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BoP Lab / Classes / T4

T4 vs SM vs FC vs FE2 pace at every track

Lap times across years say as much about the weather as the class. % of T4 is each class's best lap as a share of T4'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-SpecEPFAvsFC×vsFE2×FFFPFVFXGT1GT2GTXHPPP2vsSM×SMXSRF3STLSTUT1T2T3T4×Show 51 inactive classes
Series
Reference · what % is measured against
Tracks · untick to narrow

Closest to the field: T4 100.0% of T4 Philip Royle, Daytona International Speedway Runoffs 2015 race · SM 95.6% of T4 Travis Wiley, Virginia International Raceway Runoffs 2022 race · FC 81.7% of T4 Nigel Saurino, Mid-Ohio Sports Car Course Runoffs 2016 race · FE2 83.4% of T4 Max Grau, Indianapolis Motor Speedway Runoffs 2021 race

1:402:002:202:4021 rule changes between Runoffs 2018 and Runoffs 201921 ▾33 rule changes between Runoffs 2019 and Runoffs 202033 ▾22 rule changes between Runoffs 2020 and Runoffs 202122 ▾35 rule changes between Runoffs 2021 and Runoffs 202235 ▾24 rule changes between Runoffs 2022 and Runoffs 202324 ▾34 rule changes between Runoffs 2023 and Runoffs 202434 ▾36 rule changes between Runoffs 2024 and Runoffs 202536 ▾31 rule changes between Runoffs 2025 and Runoffs 202631 ▾T4 race best at Runoffs 2015: 2:15.994 (Philip Royle)T4 race best at Runoffs 2016: 1:40.397 (Oscar Jackson)T4 race best at Runoffs 2017: 1:56.923 (Oscar Jackson)T4 race best at Runoffs 2018: 1:54.030 (John Heinricy)T4 race best at Runoffs 2019: 2:10.959 (Nick Leverone)T4 race best at Runoffs 2020: 2:37.881 (Chi Ho)T4 race best at Runoffs 2021: 1:55.929 (John Heinricy)T4 race best at Runoffs 2022: 2:25.443 (John Heinricy)T4 race best at Runoffs 2023: 2:11.962 (Devin Anderson)T4 race best at Runoffs 2024: 2:34.208 (Alex Lozano)T4 race best at Runoffs 2025: 2:32.633 (Alex Lozano)T4 race best at Runoffs 2026: 2:35.757 (Matt Spicuzzi)T4 qualifying best at Runoffs 2015: 2:15.886 (Philip Royle)T4 qualifying best at Runoffs 2016: 1:38.813 (Jonathan Yanca)T4 qualifying best at Runoffs 2017: 1:56.566 (Oscar Jackson)T4 qualifying best at Runoffs 2018: 1:52.339 (Gresham Wagner)T4 qualifying best at Runoffs 2019: 2:11.257 (John Heinricy)T4 qualifying best at Runoffs 2020: 2:37.403 (John Heinricy)T4 qualifying best at Runoffs 2021: 1:54.397 (Stephen Blethen)T4 qualifying best at Runoffs 2022: 2:09.577 (John Heinricy)T4 qualifying best at Runoffs 2023: 2:10.514 (Devin Anderson)T4 qualifying best at Runoffs 2024: 2:34.430 (Matt Spicuzzi)T4 qualifying best at Runoffs 2025: 2:32.956 (Matt Spicuzzi)T4 qualifying best at Runoffs 2026: 2:35.876 (Matt Spicuzzi)SM race best at Runoffs 2015: 2:24.067 (Todd Lamb)SM race best at Runoffs 2016: 1:40.764 (Michael Carter)SM race best at Runoffs 2017: 1:59.100 (Michael Gagliardo)SM race best at Runoffs 2018: 1:55.278 (Michael Carter)SM race best at Runoffs 2019: 2:16.459 (Elivan Goulart)SM race best at Runoffs 2020: 2:43.748 (Preston Pardus)SM race best at Runoffs 2021: 1:58.837 (Brian Henderson)SM race best at Runoffs 2022: 2:19.107 (Travis Wiley)SM race best at Runoffs 2023: 2:16.229 (Julian DaCosta)SM race best at Runoffs 2024: 2:41.486 (Brett Kowalski)SM race best at Runoffs 2025: 2:44.430 (Kyle Greenhill)SM race best at Runoffs 2026: 2:42.725 (Francisco Barroso)SM qualifying best at Runoffs 2015: 2:18.661 (Andrew Carbonell)SM qualifying best at Runoffs 2016: 1:40.514 (Justin Hille)SM qualifying best at Runoffs 2017: 1:58.306 (Chris Haldeman)SM qualifying best at Runoffs 2018: 1:54.355 (Ken Sutherland)SM qualifying best at Runoffs 2019: 2:14.552 (Todd Buras)SM qualifying best at Runoffs 2020: 2:42.209 (Kyle Greenhill)SM qualifying best at Runoffs 2021: 1:57.695 (Brian Henderson)SM qualifying best at Runoffs 2022: 2:14.664 (Danny Steyn)SM qualifying best at Runoffs 2023: 2:14.986 (Danny Steyn)SM qualifying best at Runoffs 2024: 2:41.106 (Ethan Goulart)SM qualifying best at Runoffs 2025: 2:43.111 (Bobby Gossett)SM qualifying best at Runoffs 2026: 2:42.173 (Brett Kowalski)FC race best at Runoffs 2015: 1:55.135 (Yufeng Luo)Off the chart: FC race best at Runoffs 2016: 1:22.049 (Nigel Saurino)FC race best at Runoffs 2017: 1:36.890 (Tim Minor)FC race best at Runoffs 2018: 1:34.053 (Mitch Egner)FC race best at Runoffs 2019: 1:52.174 (Robert Allaer)FC race best at Runoffs 2020: 2:13.608 (Robert Allaer)FC race best at Runoffs 2021: 1:36.980 (Simon Sikes)FC race best at Runoffs 2022: 2:07.859 (Nolan Allaer)FC race best at Runoffs 2023: 1:51.169 (Nolan Allaer)FC race best at Runoffs 2024: 2:11.534 (Michael Varacins)FC race best at Runoffs 2025: 2:12.824 (Brandon Dixon)FC race best at