum weights set: Aston Martin Vantage AMR 3575 lbs, Audi R8 3550, BMW M4 3500, Ford Mustang 3550, McLaren 570S 3450, Mercedes AMG 3450, Porsche 718 Cayman CS MR 3200, Porsche 718 RS 3450, Toyota Supra 3350. · T1-GT4 McLaren 570S front tyre widens from 285 to 315; Mercedes AMG GT4 front tyre widens from 275 to 315. · T1 Chevrolet Camaro Gen 5 LS3-6160 adds new Spec Line 1135 with 70mm flat plate restrictor, 3550 lbs minimum weight. · T1 aftermarket sequential gearbox cars must have 1:1 or greater top gear ratio, OEM location, max 10 inch bellhousing; non-sequential cars gain 100 lbs weight break. · T1 GT4 all nine cars lose 125 lbs minimum weight with driver across the range. · T1 pre-2023 rules and spec lines removed entirely, effective 2023-03-01. · GT4 McLaren 570S maximum tyre size set to 285 front, 315 rear. · T2 and T3 Mustang 11-14 may remove upper grille fog lights, replace with mesh or screen. · SM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore. · T1 adds eight GT4 cars: Aston Martin, Audi, BMW, Ford, McLaren, Mercedes, two Porsches, Toyota, minimum weights 3200–3575 lbs, restricted by SRO 2022 rules. · 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.showhide
  • T4 Inclusion of similar car. (CLK 320) #34626other
  • AS Crate Motor Part Numbers #32944wordingwordingAS crate motor part number specification clarified; both CT400 P/N-19370604 and 19370604 engine assemblies permitted for GM vehicles.
  • AS Request wheel size change #33007tyres & wheelsfaster · tyres & wheelsAS Ford Mustang GT 5.0L (15-17) Restricted maximum wheel diameter increases to 19.0 inches.
  • AS Alternative Upper Front Control Arms for Dodge Challenger #33352wordingwordingAS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front upper control arms; SPC-66045 spec part removed.
  • AS Front Brake Caliper Adapters for Dodge Challenger #33353otherotherAS Dodge Challenger 5.7L/6.1L/6.4L V8 now allows alternate front brake calipers with adaptor brackets for component compatibility.
  • T1 Why no Camaro? #34421cars addedaddedChevrolet Camaro GT4-R added to T1 GT4 Spec Line 4035, 315 tires, 3375 lbs minimum, ineligible for Runoffs.
  • T1 Request to Remove Expiration from T1 spec lines #1350 & #1370 #34470wordingwordingT1 Dodge Viper ACR / SRT RT-10 and ACR/ACR-X spec lines 1350 and 1370 remove 12/23 expiration dates.
  • T1 Remove #34475cars addedaddedT1 GT4 McLaren 570S, Mercedes AMG GT4, and Porsche 718 Cayman GT4 CS MR now eligible for Runoffs competition.
  • T1 Error in T1 GT4 numbering scheme- #34578wordingwordingT1 GT4 BMW M4 spec line number changed from 4050 to 4030.
  • T1 C5 Approved Aero That Was Mistakenly Deleted #34374aeroslower · aeroT1 Chevrolet Corvette C5 rear spoiler to 5 inches above bumper allowed, plus 50 lbs; carbon aero parts permitted with 50 lb decrease.
  • T4 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.
  • T4 rule book corrections #34437otheraddedT3 BMW 320i 14–15 gains aftermarket intercooler; T4 BMW 320i 14–15 loses it.
  • T4 Ride Height Correction for the T3 Solstice. #34615suspension & brakessuspension & brakesT3 and T2 Pontiac Solstice GXP 07-09 minimum ride height set to 3 inches.
  • T1 Viper Cleanup #34107inductionfaster · inductionT1 Dodge Viper ACR/ACR-X restrictor increases from 50mm to 60mm flat plate.
  • T1 Viper 8300 OEM FPR Size #34268engineunclearT1 Dodge Viper ACR/ACR-X Spec Line 1370 restrictor increases to 55mm; Spec Line 1390 decreases to 55mm flat plates.
  • T1 Ford Mustang S197 (05-14) Clarification #34450wordingwordingT1 Ford Mustang S197 (05-14) must use OEM 8.8 differential housing.
  • T1 Gen 5 Camaro Engine #33875cars addedaddedT1 Chevrolet Camaro Gen 5 LS7 gains two spec lines with 70mm and 53mm restrictors, both 3450 lbs minimum.
  • T1 Inquiry to letter #33682 #34071engineslower · engineT1 Chevrolet Camaro Gen 5, Corvette C5 and C6: resleeve restricted to stock parameters for engine repair or replacement, not LS3 bore/stroke.
  • T4 2002-2006 Mini Cooper S R53 Spec Line Request #34336weight -50 lbs
  • T1 Request to reinstate T1 S197 Mustang #34048cars addedaddedT1 Ford Mustang S197 (05-14) reinstated with 5.0L Voodoo engine, 3550 lbs minimum, 75mm restrictor.
  • T4 05-06 Mini Wheel Weight #34112weight
  • T4 06-09 VW Rabbit #34153induction
  • T4 96-01 Audi a4 2.8 Spring Rate #34217suspension & brakes
  • T1 T1 GT4 adjustments #33786weightunclearT1-GT4 minimum weights set: Aston Martin Vantage AMR 3575 lbs, Audi R8 3550, BMW M4 3500, Ford Mustang 3550, McLaren 570S 3450, Mercedes AMG 3450, Porsche 718 Cayman CS MR 3200, Porsche 718 RS 3450, Toyota Supra 3350.
  • T1 Touring 1 Tire Sizes #34191tyres & wheelsfaster · tyres & wheelsT1-GT4 McLaren 570S front tyre widens from 285 to 315; Mercedes AMG GT4 front tyre widens from 275 to 315.
  • T1 Clarification for Camaro Gen5 2010-2015 #33739engineslower · engineT1 Chevrolet Camaro Gen 5 LS3-6160 adds new Spec Line 1135 with 70mm flat plate restrictor, 3550 lbs minimum weight.
  • T4 Request to Classify 2004-2008 Acura TSX in T4 #33590cars added
  • T4 T4 Mustang Brakes/Swaybar #34036suspension & brakes
  • T1 Sequential Gearbox Limitations in T1 #33691engineadded · engineT1 aftermarket sequential gearbox cars must have 1:1 or greater top gear ratio, OEM location, max 10 inch bellhousing; non-sequential cars gain 100 lbs weight break.
  • T1 T1 GT4 adjustments #33786weightfaster · weightT1 GT4 all nine cars lose 125 lbs minimum weight with driver across the range.
  • T1 Sunset of pre 2023 Touring 1 Rules. #33916removedremovedT1 pre-2023 rules and spec lines removed entirely, effective 2023-03-01.
  • T4 BMW 320I intercooler #33762other
  • T1 Corrections to T1 Spec Lines #33678tyres & wheelstyres & wheelsGT4 McLaren 570S maximum tyre size set to 285 front, 315 rear.
