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BoP Lab / Classes / FC

FC vs STU vs FE2 pace at every track

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

Closest to the field: FC 100.0% of FC Yufeng Luo, Daytona International Speedway Runoffs 2015 race · STU 85.6% of FC Franklin Church, Sonoma Raceway Runoffs 2018 qualifying · FE2 99.6% of FC Max Grau, Indianapolis Motor Speedway Runoffs 2021 qualifying

1:201:402:002:2024 rule changes between Runoffs 2018 and Runoffs 201924 ▾23 rule changes between Runoffs 2019 and Runoffs 202023 ▾13 rule changes between Runoffs 2020 and Runoffs 202113 ▾26 rule changes between Runoffs 2021 and Runoffs 202226 ▾6 rule changes between Runoffs 2022 and Runoffs 20236 ▾6 rule changes between Runoffs 2023 and Runoffs 20246 ▾21 rule changes between Runoffs 2024 and Runoffs 202521 ▾18 rule changes between Runoffs 2025 and Runoffs 202618 ▾FC race best at Runoffs 2015: 1:55.135 (Yufeng Luo)FC race best at Runoffs 2016: 1:22.049 (Nigel Saurino)FC race best at Runoffs 2017: 1:36.890 (Tim Minor)FC race best at Runoffs 2018: 1:34.053 (Mitch Egner)FC race best at Runoffs 2019: 1:52.174 (Robert Allaer)FC race best at Runoffs 2020: 2:13.608 (Robert Allaer)FC race best at Runoffs 2021: 1:36.980 (Simon Sikes)FC race best at Runoffs 2022: 2:07.859 (Nolan Allaer)FC race best at Runoffs 2023: 1:51.169 (Nolan Allaer)FC race best at Runoffs 2024: 2:11.534 (Michael Varacins)FC race best at Runoffs 2025: 2:12.824 (Brandon Dixon)FC race best at Runoffs 2026: 2:11.389 (Brandon Dixon)FC qualifying best at Runoffs 2015: 1:54.477 (Yufeng Luo)FC qualifying best at Runoffs 2016: 1:21.962 (John LaRue)FC qualifying best at Runoffs 2017: 1:36.336 (Austin McCusker)FC qualifying best at Runoffs 2018: 1:32.571 (Timothy de Silva)FC qualifying best at Runoffs 2019: 1:51.200 (Robert Allaer)FC qualifying best at Runoffs 2020: 2:12.644 (Robert Allaer)FC qualifying best at Runoffs 2021: 1:36.787 (Trent Walko)FC qualifying best at Runoffs 2022: 1:49.895 (Nolan Allaer)FC qualifying best at Runoffs 2023: 1:50.281 (Nolan Allaer)FC qualifying best at Runoffs 2024: 2:11.626 (Timothy Minor)FC qualifying best at Runoffs 2025: 2:11.259 (Brandon Dixon)FC qualifying best at Runoffs 2026: 2:10.686 (Brandon Dixon)STU race best at Runoffs 2015: 2:06.756 (Eric Heinrich)STU race best at Runoffs 2016: 1:34.597 (Cameron Maugeri)STU race best at Runoffs 2017: 1:49.387 (Rob Huffmaster)STU race best at Runoffs 2018: 1:46.514 (Kevin Boehm)STU race best at Runoffs 2019: 2:00.483 (Kevin Boehm)STU race best at Runoffs 2020: 2:28.410 (Anthony Geraci)STU race best at Runoffs 2021: 1:47.441 (Joe Moser)STU race best at Runoffs 2022: 2:32.357 (Mark Liller)STU race best at Runoffs 2023: 2:02.302 (Mark Liller)STU race best at Runoffs 2024: 2:25.824 (Thomas Noble)STU race best at Runoffs 2025: 2:24.497 (Chip Herr)STU race best at Runoffs 2026: 2:26.416 (Richard Astacio)STU qualifying best at Runoffs 2015: 2:05.494 (Eric Heinrich)STU qualifying best at Runoffs 2016: 1:32.738 (Joe Moser)STU qualifying best at Runoffs 2017: 1:48.921 (Rob Huffmaster)STU qualifying best at Runoffs 2018: 1:19.234 (Franklin Church)STU qualifying best at Runoffs 2019: 1:59.948 (Kevin Boehm)STU qualifying best at Runoffs 2020: 2:27.883 (David Fiorelli)STU qualifying best at Runoffs 2021: 1:47.078 (Joe Moser)STU qualifying best at Runoffs 2022: 2:00.615 (Johan Schwartz)STU qualifying best at Runoffs 2023: 2:00.389 (Johan Schwartz)STU qualifying best at Runoffs 2024: 2:26.227 (Thomas Noble)STU qualifying best at Runoffs 2025: 2:23.083 (Peter Cunningham)STU qualifying best at Runoffs 2026: 2:24.912 (Richard Astacio)FE2 race best at Runoffs 2018: 1:35.563 (Flinn Lazier)FE2 race best at Runoffs 2019: 1:52.154 (Liam Snyder)FE2 race best at Runoffs 2020: 2:13.271 (Owen McAllister)FE2 race best at Runoffs 2021: 1:36.655 (Max Grau)FE2 race best at Runoffs 2022: 2:12.045 (Jason Conzo)FE2 race best at Runoffs 2023: 1:51.098 (Franklin Futrelle)FE2 race best at Runoffs 2024: 2:12.748 (Porter Aiken)FE2 race best at Runoffs 2025: 2:13.339 (Franklin Futrelle)FE2 race best at Runoffs 2026: 2:11.881 (Franklin Futrelle)FE2 qualifying best at Runoffs 2018: 1:35.040 (Flinn Lazier)FE2 qualifying best at Runoffs 2019: 1:51.062 (Liam Snyder)FE2 qualifying best at Runoffs 2020: 2:12.806 (Scott Rettich)FE2 qualifying best at Runoffs 2021: 1:36.395 (Max Grau)FE2 qualifying best at Runoffs 2022: 1:50.853 (Charles Russell Turner)FE2 qualifying best at Runoffs 2023: 1:50.665 (Charles Russell Turner)FE2 qualifying best at Runoffs 2024: 2:11.506 (Porter Aiken)FE2 qualifying best at Runoffs 2025: 2:12.475 (Franklin Futrelle)FE2 qualifying best at Runoffs 2026: 2:12.326 (Franklin Futrelle)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
FCSTUFE2solid race · dashed qualifying · slower is lower
100%105%110%24 rule changes between Runoffs 2018 and Runoffs 201924 ▾23 rule changes between Runoffs 2019 and Runoffs 202023 ▾13 rule changes between Runoffs 2020 and Runoffs 202113 ▾26 rule changes between Runoffs 2021 and Runoffs 202226 ▾6 rule changes between Runoffs 2022 and Runoffs 20236 ▾6 rule changes between Runoffs 2023 and Runoffs 20246 ▾21 rule changes between Runoffs 2024 and Runoffs 202521 ▾18 rule changes between Runoffs 2025 and Runoffs 202618 ▾FC race best at Runoffs 2015: 100.0% of FC's (Yufeng Luo)FC race best at Runoffs 2016: 100.0% of FC's (Nigel Saurino)FC race best at Runoffs 2017: 100.0% of FC's (Tim Minor)FC race best at Runoffs 2018: 100.0% of FC's (Mitch Egner)FC race best at Runoffs 2019: 100.0% of FC's (Robert Allaer)FC race best at Runoffs 2020: 100.0% of FC's (Robert Allaer)FC race best at Runoffs 2021: 100.0% of FC's (Simon Sikes)FC race best at Runoffs 2022: 100.0% of FC's (Nolan Allaer)FC race best at Runoffs 2023: 100.0% of FC's (Nolan Allaer)FC race best at Runoffs 2024: 100.0% of FC's (Michael Varacins)FC race best at Runoffs 2025: 100.0% of FC's (Brandon Dixon)FC race best at Runoffs 2026: 100.0% of FC's (Brandon Dixon)FC qualifying best at Runoffs 2015: 100.0% of FC's (Yufeng Luo)FC qualifying best at Runoffs 2016: 100.0% of FC's (John LaRue)FC qualifying best at Runoffs 2017: 100.0% of FC's (Austin McCusker)FC qualifying best at Runoffs 2018: 100.0% of FC's (Timothy de Silva)FC qualifying best at Runoffs 2019: 100.0% of FC's (Robert Allaer)FC qualifying best