Runoffs 2026: 2:11.389 (Brandon Dixon)FC qualifying best at Runoffs 2015: 1:54.477 (Yufeng Luo)Off the chart: FC qualifying best at Runoffs 2016: 1:21.962 (John LaRue)FC qualifying best at Runoffs 2017: 1:36.336 (Austin McCusker)FC qualifying best at Runoffs 2018: 1:32.571 (Timothy de Silva)FC qualifying best at Runoffs 2019: 1:51.200 (Robert Allaer)FC qualifying best at Runoffs 2020: 2:12.644 (Robert Allaer)FC qualifying best at Runoffs 2021: 1:36.787 (Trent Walko)FC qualifying best at Runoffs 2022: 1:49.895 (Nolan Allaer)FC qualifying best at Runoffs 2023: 1:50.281 (Nolan Allaer)FC qualifying best at Runoffs 2024: 2:11.626 (Timothy Minor)FC qualifying best at Runoffs 2025: 2:11.259 (Brandon Dixon)FC qualifying best at Runoffs 2026: 2:10.686 (Brandon Dixon)FE2 race best at Runoffs 2018: 1:35.563 (Flinn Lazier)FE2 race best at Runoffs 2019: 1:52.154 (Liam Snyder)FE2 race best at Runoffs 2020: 2:13.271 (Owen McAllister)FE2 race best at Runoffs 2021: 1:36.655 (Max Grau)FE2 race best at Runoffs 2022: 2:12.045 (Jason Conzo)FE2 race best at Runoffs 2023: 1:51.098 (Franklin Futrelle)FE2 race best at Runoffs 2024: 2:12.748 (Porter Aiken)FE2 race best at Runoffs 2025: 2:13.339 (Franklin Futrelle)FE2 race best at Runoffs 2026: 2:11.881 (Franklin Futrelle)FE2 qualifying best at Runoffs 2018: 1:35.040 (Flinn Lazier)FE2 qualifying best at Runoffs 2019: 1:51.062 (Liam Snyder)FE2 qualifying best at Runoffs 2020: 2:12.806 (Scott Rettich)FE2 qualifying best at Runoffs 2021: 1:36.395 (Max Grau)FE2 qualifying best at Runoffs 2022: 1:50.853 (Charles Russell Turner)FE2 qualifying best at Runoffs 2023: 1:50.665 (Charles Russell Turner)FE2 qualifying best at Runoffs 2024: 2:11.506 (Porter Aiken)FE2 qualifying best at Runoffs 2025: 2:12.475 (Franklin Futrelle)FE2 qualifying best at Runoffs 2026: 2:12.326 (Franklin Futrelle)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2025R2025Road America · Runoffs 2026R2026
T4SMFCFE2solid race · dashed qualifying · slower is lower
80%85%90%95%100%105%21 rule changes between Runoffs 2018 and Runoffs 201921 ▾33 rule changes between Runoffs 2019 and Runoffs 202033 ▾22 rule changes between Runoffs 2020 and Runoffs 202122 ▾35 rule changes between Runoffs 2021 and Runoffs 202235 ▾24 rule changes between Runoffs 2022 and Runoffs 202324 ▾34 rule changes between Runoffs 2023 and Runoffs 202434 ▾36 rule changes between Runoffs 2024 and Runoffs 202536 ▾31 rule changes between Runoffs 2025 and Runoffs 202631 ▾T4 race best at Runoffs 2015: 100.0% of T4's (Philip Royle)T4 race best at Runoffs 2016: 100.0% of T4's (Oscar Jackson)T4 race best at Runoffs 2017: 100.0% of T4's (Oscar Jackson)T4 race best at Runoffs 2018: 100.0% of T4's (John Heinricy)T4 race best at Runoffs 2019: 100.0% of T4's (Nick Leverone)T4 race best at Runoffs 2020: 100.0% of T4's (Chi Ho)T4 race best at Runoffs 2021: 100.0% of T4's (John Heinricy)T4 race best at Runoffs 2022: 100.0% of T4's (John Heinricy)T4 race best at Runoffs 2023: 100.0% of T4's (Devin Anderson)T4 race best at Runoffs 2024: 100.0% of T4's (Alex Lozano)T4 race best at Runoffs 2025: 100.0% of T4's (Alex Lozano)T4 race best at Runoffs 2026: 100.0% of T4's (Matt Spicuzzi)T4 qualifying best at Runoffs 2015: 100.0% of T4's (Philip Royle)T4 qualifying best at Runoffs 2016: 100.0% of T4's (Jonathan Yanca)T4 qualifying best at Runoffs 2017: 100.0% of T4's (Oscar Jackson)T4 qualifying best at Runoffs 2018: 100.0% of T4's (Gresham Wagner)T4 qualifying best at Runoffs 2019: 100.0% of T4's (John Heinricy)T4 qualifying best at Runoffs 2020: 100.0% of T4's (John Heinricy)T4 qualifying best at Runoffs 2021: 100.0% of T4's (Stephen Blethen)T4 qualifying best at Runoffs 2022: 100.0% of T4's (John Heinricy)T4 qualifying best at Runoffs 2023: 100.0% of T4's (Devin Anderson)T4 qualifying best at Runoffs 2024: 100.0% of T4's (Matt Spicuzzi)T4 qualifying best at Runoffs 2025: 100.0% of T4's (Matt Spicuzzi)T4 qualifying best at Runoffs 2026: 100.0% of T4's (Matt Spicuzzi)SM race best at Runoffs 2015: 105.9% of T4's (Todd Lamb)SM race best at Runoffs 2016: 100.4% of T4's (Michael Carter)SM race best at Runoffs 2017: 101.9% of T4's (Michael Gagliardo)SM race best at Runoffs 2018: 101.1% of T4's (Michael Carter)SM race best at Runoffs 2019: 104.2% of T4's (Elivan Goulart)SM race best at Runoffs 2020: 103.7% of T4's (Preston Pardus)SM race best at Runoffs 2021: 102.5% of T4's (Brian Henderson)SM race best at Runoffs 2022: 95.6% of T4's (Travis Wiley)SM race best at Runoffs 2023: 103.2% of T4's (Julian DaCosta)SM race best at Runoffs 2024: 104.7% of T4's (Brett Kowalski)Off the chart: SM race best at Runoffs 2025: 107.7% of