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BoP Lab / Classes / P1

P1 vs SM vs FP vs P2 pace at every track

Lap times across years say as much about the weather as the class. % of P1 is each class's best lap as a share of P1'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 · what % is measured against
Tracks · untick to narrow

Closest to the field: P1 100.0% of P1 Gianpaolo Ciancimino, Daytona International Speedway Runoffs 2015 race · SM 121.9% of P1 Travis Wiley, Virginia International Raceway Runoffs 2022 race · FP 120.0% of P1 Kevin Ruck, Daytona International Speedway Runoffs 2015 qualifying · P2 101.1% of P1 Jeff Shafer, Indianapolis Motor Speedway Runoffs 2017 race

1:201:402:002:202:4036 rule changes between Runoffs 2018 and Runoffs 201936 ▾31 rule changes between Runoffs 2019 and Runoffs 202031 ▾41 rule changes between Runoffs 2020 and Runoffs 202141 ▾39 rule changes between Runoffs 2021 and Runoffs 202239 ▾22 rule changes between Runoffs 2022 and Runoffs 202322 ▾36 rule changes between Runoffs 2023 and Runoffs 202436 ▾22 rule changes between Runoffs 2024 and Runoffs 202522 ▾36 rule changes between Runoffs 2025 and Runoffs 202636 ▾P1 race best at Runoffs 2015: 1:49.792 (Gianpaolo Ciancimino)P1 race best at Runoffs 2016: 1:19.407 (Gianpaolo Ciancimino)P1 race best at Runoffs 2017: 1:31.499 (Jim Devenport)P1 race best at Runoffs 2018: 1:28.786 (Perry Richardson)P1 race best at Runoffs 2019: 1:43.498 (Todd Slusher)P1 race best at Runoffs 2020: 2:01.870 (James French)P1 race best at Runoffs 2021: 1:29.225 (Lee Alexander)P1 race best at Runoffs 2022: 1:54.095 (John Mcaleer)P1 race best at Runoffs 2023: 1:44.329 (Todd Vanacore)P1 race best at Runoffs 2024: 2:00.418 (Matt Romer)P1 qualifying best at Runoffs 2015: 1:49.219 (Jim Downing)P1 qualifying best at Runoffs 2016: 1:17.308 (James Devenport)P1 qualifying best at Runoffs 2017: 1:30.794 (Jim Devenport)P1 qualifying best at Runoffs 2018: 1:27.714 (Todd Slusher)P1 qualifying best at Runoffs 2019: 1:42.674 (Todd Slusher)P1 qualifying best at Runoffs 2020: 2:01.101 (James French)P1 qualifying best at Runoffs 2021: 1:29.011 (Lee Alexander)P1 qualifying best at Runoffs 2022: 1:41.601 (Todd Slusher)P1 qualifying best at Runoffs 2023: 1:42.602 (Todd Vanacore)P1 qualifying best at Runoffs 2024: 2:00.476 (Chip Romer)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)FP race best at Runoffs 2015: 2:12.419 (Kevin Ruck)FP race best at Runoffs 2016: 1:36.399 (John Walker)FP race best at Runoffs 2017: 1:53.007 (Eric Prill)FP race best at Runoffs 2018: 1:48.481 (Joe Huffaker)FP race best at Runoffs 2019: 2:08.076 (Eric Prill)FP race best at Runoffs 2020: 2:34.033 (Kevin Ruck)FP race best at Runoffs 2021: 1:59.933 (Cliff Ira)FP race best at Runoffs 2022: 2:17.641 (Mason Workman)FP race best at Runoffs 2023: 2:07.787 (Cliff Ira)FP race best at Runoffs 2024: 2:33.246 (Kevin Ruck)FP race best at Runoffs 2025: 2:34.271 (Chris Bovis)FP race best at Runoffs 2026: 2:33.240 (David Strittmatter)FP qualifying best at Runoffs 2015: 2:11.009 (Kevin Ruck)FP qualifying best at Runoffs 2016: 1:35.938 (John Walker)FP qualifying best at Runoffs 2017: 1:52.091 (Eric Prill)FP qualifying best at Runoffs 2018: 1:47.588 (Joe Huffaker)FP qualifying best at Runoffs 2019: 2:07.436 (Eric Prill)FP qualifying best at Runoffs 2020: 2:31.414 (Ethan Shippert)FP qualifying best at Runoffs 2021: 1:51.082 (Craig Chima)FP qualifying best at Runoffs 2022: 2:06.217 (Eric Prill)FP qualifying best at Runoffs 2023: 2:08.248 (Cliff Ira)FP qualifying best at Runoffs 2024: 2:32.327 (Cliff Ira)FP qualifying best at Runoffs 2025: 2:32.395 (David Strittmatter)FP qualifying best at Runoffs 2026: 2:33.275 (Stephen Simonds)P2 race best at Runoffs 2015: 1:52.355 (Jeff Shafer)P2 race best at Runoffs 2016: 1:20.904 (Jeff Shafer)P2 race best at Runoffs 2017: 1:32.481 (Jeff Shafer)P2 race best at Runoffs 2018: 1:32.071 (Chuck Bona)P2 race best at Runoffs 2019: 1:50.258 (Greg Gyann)P2 race best at Runoffs 2020: 2:09.793 (Robert Iversen)P2 race best at Runoffs 2021: 1:35.322 (Tim Day Jr)P2 race best at Runoffs 2022: 2:15.834 (Greg Gyann)P2 race best at Runoffs 2023: 1:48.829 (Lucian Pancea)P2 race best at Runoffs 2024: 2:08.322 (Bart Wolf)P2 race best at Runoffs 2026: 2:09.441 (Mike Reupert)P2 qualifying best at Runoffs 2015: 1:51.825 (Chris Farrell)P2 qualifying best at Runoffs 2016: 1:20.188 (Jeff Shafer)P2 qualifying best at Runoffs 2017: 1:31.826 (Jeff Shafer)P2 qualifying best at Runoffs 2018: 1:28.784 (Tim Day Jr)P2 qualifying best at Runoffs 2019: 1:49.111 (Robert Iversen)P2 qualifying best at Runoffs 2020: 2:08.514 (Robert Iversen)P2 qualifying best at Runoffs 2021: 1:33.235 (Tim Day Jr)P2 qualifying best at Runoffs 2022: 1:47.566 (Tim Day Jr)P2 qualifying best at Runoffs 2023: 1:48.590 (Greg Gyann)P2 qualifying best at Runoffs 2024: 2:07.405 (Bart Wolf)P2 qualifying best at Runoffs 2026: 2:10.606 (Greg Gyann)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
P1SMFPP2solid race · dashed qualifying · slower is lower
100%110%120%130%36 rule changes between Runoffs 2018 and Runoffs 201936 ▾31 rule changes between Runoffs 2019 and Runoffs 202031 ▾41 rule changes between Runoffs 2020 and Runoffs 202141 ▾39 rule changes between Runoffs 2021 and Runoffs 202239 ▾22 rule changes between Runoffs 2022 and Runoffs 202322 ▾36 rule changes between Runoffs 2023 and Runoffs 202436 ▾22 rule changes between Runoffs 2024 and Runoffs 202522 ▾36 rule changes between Runoffs 2025 and Runoffs 202636 ▾P1 race best at Runoffs 2015: 100.0% of P1's (Gianpaolo Ciancimino)P1 race best at Runoffs 2016: 100.0% of P1's (Gianpaolo Ciancimino)P1 race best at Runoffs 2017: 100.0% of P1's (Jim Devenport)P1 race best at Runoffs 2018: 100.0% of P1's (Perry Richardson)P1 race best at Runoffs 2019: 100.0% of P1's (Todd Slusher)P1 race best at Runoffs 2020: 100.0% of P1's (James French)P1 race best at Runoffs 2021: 100.0% of P1's (Lee Alexander)P1 race best at Runoffs 2022: 100.0% of P1's (John Mcaleer)P1 race best at Runoffs 2023: 100.0% of P1's (Todd Vanacore)P1 race best at Runoffs 2024: 100.0% of P1's (Matt Romer)P1 qualifying best at Runoffs 2015: 100.0% of P1's (Jim Downing)P1 qualifying best at Runoffs 2016: 100.0% of P1's (James Devenport)P1 qualifying best at Runoffs 2017: 100.0% of P1's (Jim Devenport)P1 qualifying best at Runoffs 2018: 100.0% of P1's (Todd Slusher)P1 qualifying best at Runoffs 2019: 100.0% of P1's (Todd Slusher)P1 qualifying best at Runoffs 2020: 100.0% of P1's (James French)P1 qualifying best at Runoffs 2021: 100.0% of P1's (Lee Alexander)P1 qualifying best at Runoffs 2022: 100.0% of P1's (Todd Slusher)P1 qualifying best at Runoffs 2023: 100.0% of P1's (Todd Vanacore)P1 qualifying best at Runoffs 2024: 100.0% of P1's (Chip Romer)SM race best at Runoffs 2015: 131.2% of P1's (Todd Lamb)SM race best at Runoffs 2016: 126.9% of P1's (Michael Carter)SM race best at Runoffs 2017: 130.2% of P1's (Michael Gagliardo)SM race best at Runoffs 2018: 129.8% of P1's (Michael Carter)SM race best at Runoffs 2019: 131.8% of P1's (Elivan Goulart)SM race best at Runoffs 2020: 134.4% of P1's (Preston Pardus)SM race best at Runoffs 2021: 133.2% of P1's (Brian Henderson)SM race best at Runoffs 2022: 121.9% of P1's (Travis Wiley)SM race best at Runoffs 2023: 130.6% of P1's (Julian DaCosta)SM race best at Runoffs 2024: 134.1% of P1's (Brett Kowalski)SM qualifying best at Runoffs 2015: 127.0% of P1's (Andrew Carbonell)SM qualifying best at Runoffs 2016: 130.0% of P1's (Justin Hille)SM qualifying best at Runoffs 2017: 130.3% of P1's (Chris Haldeman)SM qualifying best at Runoffs 2018: 130.4% of P1's (Ken Sutherland)SM qualifying best at Runoffs 2019: 131.0% of P1's (Todd Buras)SM qualifying best at Runoffs 2020: 133.9% of P1's (Kyle Greenhill)SM qualifying best at Runoffs 2021: 132.2% of P1's (Brian Henderson)SM qualifying best at Runoffs 2022: 132.5% of P1's (Danny Steyn)SM qualifying best at Runoffs 2023: 131.6% of P1's (Danny Steyn)SM qualifying best at Runoffs 2024: 133.7% of P1's (Ethan Goulart)FP race best at Runoffs 2015: 120.6% of P1's (Kevin Ruck)FP race best at Runoffs 2016: 121.4% of P1's (John Walker)FP race best at Runoffs 2017: 123.5% of P1's (Eric Prill)FP race best at Runoffs 2018: 122.2% of P1's (Joe Huffaker)FP race best at Runoffs 2019: 123.7% of P1's (Eric Prill)FP race best at Runoffs 2020: 126.4% of P1's (Kevin Ruck)FP race best at Runoffs 2021: 134.4% of P1's (Cliff Ira)FP race best at Runoffs 2022: 120.6% of P1's (Mason Workman)FP race best at Runoffs 2023: 122.5% of P1's (Cliff Ira)FP race best at Runoffs 2024: 127.3% of P1's (Kevin Ruck)FP qualifying best at Runoffs 2015: 120.0% of P1's (Kevin Ruck)FP qualifying best at Runoffs 2016: 124.1% of P1's (John Walker)FP qualifying best at Runoffs 2017: 123.5% of P1's (Eric Prill)FP qualifying best at Runoffs 2018: 122.7% of P1's (Joe Huffaker)FP qualifying best at Runoffs 2019: 124.1% of P1's (Eric Prill)FP qualifying best at Runoffs 2020: 125.0% of P1's (Ethan Shippert)FP qualifying best at Runoffs 2021: 124.8% of P1's (Craig Chima)FP qualifying best at Runoffs 2022: 124.2% of P1's (Eric Prill)FP qualifying best at Runoffs 2023: 125.0% of P1's (Cliff Ira)FP qualifying best at Runoffs 2024: 126.4% of P1's (Cliff Ira)P2 race best at Runoffs 2015: 102.3% of P1's (Jeff Shafer)P2 race best at Runoffs 2016: 101.9% of P1's (Jeff Shafer)P2 race best at Runoffs 2017: 101.1% of P1's (Jeff Shafer)P2 race best at Runoffs 2018: 103.7% of P1's (Chuck Bona)P2 race best at Runoffs 2019: 106.5% of P1's (Greg Gyann)P2 race best at Runoffs 2020: 106.5% of P1's (Robert Iversen)P2 race best at Runoffs 2021: 106.8% of P1's (Tim Day Jr)P2 race best at Runoffs 2022: 119.1% of P1's (Greg Gyann)P2 race best at Runoffs 2023: 104.3% of P1's (Lucian Pancea)P2 race best at Runoffs 2024: 106.6% of P1's (Bart Wolf)P2 qualifying best at Runoffs 2015: 102.4% of P1's (Chris Farrell)P2 qualifying best at Runoffs 2016: 103.7% of P1's (Jeff Shafer)P2 qualifying best at Runoffs 2017: 101.1% of P1's (Jeff Shafer)P2 qualifying best at Runoffs 2018: 101.2% of P1's (Tim Day Jr)P2 qualifying best at Runoffs 2019: 106.3% of P1's (Robert Iversen)P2 qualifying best at Runoffs 2020: 106.1% of P1's (Robert Iversen)P2 qualifying best at Runoffs 2021: 104.7% of P1's (Tim Day Jr)P2 qualifying best at Runoffs 2022: 105.9% of P1's (Tim Day Jr)P2 qualifying best at Runoffs 2023: 105.8% of P1's (Greg Gyann)P2 qualifying best at Runoffs 2024: 105.8% of P1's (Bart Wolf)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
