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BoP Lab / Classes / T4

T4 vs FP vs AS vs SMX 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)
vsAS×B-SpecEPFAFCFE2FFvsFP×FVFXGT1GT2GTXHPPP2SMvsSMX×SRF3STLSTUT1T2T3T4×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 · FP 94.6% of T4 Mason Workman, Virginia International Raceway Runoffs 2022 race · AS 85.7% of T4 Gregory Eaton, Virginia International Raceway Runoffs 2022 race · SMX 100.4% of T4 Skyler Cottrell, Road America Runoffs 2026 qualifying

1:402:002:202:4028 rule changes between Runoffs 2018 and Runoffs 201928 ▾60 rule changes between Runoffs 2019 and Runoffs 202060 ▾55 rule changes between Runoffs 2020 and Runoffs 202155 ▾63 rule changes between Runoffs 2021 and Runoffs 202263 ▾30 rule changes between Runoffs 2022 and Runoffs 202330 ▾64 rule changes between Runoffs 2023 and Runoffs 202464 ▾62 rule changes between Runoffs 2024 and Runoffs 202562 ▾75 rule changes between Runoffs 2025 and Runoffs 202675 ▾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)FP race best at Runoffs 2015: 2:12.419 (Kevin Ruck)FP race best at Runoffs 2016: 1:36.399 (John Walker)FP race best at Runoffs 2017: 1:53.007 (Eric Prill)FP race best at Runoffs 2018: 1:48.481 (Joe Huffaker)FP race best at Runoffs 2019: 2:08.076 (Eric Prill)FP race best at Runoffs 2020: 2:34.033 (Kevin Ruck)FP race best at Runoffs 2021: 1:59.933 (Cliff Ira)FP race best at Runoffs 2022: 2:17.641 (Mason Workman)FP race best at Runoffs 2023: 2:07.787 (Cliff Ira)FP race best at Runoffs 2024: 2:33.246 (Kevin Ruck)FP race best at Runoffs 2025: 2:34.271 (Chris Bovis)FP race best at Runoffs 2026: 2:33.240 (David Strittmatter)FP qualifying best at Runoffs 2015: 2:11.009 (Kevin Ruck)FP qualifying best at Runoffs 2016: 1:35.938 (John Walker)FP qualifying best at Runoffs 2017: 1:52.091 (Eric Prill)FP qualifying best at Runoffs 2018: 1:47.588 (Joe Huffaker)FP qualifying best at Runoffs 2019: 2:07.436 (Eric Prill)FP qualifying best at Runoffs 2020: 2:31.414 (Ethan Shippert)FP qualifying best at Runoffs 2021: 1:51.082 (Craig Chima)FP qualifying best at Runoffs 2022: 2:06.217 (Eric Prill)FP qualifying best at Runoffs 2023: 2:08.248 (Cliff Ira)FP qualifying best at Runoffs 2024: 2:32.327 (Cliff Ira)FP qualifying best at Runoffs 2025: 2:32.395 (David Strittmatter)FP qualifying best at Runoffs 2026: 2:33.275 (Stephen Simonds)AS race best at Runoffs 2015: 2:02.922 (Andy McDermid)AS race best at Runoffs 2016: 1:33.424 (Edward Hosni)AS race best at Runoffs 2017: 1:51.507 (Bryan Long)AS race best at Runoffs 2018: 1:50.345 (John Heinricy)AS race best at Runoffs 2019: 2:03.900 (James Jost)AS race best at Runoffs 2020: 2:27.668 (Gregory Eaton)AS race best at Runoffs 2021: 1:50.606 (Gregory Eaton)AS race best at Runoffs 2022: 2:04.578 (Gregory Eaton)AS race best at Runoffs 2023: 2:04.120 (Gregory Eaton)AS race best at Runoffs 2024: 2:26.429 (Gregory Eaton)AS race best at Runoffs 2025: 2:29.232 (Gregory Eaton)AS race best at Runoffs 2026: 2:28.471 (Andrew McDermid)AS qualifying best at Runoffs 2015: 2:01.746 (Tom Sloe)AS qualifying best at Runoffs 2016: 1:30.651 (Tom Sloe)AS qualifying best at Runoffs 2017: 1:45.220 (James Jost)AS qualifying best at Runoffs 2018: 1:47.782 (Andrew McDermid)AS