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BoP Lab / Classes / STL

STL vs FM vs FV vs GTL pace at every track

Lap times across years say as much about the weather as the class. % of STL is each class's best lap as a share of STL'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)
ASB-SpecEPFAFCFE2FFvsFM×FPvsFV×FXGT1GT2vsGTL×GTXHPPP2SMSMXSRF3STL×STUT1T2T3T4Show 49 inactive classes
Series
Reference · what % is measured against
Tracks · untick to narrow

Closest to the field: STL 100.0% of STL Kevin Boehm, Daytona International Speedway Runoffs 2015 race · FM 89.2% of STL Bryce Cornet, Sonoma Raceway Runoffs 2018 race · FV 95.5% of STL Alex Scaler, Indianapolis Motor Speedway Runoffs 2021 race · GTL 91.2% of STL Scott Twomey, Indianapolis Motor Speedway Runoffs 2021 race

1:402:002:202:4030 rule changes between Runoffs 2018 and Runoffs 201930 ▾34 rule changes between Runoffs 2019 and Runoffs 202034 ▾23 rule changes between Runoffs 2020 and Runoffs 202123 ▾12 rule changes between Runoffs 2021 and Runoffs 202212 ▾9 rule changes between Runoffs 2022 and Runoffs 20239 ▾22 rule changes between Runoffs 2023 and Runoffs 202422 ▾6 rule changes between Runoffs 2024 and Runoffs 20256 ▾5 rule changes between Runoffs 2025 and Runoffs 20265 ▾STL race best at Runoffs 2015: 2:10.269 (Kevin Boehm)STL race best at Runoffs 2016: 1:36.625 (Kevin Boehm)STL race best at Runoffs 2017: 1:52.589 (Eric Kutil)STL race best at Runoffs 2018: 1:49.754 (Danny Steyn)STL race best at Runoffs 2019: 2:07.273 (Cliff Ira)STL race best at Runoffs 2020: 2:32.115 (Joe Moser)STL race best at Runoffs 2021: 2:02.711 (Joe Moser)STL race best at Runoffs 2022: 2:07.832 (Danny Steyn)STL race best at Runoffs 2023: 2:06.682 (Joe Moser)STL race best at Runoffs 2024: 2:30.245 (Joe Moser)STL race best at Runoffs 2025: 2:32.127 (Jose Osiris Pena)STL race best at Runoffs 2026: 2:30.657 (Danny Steyn)STL qualifying best at Runoffs 2015: 2:09.672 (Kevin Boehm)STL qualifying best at Runoffs 2016: 1:35.439 (John Schmitt)STL qualifying best at Runoffs 2017: 1:52.647 (Adam Roberts)STL qualifying best at Runoffs 2018: 1:49.138 (Danny Steyn)STL qualifying best at Runoffs 2019: 2:07.203 (Danny Steyn)STL qualifying best at Runoffs 2020: 2:31.420 (Danny Steyn)STL qualifying best at Runoffs 2021: 1:51.665 (Danny Steyn)STL qualifying best at Runoffs 2022: 2:05.474 (Danny Steyn)STL qualifying best at Runoffs 2023: 2:05.779 (Danny Steyn)STL qualifying best at Runoffs 2024: 2:30.063 (Joe Moser)STL qualifying best at Runoffs 2025: 2:32.065 (Jose Osiris Pena)STL qualifying best at Runoffs 2026: 2:30.537 (Derek Ketchie)FM race best at Runoffs 2015: 1:58.029 (Joseph Burton-Harris)FM race best at Runoffs 2016: 1:27.922 (Jacob Loomis)FM race best at Runoffs 2017: 1:41.146 (Jarret Voorhies)FM race best at Runoffs 2018: 1:37.909 (Bryce Cornet)FM race best at Runoffs 2019: 2:15.816 (Bryce Cornet)FM qualifying best at Runoffs 2015: 1:57.804 (Joseph Burton-Harris)Off the chart: FM qualifying best at Runoffs 2016: 1:26.043 (Jacob Loomis)FM qualifying best at Runoffs 2017: 1:41.231 (Jarret Voorhies)FM qualifying best at Runoffs 2018: 1:37.598 (Bryce Cornet)FM qualifying best at Runoffs 2019: 1:55.124 (Bryce Cornet)FV race best at Runoffs 2015: 2:21.142 (Andrew Whitston)FV race best at Runoffs 2016: 1:38.066 (Flinn Lazier)FV race best at Runoffs 2017: 1:55.923 (Michael Varacins)FV race best at Runoffs 2018: 1:53.639 (Alex Scaler)FV race best at Runoffs 2019: 2:18.289 (Zachary Whitston)FV race best at Runoffs 2020: 2:45.816 (Alex Scaler)FV race best at Runoffs 2021: 1:57.234 (Alex Scaler)FV race best at Runoffs 2022: 2:18.093 (Andrew Whitston)FV race best at Runoffs 2023: 2:16.611 (Andrew Abbott)FV race best at Runoffs 2024: 2:44.834 (Andrew Abbott)FV race best at Runoffs 2025: 2:46.736 (Zachary Whitston)FV race best at Runoffs 2026: 2:45.272 (Brian Farnham)FV qualifying best at Runoffs 2015: 2:21.167 (Roger Siebenaler)FV qualifying best at Runoffs 2016: 1:37.942 (Alex Scaler)FV qualifying best at Runoffs 2017: 1:55.759 (Michael Varacins)FV qualifying best at Runoffs 2018: 1:52.637 (Skip Streets)FV qualifying best at Runoffs 2019: 2:15.712 (Andrew Whitston)FV qualifying best at Runoffs 2020: 2:43.994 (Hunter Phelps-Barron)FV qualifying best at Runoffs 2021: 1:57.479 (Andrew Whitston)FV qualifying best at Runoffs 2022: 2:15.116 (Brian Farnham)FV qualifying best at Runoffs 2023: 2:15.639 (Andrew Whitston)FV qualifying best at Runoffs 2024: 2:42.643 (Andrew Whitston)FV qualifying best at Runoffs 2025: 2:44.101 (Andrew Abbott)FV qualifying best at Runoffs 2026: 2:46.536 (Zachary Whitston)GTL race best at Runoffs 2015: 2:13.564 (Jim Dentici)GTL race best at Runoffs 2016: 1:35.912 (Kyle Disque)GTL race best at Runoffs 2017: 1:52.068 (Christopher Bovis)GTL race best at Runoffs 2018: 1:49.458 (Troy Ermish)GTL race best at Runoffs 2019: 2:07.837 (Bill Ball)GTL race best at