  • T4 2019-2021 Mazda MX5 ND2 #32027cars added
  • T4 Mustang OEM Grill Request #33333aeroadded · aeroT2 and T3 Mustang 11-14 may remove upper grille fog lights, replace with mesh or screen.
  • T4 Mazda OEM LSD was letter 32655 typo #33666wording
  • SM BOP for NB1 and NB2 #32309weightslower · weightSM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore.
  • T1 GT4 section to Current T1 Rules. #33632cars addedaddedT1 adds eight GT4 cars: Aston Martin, Audi, BMW, Ford, McLaren, Mercedes, two Porsches, Toyota, minimum weights 3200–3575 lbs, restricted by SRO 2022 rules.
  • T4 Allowable Springs and Sway Bars for 06-11 Civic si Spec Line #33294suspension & brakes
  • T4 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.
  • T4 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.
  • T4 T4 mustang #32789weight -25 lbs
  • T4 Mazda OEM LSD was letter 32655 #32933weight -25 lbs
  • T4 Another 2022 BRZ/86 T3 request #32945weight +225 lbs
Virginia International Raceway Runoffs 20222022-09-241:54.890Andrew Aquilante · fastest of 10 · top 5 within 3.2s+0.119s (+0.10%)2:16.067Andrew Aquilante · fastest of 8 · top 5 within 15.9s+1.654s (+1.23%)157.5Mark Boden+1.3 mph (+0.8%)2:14.664Danny Steyn · fastest of 60 · top 5 within 0.2s+0.112s (+0.08%)2:19.107Travis Wiley · fastest of 58 · top 5 within 0.9s+2.648s (+1.94%)119.2Jonathan Neudorf-0.6 mph (-0.5%)+3.040squal +19.774s102.2%qual 117.2%2:02.162Kurt Rezzetano · fastest of 13 · top 5 within 2.3s-0.776s (-0.63%)2:04.578Gregory Eaton · fastest of 11 · top 5 within 2.9s+0.678s (+0.55%)150.9James Jost-3.0 mph (-2.0%)-11.489squal +7.272s91.6%qual 106.3%2:09.577John Heinricy · fastest of 18 · top 5 within 0.7s-1.680s (-1.28%)2:25.443John Heinricy · fastest of 18 · top 5 within 2.5s+14.484s (+11.06%)127.4Nick Leverone-1.5 mph (-1.2%)+9.376squal +14.687s106.9%qual 112.8%
50 rule changes (T1: 11, SM: 1, AS: 9, T4: 29)10 weight · 7 cars added · 6 suspension & brakes · 6 tyres & wheels · 5 engine · 1 aero · 1 induction · 1 removed · 7 wording · 6 other · AS adds Hoosier W2 wet tyre option alongside R7, R6, WET/H20. · AS Dodge Challenger 08-20 gains two transmission ratio options: 2.97–0.50 or 2.26–0.63. · T1 Camaro, CTS, Firebird, GTO minimum weight reduced to 3475 lbs from 3500 lbs. · AS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty. · T1-LP Ford Mustang FP350S restrictor increases from 70mm to 75mm. · Mercedes-Benz AMG GT4 (2017-2021) added to T1 with 3400 lb minimum weight, SRO Power Level 2 engine control. · T2-T4 Touring cars with alternative springs now permitted to use performance top hats with spherical bearings on shocks and struts. · SM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation. · T1 Dodge Viper ACR displacement rises to 8400 cc OEM, minimum weight drops to 3550 lbs. · T1 Limited T1 specification reference removed; all T1 cars now have unified allowances. · T1 Mazda RX-7 added: 2700 lbs minimum weight, 44mm restrictor, 13B rotary with single Garrett Turbo #3076. · T2-T4 touring cars model year 2018+ may use aftermarket ECU with 75 lb weight penalty via spec line adjustment. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO LS3 minimum weight reduced to 3475 lbs. · T1 Camaro, CTS, Firebird, GTO with 7011 max displacement loses 50 lbs, to 3500. · T1 brake rotors no longer limited to 33mm thickness maximum. · T2-T4 grill opening removal for cooling permitted without 16 square inch limit; mesh shape must match factory. · SMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000. · AS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line. · AS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes. · AS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180. · 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. · T1 Mazda MX-5 Miata MazdaSpeed minimum weight rises to 2550 lbs, restrictor grows to 42mm. · T1 Chevrolet Corvette Cadillac XLR classified as model year 2019 and earlier. · T4 adds 2014 VW Jetta 1.8T TSI to Spec Lines. · AS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms. · AS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.showhide
  • AS Request to add Hoosier W2 #33031tyres & wheelsadded · tyres & wheelsAS adds Hoosier W2 wet tyre option alongside R7, R6, WET/H20.
  • AS correction of Dodge Challenger specification line #33151cars addedaddedAS Dodge Challenger 08-20 gains two transmission ratio options: 2.97–0.50 or 2.26–0.63.
  • T1 Correct Camaro Spec Line From Letter #30791 response to 3475lbs #32824weight -25 lbsfaster · weightT1 Camaro, CTS, Firebird, GTO minimum weight reduced to 3475 lbs from 3500 lbs.
  • T4 04-09 Mazda3 Balance Shaft Delete Kit #32795other
  • AS Request CTS-V Spec Line Error Correction #30242weightfaster · weightAS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty.
  • T1 Fix FP350S limited prep and Shelby 350 full prep issues #31680enginefaster · engineT1-LP Ford Mustang FP350S restrictor increases from 70mm to 75mm.
  • T1 Request to Classify AMG GT4 #32610cars addedaddedMercedes-Benz AMG GT4 (2017-2021) added to T1 with 3400 lb minimum weight, SRO Power Level 2 engine control.
  • T4 Request Wider Wheels for Hyundai Tiburon #32536tyres & wheels
  • T4 Request to Add Spec Line for 2004-2009 Mazda3 i 2.0 #32395weight
  • T4 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.
  • SM Update GCR Section 9.1.7.3.A.1. #32217wordingwordingSM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation.
  • T1 Viper/Z06 Parity #31942engine -50 lbsfaster · engineT1 Dodge Viper ACR displacement rises to 8400 cc OEM, minimum weight drops to 3550 lbs.
  • T1 Discrepancy in T1 allowances #32293wordingwordingT1 Limited T1 specification reference removed; all T1 cars now have unified allowances.
  • T1 T1 RX7 classification #32352cars addedaddedT1 Mazda RX-7 added: 2700 lbs minimum weight, 44mm restrictor, 13B rotary with single Garrett Turbo #3076.
  • T4 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.
  • T4 Request JWT BSR Kit for 02-06 Nissan Sentra SE-R/Spec V #31685other
  • T4 Please Confirm Touring 4 (98-00) BMW 323 is E46 generation #31972other
  • T4 RX-8 Spring Part Numbers (E&O) #32151suspension & brakes
  • T4 04-09 Mazda3 Tire Limit Clarification #32249tyres & wheels
  • T4 Shock Part Number Errors & Omissions #32252suspension & brakes
  • T4 Update Solo Spec Coupe to latest '20 specs for Road Racing #32262other
  • T4 Request 2016 Mazda MX5 springs #32265suspension & brakes
  • T1 Weight reduction E&O #30791weight -25 lbsfaster · weightT1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO LS3 minimum weight reduced to 3475 lbs.
