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BoP Lab / Classes / STL

STL vs FF vs FV vs FM 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-SpecEPFAFCFE2vsFF×vsFM×FPvsFV×FXGT1GT2GTXHPPP2SMSMXSRF3STL×STUT1T2T3T4Show 50 inactive classes
Series
Reference class · the yardstick the % column and chart are measured against
Tracks · untick to narrow

Quickest here: STL 1:35.439 John Schmitt, Runoffs 2016 qualifying · FF 1:29.213 Neil Verhagen, Runoffs 2016 qualifying · FV 1:37.942 Alex Scaler, Runoffs 2016 qualifying · FM 1:26.043 Jacob Loomis, Runoffs 2016 qualifying

1:402:002:202:4020 rule changes between Runoffs 2018 and Runoffs 201920 ▾21 rule changes between Runoffs 2019 and Runoffs 202021 ▾18 rule changes between Runoffs 2020 and Runoffs 202118 ▾9 rule changes between Runoffs 2021 and Runoffs 20229 ▾3 rule changes between Runoffs 2022 and Runoffs 20233 ▾8 rule changes between Runoffs 2023 and Runoffs 20248 ▾7 rule changes between Runoffs 2024 and Runoffs 20257 ▾6 rule changes between Runoffs 2025 and Runoffs 20266 ▾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)FF race best at Runoffs 2015: 2:03.383 (Rick Payne)FF race best at Runoffs 2016: 1:30.133 (Neil Verhagen)FF race best at Runoffs 2017: 1:44.524 (Jonathon Kotyk)FF race best at Runoffs 2018: 1:42.049 (Jonathon Kotyk)FF race best at Runoffs 2019: 2:20.474 (Jonathan Kotyk)FF race best at Runoffs 2020: 2:24.268 (Jeffrey Bartz)FF race best at Runoffs 2021: 1:55.676 (Jonathan Kotyk)FF race best at Runoffs 2022: 2:18.358 (Jonathan Kotyk)FF race best at Runoffs 2023: 2:00.583 (Jonathan Kotyk)FF race best at Runoffs 2024: 2:22.057 (Sebastian Mateo Naranjo)FF race best at Runoffs 2025: 2:25.541 (Calvin Kautz)FF race best at Runoffs 2026: 2:23.686 (Nathan Down)FF qualifying best at Runoffs 2015: 2:02.489 (Tim Kautz)FF qualifying best at Runoffs 2016: 1:29.213 (Neil Verhagen)FF qualifying best at Runoffs 2017: 1:44.601 (Zach Holden)FF qualifying best at Runoffs 2018: 1:41.612 (Jonathon Kotyk)FF qualifying best at Runoffs 2019: 1:59.563 (Tyler O'Connor)FF qualifying best at Runoffs 2020: 2:22.916 (Simon Sikes)FF qualifying best at Runoffs 2021: 1:44.359 (Jonathan Kotyk)FF qualifying best at Runoffs 2022: 1:59.215 (Jonathan Kotyk)FF qualifying best at Runoffs 2023: 1:59.249 (Nolan Allaer)FF qualifying best at Runoffs 2024: 2:22.552 (Calvin Kautz)FF qualifying best at Runoffs 2025: 2:24.905 (Jonathan Kotyk)FF qualifying best at Runoffs 2026: 2:23.047 (David Ybarra)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)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)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)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
STLFFFVFMsolid race · dashed qualifying · slower is lower
90%95%100%105%110%20 rule changes between Runoffs 2018 and Runoffs 201920 ▾21 rule changes between Runoffs 2019 and Runoffs 202021 ▾18 rule changes between Runoffs 2020 and Runoffs 202118 ▾9 rule changes between Runoffs 2021 and Runoffs 20229 ▾3 rule changes between Runoffs 2022 and Runoffs 20233 ▾8 rule changes between Runoffs 2023 and Runoffs 20248 ▾7 rule changes between Runoffs 2024 and Runoffs 20257 ▾6 rule changes between Runoffs 2025 and Runoffs 20266 ▾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)FF race best at Runoffs 2015: 94.7% of STL's (Rick Payne)FF race best at Runoffs 2016: 93.3% of STL's (Neil Verhagen)FF race best at Runoffs 2017: 92.8% of STL's (Jonathon Kotyk)FF race best at Runoffs 2018: 93.0% of STL's (Jonathon Kotyk)FF race best at Runoffs 2019: 110.4% of STL's (Jonathan Kotyk)FF race best at Runoffs 2020: 94.8% of STL's (Jeffrey Bartz)FF race best at Runoffs 2021: 94.3% of STL's (Jonathan Kotyk)FF race best at Runoffs 2022: 108.2% of STL's (Jonathan Kotyk)FF race best at Runoffs 2023: 95.2% of STL's (Jonathan Kotyk)FF race best at Runoffs 2024: 94.6% of STL's (Sebastian Mateo Naranjo)FF race best at Runoffs 2025: 95.7% of STL's (Calvin Kautz)FF race best at Runoffs 2026: 95.4% of STL's (Nathan Down)FF qualifying best at Runoffs 2015: 94.5% of STL's (Tim Kautz)FF qualifying best at Runoffs 2016: 93.5% of STL's (Neil Verhagen)FF qualifying best at Runoffs 2017: 92.9% of STL's (Zach Holden)FF qualifying best at Runoffs 2018: 93.1% of STL's (Jonathon Kotyk)FF qualifying best at Runoffs 2019: 94.0% of STL's (Tyler O'Connor)FF qualifying best at Runoffs 2020: 94.4% of STL's (Simon Sikes)FF qualifying best at Runoffs 2021: 93.5% of STL's (Jonathan Kotyk)FF qualifying best at Runoffs 2022: 95.0% of STL's (Jonathan Kotyk)FF qualifying best at Runoffs 2023: 94.8% of STL's (Nolan Allaer)FF qualifying best at Runoffs 2024: 95.0% of STL's (Calvin Kautz)FF qualifying best at Runoffs 2025: 95.3% of STL's (Jonathan Kotyk)FF qualifying best at Runoffs 2026: 95.0% of STL's (David Ybarra)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)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)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
STLFFFVFMsolid 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
EventSTLFFFVFM
Qual bestRace bestTrapQual bestRace bestTrapvs STL% of STLQual bestRace bestTrapvs STL% of STLQual bestRace bestTrapvs 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%)2:23.047David Ybarra · fastest of 20 · top 5 within 1.4s-1.858s (-1.28%)2:23.686Nathan Down · fastest of 20 · top 5 within 1.6s-1.855s (-1.27%)138.9Tazio Stefanelli+0.5 mph (+0.3%)-6.971squal -7.490s95.4%qual 95.0%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%
6 rule changes (STL: 4, FF: 2)2 cars added · 1 tyres & wheels · 1 weight · 2 wording · FF Kent 1600 compression ratio calculation parameters reorganized: bore size and valve protrusion limits moved to separate subsections for clarity. · 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. · FF clarifies alternative tire eligibility: homologated 1989 or earlier with rocker or outboard suspension all four corners; push-rod/pull-rod cars may seek approval. · STL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.showhide
  • FF Clarification in FF Kent 1600 Compression Ratio Paragraph #40293wordingwordingFF Kent 1600 compression ratio calculation parameters reorganized: bore size and valve protrusion limits moved to separate subsections for clarity.
  • STL Spec Line Clean Up #40344cars addedremoved · cars 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.
  • FF Formula F Alternative Tire Rule Proposed Clarifications #39281tyres & wheelsadded · tyres & wheelsFF clarifies alternative tire eligibility: homologated 1989 or earlier with rocker or outboard suspension all four corners; push-rod/pull-rod cars may seek approval.