T4's (Kyle Greenhill)SM race best at Runoffs 2026: 104.5% of T4's (Francisco Barroso)SM qualifying best at Runoffs 2015: 102.0% of T4's (Andrew Carbonell)SM qualifying best at Runoffs 2016: 101.7% of T4's (Justin Hille)SM qualifying best at Runoffs 2017: 101.5% of T4's (Chris Haldeman)SM qualifying best at Runoffs 2018: 101.8% of T4's (Ken Sutherland)SM qualifying best at Runoffs 2019: 102.5% of T4's (Todd Buras)SM qualifying best at Runoffs 2020: 103.1% of T4's (Kyle Greenhill)SM qualifying best at Runoffs 2021: 102.9% of T4's (Brian Henderson)SM qualifying best at Runoffs 2022: 103.9% of T4's (Danny Steyn)SM qualifying best at Runoffs 2023: 103.4% of T4's (Danny Steyn)SM qualifying best at Runoffs 2024: 104.3% of T4's (Ethan Goulart)SM qualifying best at Runoffs 2025: 106.6% of T4's (Bobby Gossett)SM qualifying best at Runoffs 2026: 104.0% of T4's (Brett Kowalski)FC race best at Runoffs 2015: 84.7% of T4's (Yufeng Luo)FC race best at Runoffs 2016: 81.7% of T4's (Nigel Saurino)FC race best at Runoffs 2017: 82.9% of T4's (Tim Minor)FC race best at Runoffs 2018: 82.5% of T4's (Mitch Egner)FC race best at Runoffs 2019: 85.7% of T4's (Robert Allaer)FC race best at Runoffs 2020: 84.6% of T4's (Robert Allaer)FC race best at Runoffs 2021: 83.7% of T4's (Simon Sikes)FC race best at Runoffs 2022: 87.9% of T4's (Nolan Allaer)FC race best at Runoffs 2023: 84.2% of T4's (Nolan Allaer)FC race best at Runoffs 2024: 85.3% of T4's (Michael Varacins)FC race best at Runoffs 2025: 87.0% of T4's (Brandon Dixon)FC race best at Runoffs 2026: 84.4% of T4's (Brandon Dixon)FC qualifying best at Runoffs 2015: 84.2% of T4's (Yufeng Luo)FC qualifying best at Runoffs 2016: 82.9% of T4's (John LaRue)FC qualifying best at Runoffs 2017: 82.6% of T4's (Austin McCusker)FC qualifying best at Runoffs 2018: 82.4% of T4's (Timothy de Silva)FC qualifying best at Runoffs 2019: 84.7% of T4's (Robert Allaer)FC qualifying best at Runoffs 2020: 84.3% of T4's (Robert Allaer)FC qualifying best at Runoffs 2021: 84.6% of T4's (Trent Walko)FC qualifying best at Runoffs 2022: 84.8% of T4's (Nolan Allaer)FC qualifying best at Runoffs 2023: 84.5% of T4's (Nolan Allaer)FC qualifying best at Runoffs 2024: 85.2% of T4's (Timothy Minor)FC qualifying best at Runoffs 2025: 85.8% of T4's (Brandon Dixon)FC qualifying best at Runoffs 2026: 83.8% of T4's (Brandon Dixon)FE2 race best at Runoffs 2018: 83.8% of T4's (Flinn Lazier)FE2 race best at Runoffs 2019: 85.6% of T4's (Liam Snyder)FE2 race best at Runoffs 2020: 84.4% of T4's (Owen McAllister)FE2 race best at Runoffs 2021: 83.4% of T4's (Max Grau)FE2 race best at Runoffs 2022: 90.8% of T4's (Jason Conzo)FE2 race best at Runoffs 2023: 84.2% of T4's (Franklin Futrelle)FE2 race best at Runoffs 2024: 86.1% of T4's (Porter Aiken)FE2 race best at Runoffs 2025: 87.4% of T4's (Franklin Futrelle)FE2 race best at Runoffs 2026: 84.7% of T4's (Franklin Futrelle)FE2 qualifying best at Runoffs 2018: 84.6% of T4's (Flinn Lazier)FE2 qualifying best at Runoffs 2019: 84.6% of T4's (Liam Snyder)FE2 qualifying best at Runoffs 2020: 84.4% of T4's (Scott Rettich)FE2 qualifying best at Runoffs 2021: 84.3% of T4's (Max Grau)FE2 qualifying best at Runoffs 2022: 85.5% of T4's (Charles Russell Turner)FE2 qualifying best at Runoffs 2023: 84.8% of T4's (Charles Russell Turner)FE2 qualifying best at Runoffs 2024: 85.2% of T4's (Porter Aiken)FE2 qualifying best at Runoffs 2025: 86.6% of T4's (Franklin Futrelle)FE2 qualifying best at Runoffs 2026: 84.9% of T4's (Franklin Futrelle)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2025R2025Road America · Runoffs 2026R2026
T4SMFCFE2solid race · dashed qualifying · each class's best lap as a share of T4's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
EventT4SMFCFE2
Qual best Race best Trap Qual best Race best Trap vs T4 % of T4 Qual best Race best Trap vs T4 % of T4 Qual best Race best Trap vs T4 % of T4 
Road America Runoffs 20262026-09-282:35.876Matt Spicuzzi · fastest of 12 · top 5 within 2.4s+2.920s (+1.91%)2:35.757Matt Spicuzzi · fastest of 12 · top 5 within 2.7s+3.124s (+2.05%)127.6Matt Spicuzzi-6.0 mph (-4.5%)2:42.173Brett Kowalski · fastest of 34 · top 5 within 0.3s-0.938s (-0.58%)2:42.725Francisco Barroso · fastest of 35 · top 5 within 0.2s-1.705s (-1.04%)119.6Wyatt Couch+0.3 mph (+0.3%)+6.968squal +6.297s104.5%qual 104.0%2:10.686Brandon Dixon · fastest of 10 · top 5 within 4.0s-0.573s (-0.44%)2:11.389Brandon Dixon · fastest of 10 · top 5 within 2.7s-1.435s (-1.08%)143.3Dean Kiriluk-1.8 mph (-1.2%)-24.368squal -25.190s84.4%qual 83.8%2:12.326Franklin Futrelle · fastest of 8 · top 5 within 1.9s-0.149s (-0.11%)2:11.881Franklin Futrelle · fastest of 8 · top 5 within 1.6s-1.458s (-1.09%)143.5Steve Whitston-5.5 mph (-3.7%)-23.876squal -23.550s84.7%qual 84.9%