at Runoffs 2020: 100.0% of FC's (Robert Allaer)FC qualifying best at Runoffs 2021: 100.0% of FC's (Trent Walko)FC qualifying best at Runoffs 2022: 100.0% of FC's (Nolan Allaer)FC qualifying best at Runoffs 2023: 100.0% of FC's (Nolan Allaer)FC qualifying best at Runoffs 2024: 100.0% of FC's (Timothy Minor)FC qualifying best at Runoffs 2025: 100.0% of FC's (Brandon Dixon)FC qualifying best at Runoffs 2026: 100.0% of FC's (Brandon Dixon)STU race best at Runoffs 2015: 110.1% of FC's (Eric Heinrich)Off the chart: STU race best at Runoffs 2016: 115.3% of FC's (Cameron Maugeri)STU race best at Runoffs 2017: 112.9% of FC's (Rob Huffmaster)STU race best at Runoffs 2018: 113.2% of FC's (Kevin Boehm)STU race best at Runoffs 2019: 107.4% of FC's (Kevin Boehm)STU race best at Runoffs 2020: 111.1% of FC's (Anthony Geraci)STU race best at Runoffs 2021: 110.8% of FC's (Joe Moser)Off the chart: STU race best at Runoffs 2022: 119.2% of FC's (Mark Liller)STU race best at Runoffs 2023: 110.0% of FC's (Mark Liller)STU race best at Runoffs 2024: 110.9% of FC's (Thomas Noble)STU race best at Runoffs 2025: 108.8% of FC's (Chip Herr)STU race best at Runoffs 2026: 111.4% of FC's (Richard Astacio)STU qualifying best at Runoffs 2015: 109.6% of FC's (Eric Heinrich)STU qualifying best at Runoffs 2016: 113.1% of FC's (Joe Moser)STU qualifying best at Runoffs 2017: 113.1% of FC's (Rob Huffmaster)Off the chart: STU qualifying best at Runoffs 2018: 85.6% of FC's (Franklin Church)STU qualifying best at Runoffs 2019: 107.9% of FC's (Kevin Boehm)STU qualifying best at Runoffs 2020: 111.5% of FC's (David Fiorelli)STU qualifying best at Runoffs 2021: 110.6% of FC's (Joe Moser)STU qualifying best at Runoffs 2022: 109.8% of FC's (Johan Schwartz)STU qualifying best at Runoffs 2023: 109.2% of FC's (Johan Schwartz)STU qualifying best at Runoffs 2024: 111.1% of FC's (Thomas Noble)STU qualifying best at Runoffs 2025: 109.0% of FC's (Peter Cunningham)STU qualifying best at Runoffs 2026: 110.9% of FC's (Richard Astacio)FE2 race best at Runoffs 2018: 101.6% of FC's (Flinn Lazier)FE2 race best at Runoffs 2019: 100.0% of FC's (Liam Snyder)FE2 race best at Runoffs 2020: 99.7% of FC's (Owen McAllister)FE2 race best at Runoffs 2021: 99.7% of FC's (Max Grau)FE2 race best at Runoffs 2022: 103.3% of FC's (Jason Conzo)FE2 race best at Runoffs 2023: 99.9% of FC's (Franklin Futrelle)FE2 race best at Runoffs 2024: 100.9% of FC's (Porter Aiken)FE2 race best at Runoffs 2025: 100.4% of FC's (Franklin Futrelle)FE2 race best at Runoffs 2026: 100.4% of FC's (Franklin Futrelle)FE2 qualifying best at Runoffs 2018: 102.7% of FC's (Flinn Lazier)FE2 qualifying best at Runoffs 2019: 99.9% of FC's (Liam Snyder)FE2 qualifying best at Runoffs 2020: 100.1% of FC's (Scott Rettich)FE2 qualifying best at Runoffs 2021: 99.6% of FC's (Max Grau)FE2 qualifying best at Runoffs 2022: 100.9% of FC's (Charles Russell Turner)FE2 qualifying best at Runoffs 2023: 100.3% of FC's (Charles Russell Turner)FE2 qualifying best at Runoffs 2024: 99.9% of FC's (Porter Aiken)FE2 qualifying best at Runoffs 2025: 100.9% of FC's (Franklin Futrelle)FE2 qualifying best at Runoffs 2026: 101.3% of FC's (Franklin Futrelle)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
FCSTUFE2solid race · dashed qualifying · each class's best lap as a share of FC's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
EventFCSTUFE2
Qual best Race best Trap Qual best Race best Trap vs FC % of FC Qual best Race best Trap vs FC % of FC 
Road America Runoffs 20262026-09-282:10.686Brandon Dixon · fastest of 10 · top 5 within 4.0s-0.573s (-0.44%)2:11.389Brandon Dixon · fastest of 10 · top 5 within 2.7s-1.435s (-1.08%)143.3Dean Kiriluk-1.8 mph (-1.2%)2:24.912Richard Astacio · fastest of 17 · top 5 within 2.6s+1.829s (+1.28%)2:26.416Richard Astacio · fastest of 16 · top 5 within 1.5s+1.919s (+1.33%)145.1Hugh Stewart+0.8 mph (+0.5%)+15.027squal +14.226s111.4%qual 110.9%2:12.326Franklin Futrelle · fastest of 8 · top 5 within 1.9s-0.149s (-0.11%)2:11.881Franklin Futrelle · fastest of 8 · top 5 within 1.6s-1.458s (-1.09%)143.5Steve Whitston-5.5 mph (-3.7%)+0.492squal +1.640s100.4%qual 101.3%
18 rule changes (FC: 2, STU: 15, FE2: 1)5 cars added · 4 weight · 2 induction · 2 tyres & wheels · 4 wording · 1 other · GT3U wheel and tyre options clarified: 15x7 with 225 section at +275 lbs; 15x9 with 245 section at +275 lbs plus 1.5%; 16–18x9 with 245 section at +275 lbs plus 3.0%. · STU cars at or under 2,825 lbs minimum weight limited to 8-inch wheels; over 2,825 lbs limited to 9-inch wheels. · STU GT3U minimum weight increases from GT3 race weight plus 225 to plus 275 pounds; 2.0L unrestricted engines add 75 lbs. · STU adds BMW M50B20TU engine, 1991 cc, minimum weight per chart, must meet all STU engine regulations. · STL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. · STU Honda K20C1 Turbo I4 turbo restrictor increases from 35mm to 36mm TIR. · STU GT86 Cup car must meet 2022 Toyota GR Cup rules, tires maximum 245 section width. · STU Mazda Renesis Street Port added to Table B with 2450 lbs minimum weight and 70mm throttle body options. · STU eliminates 33 and 34 mm inlet restrictor options, removing minimum weights of 2380 and 2525 lbs. · STU Mazda MZR engines may now use Fab 9 Elite NC MX5 Performance Intake manifold as alternative option. · FC USF2000 Tube Frame may now use Hewland LD200 4-speed H-pattern as alternative to Hewland JL-200 5-speed sequential. · FC F2000 Metrik ZF2 minimum weight reduced to 1220 lbs. · STU Mazda MZR (LF, L3, L5) Turbo added; Goodwin intake removed, Jack Spania Racing 70 mm intake and Fab9 Tuning bottom-mount turbo kit approved. · STU 36mm restrictor revised to 2830 cc, 37mm to 2980 cc. · STU removes 275 tire option and 2% weight adder for cars over 3150 lbs; maximum section width now 245. · STU Honda K20 and K24 engines lose 2% weight penalty; minimum weight now per chart only. · STU Honda K24 engine swap weight increases by 2 percent, effective November 1, 2025. · FE and FE2 Enterprise bubble tail part WM138014 now allowed; FE2 must use this configuration only.showhide
  • STU Wheel and tire requirements for GT3U #40679wordingwordingGT3U wheel and tyre options clarified: 15x7 with 225 section at +275 lbs; 15x9 with 245 section at +275 lbs plus 1.5%; 16–18x9 with 245 section at +275 lbs plus 3.0%.