Runoffs 2020: 2:31.601 (Peter Shadowen)GTL race best at Runoffs 2021: 1:51.952 (Scott Twomey)GTL race best at Runoffs 2022: 2:21.180 (Michael Lewis)GTL race best at Runoffs 2023: 2:11.277 (Graham Fuller)GTL race best at Runoffs 2024: 2:30.844 (Chris Bovis)GTL qualifying best at Runoffs 2015: 2:11.387 (Jim Dentici)GTL qualifying best at Runoffs 2016: 1:35.377 (Wilson Wright)GTL qualifying best at Runoffs 2017: 1:50.331 (Christopher Bovis)GTL qualifying best at Runoffs 2018: 1:47.885 (Troy Ermish)GTL qualifying best at Runoffs 2019: 2:06.997 (Peter Shadowen)GTL qualifying best at Runoffs 2020: 2:31.943 (Chris Bovis)GTL qualifying best at Runoffs 2021: 1:51.819 (Christopher Bovis)GTL qualifying best at Runoffs 2022: 2:07.789 (Peter Shadowen)GTL qualifying best at Runoffs 2023: 2:09.564 (Peter Shadowen)GTL qualifying best at Runoffs 2024: 2:30.858 (Peter Shadowen)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
STLFMFVGTLsolid race · dashed qualifying · slower is lower
90%95%100%105%110%30 rule changes between Runoffs 2018 and Runoffs 201930 ▾34 rule changes between Runoffs 2019 and Runoffs 202034 ▾23 rule changes between Runoffs 2020 and Runoffs 202123 ▾12 rule changes between Runoffs 2021 and Runoffs 202212 ▾9 rule changes between Runoffs 2022 and Runoffs 20239 ▾22 rule changes between Runoffs 2023 and Runoffs 202422 ▾6 rule changes between Runoffs 2024 and Runoffs 20256 ▾5 rule changes between Runoffs 2025 and Runoffs 20265 ▾STL race best at Runoffs 2015: 100.0% of STL's (Kevin Boehm)STL race best at Runoffs 2016: 100.0% of STL's (Kevin Boehm)STL race best at Runoffs 2017: 100.0% of STL's (Eric Kutil)STL race best at Runoffs 2018: 100.0% of STL's (Danny Steyn)STL race best at Runoffs 2019: 100.0% of STL's (Cliff Ira)STL race best at Runoffs 2020: 100.0% of STL's (Joe Moser)STL race best at Runoffs 2021: 100.0% of STL's (Joe Moser)STL race best at Runoffs 2022: 100.0% of STL's (Danny Steyn)STL race best at Runoffs 2023: 100.0% of STL's (Joe Moser)STL race best at Runoffs 2024: 100.0% of STL's (Joe Moser)STL race best at Runoffs 2025: 100.0% of STL's (Jose Osiris Pena)STL race best at Runoffs 2026: 100.0% of STL's (Danny Steyn)STL qualifying best at Runoffs 2015: 100.0% of STL's (Kevin Boehm)STL qualifying best at Runoffs 2016: 100.0% of STL's (John Schmitt)STL qualifying best at Runoffs 2017: 100.0% of STL's (Adam Roberts)STL qualifying best at Runoffs 2018: 100.0% of STL's (Danny Steyn)STL qualifying best at Runoffs 2019: 100.0% of STL's (Danny Steyn)STL qualifying best at Runoffs 2020: 100.0% of STL's (Danny Steyn)STL qualifying best at Runoffs 2021: 100.0% of STL's (Danny Steyn)STL qualifying best at Runoffs 2022: 100.0% of STL's (Danny Steyn)STL qualifying best at Runoffs 2023: 100.0% of STL's (Danny Steyn)STL qualifying best at Runoffs 2024: 100.0% of STL's (Joe Moser)STL qualifying best at Runoffs 2025: 100.0% of STL's (Jose Osiris Pena)STL qualifying best at Runoffs 2026: 100.0% of STL's (Derek Ketchie)FM race best at Runoffs 2015: 90.6% of STL's (Joseph Burton-Harris)FM race best at Runoffs 2016: 91.0% of STL's (Jacob Loomis)FM race best at Runoffs 2017: 89.8% of STL's (Jarret Voorhies)FM race best at Runoffs 2018: 89.2% of STL's (Bryce Cornet)FM race best at Runoffs 2019: 106.7% of STL's (Bryce Cornet)FM qualifying best at Runoffs 2015: 90.8% of STL's (Joseph Burton-Harris)FM qualifying best at Runoffs 2016: 90.2% of STL's (Jacob Loomis)FM qualifying best at Runoffs 2017: 89.9% of STL's (Jarret Voorhies)FM qualifying best at Runoffs 2018: 89.4% of STL's (Bryce Cornet)FM qualifying best at Runoffs 2019: 90.5% of STL's (Bryce Cornet)FV race best at Runoffs 2015: 108.3% of STL's (Andrew Whitston)FV race best at Runoffs 2016: 101.5% of STL's (Flinn Lazier)FV race best at Runoffs 2017: 103.0% of STL's (Michael Varacins)FV race best at Runoffs 2018: 103.5% of STL's (Alex Scaler)FV race best at Runoffs 2019: 108.7% of STL's (Zachary Whitston)FV race best at Runoffs 2020: 109.0% of STL's (Alex Scaler)FV race best at Runoffs 2021: 95.5% of STL's (Alex Scaler)FV race best at Runoffs 2022: 108.0% of STL's (Andrew Whitston)FV race best at Runoffs 2023: 107.8% of STL's (Andrew Abbott)FV race best at Runoffs 2024: 109.7% of STL's (Andrew Abbott)FV race best at Runoffs 2025: 109.6% of STL's (Zachary Whitston)FV race best at Runoffs 2026: 109.7% of STL's (Brian Farnham)FV qualifying best at Runoffs 2015: 108.9% of STL's (Roger Siebenaler)FV qualifying best at Runoffs 2016: 102.6% of STL's (Alex Scaler)FV qualifying best at Runoffs 2017: 102.8% of STL's (Michael Varacins)FV qualifying best at Runoffs 2018: 103.2% of STL's (Skip Streets)FV qualifying best at Runoffs 2019: 106.7% of STL's (Andrew Whitston)FV qualifying best at Runoffs 2020: 108.3% of STL's (Hunter Phelps-Barron)FV qualifying best at Runoffs 2021: 105.2% of STL's (Andrew Whitston)FV qualifying best at Runoffs 2022: 107.7% of STL's (Brian Farnham)FV qualifying best at Runoffs 2023: 107.8% of STL's (Andrew Whitston)FV qualifying best at Runoffs 2024: 108.4% of STL's (Andrew Whitston)FV qualifying best at Runoffs 2025: 107.9% of STL's (Andrew Abbott)FV qualifying best at Runoffs 2026: 110.6% of STL's (Zachary Whitston)GTL race best at Runoffs 2015: 102.5% of STL's (Jim Dentici)GTL race best at Runoffs 2016: 99.3% of STL's (Kyle Disque)GTL race best at Runoffs 2017: 99.5% of STL's (Christopher Bovis)GTL race best at Runoffs 2018: 99.7% of STL's (Troy Ermish)GTL race best at Runoffs 2019: 100.4% of STL's (Bill Ball)GTL race best at Runoffs 2020: 99.7% of STL's (Peter Shadowen)GTL race best at Runoffs 2021: 91.2% of STL's (Scott Twomey)GTL race best at Runoffs 2022: 110.4% of STL's (Michael Lewis)GTL race best at Runoffs 2023: 103.6% of STL's (Graham Fuller)GTL race best at Runoffs 2024: 100.4% of STL's (Chris Bovis)GTL qualifying best at Runoffs 2015: 101.3% of STL's (Jim Dentici)GTL qualifying best at Runoffs 2016: 99.9% of STL's (Wilson Wright)GTL qualifying best at Runoffs 2017: 97.9% of STL's (Christopher Bovis)GTL qualifying best at Runoffs 2018: 98.9% of STL's (Troy Ermish)GTL qualifying best at Runoffs 2019: 99.8% of STL's (Peter Shadowen)GTL qualifying best at Runoffs 2020: 100.3% of STL's (Chris Bovis)GTL qualifying best at Runoffs 2021: 100.1% of STL's (Christopher Bovis)GTL qualifying best at Runoffs 2022: 101.8% of STL's (Peter Shadowen)GTL qualifying best at Runoffs 2023: 103.0% of STL's (Peter Shadowen)GTL qualifying best at Runoffs 2024: 100.5% of STL's (Peter Shadowen)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
STLFMFVGTLsolid race · dashed qualifying · each class's best lap as a share of STL's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
EventSTLFMFVGTL
Qual best Race best Trap Qual best Race best Trap vs STL % of STL Qual best Race best Trap vs STL % of STL Qual best Race best Trap vs STL % of STL 
Road America Runoffs 20262026-09-282:30.537Derek Ketchie · fastest of 16 · top 5 within 2.9s-1.528s (-1.00%)2:30.657Danny Steyn · fastest of 16 · top 5 within 0.6s-1.470s (-0.97%)134.8Mike Taylor+2.6 mph (+2.0%)2:46.536Zachary Whitston · fastest of 37 · top 5 within 1.7s+2.435s (+1.48%)2:45.272Brian Farnham · fastest of 34 · top 5 within 1.3s-1.464s (-0.88%)117.4Rick Shields+0.2 mph (+0.1%)+14.615squal +15.999s109.7%qual 110.6%
5 rule changes (STL: 4, GTL: 1)3 cars added · 1 weight · 1 wording · STL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019). · STL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. · STL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs. · GT3U class removed from GCR; GT3U cars now compete in STU. · STL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.showhide
  • STL Spec Line Clean Up #40344cars addedremovedcars addedSTL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019).
  • STL Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied.
  • STL Classifications #39885cars addedaddedSTL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs.
  • GTL Remove GT3U from GCR as it is now in STU #39862cars addedremovedcars addedGT3U class removed from GCR; GT3U cars now compete in STU.
  • STL Weight adjustment for STL #39579weightslowerweightSTL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.
Road America Runoffs 20252025-09-292:32.065Jose Osiris Pena · fastest of 14 · top 5 within 3.4s+2.002s (+1.33%)2:32.127Jose Osiris Pena · fastest of 13 · top 5 within 2.4s+1.882s (+1.25%)132.2Jon Sewell-2.1 mph (-1.5%)2:44.101Andrew Abbott · fastest of 34 · top 5 within 1.3s+1.458s (+0.90%)2:46.736Zachary Whitston · fastest of 29 · top 5 within 0.6s+1.902s (+1.15%)117.2Zachary Whitston+0.7 mph (+0.6%)+14.609squal +12.036s109.6%qual 107.9%
6 rule changes (STL: 3, GTL: 3)2 engine · 1 cars added · 1 weight · 2 wording · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof height limit. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · GTL Toyota G16E-GTS removes direct injection prohibition, allowing direct injection engines. · GTL L16 limited prep gains 32mm choke option at 1910 lbs, compression capped 12.0:1, valve lift .450 max.showhide
  • STL 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.
  • STL E&O: SMX Allowance in STL #37945wordingunclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed.
  • GTL Correct language regarding OEM Areo Devices #37137wordingwordingTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof height limit.
  • STL 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.
  • GTL G16E-GTS Fuel Injection Spec Line Change #36588engineaddedengineGTL Toyota G16E-GTS removes direct injection prohibition, allowing direct injection engines.
  • GTL GTL Alternate Weight and Choke Option for L16 engine #36653engineaddedengineGTL L16 limited prep gains 32mm choke option at 1910 lbs, compression capped 12.0:1, valve lift .450 max.