P1SMFPP2solid race · dashed qualifying · each class's best lap as a share of P1's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
EventP1SMFPP2
Qual best Race best Trap Qual best Race best Trap vs P1 % of P1 Qual best Race best Trap vs P1 % of P1 Qual best Race best Trap vs P1 % of P1 
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%)2:33.275Stephen Simonds · fastest of 26 · top 5 within 1.0s+0.880s (+0.58%)2:33.240David Strittmatter · fastest of 25 · top 5 within 1.7s-1.031s (-0.67%)132.4David Strittmatter±0.0 mph (±0.0%)2:10.606Greg Gyann · fastest of 11 · top 5 within 5.3s+3.201s (+2.51%)2:09.441Mike Reupert · fastest of 11 · top 5 within 4.2s+1.119s (+0.87%)155.0Matt Strand+2.4 mph (+1.6%)
36 rule changes (SM: 2, FP: 34)7 weight · 6 cars added · 5 induction · 4 engine · 1 aero · 9 wording · 4 other · HP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1. · 1996-2000 Honda Civic CX/DX/LX with D16Y7 engine newly classified in HP. · HP 1275 Midget/Sprite alternate intake manifold from MG-B now permitted; balance tube shortening and flange modification allowed. · HP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs. · SM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. · EP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm. · FP Volkswagen Jetta 82-84 carburation option 2 comma removed; all five models' carb specs clarified or confirmed. · FP Spec Line Volkswagen Rabbit and Scirocco 1789cc base weight corrected to 1803 lbs. · EP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm. · BMW E21 320i/is (80–83) newly classified in HP Spec Lines effective 2026-05-01. · HP BMW 318is 84-85 displacement corrected to 1767 cc, 89.0 x 71.0 mm bore and stroke. · SM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. · FP Fiat X-1/9 1300 and 1500 intake and exhaust valve sizes corrected to 36.3/(1.43) and 31.2-33.3/(1.23-1.31). · FP Fiat X-1/9 & Bertone dual carburetors choke size increases from 28mm to 30mm on intake runner manifold. · FP adds Toyota 5E 1497cc DOHC engine, 1900 lbs, 23mm restrictor, SIR fuel induction. · FP class adds Toyota 4E DOHC 1331 cc engine, 1900 lbs minimum weight, unrestricted fuel induction. · FP Fiat X1/9 fuel injection carburetors simplified to one 36 or 40 DCNF option; exhaust valve enlarged to 33.0/1.30. · EP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted. · EP BMW Z3 2.5L and other models get smaller restrictors, 50mm to 55mm, and Z3 2.5L weight rises 50 to 78 lbs. · FP Lancia Scorpion minimum weight cut to 1950 lbs from 2030 lbs. · FP VW Rabbit Convertible no longer required to remove factory roll bar. · FP Acura Integra and Honda Civic models gain 50–79 lbs minimum weight; Mazda Miata and Mercury Capri compression ratio to 11.0:1 and valve lift to .425". · FP Honda D15, D16, B16A, B18 engines gain 105–120 lbs minimum weight across seven configurations. · EP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **. · EP Mazda MX-5 1.8L 90-97 minimum weight reduced to 2125 lbs. · HP Spec Lines Austin-Healey Sprite/Midget 1098cc minimum weight drops to 1550 lbs. · HP Volvo 142 P-1800 engine gains compression ratio limit 12.0:1 and valve lift limit .425 inch. · HP Mini DOHC 1.6 valve lift limit drops to .390" from .450". · FP Scirocco 83–88 classified Prep Level 1: 1733–1803 lbs, 1715–1780 cc, iron block, aluminium head, carburetted or fuel injected. · FP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion. · EP, FP, HP: rear drum-to-disc brake conversion clarified; rotors solid, diameter limited to largest front rotor permitted. · EP Ford Mustang 94-98 fuel injected throttle body inside diameter set to 60. · FP Volkswagen Scirocco: remove two weight tiers at 1733 and 1803 lbs, two engine options, and 13-inch wheel option; allow 15-inch wheels. · HP Plymouth Arrow gains 4 or 5 speed transmission option specification. · Appendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'. · EP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock.showhide
  • FP Mini Cooper Compression Ratio #40517enginefasterengineHP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1.
  • FP 1996-2000 Honda Civic (CX, DX, VP, LX) with Engine Code D16Y7 #40322cars addedadded1996-2000 Honda Civic CX/DX/LX with D16Y7 engine newly classified in HP.
  • FP 1275 Midget/Sprit Alternate intake manifold E/O #40370inductionaddedinductionHP 1275 Midget/Sprite alternate intake manifold from MG-B now permitted; balance tube shortening and flange modification allowed.
  • FP HP Honda Civic (92-95) #40464weight -70 lbsfasterweightHP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs.
  • SM Rear Toe Link #40271wordingwordingSM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361.
  • FP Miata track width - errors and omissions #39976aerofasteraeroEP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm.
  • FP GCR Spec Line Correction #39977wordingwordingFP Volkswagen Jetta 82-84 carburation option 2 comma removed; all five models' carb specs clarified or confirmed.
  • FP CGR Spec Line Weight Correction #39978wordingwordingFP Spec Line Volkswagen Rabbit and Scirocco 1789cc base weight corrected to 1803 lbs.
  • FP Triumph GT6 Spec Change. #40098inductionfasterinductionEP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm.
  • FP Request to Classify BMW E21 320i #40110cars addedaddedBMW E21 320i/is (80–83) newly classified in HP Spec Lines effective 2026-05-01.
  • FP BMW 318is 84-85 engine displacement correction #40116wordingwordingHP BMW 318is 84-85 displacement corrected to 1767 cc, 89.0 x 71.0 mm bore and stroke.
  • 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.
  • FP Correct Valve Sizes on FP Fiat x19 1300 and 1500 #39850otherotherFP Fiat X-1/9 1300 and 1500 intake and exhaust valve sizes corrected to 36.3/(1.43) and 31.2-33.3/(1.23-1.31).
  • FP Dual Carburetor Adjustments #39851inductionfasterinductionFP Fiat X-1/9 & Bertone dual carburetors choke size increases from 28mm to 30mm on intake runner manifold.
  • FP Request Toyota 5E Series Engines #38208otheraddedFP adds Toyota 5E 1497cc DOHC engine, 1900 lbs, 23mm restrictor, SIR fuel induction.
  • FP Request for Toyota 4E Series Engines #38209cars addedaddedFP class adds Toyota 4E DOHC 1331 cc engine, 1900 lbs minimum weight, unrestricted fuel induction.
  • FP Dual Carbs for the Fiat X1/9 #39593enginefasterengineFP Fiat X1/9 fuel injection carburetors simplified to one 36 or 40 DCNF option; exhaust valve enlarged to 33.0/1.30.
  • FP TR2 Notes E&O #39180wordingwordingEP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted.
  • FP Balance of Power #39187induction +50 lbsslowerinductionEP BMW Z3 2.5L and other models get smaller restrictors, 50mm to 55mm, and Z3 2.5L weight rises 50 to 78 lbs.
  • FP Competition Adjustment Request #39259weight -80 lbsfasterweightFP Lancia Scorpion minimum weight cut to 1950 lbs from 2030 lbs.
  • FP Factory Roll Bar Removal on VW Convertible #39268wordingwordingFP VW Rabbit Convertible no longer required to remove factory roll bar.
  • FP FP Parity Request #39325weight +50 lbsslowerweightFP Acura Integra and Honda Civic models gain 50–79 lbs minimum weight; Mazda Miata and Mercury Capri compression ratio to 11.0:1 and valve lift to .425".
  • FP Adjust former-GTL Honda's with B/D-Series Engines #39374weightslowerweightFP Honda D15, D16, B16A, B18 engines gain 105–120 lbs minimum weight across seven configurations.
  • FP Please Lower Weight of 280Z #38871weight -160 lbsfasterweightEP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **.
  • FP Miata Weight Adjustment Follow Up #38949weight -25 lbsfasterweightEP Mazda MX-5 1.8L 90-97 minimum weight reduced to 2125 lbs.
  • FP Weight Break for 1098 Midget / Sprite #38970weight -80 lbsfasterweightHP Spec Lines Austin-Healey Sprite/Midget 1098cc minimum weight drops to 1550 lbs.
  • FP HP Volvo 142 spec omission #38994engineslowerengineHP Volvo 142 P-1800 engine gains compression ratio limit 12.0:1 and valve lift limit .425 inch.
  • FP HP Mini DOHC 1.6 #38996engineslowerengineHP Mini DOHC 1.6 valve lift limit drops to .390" from .450".
  • FP 83-88 FP Scirocco Spec Line Creation #38997cars addedaddedFP Scirocco 83–88 classified Prep Level 1: 1733–1803 lbs, 1715–1780 cc, iron block, aluminium head, carburetted or fuel injected.
  • FP Add to Rabbit description #39019wordingwordingFP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion.
  • FP Clean-up 9.1.5.E.7e #39025otherotherEP, FP, HP: rear drum-to-disc brake conversion clarified; rotors solid, diameter limited to largest front rotor permitted.
  • FP Add TB size to Ford Mustang (94-98) Spec Line #39130inductionaddedinductionEP Ford Mustang 94-98 fuel injected throttle body inside diameter set to 60.
  • FP Correct Existing VW Scirocco Spec Line #39140cars addedremovedcars addedFP Volkswagen Scirocco: remove two weight tiers at 1733 and 1803 lbs, two engine options, and 13-inch wheel option; allow 15-inch wheels.
  • FP HP Plymouth Arrow spec omission #38995cars addedaddedHP Plymouth Arrow gains 4 or 5 speed transmission option specification.
  • FP Add Wheel Diameter to Appendix G #39008wordingwordingAppendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'.
  • FP Add TB ID tolerance to general Prod rules #39009wordingaddedEP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock.