  • STU 9” Wheels #40433tyres & wheelsslowertyres & wheelsSTU cars at or under 2,825 lbs minimum weight limited to 8-inch wheels; over 2,825 lbs limited to 9-inch wheels.
  • STU Weight adjustment to former GT3U cars #40474weightslowerweightSTU GT3U minimum weight increases from GT3 race weight plus 225 to plus 275 pounds; 2.0L unrestricted engines add 75 lbs.
  • STU Request to allow BMW M50B20TU engine in STU #40202cars addedaddedSTU adds BMW M50B20TU engine, 1991 cc, minimum weight per chart, must meet all STU engine regulations.
  • STU Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied.
  • STU Turbo Restrictor Size Increase Request #40008inductionfasterinductionSTU Honda K20C1 Turbo I4 turbo restrictor increases from 35mm to 36mm TIR.
  • STU GT86 Cups Car in STU #40028wordingwordingSTU GT86 Cup car must meet 2022 Toyota GR Cup rules, tires maximum 245 section width.
  • STU Mazda Rx-8 Renesis - Streetported Variant & Added Weight #39785cars addedaddedSTU Mazda Renesis Street Port added to Table B with 2450 lbs minimum weight and 70mm throttle body options.
  • STU Eliminate 33 and 34 mm TIRs #39872inductionremovedinductionSTU eliminates 33 and 34 mm inlet restrictor options, removing minimum weights of 2380 and 2525 lbs.
  • STU Fab 9 Racing Intake Manifold in STU #39767cars addedaddedSTU Mazda MZR engines may now use Fab 9 Elite NC MX5 Performance Intake manifold as alternative option.
  • FC F2000 MZR Spec Line Clarity/Revision Requested #38927otheraddedFC USF2000 Tube Frame may now use Hewland LD200 4-speed H-pattern as alternative to Hewland JL-200 5-speed sequential.
  • FC Adjust F2000 Metrik ZF2 weight #39612weight -20 lbsfasterweightFC F2000 Metrik ZF2 minimum weight reduced to 1220 lbs.
  • STU Request for Permission on Aftermarket Turbo Kit and Intake #39529cars addedaddedSTU Mazda MZR (LF, L3, L5) Turbo added; Goodwin intake removed, Jack Spania Racing 70 mm intake and Fab9 Tuning bottom-mount turbo kit approved.
  • STU Turbo Inlet Restrictor Table #38961wordingwordingSTU 36mm restrictor revised to 2830 cc, 37mm to 2980 cc.
  • STU 275 Tire Rule #38983tyres & wheelsslowertyres & wheelsSTU removes 275 tire option and 2% weight adder for cars over 3150 lbs; maximum section width now 245.
  • STU STU Honda Engine weight penalty #39375weightfasterweightSTU Honda K20 and K24 engines lose 2% weight penalty; minimum weight now per chart only.
  • STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ #38746weightslowerweightSTU Honda K24 engine swap weight increases by 2 percent, effective November 1, 2025.
  • FE2 FE & FE2 Bubble Tail #38978cars addedaddedFE and FE2 Enterprise bubble tail part WM138014 now allowed; FE2 must use this configuration only.
Road America Runoffs 20252025-09-292:11.259Brandon Dixon · fastest of 10 · top 5 within 2.7s-0.367s (-0.28%)2:12.824Brandon Dixon · fastest of 9 · top 5 within 2.3s+1.290s (+0.98%)145.1Brandon Dixon+0.9 mph (+0.6%)2:23.083Peter Cunningham · fastest of 16 · top 5 within 2.6s-3.144s (-2.15%)2:24.497Chip Herr · fastest of 15 · top 5 within 3.8s-1.327s (-0.91%)144.3Chip Herr-1.0 mph (-0.7%)+11.673squal +11.824s108.8%qual 109.0%2:12.475Franklin Futrelle · fastest of 11 · top 5 within 1.4s+0.969s (+0.74%)2:13.339Franklin Futrelle · fastest of 10 · top 5 within 0.6s+0.591s (+0.45%)149.0Steve Whitston+3.7 mph (+2.6%)+0.515squal +1.216s100.4%qual 100.9%
21 rule changes (FC: 2, STU: 18, FE2: 1)7 weight · 4 cars added · 3 tyres & wheels · 2 engine · 1 induction · 3 wording · 1 other · STU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs. · STU-TCR gains GT3 TCR spec lines; 275 tyre option now costs 150 lb adder, up from 100 lb. · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · STU 2.8–3.2L N/A engines now permit 245 max tyre width; over 3150 lbs cars may run 275 with 2% weight penalty. · STU Mazda MZR intake manifold now allows Goodwin 61-2510 or Gato Performance 31972. · STU Honda JDM H23a added, 2259 cc, minimum weight per chart, must meet ST engine regulations. · STU wheels capped at 18 inches diameter; under 2,850 lbs max 8 inches wide, over 2,850 lbs max 9 inches wide. · STU-GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tyre options clarified with weight adjustments. · FE2 allows pre-approved driver safety and comfort seat and control modifications for drivers with disabilities, per logbook. · STU BMW N54/N55 3.0 classified at chart plus 3% minimum weight; N54 twin turbo not allowed. · STU Mini Cooper S SC pulley diameter reduced to 2.185 inches. · STU Honda K20C1 Turbo I4 exempted from 3% direct injection weight adder. · STU GT3U minimum weight increases 150 pounds to 250 pounds. · STU Audi 1.8T Wagon removed; Porsche 944 1800cc weight to Chart, turbo inlet restrictor deleted. · STU-GT3 reclassified as STU-GT3U, effective 1 January 2026. · STU GT3 TCR may run 275-wide DOT tires with 100 lb weight penalty; A compound prohibited at 275. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · STU BMW N54/N55 turbo inlet restrictors now required per GCR definition; twin turbo conversion to single turbo clarified. · FC tire rule clarified: four dry and four wet tires for Regionals and Majors, eight each for Runoffs; marking and declaration timing adjusted. · FF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition. · STU Mini Cooper S SC: 1900 stock pulley spec to 2.565 diameter; 2100 now permits 2.285 diameter pulley.showhide
  • STU Lotus Weight Reduction E&O #38919weightfasterweightSTU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs.