Road America Runoffs 20242024-10-012:30.063Joe Moser · fastest of 18 · top 5 within 3.7s-1.357s (-0.90%)2:30.245Joe Moser · fastest of 16 · top 5 within 4.2s-1.870s (-1.23%)134.3Joe Moser+1.3 mph (+1.0%)2:42.643Andrew Whitston · fastest of 27 · top 5 within 2.3s-1.351s (-0.82%)2:44.834Andrew Abbott · fastest of 27 · top 5 within 0.9s-0.982s (-0.59%)116.5Brian Farnham-0.7 mph (-0.6%)+14.589squal +12.580s109.7%qual 108.4%2:30.858Peter Shadowen · fastest of 14 · top 5 within 4.4s-1.085s (-0.71%)2:30.844Chris Bovis · fastest of 13 · top 5 within 3.7s-0.757s (-0.50%)133.3Peter Shadowen+1.8 mph (+1.4%)+0.599squal +0.795s100.4%qual 100.5%
22 rule changes (STL: 4, FV: 2, GTL: 16)5 cars added · 5 engine · 4 weight · 2 aero · 1 induction · 4 wording · 1 other · FV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side. · GTL adds Toyota GR86 2021–2023, 2dr RWD, 101.3 in wheelbase. · GTL adds Spec Miata 1990–2005 with legal Spec Miata engine and intake system. · GTL adds Mazda MX5 RF 2017- model with 91.0 in wheelbase. · GTL added to GT3 choke option line in GCR 9.1.2.E.13.n. · GT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR. · GTL Datsun 510 Limited Prep fuel induction increased to 34 mm chokes, minimum weight rises to 2000 lbs. · GT1-GTX rear blade spoiler: angle 50–75°, max 59.0 wide by 5.0 high inches; total area limit removed. · GT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment. · GT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. · STL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm. · STL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled. · GTL 12A rotary engines may machine and use 13B housing to O.E. 12A spec across all port types. · GTL Toyota DR86 2021–2024 added to class. · GTL BMW Mini model years changed to 2002-2013. · STL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki. · FV front wheel bearings wording clarified; specification unchanged. · GTL small unrestricted engines under 1399cc lose 38–79 lbs across Alfa, AMC, Triumph, Mini, Sprite, Fiat, Ford, Honda, Mazda, Nissan, Subaru, Toyota, Volkswagen. · GTL Honda Fit 2009-13 2-door FWD added with 99.0 in wheelbase, alternate 94.0 and 97.0 in. · GTL spec lines moved contiguous with GT2 and GT3; GTA category and specs renumbered behind GTL; P2 engine tables reorganised with restrictor and weight specifications clarified. · GTL Nissan Sentra/200SX A 1400 minimum weight reduced to 1800 lbs.showhide
  • FV Disc Brakes #36822wordingwordingFV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side.
  • GTL Request to Include Toyota GR86 in GTL #36324cars addedaddedGTL adds Toyota GR86 2021–2023, 2dr RWD, 101.3 in wheelbase.
  • GTL Inclusion of Modified Spec Miata for GTL competition #36325cars addedaddedGTL adds Spec Miata 1990–2005 with legal Spec Miata engine and intake system.
  • GTL Include Mazda MX5 RF 2017- in GTL #36428cars addedaddedGTL adds Mazda MX5 RF 2017- model with 91.0 in wheelbase.
  • GTL Add GTL to GT3 choke option line. #36236otheraddedGTL added to GT3 choke option line in GCR 9.1.2.E.13.n.
  • GTL Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerweightGT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR.
  • GTL Allow 34 mm chokes for the Datsun 510 #35661induction +50 lbsfasterinductionGTL Datsun 510 Limited Prep fuel induction increased to 34 mm chokes, minimum weight rises to 2000 lbs.
  • GTL Rear Blade Spoiler Clarification #35261aeroaeroGT1-GTX rear blade spoiler: angle 50–75°, max 59.0 wide by 5.0 high inches; total area limit removed.
  • GTL GT Direct Injection allowance and rules #35437engineaddedengineGT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment.
  • GTL GT2/3 remove Direction Injection not allowed in Spec line notes #35439engineaddedengineGT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E.
  • STL 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.
  • STL BOP Adjustments #35112weightfasterweightSTL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm.
  • STL Mazda 12A #35320engineremovedengineSTL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled.
  • GTL Rotary Engine 12A Rotor Housings #35131engineaddedengineGTL 12A rotary engines may machine and use 13B housing to O.E. 12A spec across all port types.
  • GTL Request to Include Toyota GR86 in GTL #35198cars addedaddedGTL Toyota DR86 2021–2024 added to class.
  • GTL Errors and Omissions, GTL engines & Cars #35226wordingwordingGTL BMW Mini model years changed to 2002-2013.
  • STL Alternate Carburetor Request for 79-85 RX7 12a #35181engineaddedengineSTL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki.
  • FV FV Wheel Bearing Clarification #35150wordingwordingFV front wheel bearings wording clarified; specification unchanged.
  • GTL Small Engines in GT Lite #34842weightfasterweightGTL small unrestricted engines under 1399cc lose 38–79 lbs across Alfa, AMC, Triumph, Mini, Sprite, Fiat, Ford, Honda, Mazda, Nissan, Subaru, Toyota, Volkswagen.
  • GTL Request to Classify Honda Fit body in GTL #35020cars addedaddedGTL Honda Fit 2009-13 2-door FWD added with 99.0 in wheelbase, alternate 94.0 and 97.0 in.
  • GTL Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingwordingGTL spec lines moved contiguous with GT2 and GT3; GTA category and specs renumbered behind GTL; P2 engine tables reorganised with restrictor and weight specifications clarified.
  • GTL Weight for Nissan Sentra/200SX A 1400's #34918weight -50 lbsfasterweightGTL Nissan Sentra/200SX A 1400 minimum weight reduced to 1800 lbs.
Virginia International Raceway Runoffs 20232023-09-232:05.779Danny Steyn · fastest of 22 · top 5 within 3.4s+0.305s (+0.24%)2:06.682Joe Moser · fastest of 20 · top 5 within 1.5s-1.150s (-0.90%)131.8Danny Steyn+0.1 mph (+0.1%)2:15.639Andrew Whitston · fastest of 27 · top 5 within 1.4s+0.523s (+0.39%)2:16.611Andrew Abbott · fastest of 23 · top 5 within 1.6s-1.482s (-1.07%)115.6Brian Farnham-0.2 mph (-0.2%)+9.929squal +9.860s107.8%qual 107.8%2:09.564Peter Shadowen · fastest of 11 · top 5 within 4.9s+1.775s (+1.39%)2:11.277Graham Fuller · fastest of 10 · top 5 within 2.4s-9.903s (-7.01%)142.7Peter Shadowen+6.7 mph (+4.9%)+4.595squal +3.785s103.6%qual 103.0%
9 rule changes (STL: 2, GTL: 7)5 cars added · 1 engine · 1 weight · 2 wording · STL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2. · Fields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection. · GTL 3K, 4K, 5K Toyota engines may now use 4Y block only. · GT2 and GTL add Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines as permitted options. · Spec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules. · GTL Fiat X1/9 1500 Limited Prep minimum weight increases to 2000 lbs from 1835 lbs. · GT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870. · GTL adds Ford Festiva 1988-1993 FWD hatchback with Mazda B3 1324cc engine. · GTL adds Toyota G16E-GTS 1618cc DOHC 3-cyl engine, 1945 lbs, SIR, no turbo or direct injection.showhide
  • STL Clarify STL table B - IT spec notes on Tires #34187wordingwordingSTL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2.