  • STL Weight adjustment for STL #39579weightslower · weightSTL 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%)2:24.905Jonathan Kotyk · fastest of 17 · top 5 within 1.1s+2.353s (+1.65%)2:25.541Calvin Kautz · fastest of 16 · top 5 within 0.5s+3.484s (+2.45%)138.4Tazio Stefanelli-2.3 mph (-1.6%)-6.586squal -7.160s95.7%qual 95.3%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%
7 rule changes (STL: 3, FF: 4)2 tyres & wheels · 2 weight · 1 cars added · 1 engine · 1 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. · FF adds rocker arm and outboard suspension cars option to use Hoosier bias ply slicks or VFF tyres; clarifies mixing rules. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed. · FF adds alternative tire options for older cars with rocker arm or outboard suspension: bias ply slicks or VFF radials. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · FF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition. · FF Honda Fit pistons: OEM 0.25mm oversize PN 13020-RB7-Z00 or Fast Forward PN FF800-110 now both allowed; standard diameter 73.240mm (2.8835 inches), minimum weight 198.0g.showhide
  • STL Lotus Weight Reduction #38772weight -50 lbsfaster · weightLotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs.
  • FF Page 228, FF tire rule 9.1.1.10.e #38251tyres & wheelsadded · tyres & wheelsFF adds rocker arm and outboard suspension cars option to use Hoosier bias ply slicks or VFF tyres; clarifies mixing rules.
  • 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.
  • FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change #37802tyres & wheelsadded · tyres & wheelsFF adds alternative tire options for older cars with rocker arm or outboard suspension: bias ply slicks or VFF radials.
  • 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.
  • FF Change FF/FC Weight with Sequential Gearbox #36651weightfaster · weightFF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition.
  • FF Alternative Oversize Honda Fit Pistons #37064engineadded · engineFF Honda Fit pistons: OEM 0.25mm oversize PN 13020-RB7-Z00 or Fast Forward PN FF800-110 now both allowed; standard diameter 73.240mm (2.8835 inches), minimum weight 198.0g.
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%)2:22.552Calvin Kautz · fastest of 13 · top 5 within 1.1s-0.364s (-0.25%)2:22.057Sebastian Mateo Naranjo · fastest of 13 · top 5 within 0.6s-2.211s (-1.53%)140.7Calvin Kautz+2.6 mph (+1.9%)-8.188squal -7.511s94.6%qual 95.0%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%
8 rule changes (STL: 4, FF: 2, FV: 2)3 engine · 1 aero · 1 weight · 3 wording · FF EGR blanking plate rule clarified: VTEC activation valve must be retained and functioning, no modifications permitted. · FV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side. · 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. · FF Honda Fit gains Fast Forward oversize piston ring option PN FF800-100 as alternative to Riken or Nippon. · 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.showhide
  • FF Update to FF EGR Blanking Plate Rule #36633wordingwordingFF EGR blanking plate rule clarified: VTEC activation valve must be retained and functioning, no modifications permitted.
  • FV Disc Brakes #36822wordingwordingFV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side.
  • STL ST Electric-Assisted Steering Systems #35066aeroadded · aeroSTL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems.
  • STL BOP Adjustments #35112weightfaster · weightSTL 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 #35320engineremoved · engineSTL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled.
  • FF Honda Fit Oversize Piston Rings #35305engineadded · engineFF Honda Fit gains Fast Forward oversize piston ring option PN FF800-100 as alternative to Riken or Nippon.
  • STL Alternate Carburetor Request for 79-85 RX7 12a #35181engineadded · engineSTL 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.
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%)1:59.249Nolan Allaer · fastest of 8 · top 5 within 2.8s+0.034s (+0.03%)2:00.583Jonathan Kotyk · fastest of 8 · top 5 within 0.4s-17.775s (-12.85%)138.4Calvin Kautz+0.1 mph (+0.1%)-6.099squal -6.530s95.2%qual 94.8%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%
3 rule changes (STL: 2, FF: 1)1 cars added · 1 engine · 1 wording · STL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2. · FF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. · 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.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.
  • FF Add Fast Forward Part Numbers for Honda Fit Engine #33752engineadded · engineFF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components.
  • 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.