  • STU STU-TCR Adjustments #38723weightslowerweightSTU-TCR gains GT3 TCR spec lines; 275 tyre option now costs 150 lb adder, up from 100 lb.
  • STU Lotus Weight Reduction #38772weight -50 lbsfasterweightLotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs.
  • STU 2.8-3.2L N/A Engine Allowances #38007tyres & wheelsfastertyres & wheelsSTU 2.8–3.2L N/A engines now permit 245 max tyre width; over 3150 lbs cars may run 275 with 2% weight penalty.
  • STU 2006-2015 Mazda Miata Intake Manifold #38422engineaddedengineSTU Mazda MZR intake manifold now allows Goodwin 61-2510 or Gato Performance 31972.
  • STU Requesting Approval of the JDM Honda h23a #38489cars addedaddedSTU Honda JDM H23a added, 2259 cc, minimum weight per chart, must meet ST engine regulations.
  • STU Wheel Size Inconsistency #38018tyres & wheelstyres & wheelsSTU wheels capped at 18 inches diameter; under 2,850 lbs max 8 inches wide, over 2,850 lbs max 9 inches wide.
  • STU Table C: STU-GT3U Clarification #38268weightfasterweightSTU-GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tyre options clarified with weight adjustments.
  • FE2 Driver Safety & Comfort #37965otheraddedFE2 allows pre-approved driver safety and comfort seat and control modifications for drivers with disabilities, per logbook.
  • STU BMW N54/N55 Engine Allowance Follow Up #37447cars addedaddedSTU BMW N54/N55 3.0 classified at chart plus 3% minimum weight; N54 twin turbo not allowed.
  • STU STU Mini Cooper pulley size clarification re: letter #36980 #37717inductionfasterinductionSTU Mini Cooper S SC pulley diameter reduced to 2.185 inches.
  • STU Question About a Weight Modifier #37782weightfasterweightSTU Honda K20C1 Turbo I4 exempted from 3% direct injection weight adder.
  • STU Increase Minimum Weight #37919weight +100 lbsslowerweightSTU GT3U minimum weight increases 150 pounds to 250 pounds.
  • STU Audi 1.8t Wagon STU Table B #36685cars addedremovedcars addedSTU Audi 1.8T Wagon removed; Porsche 944 1800cc weight to Chart, turbo inlet restrictor deleted.
  • STU Merger GT3 to STU #37486wordingunclearSTU-GT3 reclassified as STU-GT3U, effective 1 January 2026.
  • STU GT3 TCR Tire allowance #37494tyres & wheelsaddedtyres & wheelsSTU GT3 TCR may run 275-wide DOT tires with 100 lb weight penalty; A compound prohibited at 275.
  • STU Request to Remove Miata Hubs from General category #37138cars addedaddedSTL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved.
  • STU BMW N54/N55 Engine Allowance #37146wordingwordingSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; twin turbo conversion to single turbo clarified.
  • FC 9.1.1.10.h. FC Tire Rule #36533wordingwordingFC tire rule clarified: four dry and four wet tires for Regionals and Majors, eight each for Runoffs; marking and declaration timing adjusted.
  • FC Change FF/FC Weight with Sequential Gearbox #36651weightfasterweightFF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition.
  • STU R53 15% Pulley Request #36980enginefasterengineSTU Mini Cooper S SC: 1900 stock pulley spec to 2.565 diameter; 2100 now permits 2.285 diameter pulley.
Road America Runoffs 20242024-10-012:11.626Timothy Minor · fastest of 10 · top 5 within 1.3s-1.018s (-0.77%)2:11.534Michael Varacins · fastest of 9 · top 5 within 1.8s-2.074s (-1.55%)144.2Michael Varacins+1.8 mph (+1.2%)2:26.227Thomas Noble · fastest of 18 · top 5 within 2.3s-1.656s (-1.12%)2:25.824Thomas Noble · fastest of 17 · top 5 within 2.4s-2.586s (-1.74%)145.3Thomas Noble+1.1 mph (+0.8%)+14.290squal +14.601s110.9%qual 111.1%2:11.506Porter Aiken · fastest of 18 · top 5 within 0.5s-1.300s (-0.98%)2:12.748Porter Aiken · fastest of 17 · top 5 within 2.0s-0.523s (-0.39%)145.3Porter Aiken+1.9 mph (+1.3%)+1.214squal -0.120s100.9%qual 99.9%
6 rule changes (FC: 2, STU: 4)2 aero · 1 cars added · 1 induction · 1 weight · 1 other · STU RWD turbo cars no longer required to reduce inlet restrictor by 1 mm from table minimum. · FC F2000 Metrik ZF2 added as spec line car with Brembo 4-piston calipers and vented rotors permitted. · STU Mini Cooper S SC gains alternate LEAP OMICRON hood scoop part LEP-OMICRON3 as permitted option. · STU BMW S54 B32 OEM dry sump oiling system now permitted. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems.showhide
  • STU RWD Turbo Disadvantage #36255inductionfasterinductionSTU RWD turbo cars no longer required to reduce inlet restrictor by 1 mm from table minimum.
  • FC Four Pot Calipers #35481cars addedaddedFC F2000 Metrik ZF2 added as spec line car with Brembo 4-piston calipers and vented rotors permitted.
  • STU Letter #35397 addendum #35453aeroaddedaeroSTU Mini Cooper S SC gains alternate LEAP OMICRON hood scoop part LEP-OMICRON3 as permitted option.
  • STU S54 Drysump #35464otheraddedSTU BMW S54 B32 OEM dry sump oiling system now permitted.
  • STU ST Electric-Assisted Steering Systems #35066aeroaddedaeroSTL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems.
  • FC Please correct omitted punctuation #34890weight
Virginia International Raceway Runoffs 20232023-09-231:50.281Nolan Allaer · fastest of 11 · top 5 within 2.3s+0.386s (+0.35%)1:51.169Nolan Allaer · fastest of 11 · top 5 within 2.5s-16.690s (-13.05%)143.5Robert Allaer+2.3 mph (+1.7%)2:00.389Johan Schwartz · fastest of 13 · top 5 within 2.3s-0.226s (-0.19%)2:02.302Mark Liller · fastest of 14 · top 5 within 1.6s-30.055s (-19.73%)144.0Mark Liller+0.1 mph (+0.1%)+11.133squal +10.108s110.0%qual 109.2%1:50.665Charles Russell Turner · fastest of 26 · top 5 within 2.3s-0.188s (-0.17%)1:51.098Franklin Futrelle · fastest of 19 · top 5 within 1.4s-20.947s (-15.86%)141.3Franklin Futrelle-0.6 mph (-0.4%)-0.071squal +0.384s99.9%qual 100.3%
6 rule changes (FC: 3, STU: 3)2 cars added · 1 engine · 1 weight · 2 wording · FC tire marking rule clarified: four dry and four wet tires for Regional/Major/Super Tour, eight each for Runoffs; undeclared tire penalty removed. · STU adds 2022 Toyota GR Cup and GR86 Cup, both 2387cc, 2700 lbs, 18-inch wheels, 245/620R18 slicks. · USF2000 Van Diemen with Mazda MZR LF-DE 2.0L added to FC as spec line car; removed from FX. · STU Mazda BP5A now classified at 1839 cc displacement, 2510 lbs minimum weight, alternate intake manifold permitted. · STU minimum weights adjusted: 2450 cc to 2595 lbs, 2600 cc to 2710 lbs. · FC/FF PE3-8400 ECU tune-file firmware version changes from V3.04.50 to V3.04.35.showhide
  • FC Review FC Runoffs Tire Marking Rule #34274wordingwordingFC tire marking rule clarified: four dry and four wet tires for Regional/Major/Super Tour, eight each for Runoffs; undeclared tire penalty removed.