  • GTL Please classify Fields Cardinal V8 #33784cars addedaddedFields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection.
  • GTL Toyota 4Y Engine Classification Request #33562engineaddedengineGTL 3K, 4K, 5K Toyota engines may now use 4Y block only.
  • GTL Toyota 4A-F and 4A-FE 1.6L DOHC 16V Engine Request #33415cars addedaddedGT2 and GTL add Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines as permitted options.
  • STL Spec MX5 in STL #33473cars addedaddedSpec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules.
  • GTL Fiat HP Limited Prep X1/9 Weight in GTL #33297weightslowerweightGTL Fiat X1/9 1500 Limited Prep minimum weight increases to 2000 lbs from 1835 lbs.
  • GTL GT2 (TA2)/GTA Part Number Update #33315wordingwordingGT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870.
  • GTL Request to add Ford Festiva to GTL #33335cars addedaddedGTL adds Ford Festiva 1988-1993 FWD hatchback with Mazda B3 1324cc engine.
  • GTL Engine Request #33064cars addedaddedGTL adds Toyota G16E-GTS 1618cc DOHC 3-cyl engine, 1945 lbs, SIR, no turbo or direct injection.
Virginia International Raceway Runoffs 20222022-09-242:05.474Danny Steyn · fastest of 24 · top 5 within 2.3s-1.729s (-1.36%)2:07.832Danny Steyn · fastest of 22 · top 5 within 1.9s+0.559s (+0.44%)131.7Trever Degioanni-3.2 mph (-2.3%)2:15.116Brian Farnham · fastest of 29 · top 5 within 1.1s-0.596s (-0.44%)2:18.093Andrew Whitston · fastest of 28 · top 5 within 1.2s-0.196s (-0.14%)115.8Jonathan Weisheit+1.1 mph (+0.9%)+10.261squal +9.642s108.0%qual 107.7%2:07.789Peter Shadowen · fastest of 14 · top 5 within 2.2s+0.792s (+0.62%)2:21.180Michael Lewis · fastest of 13 · top 5 within 2.1s+13.343s (+10.44%)136.0Peter Shadowen+4.9 mph (+3.7%)+13.348squal +2.315s110.4%qual 101.8%
12 rule changes (STL: 5, FV: 4, GTL: 3)3 engine · 2 cars added · 1 tyres & wheels · 1 weight · 5 wording · GT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps. · FV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077. · FV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs. · Ginetta G40 added to GTL with Ford Zetec 1796cc engine, 2050 lbs minimum weight, 22.5mm SIR. · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · FV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · STL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. · STL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb. · FV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight. · GT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight.showhide
  • GTL Tail lights on all GT category race cars. #32799wordingwordingGT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps.
  • FV Connecting Rod Update Request for 9.1.1.C Formula Vee (FV) 5.C.6 #32160engineaddedengineFV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077.
  • FV E&O clarification of connecting rod center-to-center length #32183wordingwordingFV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs.
  • GTL Request to Classify Ginetta G40 in GTL #31599cars addedaddedGinetta G40 added to GTL with Ford Zetec 1796cc engine, 2050 lbs minimum weight, 22.5mm SIR.
  • STL Single TB Weight Modifiers #31449weightfasterweightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs.
  • STL Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels.
  • FV Update direct replacement connecting rod information #31843wordingwordingFV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight.
  • STL Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed.
  • STL Mazda Renesis Restriction #31467enginefasterengineSTL Mazda Renesis flat plate restrictor increases from 55mm to 60mm.
  • STL Clarification of 79-85 RX7 Spec line #31621wordingwordingSTL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb.
  • FV Formula V Connecting Rod Replacement #31448engineaddedengineFV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight.
  • GTL Request car classification #31032cars addedaddedGT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight.
Indianapolis Motor Speedway Runoffs 20212021-09-251:51.665Danny Steyn · fastest of 42 · top 5 within 1.7s-0.982s (-0.87%)2:02.711Joe Moser · fastest of 37 · top 5 within 3.2s+10.122s (+8.99%)131.8Max Gee1:57.479Andrew Whitston · fastest of 48 · top 5 within 0.8s+1.720s (+1.49%)1:57.234Alex Scaler · fastest of 47 · top 5 within 1.0s+1.311s (+1.13%)124.0Mark Edwards-5.477squal +5.814s95.5%qual 105.2%1:51.819Christopher Bovis · fastest of 22 · top 5 within 1.8s+1.488s (+1.35%)1:51.952Scott Twomey · fastest of 19 · top 5 within 1.7s-0.116s (-0.10%)129.5Brian Linn-10.759squal +0.154s91.2%qual 100.1%
23 rule changes (STL: 15, GTL: 8)5 cars added · 3 aero · 3 engine · 3 induction · 2 weight · 1 suspension & brakes · 3 wording · 3 other · STL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix. · GTL Honda B18 split into B18A/B at 1797 cc 2050 lbs and B18C at 1834 cc 2065 lbs. · GTL Nissan B13 Sentra may have hood bulge maximum 1.5 inches high by 10.0 long by 6.0 wide. · unclear · STL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. · STL Pontiac Solstice/Saturn Sky allowed 4 inch ride height. · STL Mazda B5 DOHC added to class; must meet all STL regulations. · STL Honda B16A (JDM) restrictor reduced from 54mm to 53mm. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · GTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs, 28mm SIR option with 175 lb penalty removed. · STL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · GTL adds FIAT X-1/9 Bertone 1500 SOHC, 1498 cc, 2000 lbs, fuel injection or carburetors permitted. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork. · STL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment. · GTL Nissan MRA8DE 1.8L engine added, 1797 cc, DOHC, 2050 lbs minimum weight. · GTL Mazda 13B SIR increases from 26 mm to 28 mm; 27 mm option with 175 lbs removed. · STL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity. · STL Honda F20C drops 2% weight penalty, minimum weight reduced. · STL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm. · ST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.showhide
  • STL Request to clean up Spec MX-5 Redundancy #31069wordingwordingSTL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations.
  • GTL Request to Update GTA Obsolete Part Numbers #30615wordingwordingGTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix.