Road America Runoffs 20252025-09-292:43.111Bobby 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%)2:32.395David Strittmatter · fastest of 20 · top 5 within 2.9s+0.068s (+0.04%)2:34.271Chris Bovis · fastest of 19 · top 5 within 1.8s+1.025s (+0.67%)132.4David Strittmatter-1.1 mph (-0.8%)
22 rule changes (SM: 4, FP: 17, P2: 1)7 weight · 5 induction · 3 cars added · 1 engine · 5 wording · 1 other · EP BMW Z4 03-05 gains 52mm flat plate intake restrictor. · EP Fiat 124 Spider Competition 1600 and 2000 minimum weight drops 50 lbs to 2000; carburetors now allow 36mm chokes instead of 34mm. · HP Fiat X-1/9 and Bertone 1500 minimum weights reduced to 1740 lbs, 1784 lbs, 1827 lbs; 1300 models to 1600, 1640, 1680 lbs; additional 1300 and 1500 specs to 2010, 1900 lbs. · 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. · 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. · Chevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs. · HP Ford Festiva 88-93 minimum weight lowered to 1600 lbs, competition weight to 1640, prepared weight to 1680; compression ratio raised to 11.0:1. · EP BMW Z3 2.5L, Z3 2.8L, 328i E36/E46, 325i E36/E46 intake restrictors reduced 4mm each, to 52–58mm. · FP Acura Integra and Honda Civic models restricted from 55mm to 51mm intake; Del Sol VTEC weight raised to 2290, 2347, 2405 lbs. · EP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36. · EP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450. · EP Mazda MX-5 Miata 99-05 minimum weight reduced to 2100 lbs, 2153 lbs with power, 2205 lbs modified. · FP Volkswagen Jetta Mark IV 4dr FWD added to GTL-FP Cars classification with 98.2 in wheelbase. · FP adds optional induction chokes as alternative to SIR, same size as listed restrictor. · EP BMW models now require flat plate intake restrictors: Z3 2.5L 52mm, Z3 2.8L 55mm, 328i E36 58mm, 328i/ci E46 58mm, 325i E46 56mm, 325i E36 56mm, 325is M-Technic 56mm. · EP BMW 325i/is E30 84-91 weight reduced to 2150 lbs base, 2204 lbs with turbo, 2258 lbs supercharged. · FP Sprite and Midget 1275cc and 1500cc bore, stroke, displacement, and valve specifications corrected to factory dimensions. · F Production now permits GT-Lite cars meeting Appendix N specs to compete, governed by Appendix N not PCS 9.1.5. · P2 2000 cc Pinto engine car minimum weight set to 1335 lbs. · 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. · HP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1.showhide
  • FP BMW Z4 update #38490inductionslowerinductionEP BMW Z4 03-05 gains 52mm flat plate intake restrictor.
  • FP EP Fiat 124 Spider Competition Adjustment Request #38498weight -50 lbsfasterweightEP Fiat 124 Spider Competition 1600 and 2000 minimum weight drops 50 lbs to 2000; carburetors now allow 36mm chokes instead of 34mm.
  • FP Base Weight Adjustment for H-Production X1/9 Spec Lines #38255weight -50 lbsfasterweightHP Fiat X-1/9 and Bertone 1500 minimum weights reduced to 1740 lbs, 1784 lbs, 1827 lbs; 1300 models to 1600, 1640, 1680 lbs; additional 1300 and 1500 specs to 2010, 1900 lbs.
  • 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.
  • 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.
  • FP Request for Classification of Chevrolet Spark #37755cars addedaddedChevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs.
  • FP Request to Lower Ford Festiva Minimum Weight to 1600 LBS #37939weight -100 lbsfasterweightHP Ford Festiva 88-93 minimum weight lowered to 1600 lbs, competition weight to 1640, prepared weight to 1680; compression ratio raised to 11.0:1.
  • FP Request Competition Adjustment to BMW Z3 2.5L #37120inductionslowerinductionEP BMW Z3 2.5L, Z3 2.8L, 328i E36/E46, 325i E36/E46 intake restrictors reduced 4mm each, to 52–58mm.
  • FP FP Class Adjustments #37458inductionslowerinductionFP Acura Integra and Honda Civic models restricted from 55mm to 51mm intake; Del Sol VTEC weight raised to 2290, 2347, 2405 lbs.
  • FP Interpretation of Production Rules on Mirrors #37235wordingaddedEP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36.
  • FP Weight Reduction for Honda S2000 #37466weightfasterweightEP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450.
  • FP Mazda 1999 Miata 1.8L #37488weight -50 lbsfasterweightEP Mazda MX-5 Miata 99-05 minimum weight reduced to 2100 lbs, 2153 lbs with power, 2205 lbs modified.
  • FP Errors & Omissions #37648cars addedaddedFP Volkswagen Jetta Mark IV 4dr FWD added to GTL-FP Cars classification with 98.2 in wheelbase.
  • FP GTL/FP consolidation 2025 Rules #37659inductionaddedinductionFP adds optional induction chokes as alternative to SIR, same size as listed restrictor.
  • FP Effective date for Jan 2025 GCR updates #37654inductionslowerinductionEP BMW models now require flat plate intake restrictors: Z3 2.5L 52mm, Z3 2.8L 55mm, 328i E36 58mm, 328i/ci E46 58mm, 325i E46 56mm, 325i E36 56mm, 325is M-Technic 56mm.
  • FP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line #37119weight -50 lbsfasterweightEP BMW 325i/is E30 84-91 weight reduced to 2150 lbs base, 2204 lbs with turbo, 2258 lbs supercharged.
  • FP Fix Error in Spridget Spec Line #37437wordingwordingFP Sprite and Midget 1275cc and 1500cc bore, stroke, displacement, and valve specifications corrected to factory dimensions.
  • FP Create ruleset that allows GTL cars to run in FP #37485cars addedaddedF Production now permits GT-Lite cars meeting Appendix N specs to compete, governed by Appendix N not PCS 9.1.5.
  • P2 2000 cc Pinto Engine Car Weight #37187weightslowerweightP2 2000 cc Pinto engine car minimum weight set to 1335 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.
  • FP 1275 HP Spridget Level 2 Only #36518enginefasterengineHP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1.
Road America Runoffs 20242024-10-012:00.476Chip Romer · fastest of 12 · top 5 within 1.5s-0.625s (-0.52%)2:00.418Matt Romer · fastest of 9 · top 5 within 2.1s-1.452s (-1.19%)168.3Jason Miller+8.7 mph (+5.4%)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%)+41.068squal +40.630s134.1%qual 133.7%2:32.327Cliff Ira · fastest of 26 · top 5 within 2.1s+0.913s (+0.60%)2:33.246Kevin Ruck · fastest of 24 · top 5 within 1.4s-0.787s (-0.51%)133.5David Strittmatter+0.3 mph (+0.2%)+32.828squal +31.851s127.3%qual 126.4%2:07.405Bart Wolf · fastest of 14 · top 5 within 3.0s-1.109s (-0.86%)2:08.322Bart Wolf · fastest of 13 · top 5 within 0.6s-1.471s (-1.13%)152.5Lucian Pancea-0.6 mph (-0.4%)+7.904squal +6.929s106.6%qual 105.8%
36 rule changes (P1: 6, SM: 4, FP: 21, P2: 5)11 weight · 4 cars added · 3 engine · 2 induction · 1 removed · 14 wording · 1 other · FP Honda CRX/CRX Si 84-87 block material changes from iron to aluminium. · 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. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.). · Nissan 300ZX 84–89 added to EP, 2550–2678 lbs, 2960 cc SOHC, fuel injection, 12.0:1 compression, 0.500" valve lift limit. · Mazda RX-7 92-97 added to EP Prep as Level 2 rotary 13B 6-port, 2200–2310 lbs, carb or fuel injection, 42 mm choke. · EP Mazda RX-8 (04-11) alternate spec line removed; single spec line retained. · FP Honda CRX 84-87 plastic front header nose panel, rocker skirts, door caps can now be replica alternate material stock appearance. · FP Acura Integra 90-01 and Honda Civic Del Sol VTEC, Civic Si 99-00 require 55mm flat plate intake restrictor. · P1 engine approval process wording clarified; unspecified engines need case-by-case Board review. · P2 Spec Line E engine notes clarify oil system, ECU, and exhaust remain unrestricted; wording only. · P2 FIA Group CN notes clarify V de V European Proto Endurance Challenge bodywork, rear diffuser, wing, wheels, assisted shifting allowed; regulations link provided. · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588. · FP Mazda Protégé ES (01-03) renamed to Mazda Protégé ES/5 (01-03). · P1 removes redundant effective date language from ECU stall prohibition rule. · P1 Honda K20A-FD2 engine terminology corrected from 'spec' to proper series designation; FIA certification documentation requirement removed. · HP Honda Civic 1.5 1988-91 minimum weight drops 70 lbs to 2175; also 2-speed and 3-speed minimums cut 72 and 73 lbs. · EP BMW Z3 2.5L minimum weight increased to 2500 lbs, 2563 lbs with power adder, 2625 lbs with two power adders. · FP Honda throttle body inside diameters corrected across seven models: Civic 1.5 to 42", Civic Si to 55", CRX 1.5 to 42", CRX 84-87 to 33/42", CRX Si 88-91 to 55". · EP Mazda MX-5 1.8L (90-97) minimum weight cut to 2150 lbs; (94-97) variants to 2000, 2050, 2100 lbs. · EP Triumph GT6 dual 1.75-inch carburetors weight rises to 1940 lbs; triple Weber 40 DCOE option added at 1990 lbs. · EP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm. · EP Triumph TR8 dry sump allowance moved from Carburetor line to Notes. · EP Porsche 944/924S 2.5L and 2.7L minimum weights corrected: 2479cc to 2306–2363 lbs, 2681cc to 2358–2415 lbs. · P1 Engine Table line H restrictor grows to 32 mm, weight rises to 1450 lbs; line I restrictor to 31 mm, weight to 1475 lbs. · P1 Group CN Honda K20A-FD2 removes engine modification restrictions; CRB may add intake restrictor if needed. · P2 AMAC and related cars: clarified B.1 modified engine range to 2008 and older stock engines only, with 38mm restrictor and 1025 lbs minimum weight. · P2 Suzuki GSX-R1000 engine: 2007–2008 crankcase 11300-21860 may be replaced with 2016–2019 GSX-S1000 part 11301-04840. · EP Porsche 944/924S combines 2.5L and 2.7L variants (83-89), raises weight to 2250–2415 lbs, allows 2681cc displacement. · FP Toyota Corolla 2TC loses 43 lbs to 1810; HP Corolla loses 50–52 lbs to 1910–2006. · EP Triumph GT6 minimum weight drops to 1800 lbs. · P2 Table 1 engine date ranges clarified: Stock Engine replaced with specific marques Suzuki, Yamaha, Honda, BMW for 2009-newer and 2008-older rows.showhide
  • FP Errors/emissions Honda Civic/CRX #36700enginefasterengineFP Honda CRX/CRX Si 84-87 block material changes from iron to aluminium.
  • 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 #36556engineaddedengineSM 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.
  • FP Errant entry in HP production line item #36231wordingwordingHP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.).
  • FP NIssan 300ZX Z31 to EP #35830cars addedaddedNissan 300ZX 84–89 added to EP, 2550–2678 lbs, 2960 cc SOHC, fuel injection, 12.0:1 compression, 0.500" valve lift limit.
  • FP RX7 1993 and Up Request In EP Spec Lines, classify #36031cars addedaddedMazda RX-7 92-97 added to EP Prep as Level 2 rotary 13B 6-port, 2200–2310 lbs, carb or fuel injection, 42 mm choke.
  • FP Clean-up Multiple EP RX-8 Spec Lines In EP #36156cars addedremovedcars addedEP Mazda RX-8 (04-11) alternate spec line removed; single spec line retained.
  • FP Request to Replace CRX Plastic Panels #35876cars addedaddedFP Honda CRX 84-87 plastic front header nose panel, rocker skirts, door caps can now be replica alternate material stock appearance.
  • FP FP data and parity #35896inductionaddedinductionFP Acura Integra 90-01 and Honda Civic Del Sol VTEC, Civic Si 99-00 require 55mm flat plate intake restrictor.
  • P1 Update GCR section 9.1.8.B.J.7 #35907wordingwordingP1 engine approval process wording clarified; unspecified engines need case-by-case Board review.