qualifying best at Runoffs 2019: 2:02.938 (Gregory Eaton)AS qualifying best at Runoffs 2020: 2:27.045 (Gregory Eaton)AS qualifying best at Runoffs 2021: 1:50.427 (Drew Cattell)AS qualifying best at Runoffs 2022: 2:02.162 (Kurt Rezzetano)AS qualifying best at Runoffs 2023: 2:03.082 (Daniel Richardson)AS qualifying best at Runoffs 2024: 2:26.578 (Gregory Eaton)AS qualifying best at Runoffs 2025: 2:26.792 (Andrew McDermid)AS qualifying best at Runoffs 2026: 2:26.911 (Andrew McDermid)SMX race best at Runoffs 2023: 2:12.616 (Noah Harmon)SMX race best at Runoffs 2024: 2:36.278 (Ethan Jacobs)SMX race best at Runoffs 2025: 2:37.091 (Michael Tinis)SMX race best at Runoffs 2026: 2:36.414 (Cam Ebben)SMX qualifying best at Runoffs 2023: 2:11.435 (Nathan Nicholson)SMX qualifying best at Runoffs 2024: 2:35.651 (Ethan Lampe)SMX qualifying best at Runoffs 2025: 2:36.232 (Cam Ebben)SMX qualifying best at Runoffs 2026: 2:36.472 (Skyler Cottrell)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
T4FPASSMXsolid race · dashed qualifying · slower is lower
90%92%94%96%98%100%102%28 rule changes between Runoffs 2018 and Runoffs 201928 ▾60 rule changes between Runoffs 2019 and Runoffs 202060 ▾55 rule changes between Runoffs 2020 and Runoffs 202155 ▾63 rule changes between Runoffs 2021 and Runoffs 202263 ▾30 rule changes between Runoffs 2022 and Runoffs 202330 ▾64 rule changes between Runoffs 2023 and Runoffs 202464 ▾62 rule changes between Runoffs 2024 and Runoffs 202562 ▾75 rule changes between Runoffs 2025 and Runoffs 202675 ▾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)FP race best at Runoffs 2015: 97.4% of T4's (Kevin Ruck)FP race best at Runoffs 2016: 96.0% of T4's (John Walker)FP race best at Runoffs 2017: 96.7% of T4's (Eric Prill)FP race best at Runoffs 2018: 95.1% of T4's (Joe Huffaker)FP race best at Runoffs 2019: 97.8% of T4's (Eric Prill)FP race best at Runoffs 2020: 97.6% of T4's (Kevin Ruck)FP race best at Runoffs 2021: 103.5% of T4's (Cliff Ira)FP race best at Runoffs 2022: 94.6% of T4's (Mason Workman)FP race best at Runoffs 2023: 96.8% of T4's (Cliff Ira)FP race best at Runoffs 2024: 99.4% of T4's (Kevin Ruck)FP race best at Runoffs 2025: 101.1% of T4's (Chris Bovis)FP race best at Runoffs 2026: 98.4% of T4's (David Strittmatter)FP qualifying best at Runoffs 2015: 96.4% of T4's (Kevin Ruck)FP qualifying best at Runoffs 2016: 97.1% of T4's (John Walker)FP qualifying best at Runoffs 2017: 96.2% of T4's (Eric Prill)FP qualifying best at Runoffs 2018: 95.8% of T4's (Joe Huffaker)FP qualifying best at Runoffs 2019: 97.1% of T4's (Eric Prill)FP qualifying best at Runoffs 2020: 96.2% of T4's (Ethan Shippert)FP qualifying best at Runoffs 2021: 97.1% of T4's (Craig Chima)FP qualifying best at Runoffs 2022: 97.4% of T4's (Eric Prill)FP qualifying best at Runoffs 2023: 98.3% of T4's (Cliff Ira)FP qualifying best at Runoffs 2024: 98.6% of T4's (Cliff Ira)FP qualifying best at Runoffs 2025: 99.6% of T4's (David Strittmatter)FP qualifying best at Runoffs 2026: 98.3% of T4's (Stephen Simonds)AS race best at Runoffs 2015: 90.4% of T4's (Andy McDermid)AS race best at Runoffs 2016: 93.1% of T4's (Edward Hosni)AS race best at Runoffs 2017: 95.4% of T4's (Bryan Long)AS race best at Runoffs 2018: 96.8% of T4's (John Heinricy)AS race best at Runoffs 2019: 94.6% of T4's (James Jost)AS race best at Runoffs 2020: 93.5% of T4's (Gregory Eaton)AS race best at Runoffs 2021: 95.4% of T4's (Gregory Eaton)Off the chart: AS race best at Runoffs 2022: 85.7% of T4's (Gregory Eaton)AS race best at Runoffs 2023: 94.1% of T4's (Gregory Eaton)AS race best at Runoffs 2024: 95.0% of T4's (Gregory Eaton)AS race best at Runoffs 2025: 97.8% of T4's (Gregory Eaton)AS race best at Runoffs 2026: 95.3% of T4's (Andrew McDermid)AS qualifying best at Runoffs 2015: 89.6% of T4's (Tom Sloe)AS qualifying best at Runoffs 2016: 91.7% of T4's (Tom Sloe)AS qualifying best at Runoffs 2017: 90.3% of T4's (James Jost)AS qualifying best at Runoffs 2018: 95.9% of T4's (Andrew McDermid)AS qualifying best at Runoffs 2019: 93.7% of T4's (Gregory Eaton)AS qualifying best at Runoffs 2020: 93.4% of T4's (Gregory Eaton)AS qualifying best at Runoffs 2021: 96.5% of T4's (Drew Cattell)AS qualifying best at Runoffs 2022: 94.3% of T4's (Kurt Rezzetano)AS qualifying best at Runoffs 2023: 94.3% of T4's (Daniel Richardson)AS qualifying best at Runoffs 2024: 94.9% of T4's (Gregory Eaton)AS qualifying best at Runoffs 2025: 96.0% of T4's (Andrew McDermid)AS qualifying best at Runoffs 2026: 94.2% of T4's (Andrew McDermid)SMX race best at Runoffs 2023: 100.5% of T4's (Noah Harmon)SMX race best at Runoffs 2024: 101.3% of T4's (Ethan Jacobs)SMX race best at Runoffs 2025: 102.9% of T4's (Michael Tinis)SMX race best at Runoffs 2026: 100.4% of T4's (Cam Ebben)SMX qualifying best at Runoffs 2023: 100.7% of T4's (Nathan Nicholson)SMX qualifying best at Runoffs 2024: 100.8% of T4's (Ethan Lampe)SMX qualifying best at Runoffs 2025: 102.1% of T4's (Cam Ebben)SMX qualifying best at Runoffs 2026: 100.4% of T4's (Skyler Cottrell)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
T4FPASSMXsolid 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
EventT4FPASSMX
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%)2:33.275Stephen Simonds · fastest of 26 · top 5 within 1.0s+0.880s (+0.58%)2:33.240David Strittmatter · fastest of 25 · top 5 within 1.7s-1.031s (-0.67%)132.4David Strittmatter±0.0 mph (±0.0%)-2.517squal -2.601s98.4%qual 98.3%2:26.911Andrew McDermid · fastest of 8 · top 5 within 3.4s+0.119s (+0.08%)2:28.471Andrew McDermid · fastest of 8 · top 5 within 2.4s-0.761s (-0.51%)151.0Andrew McDermid-0.6 mph (-0.4%)-7.286squal -8.965s95.3%qual 94.2%2:36.472Skyler Cottrell · fastest of 21 · top 5 within 0.4s+0.240s (+0.15%)2:36.414Cam Ebben · fastest of 21 · top 5 within 1.1s-0.677s (-0.43%)128.4Christian Hoagland-0.6 mph (-0.5%)+0.657squal +0.596s100.4%qual 100.4%
75 rule changes (T4: 26, FP: 34, AS: 13, SMX: 2)20 weight · 12 engine · 11 induction · 7 cars added · 6 suspension & brakes · 5 tyres & wheels · 2 removed · 5 wording · 7 othershowhide
  • AS 2016+ Camaro Spec Line Full Prep #39646tyres & wheels
  • AS Consideration of Pirelli P Zero Trofeo Track for AS Competition #40495tyres & wheels
  • T4 02-06 R53 Mini Cooper Hotchkins Rear Camber Arms #40677suspension & brakes
  • AS Change in 9.1.6.D.4.d.5 in Suspension Mounting Points #40094other
  • AS Re-Add 4.6L 4v 96-04 Mustang Cobra #40239weight
  • AS Errors and Omissions #40532weight