  • T1 Performance Adjustment Request for Camaro #31521weight -50 lbsfaster · weightT1 Camaro, CTS, Firebird, GTO with 7011 max displacement loses 50 lbs, to 3500.
  • T1 Remove 33m Brake rotor thickness rule #31954suspension & brakessuspension & brakesT1 brake rotors no longer limited to 33mm thickness maximum.
  • T4 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.
  • T4 BRZ vs BRZ TS #32022tyres & wheels
  • T4 MX-5 Durability Detailed #31102weight
  • T4 Request Allowances for 2005 - 2010 Mustang #31624wording
  • AS Proposed Revisions to SCCA GCR 2021 Appendix M, Part 3 #30295wordingwordingSMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000.
  • AS specification line consolidation and correction #31846cars addedremoved · cars addedAS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line.
  • AS correction of SMG specification line #31847wordingremovedAS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes.
  • AS Alternate cylinder heads for full prep engine builds - Evaluation #31851engineadded · engineAS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180.
  • T4 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.
  • T4 Please Adjust 98-00 BMW 323 Min Weight to Reflect Current Class #31595weight -200 lbs
  • T4 Consolidate 12-13 and 14-15 Honda Civic Si spec lines for T4 #31596removed
  • T4 Request to clarify radiator hoses #31682otheraddedT2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted.
  • T4 Clarify Permitted/Allowed #31743wordingwordingT2, T3, T4: clarified that 'permitted' or 'allowed' parts in spec lines are alternatives to category rule allowances, not replacements.
  • T4 Correct RSX wording #31746tyres & wheels
  • T4 Camaro #31751suspension & brakes
  • T1 Turbo Miata Help #31315weight +200 lbsslower · weightT1 Mazda MX-5 Miata MazdaSpeed minimum weight rises to 2550 lbs, restrictor grows to 42mm.
  • T1 Fix the T1 Corvette heading #31528cars addedaddedT1 Chevrolet Corvette Cadillac XLR classified as model year 2019 and earlier.
  • T4 Nissan Sentra SE-R Spec. V #30958cars added
  • T4 Mazda RX-8 Spec Line Suspension Parts #31113induction
  • T4 Diverter Valve Plunger Upgrade #31307engine
  • T4 Adjust Honda FWD in T4 to encourage more Drivetrain Diversity #31472tyres & wheels
  • T4 Touring 4 BOP adjustments for 2022 #31482weight -175 lbs
  • T4 Request to Classify 2014 VW Jetta 1.8t TSI #30436cars addedaddedT4 adds 2014 VW Jetta 1.8T TSI to Spec Lines.
  • AS Request for adjustable Front Upper Control Arms on 4th Gen F-Body #30457otheraddedAS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms.
  • AS Request Pontiac GTO tire size change #30881weightslower · weightAS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.
Indianapolis Motor Speedway Runoffs 20212021-09-251:42.292Andrew Aquilante · fastest of 22 · top 5 within 1.3s+0.499s (+0.49%)1:43.752Mark Boden · fastest of 22 · top 5 within 1.0s+0.881s (+0.86%)159.2Mark Boden1:57.695Brian Henderson · fastest of 90 · top 5 within 0.5s-0.611s (-0.52%)1:58.837Brian Henderson · fastest of 88 · top 5 within 0.3s-0.263s (-0.22%)119.8Kyle Greenhill+15.085squal +15.403s114.5%qual 115.1%1:50.427Drew Cattell · fastest of 31 · top 5 within 1.9s+5.207s (+4.95%)1:50.606Gregory Eaton · fastest of 28 · top 5 within 1.7s-0.901s (-0.81%)153.8James Jost+6.854squal +8.135s106.6%qual 108.0%1:54.397Stephen Blethen · fastest of 47 · top 5 within 0.9s-2.169s (-1.86%)1:55.929John Heinricy · fastest of 46 · top 5 within 1.0s-0.994s (-0.85%)127.3Alexander Schefer+12.177squal +12.105s111.7%qual 111.8%
53 rule changes (T1: 18, SM: 1, AS: 14, T4: 20)16 cars added · 12 weight · 6 engine · 3 induction · 3 tyres & wheels · 1 suspension & brakes · 9 wording · 3 other · T1 BMW E46, E36, Z3 minimum weight raised to 2700 lbs; 3.4L engine car to 2750 lbs. · T1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm. · T1 Corvette and Cadillac XLR: Casting #799 heads now permitted on LS6 engines, no other head modifications allowed. · AS Cadillac CTS-V 6.0L LS6 removes 295-tire 50 lb penalty. · AS consolidates seven SN95 Mustang '94-'04 spec lines into three unified lines by model year and engine. · AS Camaro/Firebird LT1 and LS1 transmission changed to TUET1 6362; Mustang GT 4.6L/5spd to TUKT16901, loses 300 lbs. · AS Camaro & Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted. · AS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants. · T1 Mustang GT5.0L 18+ Performance Pack, Bullet, Mach 1 allowed with 100 lb penalty; Shelby/GT350/GT500 restrictor opens 65 mm to 70 mm. · T1 Dodge Viper SRT-10 Incl. Coupe 08-10 restrictor increases from 45mm to 57mm. · T1 Corvette C7 Grand Sport now included; intake restrictor increases from 70 mm to 73 mm. · T1 Corvette Z06 06-13 now allows aluminum chassis replacement with equivalent OE steel chassis. · T3 Honda Civic Type-R 2020+ allowed brake rotor #45251-TGH-A01 with 25 lb penalty. · T1 Chevrolet Camaro with 6162 displacement minimum weight reduced to 3500 lbs. · T1-LP Chevrolet Corvette C5 Z06, C6 Grand Sport, and Z06 dry sump kit notes clarified to remove duplicates. · SM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture. · T2-T4 clutch discs and pressure plates must be at least 95% of factory OEM weight, bolted to unmodified stock flywheel. · AS Mustang 4.6L 5spd gains cold air intake freedom; 5.0L 6spd now requires 56mm flat plate restrictor. · AS CTS-V 5.7L LS6 and 6.0L LS2 may use Driveshaft Shop P/N GMCTSV2-C carbon fiber driveshaft. · AS Chevrolet Camaro SS V8 6.2L Restricted Prep model years extended from 10–13 to 10–15. · T1 LP aero adjustments: removed 50 lb weight allowance for stock OEM manifold/headers, reorganised aero and engine durability allowances into numbered list. · T1 Ford Mustang Challenge maximum displacement changes to 4600 cc for 3-valve engines, 5000 cc for others. · T1 BMW E46 allows carbon or fiberglass OEM-style dashboards with 25 pound weight penalty instead of requiring stock dash pad. · T1 Ford Mustang/Thunderbird specification removed Thunderbird model; now Shelby/Shelby GT350/GT500 only through 2018. · T1 Dodge Viper ACR 8400cc OEM added with 3600 lb minimum weight, 55mm flat-plate restrictor. · BMW M2CS Club Sport added to T1 Spec Lines classification. · Porsche 997.1 GT3 Cup (2006–2011) classified in T1 at 3600cc displacement, 3150 lbs minimum weight, no restrictor. · Toyota Supra 2020- added to T2 with 2998 cc engine, 3450 lbs minimum weight, 19×10 wheels, 295 tyres. · AS Ford Mustang GT 5.0L 15-17 Restricted added to Spec Line with 3600 lbs minimum weight, 55mm restrictor, 18×10 wheels, 295 tires. · AS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed. · AS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 and Challenger 08-20 specs removed. · AS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with weight minimums 3250–3500 and 3350–3600 lbs respectively. · T1 Limited Prep Chevrolet Corvette Z06 years extend to 2013, from 2012. · T2 BMW M2 CS Cup 2020+ classified at 2979 cc, 3625 lbs, 295 tires, 10.5×18 wheels, 380/390 mm brakes. · 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. · AS Dodge Challenger gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres; compression to 10.9:1 max. · AS Camaro & Firebird (93-02) and Ford Mustang Coupe GT (05-14) spec lines consolidated; Camaro/Firebird now allows both LT1 and LS1 engines; Mustang now allows both 4.6L 3-valve and 5.0L 4-valve engines with restrictor. · T1 Corvette C8 Z51 gets wider wheels and tyres, loses 100 lbs to 3550. · T3 Alfa Romeo 4C Launch Edition variant now allowed.showhide
  • T1 T1 E46 BOP E&O for Letter # 29970 #30934weight +100 lbsslower · weightT1 BMW E46, E36, Z3 minimum weight raised to 2700 lbs; 3.4L engine car to 2750 lbs.