  • STU 2022 Toyota GR Cup for STU #34449cars addedaddedSTU adds 2022 Toyota GR Cup and GR86 Cup, both 2387cc, 2700 lbs, 18-inch wheels, 245/620R18 slicks.
  • FC USF2000 Van Diemen with Mazda MZR LF-DE 2.0L in FC #34329cars addedaddedUSF2000 Van Diemen with Mazda MZR LF-DE 2.0L added to FC as spec line car; removed from FX.
  • STU Alternate OEM Miata Intake Manifold #33827engineaddedengineSTU Mazda BP5A now classified at 1839 cc displacement, 2510 lbs minimum weight, alternate intake manifold permitted.
  • STU E&O STU NA Weight Chart. #33737weightfasterweightSTU minimum weights adjusted: 2450 cc to 2595 lbs, 2600 cc to 2710 lbs.
  • FC E&O 9.1.1.B.16.j #33634wordingwordingFC/FF PE3-8400 ECU tune-file firmware version changes from V3.04.50 to V3.04.35.
Virginia International Raceway Runoffs 20222022-09-241:49.895Nolan Allaer · fastest of 12 · top 5 within 1.5s-1.305s (-1.17%)2:07.859Nolan Allaer · fastest of 13 · top 5 within 3.8s+15.685s (+13.98%)141.2Tim Minor-0.6 mph (-0.4%)2:00.615Johan Schwartz · fastest of 21 · top 5 within 2.6s+0.667s (+0.56%)2:32.357Mark Liller · fastest of 19 · top 5 within 4.3s+31.874s (+26.46%)143.9Johan Schwartz+0.1 mph (+0.1%)+24.498squal +10.720s119.2%qual 109.8%1:50.853Charles Russell Turner · fastest of 25 · top 5 within 1.1s-0.209s (-0.19%)2:12.045Jason Conzo · fastest of 22 · top 5 within 1.8s+19.891s (+17.74%)141.9Eric Cruz-0.6 mph (-0.5%)+4.186squal +0.958s103.3%qual 100.9%
26 rule changes (FC: 5, STU: 21)6 weight · 4 engine · 2 aero · 2 cars added · 2 tyres & wheels · 10 wording · STU Mazda 13B Turbo added as Chart Limited displacement, streetport only, alternative turbos only. · STU OEM louver vents no longer count against vent allowance or 200 square inch limit. · STU non-4-valve engines gain 9% base engine weight reduction allowance; 2400cc minimum weight drops 1 lb to 2595. · FC Zetec ECU: Performance Electronics model designation changed from PE-3 to PE3-8400; monitor firmware updated to V3.04.50. · STU normally-aspirated engines 2976cc–3200cc with single throttle body lose 10% base engine weight reduction allowance. · ST removes redundant language about engine balance shaft removal and alternate pulley installation. · STU cars that qualified for 9 inch wheels in 2021 may continue running them through 2022 only. · STU splitter definition clarified: must attach to lowest point of front, have no vertical deviations. · STU BMW E36 M3 (95-99) S52B32 minimum weight cut to 3110 lbs from 3200, displacement to 3152 cc. · STU BMW S50B32 Euro maximum displacement 3201 cc, minimum weight 3300 lbs, permits 0.040 overbore and 0.5 compression increase. · ST engine swap origin rule narrowed: North America changed to United States only for case-by-case approval. · STU Honda CRX 84-91 and Civic Del Sol 93-97 both ineligible for front-wheel-drive weight reductions. · STU wheel width rule clarified: under 2950 lbs uses max 8.0 inches, 2950 lbs and over uses max 9.0 inches. · STU single-throttle body cars get lower minimum weights: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs. · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STU Audi A4 1.8T minimum weight fixed to 3050 lbs, K04 turbo removed, VF30 with 35mm restrictor required; Porsche 944 1800 weight fixed to 3050 lbs, VW/Audi 1.8L engine removed, 35mm inlet restrictor required. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · STU engines may delete balance shafts and plug openings; alternate pulleys or gears allowed only for timing belt or chain operation. · STU hood vents now allow louvers within 200 square inches. · FC chassis/frame section cleaned up: panels between main tubes must prevent cockpit intrusion; suspension cannot mount to exterior panels; engine/gearbox exempt from load-bearing restrictions. · STU adds Honda K23 with 2354 cc displacement and chart minimum weight, K24 block allowed with K23 internals and head. · STU Honda K23 relaxes internal engine requirement, now needs only K23 crankshaft. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · FC Zetec ECU requirements clarified: Pectel T2 or PE-3 required with specified communications ports and SCCA tune-file/map from official website. · FC composite anti-intrusion panels of non-uniform thickness limited to eight fasteners per side. · FC tire marking requirements clarified: competitor must ensure tires declared, marked, and logged by Tech before qualifying or race use.showhide
  • STU Request Mazda 13 B turbo #32668cars addedaddedSTU Mazda 13B Turbo added as Chart Limited displacement, streetport only, alternative turbos only.
  • STU Hood Vents and Intercooler Scoops #32733aeroaddedaeroSTU OEM louver vents no longer count against vent allowance or 200 square inch limit.
  • STU Non 4 valve weight reduction removed #32808weightfasterweightSTU non-4-valve engines gain 9% base engine weight reduction allowance; 2400cc minimum weight drops 1 lb to 2595.
  • FC Add Specification to Performance Electronics ECU for Ford Zetec #32761wordingwordingFC Zetec ECU: Performance Electronics model designation changed from PE-3 to PE3-8400; monitor firmware updated to V3.04.50.
  • STU Error in new minimum weight table when combined with other text #32711engineslowerengineSTU normally-aspirated engines 2976cc–3200cc with single throttle body lose 10% base engine weight reduction allowance.
  • STU Redundant Language in May GCR #32713wordingwordingST removes redundant language about engine balance shaft removal and alternate pulley installation.
  • STU Opposed to the Proposed STU Weight Chart #32381tyres & wheelsaddedtyres & wheelsSTU cars that qualified for 9 inch wheels in 2021 may continue running them through 2022 only.
  • STU Clarification request for GCR 9.1.4.D.3.a Splitter Definition #32414wordingwordingSTU splitter definition clarified: must attach to lowest point of front, have no vertical deviations.
  • STU Request Adjustment to Min Weight for STU BMW E36 M3 (95-99) #31535weight -90 lbsfasterweightSTU BMW E36 M3 (95-99) S52B32 minimum weight cut to 3110 lbs from 3200, displacement to 3152 cc.