  • FP Mini Cooper Compression Ratio #40517engine
  • T4 Is it time? #40653cars added
  • T4 Combine T4 BRZ/86/FRS generations #40656weight
  • FP 1996-2000 Honda Civic (CX, DX, VP, LX) with Engine Code D16Y7 #40322engine
  • FP 1275 Midget/Sprit Alternate intake manifold E/O #40370induction
  • FP HP Honda Civic (92-95) #40464weight -70 lbs
  • SMX Rear Toe Link #40271other
  • T4 Dodge Neon DOHC Weight #40329weight
  • AS Clarification for LM7 Holley Carburetor #40167engine
  • 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
  • FP Miata track width - errors and omissions #39976wording
  • FP GCR Spec Line Correction #39977induction
  • FP CGR Spec Line Weight Correction #39978weight
  • FP Triumph GT6 Spec Change. #40098induction
  • FP Request to Classify BMW E21 320i #40110cars added
  • FP BMW 318is 84-85 engine displacement correction #40116engine
  • T4 2003 Honda Civic Si Classification #39999cars added
  • AS Header Information Update for EFI Engine Build Sheets #39886engine
  • AS Errors and Omissions #39933weight
  • SMX Part Number Change Request #39914wording
  • T4 16-24 ND MX5 T4 #39934suspension & brakes
  • AS Re-Organization of AS Spec lines for 2026 #39887removed
  • FP Correct Valve Sizes on FP Fiat x19 1300 and 1500 #39850engine
  • FP Dual Carburetor Adjustments #39851induction
  • T4 ND MX-5 Spec Line Rewrite Request #39802weight -100 lbs
  • T4 4.0 Mustang spec line cleanup #39831induction
  • AS Edelbrock manifold (& timing kit) to Chevy LS Spec Lines Request #39055weight
  • FP Request Toyota 5E Series Engines #38208engine
  • FP Request for Toyota 4E Series Engines #38209engine
  • FP Dual Carbs for the Fiat X1/9 #39593induction
  • T4 T4 and T3 Feedback #39230removed
  • T4 T4 Mustang 4.0 #39489induction
  • T4 Allow Alt Bushing Material in Toe Links #39607suspension & brakes
  • AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501induction
  • T4 Alternate Placement of Fuse Panel and Electronics Request #39370other
  • T4 Clarify T4 Brake Rotor Allowance #39503suspension & brakes
  • AS 1994 Mustang Spec Line Request #39104engine
  • FP TR2 Notes E&O #39180weight
  • FP Balance of Power #39187weight +50 lbs
  • FP Competition Adjustment Request #39259weight -80 lbs
  • FP Factory Roll Bar Removal on VW Convertible #39268wording
  • FP FP Parity Request #39325weight +50 lbs
  • FP Adjust former-GTL Honda's with B/D-Series Engines #39374engine
  • T4 Classing 1995-99 Dodge Neon SOHC #39285cars added
  • AS Cadillac CTS-V BOP Weight Change #38640weight -50 lbs
  • FP Please Lower Weight of 280Z #38871weight -160 lbs
  • FP Miata Weight Adjustment Follow Up #38949weight -25 lbs
  • FP Weight Break for 1098 Midget / Sprite #38970weight -80 lbs
  • FP HP Volvo 142 spec omission #38994engine
  • FP HP Mini DOHC 1.6 #38996engine
  • FP 83-88 FP Scirocco Spec Line Creation #38997cars added
  • FP Add to Rabbit description #39019wording
  • FP Clean-up 9.1.5.E.7e #39025suspension & brakes
  • FP Add TB size to Ford Mustang (94-98) Spec Line #39130induction
  • FP Correct Existing VW Scirocco Spec Line #39140weight
  • 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
  • FP HP Plymouth Arrow spec omission #38995wording
  • FP Add Wheel Diameter to Appendix G #39008tyres & wheels