  • T1 Request BoP for the Viper in 1 LP #29968enginefaster · engineT1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm.
  • T1 LS6 Alternative Head Question #30074cars addedaddedT1 Corvette and Cadillac XLR: Casting #799 heads now permitted on LS6 engines, no other head modifications allowed.
  • T4 Wrong Part Number on 320i Spec Line #30645wording
  • AS Request CTS-V Spec Line Error Correction #30242weightfaster · weightAS Cadillac CTS-V 6.0L LS6 removes 295-tire 50 lb penalty.
  • AS Request to consolidate SN95 Mustang '94-'04 Mustang spec lines #30428wordingwordingAS consolidates seven SN95 Mustang '94-'04 spec lines into three unified lines by model year and engine.
  • AS American Sedan Transmission Rule Change Request #30595enginefaster · engineAS Camaro/Firebird LT1 and LS1 transmission changed to TUET1 6362; Mustang GT 4.6L/5spd to TUKT16901, loses 300 lbs.
  • AS Correction to specifications inadvertently deleted #30691wordingwordingAS Camaro & Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted.
  • AS weight adjustments #30700weight +50 lbsslower · weightAS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants.
  • T1 T1-LP - Add Performance Pack, Bullet, Mach 1 to 18+ Mustang #29849enginefaster · engineT1 Mustang GT5.0L 18+ Performance Pack, Bullet, Mach 1 allowed with 100 lb penalty; Shelby/GT350/GT500 restrictor opens 65 mm to 70 mm.
  • T1 Request BoP for the Viper in 1 LP #29968enginefaster · engineT1 Dodge Viper SRT-10 Incl. Coupe 08-10 restrictor increases from 45mm to 57mm.
  • T1 Request to classify C7 and 13Viper in T1 LP #29969inductionfaster · inductionT1 Corvette C7 Grand Sport now included; intake restrictor increases from 70 mm to 73 mm.
  • T1 Request LP Z06 steel chassis #30589cars addedaddedT1 Corvette Z06 06-13 now allows aluminum chassis replacement with equivalent OE steel chassis.
  • T4 Civic Type R Brake Rotors #29817weightslower · weightT3 Honda Civic Type-R 2020+ allowed brake rotor #45251-TGH-A01 with 25 lb penalty.
  • T1 Request For Reduction in Weight/Penalties for Camaro #30443weightfaster · weightT1 Chevrolet Camaro with 6162 displacement minimum weight reduced to 3500 lbs.
  • T1 Fix dry sump Contradictions in T1-LP vs T2 #30596wordingwordingT1-LP Chevrolet Corvette C5 Z06, C6 Grand Sport, and Z06 dry sump kit notes clarified to remove duplicates.
  • T4 Mini Cooper Spec Line Anomalies #30478weight
  • T4 Request CAI Mustang in T4 #30562induction
  • SM Updates - Obsolete Parts & BOP Parts #30438wordingaddedSM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture.
  • T4 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.
  • AS AS Mustang LP 4.6 3V Classification Transmission Request #29886enginefaster · engineAS Mustang 4.6L 5spd gains cold air intake freedom; 5.0L 6spd now requires 56mm flat plate restrictor.
  • AS Request CF driveshaft on CTS-V for durability improvement #30117otheraddedAS CTS-V 5.7L LS6 and 6.0L LS2 may use Driveshaft Shop P/N GMCTSV2-C carbon fiber driveshaft.
  • AS Adjustment to model years of 5th generation RP Camaro #30348cars addedaddedAS Chevrolet Camaro SS V8 6.2L Restricted Prep model years extended from 10–13 to 10–15.
  • T1 T1 LP Aero adjustments #30196weightslower · weightT1 LP aero adjustments: removed 50 lb weight allowance for stock OEM manifold/headers, reorganised aero and engine durability allowances into numbered list.
  • T4 E & O T4 Mustang Wheels #30245tyres & wheels
  • T1 Request to Clarify Miller Mustang Classification #28728engineengineT1 Ford Mustang Challenge maximum displacement changes to 4600 cc for 3-valve engines, 5000 cc for others.
  • T1 BMW E46 Carbon Dash #29806weightslower · weightT1 BMW E46 allows carbon or fiberglass OEM-style dashboards with 25 pound weight penalty instead of requiring stock dash pad.
  • T1 Request to Update T1 Mustang Spec Line #30001cars addedremoved · cars addedT1 Ford Mustang/Thunderbird specification removed Thunderbird model; now Shelby/Shelby GT350/GT500 only through 2018.
  • T1 Dodge Viper 8400 OEM??? #30174cars addedaddedT1 Dodge Viper ACR 8400cc OEM added with 3600 lb minimum weight, 55mm flat-plate restrictor.
  • T1 Class BMW M2CS Club Sport #30195cars addedaddedBMW M2CS Club Sport added to T1 Spec Lines classification.
  • T1 997.1 GT3 Cup #30229cars addedaddedPorsche 997.1 GT3 Cup (2006–2011) classified in T1 at 3600cc displacement, 3150 lbs minimum weight, no restrictor.
  • T4 2021 Toyota Supra #29567cars addedaddedToyota Supra 2020- added to T2 with 2998 cc engine, 3450 lbs minimum weight, 19×10 wheels, 295 tyres.