  • GTL Request clarification for the Honda B18a,bVS B18c #30482cars addedaddedGTL Honda B18 split into B18A/B at 1797 cc 2050 lbs and B18C at 1834 cc 2065 lbs.
  • GTL Request to Allow Hood Bulge on Nissan B13 Sentra #30504aeroaddedaeroGTL Nissan B13 Sentra may have hood bulge maximum 1.5 inches high by 10.0 long by 6.0 wide.
  • GTL Request BMW E21 Classing #30582otherunclearunclear
  • STL VW Engine Request #30625engineaddedengineSTL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs.
  • STL Solstice Ride Height #30183otheraddedSTL Pontiac Solstice/Saturn Sky allowed 4 inch ride height.
  • STL Request Mazda B5 DOHC #30420cars addedaddedSTL Mazda B5 DOHC added to class; must meet all STL regulations.
  • STL Honda B16A (JDM) Restrictor change #30531engineslowerengineSTL Honda B16A (JDM) restrictor reduced from 54mm to 53mm.
  • STL 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.
  • GTL Request for Help for Mazda 12A #29754induction +50 lbsslowerinductionGTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs, 28mm SIR option with 175 lb penalty removed.
  • STL GM Ecotec engines in STL #30247engineaddedengineSTL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor.
  • STL Super Touring Alternate Miata Hubs #30345cars addedaddedST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1.
  • GTL Request LP HP Fiat X1/9 & Bertone 1500 to GTL #30058cars addedaddedGTL adds FIAT X-1/9 Bertone 1500 SOHC, 1498 cc, 2000 lbs, fuel injection or carburetors permitted.
  • STL Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment.
  • STL Super Touring Wing Clarification #30111aeroaeroSTL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork.
  • STL Transmission Options #30118otheraddedSTL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment.
  • GTL Please Add GTL Nissan 1.8L Engine MRA8DE #29805cars addedaddedGTL Nissan MRA8DE 1.8L engine added, 1797 cc, DOHC, 2050 lbs minimum weight.
  • GTL Increase 13b SIR size #29867inductionfasterinductionGTL Mazda 13B SIR increases from 26 mm to 28 mm; 27 mm option with 175 lbs removed.
  • STL Request for FWD and RWD Parity #29728weightfasterweightSTL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity.
  • STL Request to Remove Honda F20C 2% Weight Penalty #29815weightfasterweightSTL Honda F20C drops 2% weight penalty, minimum weight reduced.
  • STL Request for FWD and RWD Parity #30023inductionslowerinductionSTL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm.
  • STL Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
Road America Runoffs 20202020-10-022:31.420Danny Steyn · fastest of 33 · top 5 within 3.1s2:32.115Joe Moser · fastest of 30 · top 5 within 1.5s132.9Darin Treakle2:43.994Hunter Phelps-Barron · fastest of 28 · top 5 within 0.6s2:45.816Alex Scaler · fastest of 24 · top 5 within 1.5s117.1Hunter Phelps-Barron+13.701squal +12.574s109.0%qual 108.3%2:31.943Chris Bovis · fastest of 14 · top 5 within 6.3s2:31.601Peter Shadowen · fastest of 14 · top 5 within 7.2s131.4Peter Shadowen-0.514squal +0.523s99.7%qual 100.3%
34 rule changes (STL: 11, FV: 6, GTL: 17)8 cars added · 5 tyres & wheels · 4 aero · 4 engine · 1 induction · 1 suspension & brakes · 1 weight · 9 wording · 1 other · GT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line. · GTL Mazda 13B restrictor increases from 24mm to 26mm SIR, minimum weight rises to 2125 lbs, alternative 27mm SIR option adds 175 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. · FV now permits 4 bolt wheels in addition to existing specifications. · FV now allows 4-bolt pattern wheels in addition to existing specifications. · GTL: Toyota MR2 Spyder 1999–2007 newly classified for GTL competition. · TA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications. · STO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change. · GT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b. · GTL Mazda 13B restrictor size addressed in response to letter 28518; see that letter for details. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · GTL SIR stall test procedure clarified: system tested as raced, competitor must prevent air bypass behind restrictor. · STL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum. · STL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC. · STL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants. · GTL wing mount openings excluded from square inch area limit. · STL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STL Mazda MZR restrictor reduced from 54 mm to 53 mm. · STL Mazda MZR restrictor reduces from 55 mm to 53 mm. · FV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. · GTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side view. · GTL wing mounting posts limited to 85 square inches each, measured flat from side view. · GTL wing endplates maximum area increased to 64 square inches from 8.5 by 3.0 inches rectangle. · GTL Mazda 12A street port minimum weight drops to 1950 lbs. · STL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes. · GT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications. · FV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020. · Formula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020. · GTX Misc. adds Factory Five Type 65 Coupe R Ford 302/351 and 5.0/5.2L NA at 2600 lbs, plus Ferrari 458/488 Challenge, Ford FP350S, Chevrolet C6, Lamborghini Super Trofeo. · GTL adds Jetta Mk1 two-door classification effective 2020-01-01. · FV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits. · GTL Honda CRX 84-87 and 88-91 lose permission to use IRS with 2.5% weight penalty.showhide
  • GTL GT Category Wording #29193wordingaddedGT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line.
  • GTL Request to change the Mazda 13b restrictor size #28518induction +175 lbsfasterinductionGTL Mazda 13B restrictor increases from 24mm to 26mm SIR, minimum weight rises to 2125 lbs, alternative 27mm SIR option adds 175 lbs.
  • STL Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds.
  • STL ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules.
  • FV Support for Recommended Item - 4 bolt wheels in FV #29084cars addedaddedFV now permits 4 bolt wheels in addition to existing specifications.
  • FV Support for 4-bolt pattern wheels #28955 #29118tyres & wheelsaddedtyres & wheelsFV now allows 4-bolt pattern wheels in addition to existing specifications.
  • GTL Request to classify 1999-2007 Toyota MR2 Spyder body #28870cars addedaddedGTL: Toyota MR2 Spyder 1999–2007 newly classified for GTL competition.
  • GTL TA2 Gurney flap wicker clarification #28874wordingwordingTA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications.
  • GTL STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change.
  • GTL GT Gurney flap wicker clarification #28909wordingwordingGT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b.
  • GTL Mazda 13b Restrictor Size Follow up to Letter 28518 #29015wordingunclearGTL Mazda 13B restrictor size addressed in response to letter 28518; see that letter for details.