31 rule changes (T4: 26, SM: 2, FC: 2, FE2: 1)6 weight · 5 cars added · 5 suspension & brakes · 3 induction · 2 tyres & wheels · 1 removed · 1 wording · 8 othershowhide
  • T4 02-06 R53 Mini Cooper Hotchkins Rear Camber Arms #40677suspension & brakes
  • T4 Is it time? #40653cars added
  • T4 Combine T4 BRZ/86/FRS generations #40656weight
  • SM Rear Toe Link #40271other
  • T4 Dodge Neon DOHC Weight #40329weight
  • T4 SPB In T4 #39973other
  • T4 02-06 Mini Cooper S #40106weight -50 lbs
  • T4 02-06 Mini Cooper S Fuel #40107other
  • T4 Shock error #40176suspension & brakes
  • T4 Max Tire Sizes #40183tyres & wheels
  • T4 2003 Honda Civic Si Classification #39999cars added
  • SM Part Number Change Request #39914wording
  • T4 16-24 ND MX5 T4 #39934suspension & brakes
  • T4 ND MX-5 Spec Line Rewrite Request #39802weight -100 lbs
  • T4 4.0 Mustang spec line cleanup #39831induction
  • T4 T4 and T3 Feedback #39230removed
  • T4 T4 Mustang 4.0 #39489induction
  • T4 Allow Alt Bushing Material in Toe Links #39607suspension & brakes
  • FC F2000 MZR Spec Line Clarity/Revision Requested #38927other
  • FC Adjust F2000 Metrik ZF2 weight #39612weight -20 lbs
  • T4 Alternate Placement of Fuse Panel and Electronics Request #39370other
  • T4 Clarify T4 Brake Rotor Allowance #39503suspension & brakes
  • T4 Classing 1995-99 Dodge Neon SOHC #39285cars added
  • T4 02-06 Mini Cooper Gear Ratios #38966other
  • T4 Reinstatement of the 2005-2010 Cobalt into T4 #38987cars added
  • T4 Request to Classify Mercedes C230K #39080cars added
  • T4 ND Gearset Request for T4 #39166other
  • T4 E&O wheel size on ND #39168tyres & wheels
  • T4 ND Spec Lines Wrong PT#'s #39170weight
  • T4 Touring 4 Post-Runoffs BOP Adjustments and Changes #39251induction -100 lbs
  • FE2 FE & FE2 Bubble Tail #38978other
Road America Runoffs 20252025-09-292:32.956Matt Spicuzzi · fastest of 10 · top 5 within 3.8s-1.474s (-0.95%)2:32.633Alex Lozano · fastest of 10 · top 5 within 4.3s-1.575s (-1.02%)133.7Alex Lozano+4.4 mph (+3.4%)2:43.111Bobby Gossett · fastest of 32 · top 5 within 0.3s+2.005s (+1.24%)2:44.430Kyle Greenhill · fastest of 28 · top 5 within 0.3s+2.944s (+1.82%)119.3Francisco Barroso-0.6 mph (-0.5%)+11.797squal +10.155s107.7%qual 106.6%2:11.259Brandon Dixon · fastest of 10 · top 5 within 2.7s-0.367s (-0.28%)2:12.824Brandon Dixon · fastest of 9 · top 5 within 2.3s+1.290s (+0.98%)145.1Brandon Dixon+0.9 mph (+0.6%)-19.809squal -21.697s87.0%qual 85.8%2:12.475Franklin Futrelle · fastest of 11 · top 5 within 1.4s+0.969s (+0.74%)2:13.339Franklin Futrelle · fastest of 10 · top 5 within 0.6s+0.591s (+0.45%)149.0Steve Whitston+3.7 mph (+2.6%)-19.294squal -20.481s87.4%qual 86.6%
36 rule changes (T4: 29, SM: 4, FC: 2, FE2: 1)7 weight · 6 tyres & wheels · 5 cars added · 2 engine · 2 suspension & brakes · 1 aero · 1 induction · 3 wording · 9 othershowhide
  • T4 Incorrect Touring Heading #38451wording
  • T4 Allow B-Spec cars to run in T4 #38439other
  • SM SMX Data Submission - Penalties #38248other
  • SM SMX Penaly Clarification updated language #38337wording
  • T4 T4 Mustang #38059weight -100 lbs
  • T4 SSC tire allowance #38216tyres & wheels
  • SM Clarify Tire Marking Regs #38005tyres & wheels
  • T4 Correct Ring and Pinion Ratio to T3, Sorry I Mean T4 3.7 V6 Stang #38041wording
  • T4 T4 Mustang #38058aero
  • FE2 Driver Safety & Comfort #37965other
  • T4 Ford Mustang V6 (05-14) #37516other
  • T4 Request to Classify Club Spec in Appropriate Touring Classes #37523cars added
  • T4 Remove spec lines that have expired #37269induction
  • T4 2016-2018 Mazda Miata MX5 #37085weight -75 lbs
  • SM E&O SMX Regs 9.1.7.1.D.5.u-.w #37070other
  • T4 Redundant Verbiage Regarding Mustang Spec Lines for Driveshaft #36484suspension & brakes
  • T4 R53 Mini Cooper S Weight Reduction Request #36612weight
  • T4 Allowable Wheel Offset #36855tyres & wheels
  • T4 Fuel Emissions Components #37076engine
  • T4 2019-2024 Mazda 3 for T4 #37077cars added
  • T4 fix brake wording #37129suspension & brakes
  • T4 Evaporative emissions systems #37130engine
  • T4 Allow Spec MX5 upgrade kit for 2009-11 RX8 S2 Transmision #37140other
  • T4 Move Spec Boxster to T4 #37158cars added
  • T4 3.7 Mustangs to T4 #37188cars added
  • T4 BMW 320i Spec Line #37204other
  • T4 MX5 2006-2015 NC Help #37221other
  • T4 Classification for a 2005 Cadillac CTS 3.6 liter 6 speed manual #37224cars added
  • T4 Civic SI in T4 #37248weight -50 lbs