  • T4 06-15 MX-5 Durability #29781other
  • T4 Request for Update to T4 Spec Line for Chevrolet Sonic (2011-) #29838induction
  • T4 NC MX-5 06-15 Part Number updates for 2021 #29921weight
  • T4 BMW Z4 2.5L (03-05) Spec Line #30037weight -50 lbs
  • T4 Sway Bars for T4 2016+ MX5 Mazda #30063suspension & brakes
  • T4 Change part numbers on BRZ, FRS lines in T4 #30104wording
  • T4 T4 Mustang Axle Ratio and Wheels #30149tyres & wheels
  • AS Request for 2015 -2017 Ford Mustang Spec Line #29514cars addedaddedAS Ford Mustang GT 5.0L 15-17 Restricted added to Spec Line with 3600 lbs minimum weight, 55mm restrictor, 18×10 wheels, 295 tires.
  • AS Request Trunk lid / Rear Hatch clarification #29591wordingwordingAS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed.
  • AS Common Weight for CTS-V Tire #29759weightfaster · weightAS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 and Challenger 08-20 specs removed.
  • AS Correction to specifications inadvertently deleted #30041cars addedaddedAS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with weight minimums 3250–3500 and 3350–3600 lbs respectively.
  • T1 Correct T1 Limited Prep Years #29708cars addedaddedT1 Limited Prep Chevrolet Corvette Z06 years extend to 2013, from 2012.
  • T4 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.
  • T4 Allow the SpecMX-5 Update Kit Into Touring 4 for the MX-5 #29681other
  • T4 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.
  • T4 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.
  • AS Request Additional Engine Options for Dodge Challenger Spec Line #29543cars addedaddedAS Dodge Challenger gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres; compression to 10.9:1 max.
  • AS Rule simplification spec line communization #29824cars addedcars addedAS Camaro & Firebird (93-02) and Ford Mustang Coupe GT (05-14) spec lines consolidated; Camaro/Firebird now allows both LT1 and LS1 engines; Mustang now allows both 4.6L 3-valve and 5.0L 4-valve engines with restrictor.
  • T1 Changes to Corvette C8 #29898weight -100 lbsfaster · weightT1 Corvette C8 Z51 gets wider wheels and tyres, loses 100 lbs to 3550.
  • T4 Alfa Romeo 4C Launch Edition #29531cars addedaddedT3 Alfa Romeo 4C Launch Edition variant now allowed.
  • T4 Post Runoffs Feedback for T4 #29752tyres & wheels -50 lbs
Road America Runoffs 20202020-10-022:17.646Andrew Aquilante · fastest of 15 · top 5 within 3.7s2:18.701Mark Boden · fastest of 14 · top 5 within 3.0s158.8James Candelaria2:42.209Kyle Greenhill · fastest of 77 · top 5 within 0.5s2:43.748Preston Pardus · fastest of 75 · top 5 within 1.0s121.3Kyle Greenhill+25.047squal +24.563s118.1%qual 117.8%2:27.045Gregory Eaton · fastest of 18 · top 5 within 0.6s2:27.668Gregory Eaton · fastest of 15 · top 5 within 1.5s149.2Gregory Eaton+8.967squal +9.399s106.5%qual 106.8%2:37.403John Heinricy · fastest of 20 · top 5 within 2.5s2:37.881Chi Ho · fastest of 19 · top 5 within 1.6s130.2Chi Ho+19.180squal +19.757s113.8%qual 114.4%
56 rule changes (T1: 13, SM: 2, AS: 16, T4: 25)13 cars added · 8 suspension & brakes · 6 weight · 5 engine · 4 aero · 2 tyres & wheels · 13 wording · 5 other · SM allows aftermarket radiators in original location with stock OEM cooling fan, and permits 1990-1997 cars to install upper radiator seal NA75-50-OK7A. · AS Dodge Challenger 5.7L V8 now requires iron block instead of aluminum, compression to 10.5:1 max, intake valve 12.7 mm, exhaust 12.3 mm, intake timing 188 degrees, exhaust timing 205 degrees. · AS Dodge Challenger 08-14 rear spoiler: 1GL20RXF replaced with 1GL20TZZAB; 82211606 still permitted. · SM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure. · T1 rear wing wording clarifies Gurney flap terminology in chord length and mounting height rules. · AS class pursuing specified list of eligible tires; list details unclear from text provided. · AS class tire eligibility list under development; no specifications changed yet. · AS Coyote Mustang restrictor plate under review for 2021; no change effective yet. · AS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration. · AS Ford Mustang Coupe GT 4.6L 3V Restricted Prep now permits Ford Performance camshaft kit P/N M-6550-3V. · 2010-2014 Camaro remains classified in AS; no specification changes. · AS class cylinder head supplier discontinuation; replacement option pending for 2021 season. · AS Mustang, Capri, Camaro, and Firebird maximum brake rotor diameter increased from 12.2 to 13.1 inches. · unclear · Request to add vehicle to T2, T3, T4 roster; refer to letter #27663 in June 2020 Fastrack for decision. · T1 and T2 Corvettes now allow coilover suspension with 800 lb max coil springs; T1 Z06 conversion no longer T1-only. · 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 Porsche 996 GT3 Cup eligible model years changed from 02-05 to 98-04. · T1 Chevrolet Corvette Cadillac XLR may install SCRSPLR-001 rear spoiler with OE bodywork. · T1 Camaro OEM 366mm rear rotor and caliper allowed without weight penalty. · T3 BMW Z3 M & Coupe 98-99 minimum weight reduced to 3150 lbs. · T1 Porsche 996 Spec Lines: 996 Cup Replica Rear deck lid now allowed. · T1 Acura NSX Turbo and Audi TTRS now require DOT tires per GCR section 9.3. · T1 BMW E46 and E36 models permitted with S54 engine; displacement corrected to 3250 cc from 3200 cc. · AS rear trailing arms may be replaced with tubular arms maintaining stock length and axle location purpose only. · AS Ford and GM full prep cars get increased weight reduction from 150 to 200 lbs. · 05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam permitted. · 10-15 Camaro Full Prep classified AS with 3400 lbs base weight, 3700 lbs over 313 CID, specific head castings and Edelbrock heads permitted. · T1 adds Subaru WRX, WRX STI 2005-2020: 2457 cc, 3000 lbs minimum, 46 mm restrictor, alternate turbo permitted. · T1-LP Ford Mustang FP350S restrictor enlarged to 70mm; GT and GT5.0L weights increased to 3500 lbs, Brembo BBK at no penalty, restrictors removed from notes. · Ford Mustang/Thunderbird 5000 Coyote OEM added to T1; 2015-17 at 3450 lbs, 2018+ at 3450 lbs with 65mm flat plate restrictor. · T1 BMW M3 E92 (08-13) carbon dash allowed with 25 lb penalty added. · T1 Corvette C5 Z06, C6 coupe and Grand Sport, C6 Z06 may convert leaf springs to coilover suspension. · Pontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18x9.5, Sky weight drops to 3200 lbs. · Mazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01. · 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. · 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.showhide
  • SM Radiator E&O Clarifications #29294wordingwordingSM allows aftermarket radiators in original location with stock OEM cooling fan, and permits 1990-1997 cars to install upper radiator seal NA75-50-OK7A.