  • FP Add TB ID tolerance to general Prod rules #39009induction
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%)2:32.395David Strittmatter · fastest of 20 · top 5 within 2.9s+0.068s (+0.04%)2:34.271Chris Bovis · fastest of 19 · top 5 within 1.8s+1.025s (+0.67%)132.4David Strittmatter-1.1 mph (-0.8%)+1.638squal -0.561s101.1%qual 99.6%2:26.792Andrew McDermid · fastest of 11 · top 5 within 3.9s+0.214s (+0.15%)2:29.232Gregory Eaton · fastest of 10 · top 5 within 4.0s+2.803s (+1.91%)151.5Andrew McDermid+1.9 mph (+1.3%)-3.401squal -6.164s97.8%qual 96.0%2:36.232Cam Ebben · fastest of 20 · top 5 within 0.2s+0.581s (+0.37%)2:37.091Michael Tinis · fastest of 19 · top 5 within 0.3s+0.813s (+0.52%)129.1Camden Gruber-0.4 mph (-0.3%)+4.458squal +3.276s102.9%qual 102.1%
62 rule changes (T4: 29, FP: 17, AS: 11, SMX: 5)16 weight · 8 engine · 7 cars added · 7 induction · 5 tyres & wheels · 2 suspension & brakes · 1 aero · 3 wording · 13 othershowhide
  • T4 Incorrect Touring Heading #38451wording
  • AS RE: Previous Letter 37695 Update #38245weight -75 lbs
  • FP BMW Z4 update #38490induction
  • FP EP Fiat 124 Spider Competition Adjustment Request #38498weight -50 lbs
  • T4 Allow B-Spec cars to run in T4 #38439other
  • AS Errors and Omissions #38234engine
  • FP Base Weight Adjustment for H-Production X1/9 Spec Lines #38255weight -50 lbs
  • SMX SMX Data Submission - Penalties #38248other
  • SMX SMX Penaly Clarification updated language #38337wording
  • T4 T4 Mustang #38059weight -100 lbs
  • T4 SSC tire allowance #38216tyres & wheels
  • AS Errors and Omission #38055induction
  • AS Request to Add LS1/LS6 Intakes for 5.3L Truck Engine EnO #38197engine
  • SMX Clarify Tire Marking Regs #38004tyres & wheels
  • SMX SMX Data Submission Timeframe #38039other
  • T4 Correct Ring and Pinion Ratio to T3, Sorry I Mean T4 3.7 V6 Stang #38041wording
  • T4 T4 Mustang #38058aero
  • AS Flotek Head Plunge Cut Inconsistencies #37502other
  • AS Notes clean up #37693weight
  • FP Request for Classification of Chevrolet Spark #37755cars added
  • FP Request to Lower Ford Festiva Minimum Weight to 1600 LBS #37939weight -100 lbs
  • AS Race memo #37902engine
  • FP Request Competition Adjustment to BMW Z3 2.5L #37120induction
  • FP FP Class Adjustments #37458weight
  • FP Interpretation of Production Rules on Mirrors #37235other
  • FP Weight Reduction for Honda S2000 #37466weight
  • FP Mazda 1999 Miata 1.8L #37488weight -50 lbs
  • FP Errors & Omissions #37648cars added
  • FP GTL/FP consolidation 2025 Rules #37659induction
  • FP Effective date for Jan 2025 GCR updates #37654induction
  • T4 Ford Mustang V6 (05-14) #37516other
  • T4 Request to Classify Club Spec in Appropriate Touring Classes #37523cars added
  • AS Increase Coyote Engine Restrictor to 80mm #36177induction
  • AS Performance Pack for 2015+ Mustang #36867weight
  • AS Gear Ratios #37131engine
  • AS ECU specs for LS engine #37208engine
  • FP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line #37119weight -50 lbs
  • FP Fix Error in Spridget Spec Line #37437engine
  • FP Create ruleset that allows GTL cars to run in FP #37485other
  • T4 Remove spec lines that have expired #37269induction
  • T4 2016-2018 Mazda Miata MX5 #37085weight -75 lbs