  • STU BMW E36 M3 Canadian (North American) S50B32 engine #31866engineaddedengineSTU BMW S50B32 Euro maximum displacement 3201 cc, minimum weight 3300 lbs, permits 0.040 overbore and 0.5 compression increase.
  • STU Engine Swap Origin Country #32209wordingwordingST engine swap origin rule narrowed: North America changed to United States only for case-by-case approval.
  • STU CRX/Civic Del Sol #32214weightslowerweightSTU Honda CRX 84-91 and Civic Del Sol 93-97 both ineligible for front-wheel-drive weight reductions.
  • STU Error correction #32383wordingwordingSTU wheel width rule clarified: under 2950 lbs uses max 8.0 inches, 2950 lbs and over uses max 9.0 inches.
  • STU Single TB Weight Modifiers Add to Chart #32393weightfasterweightSTU single-throttle body cars get lower minimum weights: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs.
  • STU Single TB Weight Modifiers #31449weightfasterweightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs.
  • STU Request to Remove A4 1.8t from STU Spec Line Tables #31465weightslowerweightSTU Audi A4 1.8T minimum weight fixed to 3050 lbs, K04 turbo removed, VF30 with 35mm restrictor required; Porsche 944 1800 weight fixed to 3050 lbs, VW/Audi 1.8L engine removed, 35mm inlet restrictor required.
  • STU Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels.
  • STU Request Allowance for Balance Shaft Delete in STU #31434enginefasterengineSTU engines may delete balance shafts and plug openings; alternate pulleys or gears allowed only for timing belt or chain operation.
  • STU Request Louvers in hood vents #31916aeroaddedaeroSTU hood vents now allow louvers within 200 square inches.
  • FC Clean up Chassis/Frame section #31867wordingwordingFC chassis/frame section cleaned up: panels between main tubes must prevent cockpit intrusion; suspension cannot mount to exterior panels; engine/gearbox exempt from load-bearing restrictions.
  • STU Request to Add Honda K23 Spec Line #30682cars addedaddedSTU adds Honda K23 with 2354 cc displacement and chart minimum weight, K24 block allowed with K23 internals and head.
  • STU RE: Aug FT letter 30682 #31060enginefasterengineSTU Honda K23 relaxes internal engine requirement, now needs only K23 crankshaft.
  • STU Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed.
  • FC Clarify Zetec ECU requirements #31554wordingwordingFC Zetec ECU requirements clarified: Pectel T2 or PE-3 required with specified communications ports and SCCA tune-file/map from official website.
  • FC Clarify composite anti-intrusion panel language #31426wordingwordingFC composite anti-intrusion panels of non-uniform thickness limited to eight fasteners per side.
  • FC Clarify tire marking requirements #31455wordingwordingFC tire marking requirements clarified: competitor must ensure tires declared, marked, and logged by Tech before qualifying or race use.
Indianapolis Motor Speedway Runoffs 20212021-09-251:36.787Trent Walko · fastest of 31 · top 5 within 1.7s+0.451s (+0.47%)1:36.980Simon Sikes · fastest of 31 · top 5 within 2.0s+0.090s (+0.09%)141.6Tim Minor1:47.078Joe Moser · fastest of 30 · top 5 within 2.0s-1.843s (-1.69%)1:47.441Joe Moser · fastest of 28 · top 5 within 1.8s-1.946s (-1.78%)146.9Kip VanSteenburg+10.461squal +10.291s110.8%qual 110.6%1:36.395Max Grau · fastest of 28 · top 5 within 0.7s1:36.655Max Grau · fastest of 28 · top 5 within 0.7s146.2Gray Fowler-0.325squal -0.392s99.7%qual 99.6%
13 rule changes (FC: 1, STU: 12)2 cars added · 2 weight · 1 aero · 1 engine · 1 suspension & brakes · 5 wording · 1 other · STU fender flare wording clarified: flare of exterior contour may not change wheel opening size, location or shape from side view. · STU Mazda 12A Bridgeport weight reduced from 2550 lbs to 2350 lbs. · STU fender flare rules clarified: maximum 2 inches total, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry. · STU Honda S2000 now allows F20/F22 K24 crankshaft with chart weight for achieved displacement. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · FC Pinto engine loses 10 lbs to 1190; Pinto aluminum head loses 10 lbs to 1190; Zetec loses 10 lbs to 1210. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STU Porsche PDK automatic transmission limited to 8 forward speeds; sequential DCT systems require 3.5% minimum weight increase. · STU Mazda 13B Street Port 2400 removes choke location rule, allows auto-type 2bbl with any dual-Y manifold. · STU driveshaft and half-shafts now explicitly permitted in steel or aluminum, removing OEM material requirement. · STU Mazda 13B Spec and Bridge Port removed; Street Port added at 2400 lbs minimum weight. · ST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.showhide
  • STU STU Fender flares #30696wordingwordingSTU fender flare wording clarified: flare of exterior contour may not change wheel opening size, location or shape from side view.
  • STU Request weight reduction for 12A bridgeport motor in Miata #30751weight -200 lbsfasterweightSTU Mazda 12A Bridgeport weight reduced from 2550 lbs to 2350 lbs.
  • STU Request for Fender Flare Clarification #30375wordingwordingSTU fender flare rules clarified: maximum 2 inches total, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry.
  • STU Provision for Interchangeable Engine Components Already Allowed #30342engineaddedengineSTU Honda S2000 now allows F20/F22 K24 crankshaft with chart weight for achieved displacement.
  • STU ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingwordingST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section.
  • FC Request for FC Weight Change #30171weightfasterweightFC Pinto engine loses 10 lbs to 1190; Pinto aluminum head loses 10 lbs to 1190; Zetec loses 10 lbs to 1210.
  • STU Super Touring Alternate Miata Hubs #30345cars addedaddedST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1.
  • STU Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment.
  • STU Porsche PDK #30081wordingwordingSTU Porsche PDK automatic transmission limited to 8 forward speeds; sequential DCT systems require 3.5% minimum weight increase.
  • STU Reference Letter #29333 Proposed STU 13B Spec Line Changes #30086wordingwordingSTU Mazda 13B Street Port 2400 removes choke location rule, allows auto-type 2bbl with any dual-Y manifold.
  • STU Drive Shaft Request #30087otherotherSTU driveshaft and half-shafts now explicitly permitted in steel or aluminum, removing OEM material requirement.
  • STU 13B Rules Adjustment #29333cars addedremovedcars addedSTU Mazda 13B Spec and Bridge Port removed; Street Port added at 2400 lbs minimum weight.