  • AS Dodge Challenger AS Spec Line Clarification #28698engineslower · engineAS Dodge Challenger 5.7L V8 now requires iron block instead of aluminum, compression to 10.5:1 max, intake valve 12.7 mm, exhaust 12.3 mm, intake timing 188 degrees, exhaust timing 205 degrees.
  • AS Dodge Challenger AS Spec Line Clarification #2 #28699aeroaeroAS Dodge Challenger 08-14 rear spoiler: 1GL20RXF replaced with 1GL20TZZAB; 82211606 still permitted.
  • SM Modifications to prevent failures of Rear Brake Caliper Pin #28953suspension & brakessuspension & brakesSM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure.
  • T1 Touring Gurney flap wicker clarification #29013wordingwordingT1 rear wing wording clarifies Gurney flap terminology in chord length and mounting height rules.
  • T4 Scion FRS Solo Spec Coupe Gear Ratio #29021other
  • AS Support for R-Type Specification Tires #27450wordingunclearAS class pursuing specified list of eligible tires; list details unclear from text provided.
  • AS Spec Tire Request #27519wordingunclearAS class tire eligibility list under development; no specifications changed yet.
  • AS Restrictor Plate Change for RP 2011+ Mustang with Coyote Engine #27675wordingunclearAS Coyote Mustang restrictor plate under review for 2021; no change effective yet.
  • AS 2005-2009 Restricted Prep 4.6 3V #27908engineadded · engineAS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration.
  • AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909engineadded · engineAS Ford Mustang Coupe GT 4.6L 3V Restricted Prep now permits Ford Performance camshaft kit P/N M-6550-3V.
  • AS Request for Full Preparation Classification for 2010-2014 Camaro #28030wordingunclear2010-2014 Camaro remains classified in AS; no specification changes.
  • AS Cylinder Heads #28696wordingunclearAS class cylinder head supplier discontinuation; replacement option pending for 2021 season.
  • AS Request for Max Rotor Diameter Change #28748otherfasterAS Mustang, Capri, Camaro, and Firebird maximum brake rotor diameter increased from 12.2 to 13.1 inches.
  • AS Request increase rotor diameter #28797wordingunclearunclear
  • T4 T4 RX8 bodywork clarification #28941aero
  • T4 2006-2015 MX-5 Clarification #28942tyres & wheels
  • T4 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.
  • T1 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.
  • T4 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.
  • AS weight adjustments for 2020 season #28785weight -50 lbs
  • T1 Additional Clarification on 996 Cup in T1 From Letter #28040 #28060cars addedaddedT1 Porsche 996 GT3 Cup eligible model years changed from 02-05 to 98-04.
  • T1 Request SPEC Corvette Rear Spolier #28182aeroadded · aeroT1 Chevrolet Corvette Cadillac XLR may install SCRSPLR-001 rear spoiler with OE bodywork.
  • T1 T1 Rear Brake Rotor Size Exemption for Gen 5 Camaro #28402cars addedaddedT1 Camaro OEM 366mm rear rotor and caliper allowed without weight penalty.
  • T4 Request to change allowed header part # for T4 06-15 Miata #28223wording
  • T4 Z3M Roadster Weight #28437weightfaster · weightT3 BMW Z3 M & Coupe 98-99 minimum weight reduced to 3150 lbs.
  • T1 Request 996 GT3 Trunk for Wing Allowance. #28153aeroadded · aeroT1 Porsche 996 Spec Lines: 996 Cup Replica Rear deck lid now allowed.
  • T1 All Touring, Change DOT Tire Language 9.1.9.1, 9.3.45 #28452wordingwordingT1 Acura NSX Turbo and Audi TTRS now require DOT tires per GCR section 9.3.
  • T1 Request for E46 wagon with S54 engine in T1 #27427enginefaster · engineT1 BMW E46 and E36 models permitted with S54 engine; displacement corrected to 3250 cc from 3200 cc.
  • T4 Request for 12-13 and 14-15 Honda Civic Springs #27848suspension & brakes
  • T4 Request to Clarify T4 05-10 Mustang Spring Allowance #27899suspension & brakes
  • AS Rear Trailing Arms #28007suspension & brakesadded · suspension & brakesAS rear trailing arms may be replaced with tubular arms maintaining stock length and axle location purpose only.
  • AS Weight reduction for cars running iron heads #28010weightfaster · weightAS Ford and GM full prep cars get increased weight reduction from 150 to 200 lbs.
  • AS 05-10 Mustang with HR cam classification #28226cars addedadded05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam permitted.
  • AS 10-15 Camaro Full Prep classification #28227cars addedadded10-15 Camaro Full Prep classified AS with 3400 lbs base weight, 3700 lbs over 313 CID, specific head castings and Edelbrock heads permitted.
  • T1 Request to include Subaru WRX/STI 02-18 in T1 #24916cars addedaddedT1 adds Subaru WRX, WRX STI 2005-2020: 2457 cc, 3000 lbs minimum, 46 mm restrictor, alternate turbo permitted.
  • T1 Request Ford Mustang FP350S T1-LP weight and restrictor change #26662weight +100 lbsfaster · weightT1-LP Ford Mustang FP350S restrictor enlarged to 70mm; GT and GT5.0L weights increased to 3500 lbs, Brembo BBK at no penalty, restrictors removed from notes.
  • T1 Request to classify Ford Coyote 3rd Gen OEM #27145cars addedaddedFord Mustang/Thunderbird 5000 Coyote OEM added to T1; 2015-17 at 3450 lbs, 2018+ at 3450 lbs with 65mm flat plate restrictor.
  • T1 Request alternate dashboard #27276otheraddedT1 BMW M3 E92 (08-13) carbon dash allowed with 25 lb penalty added.
  • T1 Request for Allowance of Coil Springs on Limited Prep C6 Corvette #27713suspension & brakesadded · suspension & brakesT1 Corvette C5 Z06, C6 coupe and Grand Sport, C6 Z06 may convert leaf springs to coilover suspension.
  • T4 Request to Allow Brake Upgrade on T4 Mustang #27329suspension & brakes
  • T4 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.
  • T4 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.
  • T4 Request for 2014-2018 Mazda 3 GT Brakes #27659suspension & brakes
  • T4 Request to allow aftermarket OEM coolant expansion tank #27763engine
  • T4 Request to allow aftermarket OEM power steering reservoir #27764wording
  • T4 Request for Factory Installed Wings on Subaru BRZ #27831other
  • T4 Request for Replacement Clutches #27892other
  • T4 Request to Classify Chevy Sonic 1.4 In T4 #27906cars added
  • T4 Weight Change Request for 1999 Mazda Miata #28129weight -50 lbs
  • T4 Clarification of On-Board Fire System for T2 #27183wordingwordingT2 must have fire system installed; T3 and T4 may have one per GCR 9.3.