  • SMX 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
  • FP 1275 HP Spridget Level 2 Only #36518other
  • 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%)2:32.327Cliff Ira · fastest of 26 · top 5 within 2.1s+0.913s (+0.60%)2:33.246Kevin Ruck · fastest of 24 · top 5 within 1.4s-0.787s (-0.51%)133.5David Strittmatter+0.3 mph (+0.2%)-0.962squal -2.103s99.4%qual 98.6%2:26.578Gregory Eaton · fastest of 18 · top 5 within 2.6s-0.467s (-0.32%)2:26.429Gregory Eaton · fastest of 18 · top 5 within 2.5s-1.239s (-0.84%)149.6Gregory Eaton+0.4 mph (+0.3%)-7.779squal -7.852s95.0%qual 94.9%2:35.651Ethan Lampe · fastest of 23 · top 5 within 0.7s2:36.278Ethan Jacobs · fastest of 22 · top 5 within 0.7s129.5Michael Borden+2.070squal +1.221s101.3%qual 100.8%
64 rule changes (T4: 28, FP: 21, AS: 11, SMX: 4)18 weight · 10 cars added · 6 induction · 6 suspension & brakes · 5 engine · 2 aero · 1 removed · 1 tyres & wheels · 4 wording · 11 othershowhide
  • FP Errors/emissions Honda Civic/CRX #36700wording
  • AS Mustang transmission ratios #36662engine
  • SMX SMX Camera Rule Correction #36496wording
  • SMX AIM ECU Protocol #36556engine
  • SMX OE versus OEM Definitons #36608other
  • SMX Shifter Bushing #36611suspension & brakes
  • FP Errant entry in HP production line item #36231other
  • 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
  • AS Request for Classification of 2018-2023 mustang In #35764cars added
  • FP NIssan 300ZX Z31 to EP #35830cars added
  • FP RX7 1993 and Up Request In EP Spec Lines, classify #36031cars added
  • FP Clean-up Multiple EP RX-8 Spec Lines In EP #36156wording
  • 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
  • AS 6th gen Camaro limited prep #35733cars added
  • AS Chevrolet/Pontiac Camaro & Firebird (82-92) 5.7L V8 LS1 Alum BLK #35825cars added
  • AS Full Prep Head #35891other
  • FP Request to Replace CRX Plastic Panels #35876wording
  • FP FP data and parity #35896induction
  • 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
  • AS Restricted Prep Aftermarket Parts Request #35682other
  • AS Allowance of 11 #35824tyres & wheels
  • T4 Corrections to T4 RX8 Spec line #35767aero
  • AS Request to Classify 1970-1981 Camaro and Firebird in AS #33659cars added
  • AS Fuel Cell 12 #34194other
  • AS Please Classify the 6th Gen Into AS. #35448cars added
  • AS spec lines #35713cars added
  • FP GCR Correction - Redundant HP Spec Lines #35623engine
  • FP Update FP Protege (01-03) Model Info #35715other
  • T4 Reorganize Spec Lines #35375induction
  • T4 Allow any 400lb rear spring in the RX8 #35433suspension & brakes
  • T4 370Z Brake Rotor Size Correction #35487suspension & brakes
  • FP Update 1988-1991 Civic to Match 1988-1991 CRX #35399weight
  • 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
  • FP FP data #35060weight +25 lbs
  • FP Request to Review Z3 2.5 Spec Line #35073weight +50 lbs
  • FP Corrections to Honda Spec Lines in FP #35250induction
  • FP Miata Alternate Head #35253weight -50 lbs
  • FP Triumph GT6 Adjustments #35255weight
  • FP Honda S2000 throttle body #35272induction
  • FP Correction within Triumph TR8 Spec Line #35315engine
  • FP Correction to EP 924S/944 Spec Line #35317weight