  • P2 CN Spec ECU #35835wordingwordingP2 Spec Line E engine notes clarify oil system, ECU, and exhaust remain unrestricted; wording only.
  • P2 E&O - Correct FIA Group CN spec line notes #35900wordingwordingP2 FIA Group CN notes clarify V de V European Proto Endurance Challenge bodywork, rear diffuser, wing, wheels, assisted shifting allowed; regulations link provided.
  • FP GCR Correction - Redundant HP Spec Lines #35623removedremovedHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588.
  • FP Update FP Protege (01-03) Model Info #35715wordingwordingFP Mazda Protégé ES (01-03) renamed to Mazda Protégé ES/5 (01-03).
  • P1 Remove redundant effective date language in GCR 9.1.8.B.J.4 #35693wordingwordingP1 removes redundant effective date language from ECU stall prohibition rule.
  • P1 Correct engine series terminology #35694wordingwordingP1 Honda K20A-FD2 engine terminology corrected from 'spec' to proper series designation; FIA certification documentation requirement removed.
  • FP Update 1988-1991 Civic to Match 1988-1991 CRX #35399weightfasterweightHP Honda Civic 1.5 1988-91 minimum weight drops 70 lbs to 2175; also 2-speed and 3-speed minimums cut 72 and 73 lbs.
  • FP FP data #35060weight +25 lbs
  • FP Request to Review Z3 2.5 Spec Line #35073weight +50 lbsslowerweightEP BMW Z3 2.5L minimum weight increased to 2500 lbs, 2563 lbs with power adder, 2625 lbs with two power adders.
  • FP Corrections to Honda Spec Lines in FP #35250wordingunclearFP Honda throttle body inside diameters corrected across seven models: Civic 1.5 to 42", Civic Si to 55", CRX 1.5 to 42", CRX 84-87 to 33/42", CRX Si 88-91 to 55".
  • FP Miata Alternate Head #35253weight -50 lbsfasterweightEP Mazda MX-5 1.8L (90-97) minimum weight cut to 2150 lbs; (94-97) variants to 2000, 2050, 2100 lbs.
  • FP Triumph GT6 Adjustments #35255weightslowerweightEP Triumph GT6 dual 1.75-inch carburetors weight rises to 1940 lbs; triple Weber 40 DCOE option added at 1990 lbs.
  • FP Honda S2000 throttle body #35272inductionfasterinductionEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
  • FP Correction within Triumph TR8 Spec Line #35315wordingwordingEP Triumph TR8 dry sump allowance moved from Carburetor line to Notes.
  • FP Correction to EP 924S/944 Spec Line #35317weightweightEP Porsche 944/924S 2.5L and 2.7L minimum weights corrected: 2479cc to 2306–2363 lbs, 2681cc to 2358–2415 lbs.
  • P1 Please correct omitted punctuation #34890weight
  • P1 Adjust restrictors and weights for Engine Table lines H and I #35229weightslowerweightP1 Engine Table line H restrictor grows to 32 mm, weight rises to 1450 lbs; line I restrictor to 31 mm, weight to 1475 lbs.
  • P1 Revise Group CN Honda K20A-FD2 Spec Line #35337wordingunclearP1 Group CN Honda K20A-FD2 removes engine modification restrictions; CRB may add intake restrictor if needed.
  • P2 E&O - Clarify B.1 modified engine range in AMAC spec lines #35225wordingwordingP2 AMAC and related cars: clarified B.1 modified engine range to 2008 and older stock engines only, with 38mm restrictor and 1025 lbs minimum weight.
  • P2 Replacement Engine Crankcase for 07/08 Suzuki GSX-R1000 Engines #35340engineaddedengineP2 Suzuki GSX-R1000 engine: 2007–2008 crankcase 11300-21860 may be replaced with 2016–2019 GSX-S1000 part 11301-04840.
  • FP Porsche 944/924S Rule Change Request #35002weightslowerweightEP Porsche 944/924S combines 2.5L and 2.7L variants (83-89), raises weight to 2250–2415 lbs, allows 2681cc displacement.
  • FP FP and HP Toyota Corolla #35030weight -43 lbsfasterweightFP Toyota Corolla 2TC loses 43 lbs to 1810; HP Corolla loses 50–52 lbs to 1910–2006.
  • FP Triumph GT6 Adjustments #35054weight -30 lbsfasterweightEP Triumph GT6 minimum weight drops to 1800 lbs.
  • P2 Correct Table 1 for Engine Date Range Specifications #35182wordingwordingP2 Table 1 engine date ranges clarified: Stock Engine replaced with specific marques Suzuki, Yamaha, Honda, BMW for 2009-newer and 2008-older rows.
Virginia International Raceway Runoffs 20232023-09-231:42.602Todd Vanacore · fastest of 10 · top 5 within 0.9s+1.001s (+0.99%)1:44.329Todd Vanacore · fastest of 9 · top 5 within 0.7s-9.766s (-8.56%)158.5Jason Miller+1.2 mph (+0.8%)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%)+31.900squal +32.384s130.6%qual 131.6%2:08.248Cliff Ira · fastest of 21 · top 5 within 1.0s+2.031s (+1.61%)2:07.787Cliff Ira · fastest of 20 · top 5 within 0.8s-9.854s (-7.16%)133.7Cliff Ira+1.1 mph (+0.9%)+23.458squal +25.646s122.5%qual 125.0%1:48.590Greg Gyann · fastest of 12 · top 5 within 1.7s+1.024s (+0.95%)1:48.829Lucian Pancea · fastest of 11 · top 5 within 0.9s-27.005s (-19.88%)150.9Lucian Pancea-0.2 mph (-0.2%)+4.500squal +5.988s104.3%qual 105.8%
22 rule changes (P1: 7, SM: 1, FP: 6, P2: 8)5 cars added · 3 engine · 2 aero · 1 weight · 11 wording · FP and HP Sprite and Spitfire 1500 intake valve size corrected to 36.6 mm, removing prior decimal specifications. · HP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with year and body-type clarifications. · P1 SIR testing: vehicle deemed compliant if it stalls within 3 seconds of the stall test. · P1 intake restrictor rule clarified: flat plate, venturi, or Single Inlet Restrictor required; all intake air must pass through. · P1 ducted air rule clarified: top-exit ducted air must pass through heat exchanger, except cockpit opening and engine bay vents. · Ford Fiesta HP model years change to 11-19; Chevrolet Sonic FP model years change to 12-19. · Toyota Celica 78-80 classified FP Prep level 2, 2100–2205 lbs, 2190 cc SOHC four-cylinder, stock carburetion, 11.0:1 compression limit, .450" valve lift limit. · P2 minimum side body height must equal front axle centerline height, viewed from side. · P2 closed cockpit single seat cars now prohibited unless Table 1 spec line permits. · P1 aero height limit, front/rear overhang, and cockpit dimensions corrected to metric-inch equivalents. · P2 engine table spec line B.1 redundant effective date language removed and table updated. · P2 motorcycle restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weights increased to 1100 lbs for 2009+ engines; cockpit length corrected to 23.622 inches. · P1 suspension covers must have symmetrical upper and lower surfaces, no airfoil cross-sections or angled downforce. · FP Mazda Protégé ES (01-03) renamed to Protégé ES/5 (01-03) to include P5 model variant. · EP, FP, HP port matching limited to 1 inch depth from mating surface. · Sebeco NP01-EVO and Elan NP01 added to P2 with Mazda 2.0L MZR, no restrictor required, 1600 lb minimum weight. · P2 Radical SR3/SR4, Cup, Club Sport, Pro-Sport, PR6: assisted shifting clarified from A-assisted to Aassisted; Cup engine restrictor changed from Unrestricted to Not required. · P2 chassis now allows composite materials partially installed; anti-intrusion panels attachment simplified; Stohr and converted models clarified. · SM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore. · P1 aerodynamic devices may not extend more than 1cm below lower surfaces rear of front axle; body panels covering suspension must not be airfoil-shaped or create downforce. · P1 forced induction prohibited: turbocharging and supercharging not allowed.showhide
  • FP Correct Intake Valve Size on 1500cc Midget/Spitfire #34419wordingwordingFP and HP Sprite and Spitfire 1500 intake valve size corrected to 36.6 mm, removing prior decimal specifications.
  • FP ITC to FP? #34286cars addedremovedcars addedHP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with year and body-type clarifications.
  • P1 SIR Testing #34354wordingwordingP1 SIR testing: vehicle deemed compliant if it stalls within 3 seconds of the stall test.
  • P1 E&O Single Inlet Restrictor abbreviation, etc. #34369wordingwordingP1 intake restrictor rule clarified: flat plate, venturi, or Single Inlet Restrictor required; all intake air must pass through.
  • P1 E&O Clean up ducted air provision #34410wordingwordingP1 ducted air rule clarified: top-exit ducted air must pass through heat exchanger, except cockpit opening and engine bay vents.
  • FP Request to Classify Sonic and Fiesta in HP #34264cars addedaddedFord Fiesta HP model years change to 11-19; Chevrolet Sonic FP model years change to 12-19.
  • FP Classification Request for 1978 Toyota Celica #34097cars addedaddedToyota Celica 78-80 classified FP Prep level 2, 2100–2205 lbs, 2190 cc SOHC four-cylinder, stock carburetion, 11.0:1 compression limit, .450" valve lift limit.
  • P2 Clarify minimum side body height requirement #34143wordingwordingP2 minimum side body height must equal front axle centerline height, viewed from side.
  • P2 Clarify closed cockpit single seat car allowance #34144wordingwordingP2 closed cockpit single seat cars now prohibited unless Table 1 spec line permits.
  • P1 E&O - Correct dimensional equivalents #34018wordingwordingP1 aero height limit, front/rear overhang, and cockpit dimensions corrected to metric-inch equivalents.
  • P2 Remove redundant effective date language and update engine table #34012wordingwordingP2 engine table spec line B.1 redundant effective date language removed and table updated.
  • P2 E&O - Correct dimensional equivalents #34038enginefasterengineP2 motorcycle restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weights increased to 1100 lbs for 2009+ engines; cockpit length corrected to 23.622 inches.
  • P1 November 2022 Rules Clarification for Suspension Covers #33615aerosloweraeroP1 suspension covers must have symmetrical upper and lower surfaces, no airfoil cross-sections or angled downforce.
  • FP Request to Add Mazda Protege P5 to FP #33664cars addedaddedFP Mazda Protégé ES (01-03) renamed to Protégé ES/5 (01-03) to include P5 model variant.
  • FP Review Limited Prep Port Matching Rules #33600wordingwordingEP, FP, HP port matching limited to 1 inch depth from mating surface.
  • P2 Request to Classify Sebeco NP01 #33378cars addedaddedSebeco NP01-EVO and Elan NP01 added to P2 with Mazda 2.0L MZR, no restrictor required, 1600 lb minimum weight.
  • P2 Radical spec line clarifications #33485wordingwordingP2 Radical SR3/SR4, Cup, Club Sport, Pro-Sport, PR6: assisted shifting clarified from A-assisted to Aassisted; Cup engine restrictor changed from Unrestricted to Not required.
  • P2 E&O original class intent #33519wordingwordingP2 chassis now allows composite materials partially installed; anti-intrusion panels attachment simplified; Stohr and converted models clarified.
  • P2 Update Engine Table Spec Line B.1 #33608engine
  • SM BOP for NB1 and NB2 #32309weightslowerweightSM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore.
  • P1 Clarify body panel coverage of suspension components #33318aeroaeroP1 aerodynamic devices may not extend more than 1cm below lower surfaces rear of front axle; body panels covering suspension must not be airfoil-shaped or create downforce.
  • P1 E&O clarification regarding forced induction #33123engineremovedengineP1 forced induction prohibited: turbocharging and supercharging not allowed.