  • T4 2006-2015 T4 NC Mx5 spec line #37278weight
  • T4 ND MX-5 wheel allowance #37279tyres & wheels
  • T4 T4 BOP #37281weight +75 lbs
  • T4 Allow 7.5 #37286tyres & wheels
  • FC 9.1.1.10.h. FC Tire Rule #36533tyres & wheels
  • FC Change FF/FC Weight with Sequential Gearbox #36651weight
  • T4 Bop Request 06-11 Honda Civic Si #37013other
Road America Runoffs 20242024-10-012:34.430Matt Spicuzzi · fastest of 15 · top 5 within 1.8s-2.973s (-1.89%)2:34.208Alex Lozano · fastest of 14 · top 5 within 2.2s-3.673s (-2.33%)129.3Alex Lozano-0.9 mph (-0.7%)2:41.106Ethan Goulart · fastest of 49 · top 5 within 0.5s-1.103s (-0.68%)2:41.486Brett Kowalski · fastest of 43 · top 5 within 0.3s-2.262s (-1.38%)119.9Alex Bertagnoli-1.4 mph (-1.2%)+7.278squal +6.676s104.7%qual 104.3%2:11.626Timothy Minor · fastest of 10 · top 5 within 1.3s-1.018s (-0.77%)2:11.534Michael Varacins · fastest of 9 · top 5 within 1.8s-2.074s (-1.55%)144.2Michael Varacins+1.8 mph (+1.2%)-22.674squal -22.804s85.3%qual 85.2%2:11.506Porter Aiken · fastest of 18 · top 5 within 0.5s-1.300s (-0.98%)2:12.748Porter Aiken · fastest of 17 · top 5 within 2.0s-0.523s (-0.39%)145.3Porter Aiken+1.9 mph (+1.3%)-21.460squal -22.924s86.1%qual 85.2%
34 rule changes (T4: 28, SM: 4, FC: 2)11 weight · 6 suspension & brakes · 3 induction · 2 aero · 2 cars added · 2 engine · 1 removed · 1 wording · 6 othershowhide
  • SM SMX Camera Rule Correction #36496wording
  • SM AIM ECU Protocol #36556engine
  • SM OE versus OEM Definitons #36608other
  • SM Shifter Bushing #36611suspension & brakes
  • T4 T4 Camaro V6 weight reduction #36232weight
  • T4 BOP adjustment for ND MX5s #36345weight -50 lbs
  • T4 Mustang T2/T3 #35877other
  • T4 Homologation of car to T4 #36030cars added
  • T4 T2-T4 Driveshaft Mistake...? #36050weight
  • T4 MINI Cooper S Spec Lines Corrections. #36086removed
  • T4 Allow Removal of Sound Tubes #36130induction
  • T4 B8/8.5 Audi S4 T3 and T2 #36195cars added
  • T4 Allow OEM Front Spoiler 06-08 Miata in T4 #35941aero
  • T4 T4 Mustang Weight Reduction In T4 Spec #36051weight -50 lbs
  • T4 R53 Mini Cooper S spec line request In #36056suspension & brakes
  • T4 Allow T4 and T3 RX8 to Disable/Remove Factory Oil Inj. #35761engine
  • T4 2023 ND2 Miata Classification and Allowances #35837weight
  • T4 Errors and Omissions for 06-09 VW Rabbit Rotor #35851suspension & brakes
  • T4 Driveshafts #35916weight
  • T4 GCR ERROR - letter not properly applied to GCR #35999weight
  • FC Four Pot Calipers #35481weight
  • T4 Corrections to T4 RX8 Spec line #35767aero
  • T4 Reorganize Spec Lines #35375induction
  • T4 Allow any 400lb rear spring in the RX8 #35433suspension & brakes
  • T4 370Z Brake Rotor Size Correction #35487suspension & brakes
  • T4 More Car Lightening Stuff #35319weight
  • T4 ND Missed Items #35352other
  • T4 Inclusion of B-C spec cars in T4 #35374other
  • T4 T2-T4 Set expiration dates on spec lines #35378induction
  • FC Please correct omitted punctuation #34890weight
  • T4 Mazda MX-5 ND1 Spec Line Request #34232weight +50 lbs
  • T4 BRZ/FRS/86 Spring Allowance #35038suspension & brakes
  • T4 TSX Allowance #35219other
  • T4 Requested Update of Model Years of 370Z #35231other
Virginia International Raceway Runoffs 20232023-09-232:10.514Devin Anderson · fastest of 24 · top 5 within 0.5s+0.937s (+0.72%)2:11.962Devin Anderson · fastest of 23 · top 5 within 0.1s-13.481s (-9.27%)127.8Raymond Blethen+0.5 mph (+0.4%)2:14.986Danny Steyn · fastest of 52 · top 5 within 0.1s+0.322s (+0.24%)2:16.229Julian DaCosta · fastest of 46 · top 5 within 0.3s-2.878s (-2.07%)120.3Jim Drago+1.1 mph (+0.9%)+4.267squal +4.472s103.2%qual 103.4%1:50.281Nolan Allaer · fastest of 11 · top 5 within 2.3s+0.386s (+0.35%)1:51.169Nolan Allaer · fastest of 11 · top 5 within 2.5s-16.690s (-13.05%)143.5Robert Allaer+2.3 mph (+1.7%)-20.793squal -20.233s84.2%qual 84.5%1:50.665Charles Russell Turner · fastest of 26 · top 5 within 2.3s-0.188s (-0.17%)1:51.098Franklin Futrelle · fastest of 19 · top 5 within 1.4s-20.947s (-15.86%)141.3Franklin Futrelle-0.6 mph (-0.4%)-20.864squal -19.849s84.2%qual 84.8%
24 rule changes (T4: 20, SM: 1, FC: 3)8 weight · 4 suspension & brakes · 2 cars added · 2 tyres & wheels · 1 engine · 1 induction · 2 wording · 4 othershowhide
  • T4 Inclusion of similar car. (CLK 320) #34626other
  • T4 Rules Clarification for Mazda RX8 Spec Line #34395weight
  • T4 rule book corrections #34437wording
  • T4 Ride Height Correction for the T3 Solstice. #34615suspension & brakes
  • FC Review FC Runoffs Tire Marking Rule #34274tyres & wheels
  • T4 2002-2006 Mini Cooper S R53 Spec Line Request #34336weight -50 lbs