  • STL Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
  • GTL Stall Test #28709wordingwordingGTL SIR stall test procedure clarified: system tested as raced, competitor must prevent air bypass behind restrictor.
  • STL Request to add 2016-2019 GMX-5 Spec line #28604cars addedaddedSTL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum.
  • STL Request to update PN for MX-5 #28622cars addedaddedSTL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC.
  • STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873wordingwordingSTL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants.
  • GTL GTL Wing Rule #28754aeroaddedaeroGTL wing mount openings excluded from square inch area limit.
  • STL STL Honda B18 restrictor changes #28794enginefasterengineSTL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants.
  • STL 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.
  • STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663engineslowerengineSTL Mazda MZR restrictor reduced from 54 mm to 53 mm.
  • STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664engineslowerengineSTL Mazda MZR restrictor reduces from 55 mm to 53 mm.
  • FV Update rain tire designation #28444tyres & wheelstyres & wheelsFV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3.
  • GTL Wing Mounting Upright Size #27641aeroaeroGTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side view.
  • GTL Wing Mounting Upright Size #27641aeroaeroGTL wing mounting posts limited to 85 square inches each, measured flat from side view.
  • GTL GTL wing end plates addition #28243aerofasteraeroGTL wing endplates maximum area increased to 64 square inches from 8.5 by 3.0 inches rectangle.
  • GTL Clarification to letter #27406 #28309weight -50 lbsfasterweightGTL Mazda 12A street port minimum weight drops to 1950 lbs.
  • STL Request to add wheel part numbers #28342cars addedaddedSTL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes.
  • GTL Windshield Clips #27323otheraddedGT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications.
  • FV FV Allow non-spec tire in Regional competition #26284tyres & wheelsaddedtyres & wheelsFV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020.
  • FV Request to Allow Rear Tires on the Front of Formula Vee #26537tyres & wheelsaddedtyres & wheelsFormula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020.
  • GTL Request Factory Five Daytona coupe classification #26308cars addedaddedGTX Misc. adds Factory Five Type 65 Coupe R Ford 302/351 and 5.0/5.2L NA at 2600 lbs, plus Ferrari 458/488 Challenge, Ford FP350S, Chevrolet C6, Lamborghini Super Trofeo.
  • GTL Request to Classify the MK1 two door Jetta #27648cars addedaddedGTL adds Jetta Mk1 two-door classification effective 2020-01-01.
  • FV Clarification on Wheel Bolt Pattern #27603tyres & wheelsaddedtyres & wheelsFV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.
  • GTL 88-91 Honda CRX Spec Line Correction #27233suspension & brakesremovedsuspension & brakesGTL Honda CRX 84-87 and 88-91 lose permission to use IRS with 2.5% weight penalty.
Virginia International Raceway Runoffs 20192019-10-052:07.203Danny Steyn · fastest of 36 · top 5 within 1.8s2:07.273Cliff Ira · fastest of 35 · top 5 within 1.4s134.8Cliff Ira1:55.124Bryce Cornet · fastest of 8 · top 5 within 2.3s2:15.816Bryce Cornet · fastest of 8 · top 5 within 4.9s135.7Bryce Cornet+8.543squal -12.079s106.7%qual 90.5%2:15.712Andrew Whitston · fastest of 26 · top 5 within 1.5s2:18.289Zachary Whitston · fastest of 19 · top 5 within 0.4s114.8Roger Siebenaler+11.016squal +8.509s108.7%qual 106.7%2:06.997Peter Shadowen · fastest of 19 · top 5 within 4.0s2:07.837Bill Ball · fastest of 18 · top 5 within 4.2s131.1Peter Shadowen+0.564squal -0.206s100.4%qual 99.8%
30 rule changes (STL: 11, FV: 6, GTL: 13)7 cars added · 5 engine · 3 weight · 1 induction · 1 removed · 1 suspension & brakes · 1 tyres & wheels · 8 wording · 3 other · FV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body. · STL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components. · FV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions. · GTL Fun Cup Beetle engine weight set to 1850 lbs with Weber DMTL 32/34 induction. · GTL Fun Cup Beetle removes reference to VW engine table; Fun Cup engines only permitted. · GTL Honda CRZ 10-14, CRZ 15-16, and Insight 00-06 gain alternate wheelbase option of 90.6 inches. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · FV exhaust outlet opening max distance from body rear increased from 3 to 4 inches. · STL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. · FV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed. · GTL Fun Cup Beetle added, all model years, 2-door RWD, 94.5 in wheelbase, VW Fun Cup spec chassis. · GTX tube frame cars now allowed fuel injection with maximum 90mm throttle body. · GTX adds Ligier JS2 R classification with restrictor and minimum weight. · GTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · FV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed. · GT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate. · GTL Mazda 12A may use 28mm SIR plus 175 lbs. · GTL: Ford Mustang 94-04 body newly classified for GTL racing. · STL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only. · STL Mazda Renesis minimum weight reduced to 2700 lbs. · STL Mazda MX-5 Cup brake pad compound now open. · STL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited. · STL Mazda 12 and 13B now permit port matching; porting ban removed. · FV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text. · GTL Mini 1275–1399 Iron and Aluminum Crossflow with OE common sump gearbox reduce weight by 125 lbs, up from 50 lbs. · GTL BMC thru Rover Group removes four long inactive Mini engines: 948, 970, 1071, 1098. · GTX FIA GT3: Audi R8 now 40 mm restrictor and 2900 lbs; BMW Z4 now 70 mm restrictor and 2800 lbs; Ferrari 488 now 35 mm restrictor, TIR, and 3025 lbs. · STL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline. · STL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.showhide
  • FV Allowed Modifications E&O #27398wordingwordingFV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body.
  • STL Request to Classify Spec MX-5 Challenge in STL #27399cars addedaddedSTL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components.
  • FV E&O Wheels #27230tyres & wheelsaddedtyres & wheelsFV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions.
  • GTL Fun Cup Beetle #27334wordingwordingGTL Fun Cup Beetle engine weight set to 1850 lbs with Weber DMTL 32/34 induction.
  • GTL GTL #26960wordingwordingGTL Fun Cup Beetle removes reference to VW engine table; Fun Cup engines only permitted.
  • GTL Request CRZ wheelbase change #26896cars addedaddedGTL Honda CRZ 10-14, CRZ 15-16, and Insight 00-06 gain alternate wheelbase option of 90.6 inches.