  • STU Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
Road America Runoffs 20202020-10-022:12.644Robert Allaer · fastest of 13 · top 5 within 2.1s2:13.608Robert Allaer · fastest of 11 · top 5 within 1.2s142.4Robert Allaer2:27.883David Fiorelli · fastest of 14 · top 5 within 4.1s2:28.410Anthony Geraci · fastest of 14 · top 5 within 3.1s144.2David Fiorelli+14.802squal +15.239s111.1%qual 111.5%2:12.806Scott Rettich · fastest of 25 · top 5 within 0.6s2:13.271Owen McAllister · fastest of 23 · top 5 within 0.7s143.4Owen McAllister-0.337squal +0.162s99.7%qual 100.1%
23 rule changes (FC: 4, STU: 17, FE2: 2)6 engine · 4 weight · 2 cars added · 9 wording · 2 other · FC ECU maps clarified: SCCA Club or 2013 Pro map required, available on SCCA website; 1.340 restrictor reminder. · FE2 oil cooler rule clarified: Setrab 50-625-7612 or any cooler with max core 13 inches wide by 6.5 inches high allowed. · STU fender flare rule reworded: now per-corner up to 2" total, 1% weight penalty applies to entire modification. · FC Zetec engine minimum weight increases 20 lbs to 1220 lbs. · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds. · STL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules. · STU request for alternate intake manifold denied; no change to rules. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · STU large displacement turbo engines limited by GCR turbo list; no BoP change granted. · STU sequential shifters referred to Board of Directors for approval; no rule change effective. · STU Mazda 13B Bridge Port and Street Port added with 2550 lbs and 2250 lbs minimum weight respectively. · STU Honda S2000 gains HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed options. · STU Lotus Elise Cup R and SC Exige SC gain 100 lbs minimum weight to 2300, 2500. · STU Volkswagen GTI/GLI MK5 and Jetta Mk4 may now install turbo inlet restrictor in OEM housing, per TIR spec. · STU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates to original. · STU vehicles over 2951 lbs base weight may use 9 inch wide wheels, changed from 2950 lbs. · STU turbocharged engines now use base weight instead of minimum weight; DFI cars add 3% to base weight. · FC allows Eagle #CRS5483F3D connecting rods alongside original Ford; crankshaft replacement clarified to original Ford only. · FC allows Mahle #930169439 piston as new option alongside Ford original, Sealed Power #H872cp, United Engine and Machine #SO2763. · FE minimum weight rises to 1270 lbs; FE2 minimum weight rises to 1270 lbs; new spring options added; tire warmers prohibited. · STU allows OEM electronic throttle bodies, manual conversion, cam changes, and manual-to-electronic conversion with same inner diameter.showhide
  • FC Urgent: SCCA PE3 map unsuitable #29475wordingwordingFC ECU maps clarified: SCCA Club or 2013 Pro map required, available on SCCA website; 1.340 restrictor reminder.
  • FE2 FE/FE2 Oil Cooler #29293wordingwordingFE2 oil cooler rule clarified: Setrab 50-625-7612 or any cooler with max core 13 inches wide by 6.5 inches high allowed.
  • STU Request for Advanced Aero Rule Wording Clarification. #29124wordingwordingSTU fender flare rule reworded: now per-corner up to 2" total, 1% weight penalty applies to entire modification.
  • FC Request for weight adjustments to equalize FC competition. #28888weightslowerweightFC Zetec engine minimum weight increases 20 lbs to 1220 lbs.
  • STU Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds.
  • STU ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules.
  • STU Request for Alternate Intake Manifold #26514wordingunclearSTU request for alternate intake manifold denied; no change to rules.
  • STU Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
  • STU Request BoP for my Car #29004wordingunclearSTU large displacement turbo engines limited by GCR turbo list; no BoP change granted.
  • STU Sequential Shifters in STU #29031wordingunclearSTU sequential shifters referred to Board of Directors for approval; no rule change effective.
  • STU Rotary Help #27833cars addedaddedSTU Mazda 13B Bridge Port and Street Port added with 2550 lbs and 2250 lbs minimum weight respectively.
  • STU Request to approve Honda S2000 HKS supercharger #27281otheraddedSTU Honda S2000 gains HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed options.
  • STU Request BoP on the Lotus #27637weight +100 lbsslowerweightSTU Lotus Elise Cup R and SC Exige SC gain 100 lbs minimum weight to 2300, 2500.
  • STU Turbo Inlet Restrictor On MK5 Volkswagen #27704otherslowerSTU Volkswagen GTI/GLI MK5 and Jetta Mk4 may now install turbo inlet restrictor in OEM housing, per TIR spec.
  • STU Honda K20C1 removal #27732engineslowerengineSTU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm.
  • STU Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineaddedengineSTU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs.
  • STU Alternate Engine for Porsche 944 #28259engineaddedengineSTU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates to original.
  • STU Please Modify the STU Wheel Size Rule for Clarity #27694weightfasterweightSTU vehicles over 2951 lbs base weight may use 9 inch wide wheels, changed from 2950 lbs.
  • STU Turbo Engine Cars Base Weight #28032wordingwordingSTU turbocharged engines now use base weight instead of minimum weight; DFI cars add 3% to base weight.
  • FC Request for Better Zetec Connecting Rods #27710engineaddedengineFC allows Eagle #CRS5483F3D connecting rods alongside original Ford; crankshaft replacement clarified to original Ford only.
  • FC Add Alternate Piston #27795engineaddedengineFC allows Mahle #930169439 piston as new option alongside Ford original, Sealed Power #H872cp, United Engine and Machine #SO2763.
  • FE2 FE / FE2 Update Rules #27624weightslowerweightFE minimum weight rises to 1270 lbs; FE2 minimum weight rises to 1270 lbs; new spring options added; tire warmers prohibited.
  • STU Request for an electronic throttle body #27342engineaddedengineSTU allows OEM electronic throttle bodies, manual conversion, cam changes, and manual-to-electronic conversion with same inner diameter.
Virginia International Raceway Runoffs 20192019-10-051:51.200Robert Allaer · fastest of 10 · top 5 within 3.1s1:52.174Robert Allaer · fastest of 9 · top 5 within 2.7s141.8Robert Allaer1:59.948Kevin Boehm · fastest of 25 · top 5 within 3.5s2:00.483Kevin Boehm · fastest of 25 · top 5 within 2.5s143.8Kevin Boehm+8.309squal +8.748s107.4%qual 107.9%1:51.062Liam Snyder · fastest of 20 · top 5 within 1.3s1:52.154Liam Snyder · fastest of 19 · top 5 within 0.7s142.6Robert Vanman-0.020squal -0.138s100.0%qual 99.9%
24 rule changes (FC: 2, STU: 22)5 cars added · 4 engine · 3 aero · 3 induction · 8 wording · 1 other · STU wing assembly wording corrected: no part may be higher than roof height. · STU Nissan SR20DET removes -2mm penalty from Table B. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · STU aftermarket side skirts now allowed if they meet 3-inch ride height, lack ducts except jacks or exhaust, don't exceed fascia width, stay below door bottom, and don't reinforce chassis. · STU wheel flare wording clarified: each fender may be flared to 2" with 1% weight penalty, maintaining OEM profile. · FC Wiseco piston and Crower rod part numbers updated; minimum weight unchanged at 976 grams. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · STU Mazda 13B Bridge Port now permits ELITE ROTARY SHOP FD V2.0 intake manifold; stock throttle body requirement removed. · STU Mazda MZR gains alternate Goodwin intake manifold option with stock or Acura throttle body. · STU alternate suspension components rule moved from section E to section D. · STU Honda/Acura B20 now permits B16 or B18 VTEC cylinder head and matching intake manifold. · STU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero. · STU Honda Civic Si TCA 2017- requires 37mm TIR throttle as of June 1, 2019. · STU BMW S54B32 OEM classified separately from E46, displacement 3246 cc, minimum weight 3300 lbs, OEM engine mandatory. · Honda Civic Si 2017- added to STU with 1500cc displacement, 2800 lbs minimum weight, OEM engine and bodywork, specific HPD parts allowed. · STU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum; no Super Touring allowances, OEM intake and cams, 1mm overbore, compression +0.5 permitted. · STU Mazda 13B and 13B Bridge Port may use 13B RE or REW housings and intake with turbo removed. · STU Honda K24 may use intake part numbers 17100-RRB-A00 or 17100-PRB-A10. · STU Mazda 12A Bridge Port added, minimum weight 2550 lbs, Nikki or Auto-type carburettor with specified modifications. · STU World Challenge car weight rule deleted; no replacement specified. · STU AWD/RWD cars no longer must reduce restrictor 1 mm from table. · STU rear wing maximum 12" cord, 72 sq in end plates each, roof height max, body width limit. · FC Wiseco piston and connecting rod minimum weight corrected to 976 grams. · STU adds Honda K20C1 Turbo I4, 1996 cc, 3025 lbs minimum weight, 36mm TIR required.showhide
  • STU Request to correct E&O advanced aerodynamics #27290wordingwordingSTU wing assembly wording corrected: no part may be higher than roof height.