  • FC USF2000 Van Diemen with Mazda MZR LF-DE 2.0L in FC #34329weight
  • T4 05-06 Mini Wheel Weight #34112weight
  • T4 06-09 VW Rabbit #34153induction
  • T4 96-01 Audi a4 2.8 Spring Rate #34217suspension & brakes
  • T4 Request to Classify 2004-2008 Acura TSX in T4 #33590cars added
  • T4 T4 Mustang Brakes/Swaybar #34036suspension & brakes
  • T4 BMW 320I intercooler #33762other
  • T4 2019-2021 Mazda MX5 ND2 #32027cars added
  • T4 Mustang OEM Grill Request #33333other
  • T4 Mazda OEM LSD was letter 32655 typo #33666wording
  • FC E&O 9.1.1.B.16.j #33634engine
  • SM BOP for NB1 and NB2 #32309weight
  • T4 Allowable Springs and Sway Bars for 06-11 Civic si Spec Line #33294suspension & brakes
  • T4 Touring (T2-T5) Category #33617tyres & wheels
  • T4 ENO 9.1.9.2.D.1.e.1.a. #33651other
  • T4 T4 mustang #32789weight -25 lbs
  • T4 Mazda OEM LSD was letter 32655 #32933weight -25 lbs
  • T4 Another 2022 BRZ/86 T3 request #32945weight +225 lbs
Virginia International Raceway Runoffs 20222022-09-242:09.577John Heinricy · fastest of 18 · top 5 within 0.7s-1.680s (-1.28%)2:25.443John Heinricy · fastest of 18 · top 5 within 2.5s+14.484s (+11.06%)127.4Nick Leverone-1.5 mph (-1.2%)2:14.664Danny Steyn · fastest of 60 · top 5 within 0.2s+0.112s (+0.08%)2:19.107Travis Wiley · fastest of 58 · top 5 within 0.9s+2.648s (+1.94%)119.2Jonathan Neudorf-0.6 mph (-0.5%)-6.336squal +5.087s95.6%qual 103.9%1:49.895Nolan Allaer · fastest of 12 · top 5 within 1.5s-1.305s (-1.17%)2:07.859Nolan Allaer · fastest of 13 · top 5 within 3.8s+15.685s (+13.98%)141.2Tim Minor-0.6 mph (-0.4%)-17.584squal -19.682s87.9%qual 84.8%1:50.853Charles Russell Turner · fastest of 25 · top 5 within 1.1s-0.209s (-0.19%)2:12.045Jason Conzo · fastest of 22 · top 5 within 1.8s+19.891s (+17.74%)141.9Eric Cruz-0.6 mph (-0.5%)-13.398squal -18.724s90.8%qual 85.5%
35 rule changes (T4: 29, SM: 1, FC: 5)9 suspension & brakes · 6 tyres & wheels · 5 engine · 4 weight · 2 cars added · 1 induction · 1 removed · 3 wording · 4 othershowhide
  • T4 04-09 Mazda3 Balance Shaft Delete Kit #32795other
  • FC Add Specification to Performance Electronics ECU for Ford Zetec #32761engine
  • T4 Request Wider Wheels for Hyundai Tiburon #32536tyres & wheels
  • T4 Request to Add Spec Line for 2004-2009 Mazda3 i 2.0 #32395weight
  • T4 Request Alternate Front & Rear Strut/Shock Top Hats #32452suspension & brakes
  • SM Update GCR Section 9.1.7.3.A.1. #32217suspension & brakes
  • T4 Request to Allow the Use of Aftermarket ECU's in Touring #31067engine
  • T4 Request JWT BSR Kit for 02-06 Nissan Sentra SE-R/Spec V #31685other
  • T4 Please Confirm Touring 4 (98-00) BMW 323 is E46 generation #31972other
  • T4 RX-8 Spring Part Numbers (E&O) #32151suspension & brakes
  • T4 04-09 Mazda3 Tire Limit Clarification #32249tyres & wheels
  • T4 Shock Part Number Errors & Omissions #32252suspension & brakes
  • T4 Update Solo Spec Coupe to latest '20 specs for Road Racing #32262other
  • T4 Request 2016 Mazda MX5 springs #32265suspension & brakes
  • T4 Reply to letter #31486/29879 T2-T4 Grill openings #31935suspension & brakes
  • T4 BRZ vs BRZ TS #32022tyres & wheels
  • T4 MX-5 Durability Detailed #31102weight
  • T4 Request Allowances for 2005 - 2010 Mustang #31624wording
  • FC Clean up Chassis/Frame section #31867engine
  • T4 Reply to letter 29879 T2-T4 Grill Openings #31486suspension & brakes
  • T4 Please Adjust 98-00 BMW 323 Min Weight to Reflect Current Class #31595weight -200 lbs
  • T4 Consolidate 12-13 and 14-15 Honda Civic Si spec lines for T4 #31596removed
  • T4 Request to clarify radiator hoses #31682wording
  • T4 Clarify Permitted/Allowed #31743suspension & brakes
  • T4 Correct RSX wording #31746tyres & wheels
  • T4 Camaro #31751suspension & brakes
  • FC Clarify Zetec ECU requirements #31554engine
  • T4 Nissan Sentra SE-R Spec. V #30958cars added
  • T4 Mazda RX-8 Spec Line Suspension Parts #31113induction
  • T4 Diverter Valve Plunger Upgrade #31307engine
  • T4 Adjust Honda FWD in T4 to encourage more Drivetrain Diversity #31472tyres & wheels
  • T4 Touring 4 BOP adjustments for 2022 #31482weight -175 lbs
  • FC Clarify composite anti-intrusion panel language #31426wording
  • FC Clarify tire marking requirements #31455tyres & wheels
  • T4 Request to Classify 2014 VW Jetta 1.8t TSI #30436cars added