Virginia International Raceway Runoffs 20222022-09-241:41.601Todd Slusher · fastest of 9 · top 5 within 2.3s-1.073s (-1.05%)1:54.095John Mcaleer · fastest of 9 · top 5 within 1.4s+10.597s (+10.24%)157.2Jason Miller+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%)+25.012squal +33.063s121.9%qual 132.5%2:06.217Eric Prill · fastest of 18 · top 5 within 1.5s-1.219s (-0.96%)2:17.641Mason Workman · fastest of 15 · top 5 within 3.2s+9.565s (+7.47%)132.5Cliff Ira+1.2 mph (+0.9%)+23.546squal +24.616s120.6%qual 124.2%1:47.566Tim Day Jr · fastest of 12 · top 5 within 3.0s-1.545s (-1.42%)2:15.834Greg Gyann · fastest of 12 · top 5 within 10.1s+25.576s (+23.20%)151.1Robert Iversen+1.8 mph (+1.2%)+21.739squal +5.965s119.1%qual 105.9%
39 rule changes (P1: 3, SM: 1, FP: 25, P2: 10)7 engine · 5 cars added · 4 weight · 3 induction · 1 aero · 1 suspension & brakes · 1 tyres & wheels · 15 wording · 2 other · Volkswagen New Beetle 2.5L 5-cyl DOHC classified in EP at 2400–2520 lbs with fuel injection. · EP Mazda RX-7 12A/13B and 13B now permit 2 bbl fuel injected throttle body with 42mm chokes on dual-y manifold. · EP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc. · P1 motorcycle-based engines with individual throttle bodies must use flat plate intake restrictors within 4 inches of primary butterfly. · EP Subaru BRZ title updated to include model years 13–20; Toyota 86/Scion FR-S title likewise updated to 13–20. · FP Lotus Super Seven 91.7 ci minimum weight increases 50 lbs, to 1580. · EP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with 150 lbs penalty. · BMW 128i (08-13) classified in EP at 2700 lbs minimum with 2996 cc engine, stock throttle body, 11.0:1 compression and 0.400" valve lift limits. · EP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles. · Mazda Protégé ES 99-00 classified FP, 2150–2258 lbs, 1839 cc DOHC, fuel injection, 11.0:1 compression, 0.450" valve lift. · P1 bodywork rules clarified: cycle fenders prohibited, side body minimum height at front axle centerline, air ducting for downforce banned. · P2 chassis construction clarified: full composite allowed; partial composite must roll without composite parts installed. · P2 classification wording cleaned up in GCR section 9.1.8.C and GCR contents. · EP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection. · EP, FP, HP Production clarify idle control valve options: stock original allowed, removable with blocked ports, or mechanical replaced with electronic stock type. · FP BMW 325e/es displacement corrected to 2693 cc. · P2 Oldsmobile cam rules correct spelling from 'after market' to 'aftermarket' in two sections. · SM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation. · EP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate. · Ford Mustang 94-98 weight reduced to 2550/2614/2678 lbs; 99-03 3.8L classified EP at 2700/2768/2835 lbs. · EP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45. · FP VW Golf III/Jetta III 93-98 intake valve shrinks to 39.5 mm (1.56 in), exhaust to 32.9 mm (1.30 in). · P2 adds Beasley B2 at 1350 lbs with Mazda 12A, 40.5mm venturi, and up to 16.5in wing chord. · P2 wings: terminology change from 'cord' to 'chord', and 'only' removed from Bobsy and Jondal notes. · P2 Converted F5 cars renamed F500, must retain F500 suspension, minimum width 55 inches. · EP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked. · P2 motorcycle engines gain 5cc to 1505cc max, two-stroke gains 5cc to 1205cc max, automotive engines add 50 lbs minimum weight to 1350 lbs. · EP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width. · EP, FP, HP front-wheel-drive cars may alter body and subframes to install alternate axle shaft, matching RWD freedom. · EP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400. · FP Honda Civic Del Sol VTEC compression ratio limited to 11.0:1, valve lift to .425", removes dry sump and internal engine prep allowances. · FP Honda Prelude 84-87 and Mazda GLC/323 86-88 valve lift measurement method clarified, Level 1 parts list removed. · P1 2-cycle 6-cylinder maximum displacement increases to 1725 cc, restrictor shrinks to 40mm, minimum weight drops to 1275 lbs. · P2 Control Area definition clarified: rectangular zone from rear edge of front tires to front edge of rear tires, full car width. · EP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; compression ratio 12.0:1 max, valve lift 0.500" max, dry sump allowed. · Toyota Corolla GTS RWD (84-87) and FX16 FWD (87-88) added to HP; old Corolla (84-87) removed. · P2 specification line B.1 engine table entry amended; details of change not provided in excerpt. · P2 Control Area definition clarified: rear tire edge and front tire edge bounds, car's lower surface width, floor extensions and aerodynamic attachments included, vertical structures prohibited. · Toyota MR-2 1.6L 85-89 HP track width corrected to 15×47 / 15×47 inches; stock track baseline now 103% plus 2.5 inches.showhide
  • FP Request to classify VW New Beetle 2.5L in EP #32725cars addedaddedVolkswagen New Beetle 2.5L 5-cyl DOHC classified in EP at 2400–2520 lbs with fuel injection.
  • FP Request Rotary Injection on Dual Y manifold #32775inductionaddedinductionEP Mazda RX-7 12A/13B and 13B now permit 2 bbl fuel injected throttle body with 42mm chokes on dual-y manifold.
  • FP Request for Corrado Stroke & Displacement Correction #32985wordingwordingEP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc.
  • P1 Clarify authorization to use flat plate intake restrictor #32964engineaddedengineP1 motorcycle-based engines with individual throttle bodies must use flat plate intake restrictors within 4 inches of primary butterfly.
  • FP Subaru BRZ Model Years #32500wordingwordingEP Subaru BRZ title updated to include model years 13–20; Toyota 86/Scion FR-S title likewise updated to 13–20.
  • FP Weight Adjustment of Lotus 7 #32213weight +50 lbsslowerweightFP Lotus Super Seven 91.7 ci minimum weight increases 50 lbs, to 1580.
  • FP EP MX-5 Global Cup Car #32218weightweightEP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with 150 lbs penalty.
  • FP Please Class BMW 128i in EP #32370cars addedaddedBMW 128i (08-13) classified in EP at 2700 lbs minimum with 2996 cc engine, stock throttle body, 11.0:1 compression and 0.400" valve lift limits.
  • FP Inconsistency in Body Work Descriptions #32396aeroaddedaeroEP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles.
  • FP Request to classify the 1999-2000 Mazda Protege in FP #32398cars addedaddedMazda Protégé ES 99-00 classified FP, 2150–2258 lbs, 1839 cc DOHC, fuel injection, 11.0:1 compression, 0.450" valve lift.
  • P1 E&O Clarification of Bodywork Rules #32468wordingwordingP1 bodywork rules clarified: cycle fenders prohibited, side body minimum height at front axle centerline, air ducting for downforce banned.
  • P2 E&O Clarification of Chassis Construction Requirements #32469wordingwordingP2 chassis construction clarified: full composite allowed; partial composite must roll without composite parts installed.
  • P2 Clean up P2 wording #32525wordingwordingP2 classification wording cleaned up in GCR section 9.1.8.C and GCR contents.
  • FP Mazda RX8 with 13b Rotary #32170engineengineEP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection.
  • FP Request Idle control valve clarification #32178wordingwordingEP, FP, HP Production clarify idle control valve options: stock original allowed, removable with blocked ports, or mechanical replaced with electronic stock type.
  • FP Correct FP BMW 325e/es Displacement #32394wordingunclearFP BMW 325e/es displacement corrected to 2693 cc.
  • P2 After Market to Aftermarket #32373wordingwordingP2 Oldsmobile cam rules correct spelling from 'after market' to 'aftermarket' in two sections.
  • 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.
  • FP EP Adjustments #31858inductionslowerinductionEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
  • FP 1999 3.8L Ford Mustang to EP? #31635weightfasterweightFord Mustang 94-98 weight reduced to 2550/2614/2678 lbs; 99-03 3.8L classified EP at 2700/2768/2835 lbs.
  • FP Improved Touring Tires #32064tyres & wheelsaddedtyres & wheelsEP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45.
  • FP VW Golf Jetta 2.0L intake and exhaust size correction. #32173engineslowerengineFP VW Golf III/Jetta III 93-98 intake valve shrinks to 39.5 mm (1.56 in), exhaust to 32.9 mm (1.30 in).
  • P2 Add spec line for Beasley B2 #32147cars addedaddedP2 adds Beasley B2 at 1350 lbs with Mazda 12A, 40.5mm venturi, and up to 16.5in wing chord.
  • P2 E&O Table 1 spec line wing terminology #32148wordingwordingP2 wings: terminology change from 'cord' to 'chord', and 'only' removed from Bobsy and Jondal notes.
  • P2 E&O class name #32196wordingwordingP2 Converted F5 cars renamed F500, must retain F500 suspension, minimum width 55 inches.
  • FP Throttle Body and Idle Air #31800wordingwordingEP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked.
  • P2 E&O Engine section #31969weightslowerweightP2 motorcycle engines gain 5cc to 1505cc max, two-stroke gains 5cc to 1205cc max, automotive engines add 50 lbs minimum weight to 1350 lbs.
  • FP Porsche 968 Engine Questions #31478engineengineEP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width.
  • FP PCS E. 2. n. 4. Add Axle Shaft to Allow FWD the Same Freedom #31592otheraddedEP, FP, HP front-wheel-drive cars may alter body and subframes to install alternate axle shaft, matching RWD freedom.
  • FP BMW Z3 2.5L Spec Line #31724engineaddedengineEP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400.
  • FP FP Del Sol VTEC #31859engineslowerengineFP Honda Civic Del Sol VTEC compression ratio limited to 11.0:1, valve lift to .425", removes dry sump and internal engine prep allowances.
  • FP Standardize Level 2 Classifications in FP #31868wordingwordingFP Honda Prelude 84-87 and Mazda GLC/323 86-88 valve lift measurement method clarified, Level 1 parts list removed.
  • P1 Displacement & Weight Change Request for 2-Cycle 6 Cylinder #31609enginefasterengineP1 2-cycle 6-cylinder maximum displacement increases to 1725 cc, restrictor shrinks to 40mm, minimum weight drops to 1275 lbs.
  • P2 E&O letter #31539 – Control Area definition #31783wordingwordingP2 Control Area definition clarified: rectangular zone from rear edge of front tires to front edge of rear tires, full car width.
  • FP 944S2 Restrictor #31396inductionslowerinductionEP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; compression ratio 12.0:1 max, valve lift 0.500" max, dry sump allowed.
  • FP Classing Clarification for 1986 Toyota Corolla FX16 #31527cars addedaddedToyota Corolla GTS RWD (84-87) and FX16 FWD (87-88) added to HP; old Corolla (84-87) removed.
  • P2 BoP adjustment effective 1-1-22 #31538otherunclearP2 specification line B.1 engine table entry amended; details of change not provided in excerpt.
  • P2 E&O clarification of "Control Area" definition #31539wordingwordingP2 Control Area definition clarified: rear tire edge and front tire edge bounds, car's lower surface width, floor extensions and aerodynamic attachments included, vertical structures prohibited.
  • FP E&O; MR2 Track #31120suspension & brakessuspension & brakesToyota MR-2 1.6L 85-89 HP track width corrected to 15×47 / 15×47 inches; stock track baseline now 103% plus 2.5 inches.