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%)1:59.215Jonathan Kotyk · fastest of 13 · top 5 within 1.2s-0.348s (-0.29%)2:18.358Jonathan Kotyk · fastest of 12 · top 5 within 2.4s-2.116s (-1.51%)138.3Tim Kautz+2.2 mph (+1.6%)+10.526squal -6.259s108.2%qual 95.0%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%
9 rule changes (STL: 5, FV: 4)3 engine · 1 tyres & wheels · 1 weight · 4 wording · 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. · 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.showhide
  • FV Connecting Rod Update Request for 9.1.1.C Formula Vee (FV) 5.C.6 #32160engineadded · engineFV 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.
  • STL Single TB Weight Modifiers #31449weightfaster · weightSTU 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 #31467enginefaster · engineSTL 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 #31448engineadded · engineFV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM 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 Gee1:44.359Jonathan Kotyk · fastest of 24 · top 5 within 1.1s-0.242s (-0.23%)1:55.676Jonathan Kotyk · fastest of 23 · top 5 within 1.8s+11.152s (+10.67%)141.6Nicholas Sheppard-7.035squal -7.306s94.3%qual 93.5%1:57.479Andrew 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%
18 rule changes (STL: 15, FF: 3)3 engine · 2 aero · 2 cars added · 2 weight · 1 induction · 1 suspension & brakes · 4 wording · 3 other · STL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. · 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. · FF block relief permitted only as needed to fit an allowed crankshaft. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · 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. · 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. · 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. · FF class cylinder head now permits optional coolant bleed line pipe thread fitting to swirl tower. · FF Honda LC1 ECU supplied by HPD is permitted effective 12/1/2020 with HPD lambda sensor. · 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.
  • STL VW Engine Request #30625engineadded · engineSTL 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 #30531engineslower · engineSTL Honda B16A (JDM) restrictor reduced from 54mm to 53mm.
  • FF Kent crankshaft clarification #30426wordingwordingFF block relief permitted only as needed to fit an allowed crankshaft.
  • 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.
  • STL GM Ecotec engines in STL #30247engineadded · engineSTL 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.
  • 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.
  • STL Request for FWD and RWD Parity #29728weightfaster · weightSTL 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 #29815weightfaster · weightSTL Honda F20C drops 2% weight penalty, minimum weight reduced.
  • STL Request for FWD and RWD Parity #30023inductionslower · inductionSTL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm.
  • FF Allow Optional Coolant Bleed Line to Correct a Known Problem #29673otheraddedFF class cylinder head now permits optional coolant bleed line pipe thread fitting to swirl tower.
  • FF Clarification regarding Honda LC1 ECU implementation date #29684wordingwordingFF Honda LC1 ECU supplied by HPD is permitted effective 12/1/2020 with HPD lambda sensor.
  • 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 Treakle2:22.916Simon Sikes · fastest of 14 · top 5 within 1.6s2:24.268Jeffrey Bartz · fastest of 14 · top 5 within 0.4s138.1Jeffrey Bartz-7.847squal -8.504s94.8%qual 94.4%2:43.994Hunter 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%
21 rule changes (STL: 11, FF: 4, FV: 6)6 engine · 6 tyres & wheels · 5 cars added · 4 wording · FF Honda LC1 ECU implementation date clarified to pending, contingent on SCCA receiving sufficient support materials. · 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. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · 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. · STL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. · FF Kent Engine alternator becomes optional instead of not required. · 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. · FF permits HPD LC1 ECU with lambda sensor; E1 ECU no longer supported but existing units may continue. · FF rain tyres now allow Hoosier W3 Radial 185/60R13 front and 205/60R13 rear. · FV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. · STL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes. · 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. · FV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.showhide
  • FF Clarification regarding Honda LC1 ECU implementation #29135wordingwordingFF Honda LC1 ECU implementation date clarified to pending, contingent on SCCA receiving sufficient support materials.
  • 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 & wheelsadded · tyres & wheelsFV now allows 4-bolt pattern wheels in addition to existing specifications.
  • STL Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
  • 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.
  • STL STL Honda B18 restrictor changes #28794enginefaster · engineSTL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants.
  • FF E&O FF Kent Engine alternator language #28204engineadded · engineFF Kent Engine alternator becomes optional instead of not required.
  • STL Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineadded · engineSTU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs.
  • STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663engineslower · engineSTL Mazda MZR restrictor reduced from 54 mm to 53 mm.
  • STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664engineslower · engineSTL Mazda MZR restrictor reduces from 55 mm to 53 mm.
  • FF Honda Racing HPD low cost ECU proposal #27563engineadded · engineFF permits HPD LC1 ECU with lambda sensor; E1 ECU no longer supported but existing units may continue.
  • FF Update rain tire designation #28443tyres & wheelsadded · tyres & wheelsFF rain tyres now allow Hoosier W3 Radial 185/60R13 front and 205/60R13 rear.
  • FV Update rain tire designation #28444tyres & wheelstyres & wheelsFV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3.
  • 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.
  • FV FV Allow non-spec tire in Regional competition #26284tyres & wheelsadded · tyres & 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 & wheelsadded · tyres & 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.
  • FV Clarification on Wheel Bolt Pattern #27603tyres & wheelsadded · tyres & wheelsFV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.
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 Ira1:59.563Tyler O'Connor · fastest of 14 · top 5 within 1.4s2:20.474Jonathan Kotyk · fastest of 14 · top 5 within 6.3s136.2Derek Ketchie+13.201squal -7.640s110.4%qual 94.0%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%1:55.124Bryce 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%
20 rule changes (STL: 11, FF: 3, FV: 6)4 engine · 3 cars added · 2 weight · 1 aero · 1 suspension & brakes · 1 tyres & wheels · 6 wording · 2 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. · 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. · 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. · 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. · FF Honda Fit cylinder honing increased to 73.315mm and oversize pistons PN 13020-RB7-Z00 now permitted with matching ring packs. · FF intake manifold thermal wrap now permitted if easily removable for inspection; no coating allowed. · FF clarifies coolant and oil catch tank capacity requirements: coolant minimum one U.S. pint, oil minimum one U.S. quart per system. · FV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text. · 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 & wheelsadded · tyres & wheelsFV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions.
  • 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 #26779enginefaster · engineSTL 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.
  • 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 #26262weightslower · weightFV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed.
  • 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 lbsfaster · weightSTL 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 #26415enginefaster · engineSTL Mazda 12 and 13B now permit port matching; porting ban removed.
  • FF Request for Oversize Honda Fit Pistons #25810enginefaster · engineFF Honda Fit cylinder honing increased to 73.315mm and oversize pistons PN 13020-RB7-Z00 now permitted with matching ring packs.
  • FF Heat Shield - Fit Intake #26102aeroadded · aeroFF intake manifold thermal wrap now permitted if easily removable for inspection; no coating allowed.
  • FF Request catch cans/tanks clarification #26158wordingwordingFF clarifies coolant and oil catch tank capacity requirements: coolant minimum one U.S. pint, oil minimum one U.S. quart per system.
  • FV FV Intake Manifold Clarification #26008wordingwordingFV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text.
  • STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746enginefaster · engineSTL 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 McHaffie1:41.612Jonathon Kotyk · fastest of 22 · top 5 within 1.7s1:42.049Jonathon Kotyk · fastest of 22 · top 5 within 1.3s115.7Denny Renfrow-7.705squal -7.526s93.0%qual 93.1%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%1:37.598Bryce 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%
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 1.2s1:44.601Zach Holden · fastest of 36 · top 5 within 1.2s1:44.524Jonathon Kotyk · fastest of 36 · top 5 within 0.5s-8.065squal -8.046s92.8%qual 92.9%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%1:41.231Jarret 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%
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 0.6s1:29.213Neil Verhagen · fastest of 14 · top 5 within 2.1s1:30.133Neil Verhagen · fastest of 14 · top 5 within 1.4s-6.492squal -6.226s93.3%qual 93.5%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%1:26.043Jacob 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%
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 2.1s2:02.489Tim Kautz · fastest of 25 · top 5 within 1.1s2:03.383Rick Payne · fastest of 22 · top 5 within 0.8s-6.886squal -7.183s94.7%qual 94.5%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%1:57.804Joseph 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%

By track

TrackEventsTypical % of STLBestLatest
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, the track and its configuration cancel out, so one figure compares across tracks and years where lap times cannot. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.