Indianapolis Motor Speedway Runoffs 20212021-09-251:54.397Stephen Blethen · fastest of 47 · top 5 within 0.9s-2.169s (-1.86%)1:55.929John Heinricy · fastest of 46 · top 5 within 1.0s-0.994s (-0.85%)127.3Alexander Schefer1:57.695Brian Henderson · fastest of 90 · top 5 within 0.5s-0.611s (-0.52%)1:58.837Brian Henderson · fastest of 88 · top 5 within 0.3s-0.263s (-0.22%)119.8Kyle Greenhill+2.908squal +3.298s102.5%qual 102.9%1:36.787Trent Walko · fastest of 31 · top 5 within 1.7s+0.451s (+0.47%)1:36.980Simon Sikes · fastest of 31 · top 5 within 2.0s+0.090s (+0.09%)141.6Tim Minor-18.949squal -17.610s83.7%qual 84.6%1:36.395Max Grau · fastest of 28 · top 5 within 0.7s1:36.655Max Grau · fastest of 28 · top 5 within 0.7s146.2Gray Fowler-19.274squal -18.002s83.4%qual 84.3%
22 rule changes (T4: 20, SM: 1, FC: 1)4 weight · 3 tyres & wheels · 2 cars added · 2 induction · 2 suspension & brakes · 2 wording · 7 othershowhide
  • T4 Wrong Part Number on 320i Spec Line #30645wording
  • T4 Civic Type R Brake Rotors #29817suspension & brakes
  • T4 Mini Cooper Spec Line Anomalies #30478weight
  • T4 Request CAI Mustang in T4 #30562induction
  • SM Updates - Obsolete Parts & BOP Parts #30438other
  • T4 Request consistency review in GCR #30263other
  • FC Request for FC Weight Change #30171weight
  • T4 E & O T4 Mustang Wheels #30245tyres & wheels
  • T4 2021 Toyota Supra #29567cars added
  • T4 06-15 MX-5 Durability #29781other
  • T4 Request for Update to T4 Spec Line for Chevrolet Sonic (2011-) #29838induction
  • T4 NC MX-5 06-15 Part Number updates for 2021 #29921weight
  • T4 BMW Z4 2.5L (03-05) Spec Line #30037weight -50 lbs
  • T4 Sway Bars for T4 2016+ MX5 Mazda #30063suspension & brakes
  • T4 Change part numbers on BRZ, FRS lines in T4 #30104wording
  • T4 T4 Mustang Axle Ratio and Wheels #30149tyres & wheels
  • T4 Request to Classify BMW M2 CS #29523cars added
  • T4 Allow the SpecMX-5 Update Kit Into Touring 4 for the MX-5 #29681other
  • T4 Request Mustang 8.8” rear axle replacement #29860other
  • T4 Cap year range on all 86s #29908other
  • T4 Alfa Romeo 4C Launch Edition #29531other
  • T4 Post Runoffs Feedback for T4 #29752tyres & wheels -50 lbs
Road America Runoffs 20202020-10-022:37.403John Heinricy · fastest of 20 · top 5 within 2.5s2:37.881Chi Ho · fastest of 19 · top 5 within 1.6s130.2Chi Ho2:42.209Kyle Greenhill · fastest of 77 · top 5 within 0.5s2:43.748Preston Pardus · fastest of 75 · top 5 within 1.0s121.3Kyle Greenhill+5.867squal +4.806s103.7%qual 103.1%2:12.644Robert Allaer · fastest of 13 · top 5 within 2.1s2:13.608Robert Allaer · fastest of 11 · top 5 within 1.2s142.4Robert Allaer-24.273squal -24.759s84.6%qual 84.3%2:12.806Scott Rettich · fastest of 25 · top 5 within 0.6s2:13.271Owen McAllister · fastest of 23 · top 5 within 0.7s143.4Owen McAllister-24.610squal -24.597s84.4%qual 84.4%
33 rule changes (T4: 25, SM: 2, FC: 4, FE2: 2)6 weight · 5 suspension & brakes · 4 engine · 3 cars added · 2 tyres & wheels · 1 aero · 1 induction · 5 wording · 6 othershowhide
  • FC Urgent: SCCA PE3 map unsuitable #29475induction
  • SM Radiator E&O Clarifications #29294engine
  • FE2 FE/FE2 Oil Cooler #29293wording
  • FC Request for weight adjustments to equalize FC competition. #28888weight
  • SM Modifications to prevent failures of Rear Brake Caliper Pin #28953suspension & brakes
  • T4 Scion FRS Solo Spec Coupe Gear Ratio #29021other
  • T4 T4 RX8 bodywork clarification #28941aero
  • T4 2006-2015 MX-5 Clarification #28942tyres & wheels
  • T4 Request to Add a Vehicle to the Roster (contd.) #27698other
  • T4 Request to Classify 2004 Mercedes Benz 320 CLK #27663cars added
  • T4 Request to change allowed header part # for T4 06-15 Miata #28223wording
  • T4 Z3M Roadster Weight #28437weight
  • T4 Request for 12-13 and 14-15 Honda Civic Springs #27848suspension & brakes
  • T4 Request to Clarify T4 05-10 Mustang Spring Allowance #27899suspension & brakes
  • T4 Request to Allow Brake Upgrade on T4 Mustang #27329suspension & brakes
  • T4 Please Switch the Solstice GXP as Specified in T2, to T3 #27413weight -50 lbs
  • T4 Request to Classify all Mazda RX8 Models in T3/T4 #27606cars added
  • T4 Request for 2014-2018 Mazda 3 GT Brakes #27659suspension & brakes
  • T4 Request to allow aftermarket OEM coolant expansion tank #27763engine
  • T4 Request to allow aftermarket OEM power steering reservoir #27764wording
  • T4 Request for Factory Installed Wings on Subaru BRZ #27831other
  • T4 Request for Replacement Clutches #27892other
  • T4 Request to Classify Chevy Sonic 1.4 In T4 #27906cars added
  • T4 Weight Change Request for 1999 Mazda Miata #28129weight -50 lbs
  • T4 Clarification of On-Board Fire System for T2 #27183wording
  • T4 Mustang Ecoboost and GT Transmission #27439other
  • T4 BRZ/FRS/86 Tire Size in T4 #27660tyres & wheels
  • T4 NC MX5 2006-2015 Spec Adjustment Request #27739weight -75 lbs
  • T4 T4 RX8 Classification Error #27902wording