  • T4 Mustang Ecoboost and GT Transmission #27439cars addedaddedT3 Ford Mustang EcoBoost gains three transmission gear ratio options.
  • T4 BRZ/FRS/86 Tire Size in T4 #27660tyres & wheels
  • T4 NC MX5 2006-2015 Spec Adjustment Request #27739weight -75 lbs
  • T4 T4 RX8 Classification Error #27902cars addedaddedT3 and T4 Mazda RX-8 Base/R3 (04-12) reclassified to include Sport and GT variants.
  • T4 Request to add Toyota 86 GT to Spec Line #27910cars addedaddedToyota 86 GT variant (2017–) added to T3 and T4 spec lines.
Virginia International Raceway Runoffs 20192019-10-051:54.771Andrew Aquilante · fastest of 19 · top 5 within 3.1s2:14.413Andrew Aquilante · fastest of 15 · top 5 within 4.8s156.2Mark Boden2:14.552Todd Buras · fastest of 60 · top 5 within 0.2s2:16.459Elivan Goulart · fastest of 56 · top 5 within 0.4s119.8Jim Drago+2.046squal +19.781s101.5%qual 117.2%2:02.938Gregory Eaton · fastest of 17 · top 5 within 0.8s2:03.900James Jost · fastest of 16 · top 5 within 2.1s153.9James Jost-10.513squal +8.167s92.2%qual 107.1%2:11.257John Heinricy · fastest of 25 · top 5 within 0.2s2:10.959Nick Leverone · fastest of 25 · top 5 within 0.6s128.9Tommy Boileau-3.454squal +16.486s97.4%qual 114.4%
42 rule changes (T1: 19, SM: 4, AS: 4, T4: 15)11 cars added · 6 weight · 5 suspension & brakes · 2 engine · 2 induction · 1 aero · 13 wording · 2 other · AS Spec Mustang (SMG) added as Restricted Prep class. · T1-LP Chevrolet Camaro 1LE 2016+ minimum weight reduced to 3500 lbs, restrictor increased to 70mm. · T2, T3, T4 spare tire and cover removal wording clarified; removable covers now explicitly allowable to remove. · AS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects. · Ford Mustang Challenge added to T1 as E&O with 4600cc displacement, 3300 lbs minimum weight, no restrictor. · T1 Chevrolet Corvette Cadillac XLR model year range removed from specification. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird and GTO intake restrictor increases from 67 mm to 70 mm. · AS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450. · T2-T4 touring tires must be DOT certified with minimum U speed rating; TCS line size is maximum unless noted. · Ford Mustang with 3.5 EcoBoost engine added to T1: 3496 cc displacement, 3300 lb minimum weight, 31 mm restrictor. · T1 Corvette C5 body allowed C7 carbon aero parts, adds fifty pounds. · T1 Audi TTRS must conform to July 24th, 2015 revision 7 GTS rules, not December 14th, 2011 revision 3. · T1 minimum ride height set to 3.5 inches, measured at rocker panel without driver. · T1 Porsche 928 S4/GTS-R minimum weight drops from 3500 to 3200 lbs; 60mm flat plate restrictor removed. · Porsche 928 S4/928 GTS-R added to T1 at 5400cc, 3500 lbs minimum, 60mm restrictor. · SM fuel pump and filter now permitted as Mazda or OEM equivalent part. · T1-LP Ford Mustang GT 5.0L 2018- classified at 3400 lbs with 65mm restrictor, T2 and T3 Mustangs limited to 2015-2017. · 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. · T3 and T4 Mazda MX-5 Miata eligibility capped at 2016–2018 model years. · AS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes. · SM allows factory Mazda ECU and injector harnesses (P/N 0000-10-020E-99, 0000-10-080D-99) on 1999–2000 model year cars, unmodified. · SM electrical rules reorganized and clarified; alternator now externally regulated only by OEM ECU or master kill switch; harness repair by splicing permitted. · SM tire tread protrusion language removed from GCR 9.1.7.C.5. · T1-LP Mustang GT350(R) spec line replaced with complete dimensions, gearing, brakes, weight 3650 lbs curb, carbon wheels standard. · Ford Mustang FP350S (2017) classified in T1-LP with 3600 lbs minimum weight, 18×11 wheels, 315 tires, 6-speed gears. · T1 suspension rules clarified: spherical bearings, solid or spherical bushings, and alternate control arms now permitted. · T1 Porsche 996 and 996 GT3 Cup lose 150–200 lbs to 3000; 997 loses 50 lbs to 3100. · Porsche 997 T1 Maximum gains PDK transmission option; GT3 Cup engine remains not allowed. · T1 Acura NSX Turbo World Challenge weight rises to 3100 lbs, restrictor shrinks to 44mm. · T1–T4 spec car classifications clarified with permitted parts, rule conformance versions, and exclusions of other touring modifications. · 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. · 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
  • AS Request to add SMG to 9.1.6.B.1 AS Intent #27140cars addedaddedAS Spec Mustang (SMG) added as Restricted Prep class.
  • T1 T1 LP 2016 Camaro and Later #27198weight -100 lbsfaster · weightT1-LP Chevrolet Camaro 1LE 2016+ minimum weight reduced to 3500 lbs, restrictor increased to 70mm.
  • T4 Request spare tire/wheel clarification #27012wordingfasterT2, T3, T4 spare tire and cover removal wording clarified; removable covers now explicitly allowable to remove.
  • T4 Research E&O Mazda MX5 #27112weight
  • AS Request Ride Height Clarification #26598wordingwordingAS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects.
  • T1 Request to return Ford Mustang Challenge Car to T1 #26751cars addedaddedFord Mustang Challenge added to T1 as E&O with 4600cc displacement, 3300 lbs minimum weight, no restrictor.
  • T1 Correct years in T1 FP Corvette spec #27023wordingwordingT1 Chevrolet Corvette Cadillac XLR model year range removed from specification.
  • T1 Request BoP Baten - T1 Camaro - Follow up to Letter # 26145 #26900inductionfaster · inductionT1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird and GTO intake restrictor increases from 67 mm to 70 mm.
  • T4 MR2 Spyder Year Correction #26936wording
  • AS Request to Revert to 2017 Weights #25885weightfaster · weightAS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450.
  • T1 Clarify DOT tires touring #26556wordingwordingT2-T4 touring tires must be DOT certified with minimum U speed rating; TCS line size is maximum unless noted.
  • T4 Request to allow piggy back ECU on 2000 Mazda Protégé #26085engine
  • T4 Request helper spring as optional #26678suspension & brakes
  • T1 Request to Classify EcoBoost Mustang #25841cars addedaddedFord Mustang with 3.5 EcoBoost engine added to T1: 3496 cc displacement, 3300 lb minimum weight, 31 mm restrictor.
  • T1 Request Corvette aerodynamic aids #26265aeroslower · aeroT1 Corvette C5 body allowed C7 carbon aero parts, adds fifty pounds.
  • T1 Audi TTRS VTS Documentation Revision #26578wordingwordingT1 Audi TTRS must conform to July 24th, 2015 revision 7 GTS rules, not December 14th, 2011 revision 3.