  • 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
  • FP Porsche 944/924S Rule Change Request #35002weight
  • FP FP and HP Toyota Corolla #35030weight -43 lbs
  • FP Triumph GT6 Adjustments #35054weight -30 lbs
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%)2:08.248Cliff Ira · fastest of 21 · top 5 within 1.0s+2.031s (+1.61%)2:07.787Cliff Ira · fastest of 20 · top 5 within 0.8s-9.854s (-7.16%)133.7Cliff Ira+1.1 mph (+0.9%)-4.175squal -2.266s96.8%qual 98.3%2:03.082Daniel Richardson · fastest of 11 · top 5 within 2.2s+0.920s (+0.75%)2:04.120Gregory Eaton · fastest of 9 · top 5 within 3.0s-0.458s (-0.37%)154.6James Jost+3.7 mph (+2.5%)-7.842squal -7.432s94.1%qual 94.3%2:11.435Nathan Nicholson · fastest of 18 · top 5 within 0.6s2:12.616Noah Harmon · fastest of 16 · top 5 within 0.1s127.8Noah Harmon+0.654squal +0.921s100.5%qual 100.7%
30 rule changes (T4: 20, FP: 6, AS: 4)6 weight · 5 suspension & brakes · 4 cars added · 3 induction · 2 engine · 2 tyres & wheels · 2 wording · 6 othershowhide
  • T4 Inclusion of similar car. (CLK 320) #34626other
  • AS Crate Motor Part Numbers #32944engine
  • AS Request wheel size change #33007tyres & wheels
  • AS Alternative Upper Front Control Arms for Dodge Challenger #33352engine
  • AS Front Brake Caliper Adapters for Dodge Challenger #33353suspension & brakes
  • T4 Rules Clarification for Mazda RX8 Spec Line #34395weight
  • T4 rule book corrections #34437wording
  • T4 Ride Height Correction for the T3 Solstice. #34615suspension & brakes
  • FP Correct Intake Valve Size on 1500cc Midget/Spitfire #34419induction
  • FP ITC to FP? #34286other
  • T4 2002-2006 Mini Cooper S R53 Spec Line Request #34336weight -50 lbs
  • FP Request to Classify Sonic and Fiesta in HP #34264cars added
  • T4 05-06 Mini Wheel Weight #34112weight
  • T4 06-09 VW Rabbit #34153induction
  • T4 96-01 Audi a4 2.8 Spring Rate #34217suspension & brakes
  • FP Classification Request for 1978 Toyota Celica #34097cars added
  • T4 Request to Classify 2004-2008 Acura TSX in T4 #33590cars added
  • T4 T4 Mustang Brakes/Swaybar #34036suspension & brakes
  • T4 BMW 320I intercooler #33762other
  • FP Request to Add Mazda Protege P5 to FP #33664other
  • T4 2019-2021 Mazda MX5 ND2 #32027cars added
  • T4 Mustang OEM Grill Request #33333other
  • T4 Mazda OEM LSD was letter 32655 typo #33666wording
  • FP Review Limited Prep Port Matching Rules #33600induction
  • 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%)2:06.217Eric Prill · fastest of 18 · top 5 within 1.5s-1.219s (-0.96%)2:17.641Mason Workman · fastest of 15 · top 5 within 3.2s+9.565s (+7.47%)132.5Cliff Ira+1.2 mph (+0.9%)-7.802squal -3.360s94.6%qual 97.4%2:02.162Kurt Rezzetano · fastest of 13 · top 5 within 2.3s-0.776s (-0.63%)2:04.578Gregory Eaton · fastest of 11 · top 5 within 2.9s+0.678s (+0.55%)150.9James Jost-3.0 mph (-2.0%)-20.865squal -7.415s85.7%qual 94.3%
63 rule changes (T4: 29, FP: 25, AS: 9)10 induction · 9 suspension & brakes · 9 weight · 7 engine · 7 tyres & wheels · 6 cars added · 1 removed · 5 wording · 9 othershowhide
  • AS Request to add Hoosier W2 #33031other
  • AS correction of Dodge Challenger specification line #33151wording
  • FP Request to classify VW New Beetle 2.5L in EP #32725cars added