  • T4 Request to add Toyota 86 GT to Spec Line #27910other
  • FC Request for Better Zetec Connecting Rods #27710engine
  • FC Add Alternate Piston #27795engine
  • FE2 FE / FE2 Update Rules #27624weight
Virginia International Raceway Runoffs 20192019-10-052:11.257John Heinricy · fastest of 25 · top 5 within 0.2s2:10.959Nick Leverone · fastest of 25 · top 5 within 0.6s128.9Tommy Boileau2:14.552Todd Buras · fastest of 60 · top 5 within 0.2s2:16.459Elivan Goulart · fastest of 56 · top 5 within 0.4s119.8Jim Drago+5.500squal +3.295s104.2%qual 102.5%1:51.200Robert Allaer · fastest of 10 · top 5 within 3.1s1:52.174Robert Allaer · fastest of 9 · top 5 within 2.7s141.8Robert Allaer-18.785squal -20.057s85.7%qual 84.7%1:51.062Liam Snyder · fastest of 20 · top 5 within 1.3s1:52.154Liam Snyder · fastest of 19 · top 5 within 0.7s142.6Robert Vanman-18.805squal -20.195s85.6%qual 84.6%
21 rule changes (T4: 15, SM: 4, FC: 2)7 weight · 3 suspension & brakes · 2 cars added · 2 engine · 2 tyres & wheels · 1 induction · 3 wording · 1 othershowhide
  • T4 Request spare tire/wheel clarification #27012tyres & wheels
  • T4 Research E&O Mazda MX5 #27112weight
  • T4 MR2 Spyder Year Correction #26936wording
  • T4 Request to allow piggy back ECU on 2000 Mazda Protégé #26085engine
  • T4 Request helper spring as optional #26678suspension & brakes
  • FC E&O Wiseco piston and Crower connecting rod #26659weight
  • T4 Request to classify 2000 - 2001 BMW 323 #25096cars added
  • SM Request to allow aftermarket fuel filters. #26370wording
  • T4 Correct Mazda MX-5 Hard Top Notes #26137weight
  • T4 Consider opening class rules to allow any thermostat #26187wording
  • T4 Cap 2016 Mazda Miata year at 2018 #26388other
  • SM Request 99-00 replacement Wire harnesses #25602engine
  • SM Organize and Clarify 9.1.7.C.1.o. #25913weight
  • SM Strike Tire Tread Language #26123tyres & wheels
  • T4 2012-2015 Honda Civic Si Performance Request #26129suspension & brakes
  • FC Correct Wiseco piston and connecting rod #25809weight
  • T4 Errors, Omissions, and Updates (Various) #22414weight
  • T4 Request for Adjustments to fiat 124 specline #25371induction
  • T4 Add Clarification to Spec Car Classifications Vehicle Spec #25774weight
  • T4 Clarify Subframe Bushings Permitted for T2-T4 #25800suspension & brakes
  • T4 Consider Solo SSC cross over classification into T4 #25802cars added
Sonoma Raceway Runoffs 20182018-10-101:52.339Gresham Wagner · fastest of 12 · top 5 within 1.1s1:54.030John Heinricy · fastest of 12 · top 5 within 0.2s106.0Ross Murray1:54.355Ken Sutherland · fastest of 48 · top 5 within 0.7s1:55.278Michael Carter · fastest of 48 · top 5 within 0.3s102.2Danny Steyn+1.248squal +2.016s101.1%qual 101.8%1:32.571Timothy de Silva · fastest of 16 · top 5 within 1.8s1:34.053Mitch Egner · fastest of 12 · top 5 within 1.6s133.1Robert Armington-19.977squal -19.768s82.5%qual 82.4%1:35.040Flinn Lazier · fastest of 9 · top 5 within 1.5s1:35.563Flinn Lazier · fastest of 9 · top 5 within 1.7s126.8Scott Rettich-18.467squal -17.299s83.8%qual 84.6%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:56.566Oscar Jackson · fastest of 40 · top 5 within 0.6s1:56.923Oscar Jackson · fastest of 38 · top 5 within 1.1s1:58.306Chris Haldeman · fastest of 86 · top 5 within 0.5s1:59.100Michael Gagliardo · fastest of 83 · top 5 within 0.6s+2.177squal +1.740s101.9%qual 101.5%1:36.336Austin McCusker · fastest of 14 · top 5 within 2.3s1:36.890Tim Minor · fastest of 14 · top 5 within 3.8s-20.033squal -20.230s82.9%qual 82.6%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:38.813Jonathan Yanca · fastest of 34 · top 5 within 2.0s1:40.397Oscar Jackson · fastest of 32 · top 5 within 0.8s1:40.514Justin Hille · fastest of 45 · top 5 within 0.3s1:40.764Michael Carter · fastest of 44 · top 5 within 0.3s+0.367squal +1.701s100.4%qual 101.7%1:21.962John LaRue · fastest of 7 · top 5 within 2.6s1:22.049Nigel Saurino · fastest of 7 · top 5 within 3.0s-18.348squal -16.851s81.7%qual 82.9%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-212:15.886Philip Royle · fastest of 22 · top 5 within 0.9s2:15.994Philip Royle · fastest of 20 · top 5 within 1.6s2:18.661Andrew Carbonell · fastest of 62 · top 5 within 0.6s2:24.067Todd Lamb · fastest of 59 · top 5 within 0.8s+8.073squal +2.775s105.9%qual 102.0%1:54.477Yufeng Luo · fastest of 11 · top 5 within 2.5s1:55.135Yufeng Luo · fastest of 10 · top 5 within 2.1s-20.859squal -21.409s84.7%qual 84.2%

By track

TrackEvents Typical % of T4 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 T4'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.