  • STU Remove -2mm penalty from SR20DET Nissan #26982enginefasterengineSTU Nissan SR20DET removes -2mm penalty from Table B.
  • STU Request clarification for manifold and throttle in STU #27004wordingwordingSTU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required.
  • STU Request to clarify afterrmarket side skirts exhaust exit #26814aeroaddedaeroSTU aftermarket side skirts now allowed if they meet 3-inch ride height, lack ducts except jacks or exhaust, don't exceed fascia width, stay below door bottom, and don't reinforce chassis.
  • STU Wheel Flare wording #26872wordingwordingSTU wheel flare wording clarified: each fender may be flared to 2" with 1% weight penalty, maintaining OEM profile.
  • FC E&O Wiseco piston and Crower connecting rod #26659wordingwordingFC Wiseco piston and Crower rod part numbers updated; minimum weight unchanged at 976 grams.
  • STU Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.
  • STU Request to Use Japanese Mazda 13b Intake Manifold #25790engineaddedengineSTU Mazda 13B Bridge Port now permits ELITE ROTARY SHOP FD V2.0 intake manifold; stock throttle body requirement removed.
  • STU Request Alternate Intake for Mazda MZR In a Rear Wheel Drive App. #26352inductionaddedinductionSTU Mazda MZR gains alternate Goodwin intake manifold option with stock or Acura throttle body.
  • STU E&O Suspension #26424wordingwordingSTU alternate suspension components rule moved from section E to section D.
  • STU Revisit B20 VTEC #26530engineaddedengineSTU Honda/Acura B20 now permits B16 or B18 VTEC cylinder head and matching intake manifold.
  • STU Move Flared Fenders to STU Advanced Aero #26564aeroaeroSTU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero.
  • STU TCA Civic SI E&O #26606inductionslowerinductionSTU Honda Civic Si TCA 2017- requires 37mm TIR throttle as of June 1, 2019.
  • STU S54 Spec line #26620cars addedcars addedSTU BMW S54B32 OEM classified separately from E46, displacement 3246 cc, minimum weight 3300 lbs, OEM engine mandatory.
  • STU Request to Class Assignment for 2017 Civic #24287cars addedaddedHonda Civic Si 2017- added to STU with 1500cc displacement, 2800 lbs minimum weight, OEM engine and bodywork, specific HPD parts allowed.
  • STU Request to run E46 3246cc in STU #25126cars addedaddedSTU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum; no Super Touring allowances, OEM intake and cams, 1mm overbore, compression +0.5 permitted.
  • STU Engine Classification for Rotary #25564engineaddedengineSTU Mazda 13B and 13B Bridge Port may use 13B RE or REW housings and intake with turbo removed.
  • STU K24/K20 Head Swap Clarification/Amendment #25899otheraddedSTU Honda K24 may use intake part numbers 17100-RRB-A00 or 17100-PRB-A10.
  • STU Request to Classify 12a Bridge Ported Rotary Engine #25985cars addedaddedSTU Mazda 12A Bridge Port added, minimum weight 2550 lbs, Nikki or Auto-type carburettor with specified modifications.
  • STU World Challenge Car Eligibility #26387wordingunclearSTU World Challenge car weight rule deleted; no replacement specified.
  • STU Request a phone call for discussion regarding weight #26398inductionfasterinductionSTU AWD/RWD cars no longer must reduce restrictor 1 mm from table.
  • STU Advanced Aero E&O #26413aeroaddedaeroSTU rear wing maximum 12" cord, 72 sq in end plates each, roof height max, body width limit.
  • FC Correct Wiseco piston and connecting rod #25809wordingwordingFC Wiseco piston and connecting rod minimum weight corrected to 976 grams.
  • STU Request to Equalize Direct Injected Turbo Cars #24890cars addedaddedSTU adds Honda K20C1 Turbo I4, 1996 cc, 3025 lbs minimum weight, 36mm TIR required.
Sonoma Raceway Runoffs 20182018-10-101:32.571Timothy de Silva · fastest of 16 · top 5 within 1.8s1:34.053Mitch Egner · fastest of 12 · top 5 within 1.6s133.1Robert Armington1:19.234Franklin Church · fastest of 10 · top 5 within 21.5s1:46.514Kevin Boehm · fastest of 9 · top 5 within 7.4s103.0Franklin Church+12.461squal -13.337s113.2%qual 85.6%1:35.040Flinn Lazier · fastest of 9 · top 5 within 1.5s1:35.563Flinn Lazier · fastest of 9 · top 5 within 1.7s126.8Scott Rettich+1.510squal +2.469s101.6%qual 102.7%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:36.336Austin McCusker · fastest of 14 · top 5 within 2.3s1:36.890Tim Minor · fastest of 14 · top 5 within 3.8s1:48.921Rob Huffmaster · fastest of 34 · top 5 within 2.0s1:49.387Rob Huffmaster · fastest of 31 · top 5 within 2.4s+12.497squal +12.585s112.9%qual 113.1%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:21.962John LaRue · fastest of 7 · top 5 within 2.6s1:22.049Nigel Saurino · fastest of 7 · top 5 within 3.0s1:32.738Joe Moser · fastest of 16 · top 5 within 2.5s1:34.597Cameron Maugeri · fastest of 16 · top 5 within 0.8s+12.548squal +10.776s115.3%qual 113.1%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-211:54.477Yufeng Luo · fastest of 11 · top 5 within 2.5s1:55.135Yufeng Luo · fastest of 10 · top 5 within 2.1s2:05.494Eric Heinrich · fastest of 18 · top 5 within 4.6s2:06.756Eric Heinrich · fastest of 17 · top 5 within 3.5s+11.621squal +11.017s110.1%qual 109.6%

By track

TrackEvents Typical % of FC Best Latest 
Road America4100.0%100.0%Runoffs 2020100.0%Runoffs 2026
Virginia International Raceway3100.0%100.0%Runoffs 2019100.0%Runoffs 2023
Indianapolis Motor Speedway2100.0%100.0%Runoffs 2017100.0%Runoffs 2021
Daytona International Speedway1100.0%100.0%Runoffs 2015100.0%Runoffs 2015
Mid-Ohio Sports Car Course1100.0%100.0%Runoffs 2016100.0%Runoffs 2016
Sonoma Raceway1100.0%100.0%Runoffs 2018100.0%Runoffs 2018
About this data
Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of FC'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.