  • T1 Request Ride Height Clarification #26599suspension & brakessuspension & brakesT1 minimum ride height set to 3.5 inches, measured at rocker panel without driver.
  • T1 Opposes Unfair weight and throttle restrictor #26719weight -300 lbsfaster · weightT1 Porsche 928 S4/GTS-R minimum weight drops from 3500 to 3200 lbs; 60mm flat plate restrictor removed.
  • T1 Request to classify the Porsche 928GTS/S4 in Touring 1 #26315cars addedaddedPorsche 928 S4/928 GTS-R added to T1 at 5400cc, 3500 lbs minimum, 60mm restrictor.
  • T4 Request to classify 2000 - 2001 BMW 323 #25096cars added
  • SM Request to allow aftermarket fuel filters. #26370otheraddedSM fuel pump and filter now permitted as Mazda or OEM equivalent part.
  • T1 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.
  • T4 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.
  • T4 Consider opening class rules to allow any thermostat #26187engineadded · engineT2, T3, T4 now allow any thermostat serving original equipment intent only.
  • T4 Cap 2016 Mazda Miata year at 2018 #26388cars addedremoved · cars addedT3 and T4 Mazda MX-5 Miata eligibility capped at 2016–2018 model years.
  • AS SMG Mustang eligibility in American sedan #26224cars addedaddedAS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes.
  • SM Request 99-00 replacement Wire harnesses #25602otheraddedSM allows factory Mazda ECU and injector harnesses (P/N 0000-10-020E-99, 0000-10-080D-99) on 1999–2000 model year cars, unmodified.
  • SM Organize and Clarify 9.1.7.C.1.o. #25913wordingwordingSM electrical rules reorganized and clarified; alternator now externally regulated only by OEM ECU or master kill switch; harness repair by splicing permitted.
  • SM Strike Tire Tread Language #26123wordingremovedSM tire tread protrusion language removed from GCR 9.1.7.C.5.
  • T4 2012-2015 Honda Civic Si Performance Request #26129suspension & brakes
  • T1 Class 2015+ Mustang GT350(R) #21466wordingwordingT1-LP Mustang GT350(R) spec line replaced with complete dimensions, gearing, brakes, weight 3650 lbs curb, carbon wheels standard.
  • T1 Request to Classify Ford FP350S in T1-LP #25341cars addedaddedFord Mustang FP350S (2017) classified in T1-LP with 3600 lbs minimum weight, 18×11 wheels, 315 tires, 6-speed gears.
  • T1 Amendment to Request #25555 #25556suspension & brakessuspension & brakesT1 suspension rules clarified: spherical bearings, solid or spherical bushings, and alternate control arms now permitted.
  • T1 Request to balance 996 v 997 T1 weight #25658weightfaster · weightT1 Porsche 996 and 996 GT3 Cup lose 150–200 lbs to 3000; 997 loses 50 lbs to 3100.
  • T1 Request to Add PDK Transmission to 997 Porsche Spec Line #25668cars addedaddedPorsche 997 T1 Maximum gains PDK transmission option; GT3 Cup engine remains not allowed.
  • T1 T1 World Challenge/Grand AM Spec Cars #25687weightslower · weightT1 Acura NSX Turbo World Challenge weight rises to 3100 lbs, restrictor shrinks to 44mm.
  • T1 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.
  • T4 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.
  • T4 Request for Adjustments to fiat 124 specline #25371induction
  • T4 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.
  • T4 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.
  • T4 Consider Solo SSC cross over classification into T4 #25802cars added
Sonoma Raceway Runoffs 20182018-10-101:39.970Kristofer Olson · fastest of 16 · top 5 within 3.8s1:41.125Kristofer Olson · fastest of 15 · top 5 within 3.0s108.6Brad McCall1:54.355Ken Sutherland · fastest of 48 · top 5 within 0.7s1:55.278Michael Carter · fastest of 48 · top 5 within 0.3s102.2Danny Steyn+14.153squal +14.385s114.0%qual 114.4%1:47.782Andrew McDermid · fastest of 12 · top 5 within 1.9s1:50.345John Heinricy · fastest of 10 · top 5 within 2.3s105.0Kevin Fandozzi+9.220squal +7.812s109.1%qual 107.8%1:52.339Gresham Wagner · fastest of 12 · top 5 within 1.1s1:54.030John Heinricy · fastest of 12 · top 5 within 0.2s106.0Ross Murray+12.905squal +12.369s112.8%qual 112.4%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:41.793Andrew Aquilante · fastest of 22 · top 5 within 2.9s1:42.871Andrew Aquilante · fastest of 21 · top 5 within 2.9s1:58.306Chris Haldeman · fastest of 86 · top 5 within 0.5s1:59.100Michael Gagliardo · fastest of 83 · top 5 within 0.6s+16.229squal +16.513s115.8%qual 116.2%1:45.220James Jost · fastest of 29 · top 5 within 6.7s1:51.507Bryan Long · fastest of 28 · top 5 within 0.9s+8.636squal +3.427s108.4%qual 103.4%1:56.566Oscar Jackson · fastest of 40 · top 5 within 0.6s1:56.923Oscar Jackson · fastest of 38 · top 5 within 1.1s+14.052squal +14.773s113.7%qual 114.5%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:28.656Ross Murray · fastest of 17 · top 5 within 1.4s1:29.309Ross Murray · fastest of 15 · top 5 within 1.1s1:40.514Justin Hille · fastest of 45 · top 5 within 0.3s1:40.764Michael Carter · fastest of 44 · top 5 within 0.3s+11.455squal +11.858s112.8%qual 113.4%1:30.651Tom Sloe · fastest of 22 · top 5 within 3.6s1:33.424Edward Hosni · fastest of 20 · top 5 within 1.0s+4.115squal +1.995s104.6%qual 102.3%1:38.813Jonathan Yanca · fastest of 34 · top 5 within 2.0s1:40.397Oscar Jackson · fastest of 32 · top 5 within 0.8s+11.088squal +10.157s112.4%qual 111.5%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-211:53.562Andrew Aquilante · fastest of 12 · top 5 within 2.5s1:55.494Andrew Aquilante · fastest of 12 · top 5 within 2.1s2:18.661Andrew Carbonell · fastest of 62 · top 5 within 0.6s2:24.067Todd Lamb · fastest of 59 · top 5 within 0.8s+28.573squal +25.099s124.7%qual 122.1%2:01.746Tom Sloe · fastest of 22 · top 5 within 2.6s2:02.922Andy McDermid · fastest of 19 · top 5 within 2.2s+7.428squal +8.184s106.4%qual 107.2%2:15.886Philip Royle · fastest of 22 · top 5 within 0.9s2:15.994Philip Royle · fastest of 20 · top 5 within 1.6s+20.500squal +22.324s117.7%qual 119.7%

By track

TrackEventsTypical % of T1BestLatest
Road America4100.0%3 of 4 with T1100.0%Runoffs 2020100.0%Runoffs 2025
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 T1'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.