Indianapolis Motor Speedway Runoffs 20212021-09-251:29.011Lee Alexander · fastest of 13 · top 5 within 2.5s-1.783s (-1.96%)1:29.225Lee Alexander · fastest of 12 · top 5 within 3.5s-2.274s (-2.49%)160.1Jason Miller1:57.695Brian 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+29.612squal +28.684s133.2%qual 132.2%1:51.082Craig Chima · fastest of 39 · top 5 within 1.2s-1.009s (-0.90%)1:59.933Cliff Ira · fastest of 33 · top 5 within 5.4s+6.926s (+6.13%)131.8Cliff Ira+30.708squal +22.071s134.4%qual 124.8%1:33.235Tim Day Jr · fastest of 16 · top 5 within 3.3s+1.409s (+1.53%)1:35.322Tim Day Jr · fastest of 10 · top 5 within 4.8s+2.841s (+3.07%)150.3Robert Iversen+6.097squal +4.224s106.8%qual 104.7%
41 rule changes (P1: 11, SM: 1, FP: 21, P2: 8)12 cars added · 6 weight · 5 engine · 1 induction · 15 wording · 2 other · P1 creates separate spec lines H and I for 2000cc and 2300cc engines at 1400 and 1445 lbs minimum weight respectively. · P1 Staudacher may run 950 lbs minimum weight with 38.5mm flat plate intake restrictor, removing prior weight-linked restrictor rule. · P2 CN Honda K20A-FD2 engine rebuild clarified: balancing, porting, polishing prohibited; valve jobs and honing must follow factory procedures. · EP Honda S2000 now allows F22c engine in 1997cc and 2157cc displacements with revised weight brackets and specifications. · EP Nissan 240-SX S13/S14 weight drops to 2400 lbs base, 2460 turbo, 2520 supercharged; comp ratio raised to 12.0:1, valve lift to 0.500 inch. · P1 adds 1355cc motorcycle-based engine line C at 1075 lbs minimum weight, no restrictor required. · P2 Converted F5 cars must retain F5 suspension and meet P2 non-spec requirements except minimum width is 55 inches. · P2 minimum body width clarified: cannot extend inward beyond vertical plane through tire centerlines. · EP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed. · Plymouth Arrow 76–80 classified in HP Prep at 1800–1890 lbs with 1598 cc iron-block OHV four-cylinder. · BMW 318i/is E30 (84-85) reclassified from FP to HP at 2200–2310 lbs, SOHC 1797cc, fuel injection, 11.0:1 compression, .425" valve lift limit. · FP Fiat X1/9 1300 loses 50 lbs to 1665; X1/9 Bertone loses 50 lbs to 1765. · Daimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors. · Porsche 924 Level 1 Prep moved from EP to FP classification. · EP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound. · 84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lb weight, 1998cc SOHC engine, two 32mm carburetors. · FP Fiat X1/9 and Bertone 1300 brake rotors now 257 x 12 mm, 10.1 inch diameter, 0.407 inch thickness. · P1 cockpit opening section allows tonneau covers to meet minimum dimensions; wording clarified on equipment attachment. · P1 Staudacher 1005cc homologated before 1-1-2014 may run 38.5mm flat plate intake restrictor at 950 lbs minimum weight. · P1 Spec Line C: FPIR not required at 1150 lbs, 1355cc max may run without FPIR at 1075 lbs. Spec Line G: up to 2000cc runs 30mm SIR at 1400 lbs, 2300cc runs 30mm SIR at 1445 lbs. · P1 classes B, C, D maximum valves per cylinder set to 4, previously unspecified. · P2 tonneau covers now allowed to meet minimum dimensions; cockpit equipment attachment wording clarified. · P2 removes effective date 01/01/2021 from six car spec lines in Table 1. · P2 engine specs B.1, B.2, B.3 limited to maximum 4 valves per cylinder. · Mazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC four-cylinder, fuel injected with 55mm throttle body, comp ratio 12.0:1 max, valve lift 0.500" max. · FP Volkswagen Golf and Jetta III and IV intake valves increase to 40.0 mm, exhaust to 33.0 mm. · P1 Spec Line A clarifies carburetor induction only, one per cylinder, balance tubes not allowed. · P1 Spec Line H notes clarify peripheral port or bridgeport allowed; wording only. · SM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture. · P1 Elan DP02-spec Mazda MZR sealed engine option removed effective 3/1/2021. · P1 Engine Table Spec Lines C and G change 'inlet restrictor' to 'intake restrictor' terminology. · P2 adds new spec line for 2-cycle 3-cylinder engine up to 820cc with 10 front, 14–15 rear wheel width. · EP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate. · FP Volkswagen Golf 1.8, Jetta, Rabbit and Scirocco gain 50 lb weight breaks, minimum weights to 1900–1733 lbs. · FP Mk2 Golf and Jetta 1.8 lose 50 lbs to 1900; HP Jetta GLI engine code removed. · EP, FP, HP Level 1 and Level 2 induction systems: carburettor jets, needles, metering rods allowed; throttle body porting permitted; wording clarified. · EP Nissan Datsun SRL 311U Roadster minimum weight reduced 75 lbs to 1925. · EP Triumph TR8 78-81 minimum weight drops to 2500 lbs. · Honda Civic EX 96-00 classified FP2 at 1975 lbs, SOHC 1590cc, fuel injection, 56mm throttle body, comp ratio 12.0:1 max, valve lift 0.450" max. · FP adds FAJS to permitted Weber-type and auto-type carburetor substitutes in two sections. · P2 motorcycle-engine cars: 2009+ stock 37mm restrictor, 2008- stock 35mm, modified 1075 lbs. Honda K20A 50mm restrictor. Various spec cars: restrictors increased or decreased 0.5–3mm.showhide
  • P1 Move 2000cc and 2300cc engine options to individual spec lines #31012cars addedaddedP1 creates separate spec lines H and I for 2000cc and 2300cc engines at 1400 and 1445 lbs minimum weight respectively.
  • P1 E&O Spec Line B notes #31095wordingwordingP1 Staudacher may run 950 lbs minimum weight with 38.5mm flat plate intake restrictor, removing prior weight-linked restrictor rule.
  • P2 P2 CN Engine Rebuild Clarification #31000wordingwordingP2 CN Honda K20A-FD2 engine rebuild clarified: balancing, porting, polishing prohibited; valve jobs and honing must follow factory procedures.
  • FP Request to Allow F22c Engine for 2000-2003 Honda S2000 #30548cars addedaddedEP Honda S2000 now allows F22c engine in 1997cc and 2157cc displacements with revised weight brackets and specifications.
  • FP Request a review of the S14 240SX in EP. #30873weight -200 lbsfasterweightEP Nissan 240-SX S13/S14 weight drops to 2400 lbs base, 2460 turbo, 2520 supercharged; comp ratio raised to 12.0:1, valve lift to 0.500 inch.
  • P1 Add 1355cc spec line #30890cars addedaddedP1 adds 1355cc motorcycle-based engine line C at 1075 lbs minimum weight, no restrictor required.
  • P2 F5 P2 Conversion #30856wordingwordingP2 Converted F5 cars must retain F5 suspension and meet P2 non-spec requirements except minimum width is 55 inches.
  • P2 Clarify minimum body width requirement #30859wordingwordingP2 minimum body width clarified: cannot extend inward beyond vertical plane through tire centerlines.
  • FP Lotus/Caterham 7 America Request #30392wordingwordingEP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed.
  • FP Request to classify ITC Plymouth Arrow #30588cars addedaddedPlymouth Arrow 76–80 classified in HP Prep at 1800–1890 lbs with 1598 cc iron-block OHV four-cylinder.
  • FP Reclassification of the 1984/85 BMW 318i from FP to HP #30661cars addedaddedBMW 318i/is E30 (84-85) reclassified from FP to HP at 2200–2310 lbs, SOHC 1797cc, fuel injection, 11.0:1 compression, .425" valve lift limit.
  • FP Fiat x1/9 Competition Adjustments #30711weight -50 lbsfasterweightFP Fiat X1/9 1300 loses 50 lbs to 1665; X1/9 Bertone loses 50 lbs to 1765.
  • FP Reclassify Daimler SP 250 #30721cars addedaddedDaimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors.
  • FP Move Porsche 924 in Level 1 Prep From EP to FP #30135cars addedaddedPorsche 924 Level 1 Prep moved from EP to FP classification.
  • FP Clarify Application of Percentage Based Weight Penalties #30669wordingwordingEP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound.
  • FP Change Classification of 84-87 Mazda 626 from FP to HP #30350cars addedadded84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lb weight, 1998cc SOHC engine, two 32mm carburetors.
  • FP Fiat X1/9 brake rotors #30423otherotherFP Fiat X1/9 and Bertone 1300 brake rotors now 257 x 12 mm, 10.1 inch diameter, 0.407 inch thickness.
  • P1 E&O tonneau cover provision in cockpit opening section #30458wordingwordingP1 cockpit opening section allows tonneau covers to meet minimum dimensions; wording clarified on equipment attachment.
  • P1 Update Spec Line B Notes #30498wordingwordingP1 Staudacher 1005cc homologated before 1-1-2014 may run 38.5mm flat plate intake restrictor at 950 lbs minimum weight.
  • P1 Update Spec Lines C and G notes #30499wordingwordingP1 Spec Line C: FPIR not required at 1150 lbs, 1355cc max may run without FPIR at 1075 lbs. Spec Line G: up to 2000cc runs 30mm SIR at 1400 lbs, 2300cc runs 30mm SIR at 1445 lbs.
  • P1 E&O Maximum Valves Per Cylinder #30559engineengineP1 classes B, C, D maximum valves per cylinder set to 4, previously unspecified.
  • P2 E&O tonneau cover provision in cockpit opening section #30459wordingwordingP2 tonneau covers now allowed to meet minimum dimensions; cockpit equipment attachment wording clarified.
  • P2 Remove effective dates in Table 1 #30468wordingwordingP2 removes effective date 01/01/2021 from six car spec lines in Table 1.
  • P2 E&O Maximum Valves Per Cylinder #30560engineengineP2 engine specs B.1, B.2, B.3 limited to maximum 4 valves per cylinder.
  • FP Please Classify Mazda3 in FP #30165cars addedaddedMazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC four-cylinder, fuel injected with 55mm throttle body, comp ratio 12.0:1 max, valve lift 0.500" max.
  • FP Golf MkIII Valve Size Request #30268enginefasterengineFP Volkswagen Golf and Jetta III and IV intake valves increase to 40.0 mm, exhaust to 33.0 mm.
  • P1 Clean up Spec Line A notes section #30424wordingwordingP1 Spec Line A clarifies carburetor induction only, one per cylinder, balance tubes not allowed.
  • P1 Clean up Spec Line H notes section #30425wordingwordingP1 Spec Line H notes clarify peripheral port or bridgeport allowed; wording only.
  • SM Updates - Obsolete Parts & BOP Parts #30438wordingaddedSM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture.
  • P1 DP02 Sealed 2ltr Engine Option #30038engineremovedengineP1 Elan DP02-spec Mazda MZR sealed engine option removed effective 3/1/2021.
  • P1 E&O restrictor terminology #30285wordingwordingP1 Engine Table Spec Lines C and G change 'inlet restrictor' to 'intake restrictor' terminology.
  • P2 Add a new spec line for a 2-cycle, 3-cylinder engine up to 820cc #30272cars addedaddedP2 adds new spec line for 2-cycle 3-cylinder engine up to 820cc with 10 front, 14–15 rear wheel width.
  • FP Alternate Front Brake Rotors and Calipers for EP AH 3000 #29893otherotherEP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate.
  • FP Request VW weight break #29963weight -50 lbsfasterweightFP Volkswagen Golf 1.8, Jetta, Rabbit and Scirocco gain 50 lb weight breaks, minimum weights to 1900–1733 lbs.
  • FP Mk2 VW Consistency and Cleanup of FP and HP Spec Lines #29195weight -50 lbsfasterweightFP Mk2 Golf and Jetta 1.8 lose 50 lbs to 1900; HP Jetta GLI engine code removed.
  • FP Correct Wording for Level 1 and Level 2 Induction Systems #29406inductionfasterinductionEP, FP, HP Level 1 and Level 2 induction systems: carburettor jets, needles, metering rods allowed; throttle body porting permitted; wording clarified.
  • FP Weight Reduction for Datsun Roadster #29409weight -75 lbsfasterweightEP Nissan Datsun SRL 311U Roadster minimum weight reduced 75 lbs to 1925.
  • FP EP TR8 Adjustment #29512weight -100 lbsfasterweightEP Triumph TR8 78-81 minimum weight drops to 2500 lbs.
  • FP Request to Classify 1996-2000 Honda Civic EX #29515cars addedaddedHonda Civic EX 96-00 classified FP2 at 1975 lbs, SOHC 1590cc, fuel injection, 56mm throttle body, comp ratio 12.0:1 max, valve lift 0.450" max.