  • STL 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.
  • FV Exhaust termination rule E&O #26702wordingwordingFV exhaust outlet opening max distance from body rear increased from 3 to 4 inches.
  • STL Request Restrictor Plate correction #26779enginefasterengineSTL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate.
  • FV E&O Dimensions #26674suspension & brakessuspension & brakesFV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed.
  • GTL Request to Classify VW Fun Cup Beetle #25986cars addedaddedGTL Fun Cup Beetle added, all model years, 2-door RWD, 94.5 in wheelbase, VW Fun Cup spec chassis.
  • GTL Request GTX Fuel injection for previous GT-1 tube frame cars #26141engineaddedengineGTX tube frame cars now allowed fuel injection with maximum 90mm throttle body.
  • GTL Request to Classify Ligier JS2 R #26535cars addedaddedGTX adds Ligier JS2 R classification with restrictor and minimum weight.
  • GTL Request for GTL Mazda 13B SIR Increase with Penalty #26572engineaddedengineGTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added.
  • STL Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.
  • FV Request to clarify Disc Brake rules bearing retainer & weights #26262weightslowerweightFV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed.
  • GTL Request Ride Height Clarification #26600wordingfasterGT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate.
  • GTL Request Mazda 12a Rotary SIR Increase #26081inductionaddedinductionGTL Mazda 12A may use 28mm SIR plus 175 lbs.
  • GTL Request to Classify Mustang 2 Body in GTL #26222cars addedaddedGTL: Ford Mustang 94-04 body newly classified for GTL racing.
  • STL Request to Allow VW 1.8L Engine #25614cars addedaddedSTL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only.
  • STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbsfasterweightSTL Mazda Renesis minimum weight reduced to 2700 lbs.
  • STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821otheraddedSTL Mazda MX-5 Cup brake pad compound now open.
  • STL Request to clarify B18C1 GSR Honda B motor table #26209cars addedaddedSTL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited.
  • STL Port Matching #26415enginefasterengineSTL Mazda 12 and 13B now permit port matching; porting ban removed.
  • FV FV Intake Manifold Clarification #26008wordingwordingFV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text.
  • GTL Request for GTL Mini Adjustments #25754weightfasterweightGTL Mini 1275–1399 Iron and Aluminum Crossflow with OE common sump gearbox reduce weight by 125 lbs, up from 50 lbs.
  • GTL BMC thru Rover Group remove long inactive mini #25771removedremovedGTL BMC thru Rover Group removes four long inactive Mini engines: 948, 970, 1071, 1098.
  • GTL GTX Homologation table update #26034otherunclearGTX FIA GT3: Audi R8 now 40 mm restrictor and 2900 lbs; BMW Z4 now 70 mm restrictor and 2800 lbs; Ferrari 488 now 35 mm restrictor, TIR, and 3025 lbs.
  • STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746enginefasterengineSTL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline.
  • STL Request E&O for Mazda Miata Spec Line #25955otherunclearSTL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.
Sonoma Raceway Runoffs 20182018-10-101:49.138Danny Steyn · fastest of 19 · top 5 within 2.5s1:49.754Danny Steyn · fastest of 17 · top 5 within 2.5s103.2Craig McHaffie1:37.598Bryce Cornet · fastest of 13 · top 5 within 0.9s1:37.909Bryce Cornet · fastest of 12 · top 5 within 1.3s124.1Melvin David Kemper Jr-11.845squal -11.540s89.2%qual 89.4%1:52.637Skip Streets · fastest of 29 · top 5 within 1.6s1:53.639Alex Scaler · fastest of 28 · top 5 within 0.4s106.3Skip Streets+3.885squal +3.499s103.5%qual 103.2%1:47.885Troy Ermish · fastest of 20 · top 5 within 4.5s1:49.458Troy Ermish · fastest of 19 · top 5 within 3.6s109.3Charles Leonard-0.296squal -1.253s99.7%qual 98.9%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:52.647Adam Roberts · fastest of 57 · top 5 within 0.8s1:52.589Eric Kutil · fastest of 50 · top 5 within 1.2s1:41.231Jarret Voorhies · fastest of 16 · top 5 within 1.7s1:41.146Jarret Voorhies · fastest of 16 · top 5 within 1.2s-11.443squal -11.416s89.8%qual 89.9%1:55.759Michael Varacins · fastest of 39 · top 5 within 1.0s1:55.923Michael Varacins · fastest of 32 · top 5 within 1.3s+3.334squal +3.112s103.0%qual 102.8%1:50.331Christopher Bovis · fastest of 26 · top 5 within 1.5s1:52.068Christopher Bovis · fastest of 20 · top 5 within 1.0s-0.521squal -2.316s99.5%qual 97.9%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:35.439John Schmitt · fastest of 34 · top 5 within 1.5s1:36.625Kevin Boehm · fastest of 31 · top 5 within 0.6s1:26.043Jacob Loomis · fastest of 8 · top 5 within 3.1s1:27.922Jacob Loomis · fastest of 8 · top 5 within 2.7s-8.703squal -9.396s91.0%qual 90.2%1:37.942Alex Scaler · fastest of 41 · top 5 within 0.3s1:38.066Flinn Lazier · fastest of 38 · top 5 within 0.7s+1.441squal +2.503s101.5%qual 102.6%1:35.377Wilson Wright · fastest of 28 · top 5 within 1.2s1:35.912Kyle Disque · fastest of 28 · top 5 within 1.1s-0.713squal -0.062s99.3%qual 99.9%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-212:09.672Kevin Boehm · fastest of 37 · top 5 within 2.5s2:10.269Kevin Boehm · fastest of 37 · top 5 within 2.1s1:57.804Joseph Burton-Harris · fastest of 10 · top 5 within 2.3s1:58.029Joseph Burton-Harris · fastest of 10 · top 5 within 1.7s-12.240squal -11.868s90.6%qual 90.8%2:21.167Roger Siebenaler · fastest of 31 · top 5 within 0.8s2:21.142Andrew Whitston · fastest of 30 · top 5 within 1.1s+10.873squal +11.495s108.3%qual 108.9%2:11.387Jim Dentici · fastest of 10 · top 5 within 2.2s2:13.564Jim Dentici · fastest of 9 · top 5 within 2.0s+3.295squal +1.715s102.5%qual 101.3%

By track

TrackEvents Typical % of STL 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 STL'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.