  • FP FAJS Carburetor #29576cars addedaddedFP adds FAJS to permitted Weber-type and auto-type carburetor substitutes in two sections.
  • P2 Balance of Performance adjustments effective 01-01-2021 #29822engineunclearP2 motorcycle-engine cars: 2009+ stock 37mm restrictor, 2008- stock 35mm, modified 1075 lbs. Honda K20A 50mm restrictor. Various spec cars: restrictors increased or decreased 0.5–3mm.
Road America Runoffs 20202020-10-022:01.101James French · fastest of 18 · top 5 within 1.1s2:01.870James French · fastest of 17 · top 5 within 1.8s159.7David Locke2:42.209Kyle Greenhill · fastest of 77 · top 5 within 0.5s2:43.748Preston Pardus · fastest of 75 · top 5 within 1.0s121.3Kyle Greenhill+41.878squal +41.108s134.4%qual 133.9%2:31.414Ethan Shippert · fastest of 23 · top 5 within 2.2s2:34.033Kevin Ruck · fastest of 21 · top 5 within 2.3s133.2Sam Henry+32.163squal +30.313s126.4%qual 125.0%2:08.514Robert Iversen · fastest of 12 · top 5 within 3.0s2:09.793Robert Iversen · fastest of 12 · top 5 within 3.9s153.1Robert Iversen+7.923squal +7.413s106.5%qual 106.1%
31 rule changes (P1: 4, SM: 2, FP: 19, P2: 6)7 cars added · 4 engine · 3 induction · 1 aero · 1 removed · 1 suspension & brakes · 1 weight · 10 wording · 3 other · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · 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. · P2 rear wing rules clarified: standard wing 6×12 inches, end plates 14-inch square; alternate 1-meter formula wing 110cm wide, 9×18 inches, end plates 14×18 inches. · EP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566. · SM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure. · Porsche 911 S 67-68 classified in EP at 1800–1890 lbs, 1991cc opposed 6-cylinder SOHC with 36mm carburetors. · FP Mazda 626 84-87 carburetor spec clarified to two auto-type sidedraft 32mm choke or fuel injection. · EP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed. · FP Volkswagen Scirocco E&O adds four engine variants with weights 1520–1853 lbs and displacements 1471–1780 cc. · Elan NP01 added to P2 Table 1 as Spec Line car with 2000cc displacement and 42mm restrictor. · FP Pre: 1990–1994 Mazda Protégé classified at 2150–2258 lbs, 1839cc DOHC, fuel injection, 11.0:1 compression, .450" valve lift limit. · HP Mini Cooper 02-06 and 07-13 convertible model years corrected to 05-08 and 09-15 respectively. · P1 intake manifolds unrestricted unless engine requires flat plate restrictor; no plenums or balance pipes on restricted individual runner manifolds. · P2 Enterprises Sports Racer now permits 55mm flat plate intake restrictor Part # WM303013 as alternative to SIR. · EP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch. · 1989-90 Nissan 240-SX SOHC added to FP Pre L2 at 2400–2520 lbs, 2389 cc, fuel injection, 11.0:1 compression, .450" valve lift limit. · P2 Enterprise Sports Racer 2.3L engine must use SIR or Flat Plate restrictor meeting peak horsepower, sized in whole or 0.5mm increments. · FP Volkswagen Jetta, Rabbit, Scirocco reclassified with weights 1520–1853 lbs, intake valves 40.0 mm, exhaust 33.0 mm, throttle 35/52 mm. · HP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure. · Porsche 914-4 2.0L classified in FP Prep 2 at 2030–2132 lbs with 1968cc OHV engine, Solex/Weber/Dellorto carbs or fuel injection, 11.0:1 compression limit, .450" valve lift limit. · FP Ford Fiesta 78-80 minimum weight reduced 130 lbs, to 1660. · P2 electronic throttle control wording clarified: ETC permitted if stock ECU throttle pedal activates original throttle shaft mechanism. · HP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF. · P1 sealed 2.0L Elan DP02-spec Mazda option removal date extended from 1/1/2020 to 1/1/2021. · Mazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed. · FP Mazda Protégé ES 2001–2003 newly classified at 2350–2468 lbs with 1991 cc DOHC four-cylinder, fuel injection, 11.0:1 compression, .450 in. valve lift limit. · P1 sealed 2.0 MZR engine removed effective 1/1/2020; competitors may run it under Spec Line G. · P1 Spec Line F: Restricted 2.0L Group becomes CN-spec Honda K20A-FD2, 2000cc, 1400 lbs minimum. · P2 adds BMW to permitted motorcycle-based engines alongside Kawasaki, Suzuki, Yamaha, Honda. · FP and HP: 1988–91 Honda Civic and CRX track widths corrected to 61.3 / 61.7 inches across multiple levels. · EP, FP, HP cylinder head rules reorganized for clarity; no performance change.showhide
  • FP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458otherfasterHP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches.
  • 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.
  • P2 E&O clarification of P2 rear wing requirements #29205aeroaeroP2 rear wing rules clarified: standard wing 6×12 inches, end plates 14-inch square; alternate 1-meter formula wing 110cm wide, 9×18 inches, end plates 14×18 inches.
  • FP EP BMW Z3 Rule Clarification #28998wordingwordingEP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566.
  • 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.
  • FP Request to Classify Porsche 911 2.0L #28456cars addedaddedPorsche 911 S 67-68 classified in EP at 1800–1890 lbs, 1991cc opposed 6-cylinder SOHC with 36mm carburetors.
  • FP Request to change to Carburetor Spec Line 84-87 Mazda 626 #28926wordingwordingFP Mazda 626 84-87 carburetor spec clarified to two auto-type sidedraft 32mm choke or fuel injection.
  • FP BMW Cylinder Head Casting and Part Numbers #28708engineslowerengineEP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed.
  • FP Correct Scirocco Spec line E&O #28892cars addedaddedFP Volkswagen Scirocco E&O adds four engine variants with weights 1520–1853 lbs and displacements 1471–1780 cc.
  • P2 Classify Elan NP01 in P2 Table 1 #28812cars addedaddedElan NP01 added to P2 Table 1 as Spec Line car with 2000cc displacement and 42mm restrictor.
  • FP Request to Classify 1990-1994 Mazda Protege #28381cars addedaddedFP Pre: 1990–1994 Mazda Protégé classified at 2150–2258 lbs, 1839cc DOHC, fuel injection, 11.0:1 compression, .450" valve lift limit.
  • FP Error in Mini Cooper Spec Line #28713wordingwordingHP Mini Cooper 02-06 and 07-13 convertible model years corrected to 05-08 and 09-15 respectively.
  • P1 E&O minimum weights and intake manifolds #28731inductioninductionP1 intake manifolds unrestricted unless engine requires flat plate restrictor; no plenums or balance pipes on restricted individual runner manifolds.
  • P2 SCCA Enterprises ESR / P2 engine restrictor testing #28669otheraddedP2 Enterprises Sports Racer now permits 55mm flat plate intake restrictor Part # WM303013 as alternative to SIR.
  • FP Caterham 7 Spec Line #28498wordingwordingEP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch.
  • FP Request to classify SOHC 1989-90 240SX in F prod L2 #28553cars addedadded1989-90 Nissan 240-SX SOHC added to FP Pre L2 at 2400–2520 lbs, 2389 cc, fuel injection, 11.0:1 compression, .450" valve lift limit.
  • P2 Add ESR inlet restrictor #27869inductionaddedinductionP2 Enterprise Sports Racer 2.3L engine must use SIR or Flat Plate restrictor meeting peak horsepower, sized in whole or 0.5mm increments.
  • FP VW Weight and Valve Size Request #27886wordingwordingFP Volkswagen Jetta, Rabbit, Scirocco reclassified with weights 1520–1853 lbs, intake valves 40.0 mm, exhaust 33.0 mm, throttle 35/52 mm.
  • FP Request to allow 40 DCOE carb for the Datsun 510 #28195engineaddedengineHP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure.
  • FP Request to classify Porsche 914 2L in LPrep FProd #28231cars addedaddedPorsche 914-4 2.0L classified in FP Prep 2 at 2030–2132 lbs with 1968cc OHV engine, Solex/Weber/Dellorto carbs or fuel injection, 11.0:1 compression limit, .450" valve lift limit.
  • FP Request Ford Fiesta Weight Adjustment #28336weightfasterweightFP Ford Fiesta 78-80 minimum weight reduced 130 lbs, to 1660.
  • P2 Request for Fly by Wire Rule Wording Change #28247wordingwordingP2 electronic throttle control wording clarified: ETC permitted if stock ECU throttle pedal activates original throttle shaft mechanism.
  • FP Request for Help for Datsun 1200 #27934inductionfasterinductionHP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF.
  • P1 Extend date for removing sealed DP02-spec 2.0L option #28046wordingunclearP1 sealed 2.0L Elan DP02-spec Mazda option removal date extended from 1/1/2020 to 1/1/2021.
  • FP Request to List Mazda Miata Throttle Body Size #27907wordingwordingMazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed.
  • FP Request to Classify 2001-2003 Mazda Protege ES in FP #27922cars addedaddedFP Mazda Protégé ES 2001–2003 newly classified at 2350–2468 lbs with 1991 cc DOHC four-cylinder, fuel injection, 11.0:1 compression, .450 in. valve lift limit.
  • P1 Remove sealed DP02-spec 2.0 MZR spec #26753removedremovedP1 sealed 2.0 MZR engine removed effective 1/1/2020; competitors may run it under Spec Line G.
  • P1 Update Revised Spec Line F #27745engineengineP1 Spec Line F: Restricted 2.0L Group becomes CN-spec Honda K20A-FD2, 2000cc, 1400 lbs minimum.
  • P2 Request for addition of BMW Engine in P2 Engine Table #27821engineaddedengineP2 adds BMW to permitted motorcycle-based engines alongside Kawasaki, Suzuki, Yamaha, Honda.
  • FP Request to Correct Track of 1988-91 Honda Civic #27487otherotherFP and HP: 1988–91 Honda Civic and CRX track widths corrected to 61.3 / 61.7 inches across multiple levels.
  • FP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingwordingEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
Virginia International Raceway Runoffs 20192019-10-051:42.674Todd Slusher · fastest of 14 · top 5 within 1.5s1:43.498Todd Slusher · fastest of 13 · top 5 within 1.0s155.9Jim Devenport2:14.552Todd Buras · fastest of 60 · top 5 within 0.2s2:16.459Elivan Goulart · fastest of 56 · top 5 within 0.4s119.8Jim Drago+32.961squal +31.878s131.8%qual 131.0%2:07.436Eric Prill · fastest of 19 · top 5 within 0.6s2:08.076Eric Prill · fastest of 18 · top 5 within 0.8s131.4Ken Kannard+24.578squal +24.762s123.7%qual 124.1%1:49.111Robert Iversen · fastest of 14 · top 5 within 0.8s1:50.258Greg Gyann · fastest of 13 · top 5 within 0.4s149.4Robert Iversen+6.760squal +6.437s106.5%qual 106.3%
36 rule changes (P1: 14, SM: 4, FP: 9, P2: 9)4 cars added · 4 engine · 2 aero · 2 induction · 2 weight · 19 wording · 3 other · P2 Honda K20A-FD2 non-composite chassis intake restrictor note clarified; restrictor implementation date removed. · FP and HP Austin-Healey Sprite Mk I / MG Midget may replace rear bodywork aft of cockpit with alternate material stock-appearing components. · EP Mazda MX-5 Global Cup classification updated to include 2019 model year. · Production classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted. · Production carburetor and fuel injection rules clarified: permitted optional carburetors listed, Weber and auto-type substitutions specified, fuel injection throttle body and butterfly dimensions detailed, intake manifold port extension pr… · EP, FP, HP carburetors: jets, needles, metering rods, needle valves unrestricted; choke parts removable; stock or optional Weber 40 DCN permitted; Weber types, auto types listed. · P2 motorcycle engines: Stock restrictor to 35mm, Modified to 34mm; weights up to 1025 and 1125 lbs respectively. B.5 restrictor to 33mm, weight to 1185 lbs. · EP Mazda MX-5/Miata model years expand from 1999-2002 to 1999-2005. · P1 traction control prohibited. · P1 permits mechanical, solenoid, and air-shifters; prohibits electronic pre-selection and multi-wheel power. · P1 minimum bodywork height rule moved and restated with new 115cm aerodynamic part height limit. · P1 consolidates fender louver rules into one section; removes duplicate allowance for louvers and clarifies brake and engine air ducts are permitted. · P2 cars limited to power application on maximum two wheels. · P2 Enterprise minimum weight increased to 1375 lbs.; peak horsepower of sealed ESR engine reduced per CRB specification. · P1 anti-intrusion panels now allowed anywhere on chassis sides instead of specified locations. · P1 bodywork wording clarified: comfort and safety for driver and passenger or driver only. · P1 Engine Table reference cleaned up; no performance change. · P1 Mazda Renesis Rotary engine spec line removed from Engine Table. · EP, FP, HP: clarified that tapered holes in ball joints can be reamed for bolt conversion, and wheel bearings and hubs unrestricted on all axles. · EP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant. · P1 Staudacher and Honda K20A-FD2 engine table wording clarified; no performance change. · FP Dodge Daytona/Chrysler Laser 84-85 added at 2100 lbs; Shelby Charger/Omni 024 83-84 weight cut to 2100 lbs. · P1 closed cockpit single-seat cars remain prohibited; rule moved from subsection J.5 to B.4. · P2 stock and modified engines get smaller restrictors (35.0mm, 34.0mm, 33.0mm) and heavier minimums (1025, 1125, 1185 lbs). · P2 Line A.1 restrictor reduced from 40mm to 38mm. · SM fuel pump and filter now permitted as Mazda or OEM equivalent part. · P1 engine table reference corrected from 'above' to 'below'; ETC/FBW/DBW throttle wording clarified on sensor and fail-safe requirements. · 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. · P1 removes TIR inlet restrictor option; deletes requirement for single turbo/supercharger unit with single restrictor. · P1 CN-spec Honda K20A-FD2 clarified: stock OEM parts required, no machining allowed. · P1 engine rules correct grammar and remove head designs from specification table. · P2 Spec Line cars now allow 1345cc Hayabusa stock engines at 1050 lb minimum with 30mm restrictor. · P2 Group CN Honda K20A-FD2 55mm intake restrictor implementation delayed from 1 January to 3 March 2019. · P2 Honda K20A-FD2 Group CN must use stock intake manifold, 64mm throttle, 55mm restrictor at 1500 lbs minimum.showhide
  • P2 Update Engine Table Line E notes #27414wordingwordingP2 Honda K20A-FD2 non-composite chassis intake restrictor note clarified; restrictor implementation date removed.
  • FP Request bodywork for Austin Healey Bugeye Sprite MK1 #27106aeroaddedaeroFP and HP Austin-Healey Sprite Mk I / MG Midget may replace rear bodywork aft of cockpit with alternate material stock-appearing components.
  • FP Request to classify the GMX5 2019 #27263cars addedaddedEP Mazda MX-5 Global Cup classification updated to include 2019 model year.
  • FP level one susp. component rule #27270wordingwordingProduction classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted.
  • FP Clarification of Carb Rules - Prep 1 #27300wordingwordingProduction carburetor and fuel injection rules clarified: permitted optional carburetors listed, Weber and auto-type substitutions specified, fuel injection throttle body and butterfly dimensions detailed, intake manifold port extension pr…
  • FP Clarification of Carb Rules - Prep 2 #27301inductioninductionEP, FP, HP carburetors: jets, needles, metering rods, needle valves unrestricted; choke parts removable; stock or optional Weber 40 DCN permitted; Weber types, auto types listed.
  • P2 Update P2 Engine Table spec lines to reflect 3/1/2019 #27254engineslowerengineP2 motorcycle engines: Stock restrictor to 35mm, Modified to 34mm; weights up to 1025 and 1125 lbs respectively. B.5 restrictor to 33mm, weight to 1185 lbs.
  • FP Request Miata Eligibility - 2003 #27121cars addedaddedEP Mazda MX-5/Miata model years expand from 1999-2002 to 1999-2005.
  • P1 E&O Transmissions #27098wordingwordingP1 traction control prohibited.
  • P1 E&O Transmissions #27005otheraddedP1 permits mechanical, solenoid, and air-shifters; prohibits electronic pre-selection and multi-wheel power.
  • P1 Move minimum height provision to #27031wordingwordingP1 minimum bodywork height rule moved and restated with new 115cm aerodynamic part height limit.
  • P1 Remove duplicative fender louver provision #27033wordingwordingP1 consolidates fender louver rules into one section; removes duplicate allowance for louvers and clarifies brake and engine air ducts are permitted.
  • P2 E&O Transmissions #27006engineslowerengineP2 cars limited to power application on maximum two wheels.
  • P2 Request to restrict all cars #26246weightslowerweightP2 Enterprise minimum weight increased to 1375 lbs.; peak horsepower of sealed ESR engine reduced per CRB specification.
  • P1 Missing word E&O #26919wordingwordingP1 anti-intrusion panels now allowed anywhere on chassis sides instead of specified locations.
  • P1 E&O correction to GCR 9.1.8.C.C. #26927wordingwordingP1 bodywork wording clarified: comfort and safety for driver and passenger or driver only.
  • P1 Clean up reference to engine table #26648wordingwordingP1 Engine Table reference cleaned up; no performance change.
  • P1 Remove redundant spec line #26692cars addedremovedcars addedP1 Mazda Renesis Rotary engine spec line removed from Engine Table.
  • FP Rollcenter Correction Clarification #25873wordingaddedEP, FP, HP: clarified that tapered holes in ball joints can be reamed for bolt conversion, and wheel bearings and hubs unrestricted on all axles.
  • FP Hardtops #26476aeroaddedaeroEP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant.
  • P1 Clean Up Engine Table Language #26590wordingwordingP1 Staudacher and Honda K20A-FD2 engine table wording clarified; no performance change.
  • FP Request Classification of Dodge Daytona in F Production #26259weight -150 lbsfasterweightFP Dodge Daytona/Chrysler Laser 84-85 added at 2100 lbs; Shelby Charger/Omni 024 83-84 weight cut to 2100 lbs.
  • P1 Move single-seat closed cockpit provision to #26376wordingwordingP1 closed cockpit single-seat cars remain prohibited; rule moved from subsection J.5 to B.4.
  • P2 Change Engine Table Lines B.1 & B.5 #25777inductionslowerinductionP2 stock and modified engines get smaller restrictors (35.0mm, 34.0mm, 33.0mm) and heavier minimums (1025, 1125, 1185 lbs).
  • P2 Change Line A.1 restrictor size #26429engineslowerengineP2 Line A.1 restrictor reduced from 40mm to 38mm.
  • SM Request to allow aftermarket fuel filters. #26370otheraddedSM fuel pump and filter now permitted as Mazda or OEM equivalent part.
  • P1 Correct errors in GCR section 9.1.8.C.J #26144wordingwordingP1 engine table reference corrected from 'above' to 'below'; ETC/FBW/DBW throttle wording clarified on sensor and fail-safe requirements.
  • 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.
  • P1 Remove redundant inlet restrictor provisions #25877wordingwordingP1 removes TIR inlet restrictor option; deletes requirement for single turbo/supercharger unit with single restrictor.
  • P1 Clarify Honda K20A-FD2 parts requirement #25949wordingwordingP1 CN-spec Honda K20A-FD2 clarified: stock OEM parts required, no machining allowed.
  • P1 Correct GCR section 9.1.8.C.J errors #25966wordingwordingP1 engine rules correct grammar and remove head designs from specification table.
  • P2 Request to Allow 1345cc Hayabusa Engines for Spec Line P2 Cars #25595cars addedaddedP2 Spec Line cars now allow 1345cc Hayabusa stock engines at 1050 lb minimum with 30mm restrictor.
  • P2 Change CN inlet restrictor implementation date #25816wordingwordingP2 Group CN Honda K20A-FD2 55mm intake restrictor implementation delayed from 1 January to 3 March 2019.
  • P2 Clarify Honda K20A-FD2 parts requirement #25950engineslowerengineP2 Honda K20A-FD2 Group CN must use stock intake manifold, 64mm throttle, 55mm restrictor at 1500 lbs minimum.
Sonoma Raceway Runoffs 20182018-10-101:27.714Todd Slusher · fastest of 19 · top 5 within 2.1s1:28.786Perry Richardson · fastest of 19 · top 5 within 0.9s144.0Johnnie Crean1:54.355Ken Sutherland · fastest of 48 · top 5 within 0.7s1:55.278Michael Carter · fastest of 48 · top 5 within 0.3s102.2Danny Steyn+26.492squal +26.641s129.8%qual 130.4%1:47.588Joe Huffaker · fastest of 15 · top 5 within 3.0s1:48.481Joe Huffaker · fastest of 14 · top 5 within 2.2s109.1Joe Huffaker+19.695squal +19.874s122.2%qual 122.7%1:28.784Tim Day Jr · fastest of 17 · top 5 within 5.0s1:32.071Chuck Bona · fastest of 18 · top 5 within 0.9s144.4Tim Day Jr+3.285squal +1.070s103.7%qual 101.2%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:30.794Jim Devenport · fastest of 19 · top 5 within 2.8s1:31.499Jim Devenport · fastest of 16 · top 5 within 2.2s1:58.306Chris Haldeman · fastest of 86 · top 5 within 0.5s1:59.100Michael Gagliardo · fastest of 83 · top 5 within 0.6s+27.601squal +27.512s130.2%qual 130.3%1:52.091Eric Prill · fastest of 42 · top 5 within 1.2s1:53.007Eric Prill · fastest of 40 · top 5 within 0.7s+21.508squal +21.297s123.5%qual 123.5%1:31.826Jeff Shafer · fastest of 26 · top 5 within 4.9s1:32.481Jeff Shafer · fastest of 24 · top 5 within 3.8s+0.982squal +1.032s101.1%qual 101.1%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:17.308James Devenport · fastest of 14 · top 5 within 2.7s1:19.407Gianpaolo Ciancimino · fastest of 13 · top 5 within 1.8s1:40.514Justin Hille · fastest of 45 · top 5 within 0.3s1:40.764Michael Carter · fastest of 44 · top 5 within 0.3s+21.357squal +23.206s126.9%qual 130.0%1:35.938John Walker · fastest of 33 · top 5 within 0.4s1:36.399John Walker · fastest of 27 · top 5 within 0.3s+16.992squal +18.630s121.4%qual 124.1%1:20.188Jeff Shafer · fastest of 18 · top 5 within 4.0s1:20.904Jeff Shafer · fastest of 16 · top 5 within 2.2s+1.497squal +2.880s101.9%qual 103.7%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-211:49.219Jim Downing · fastest of 9 · top 5 within 2.2s1:49.792Gianpaolo Ciancimino · fastest of 10 · top 5 within 1.7s2:18.661Andrew Carbonell · fastest of 62 · top 5 within 0.6s2:24.067Todd Lamb · fastest of 59 · top 5 within 0.8s+34.275squal +29.442s131.2%qual 127.0%2:11.009Kevin Ruck · fastest of 20 · top 5 within 1.6s2:12.419Kevin Ruck · fastest of 18 · top 5 within 1.1s+22.627squal +21.790s120.6%qual 120.0%1:51.825Chris Farrell · fastest of 17 · top 5 within 3.6s1:52.355Jeff Shafer · fastest of 17 · top 5 within 2.8s+2.563squal +2.606s102.3%qual 102.4%

By track

TrackEvents Typical % of P1 Best Latest 
Road America4100.0%2 of 4 with P1100.0%Runoffs 2020100.0%Runoffs 2024
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 P1's best on the same day: the weather and the day cancel out, so one figure compares across years where lap times cannot; a class that suits one track more than another still reads differently there. 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.