  • FP Request Rotary Injection on Dual Y manifold #32775engine
  • FP Request for Corrado Stroke & Displacement Correction #32985engine
  • T4 04-09 Mazda3 Balance Shaft Delete Kit #32795other
  • AS Request CTS-V Spec Line Error Correction #30242weight
  • FP Subaru BRZ Model Years #32500other
  • T4 Request Wider Wheels for Hyundai Tiburon #32536tyres & wheels
  • FP Weight Adjustment of Lotus 7 #32213weight +50 lbs
  • FP EP MX-5 Global Cup Car #32218weight
  • FP Please Class BMW 128i in EP #32370cars added
  • FP Inconsistency in Body Work Descriptions #32396other
  • FP Request to classify the 1999-2000 Mazda Protege in FP #32398cars added
  • 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
  • FP Mazda RX8 with 13b Rotary #32170induction
  • FP Request Idle control valve clarification #32178engine
  • FP Correct FP BMW 325e/es Displacement #32394engine
  • 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
  • FP EP Adjustments #31858induction
  • FP 1999 3.8L Ford Mustang to EP? #31635weight
  • FP Improved Touring Tires #32064tyres & wheels
  • FP VW Golf Jetta 2.0L intake and exhaust size correction. #32173induction
  • T4 Reply to letter #31486/29879 T2-T4 Grill openings #31935suspension & brakes
  • T4 BRZ vs BRZ TS #32022tyres & wheels
  • FP Throttle Body and Idle Air #31800induction
  • T4 MX-5 Durability Detailed #31102weight
  • T4 Request Allowances for 2005 - 2010 Mustang #31624wording
  • AS Proposed Revisions to SCCA GCR 2021 Appendix M, Part 3 #30295other
  • AS specification line consolidation and correction #31846wording
  • AS correction of SMG specification line #31847suspension & brakes
  • AS Alternate cylinder heads for full prep engine builds - Evaluation #31851engine
  • FP Porsche 968 Engine Questions #31478induction
  • FP PCS E. 2. n. 4. Add Axle Shaft to Allow FWD the Same Freedom #31592tyres & wheels
  • FP BMW Z3 2.5L Spec Line #31724induction
  • FP FP Del Sol VTEC #31859induction
  • FP Standardize Level 2 Classifications in FP #31868induction
  • 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
  • FP 944S2 Restrictor #31396induction
  • FP Classing Clarification for 1986 Toyota Corolla FX16 #31527cars added
  • 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
  • T4 Request to Classify 2014 VW Jetta 1.8t TSI #30436cars added
  • AS Request for adjustable Front Upper Control Arms on 4th Gen F-Body #30457other
  • AS Request Pontiac GTO tire size change #30881weight
  • FP E&O; MR2 Track #31120wording
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 Schefer1:51.082Craig Chima · fastest of 39 · top 5 within 1.2s-1.009s (-0.90%)1:59.933Cliff Ira · fastest of 33 · top 5 within 5.4s+6.926s (+6.13%)131.8Cliff Ira+4.004squal -3.315s103.5%qual 97.1%1:50.427Drew Cattell · fastest of 31 · top 5 within 1.9s+5.207s (+4.95%)1:50.606Gregory Eaton · fastest of 28 · top 5 within 1.7s-0.901s (-0.81%)153.8James Jost-5.323squal -3.970s95.4%qual 96.5%
55 rule changes (T4: 20, FP: 21, AS: 14)16 weight · 12 cars added · 6 engine · 4 suspension & brakes · 3 induction · 3 tyres & wheels · 4 wording · 7 othershowhide
  • FP Request to Allow F22c Engine for 2000-2003 Honda S2000 #30548engine
  • FP Request a review of the S14 240SX in EP. #30873weight -200 lbs
  • FP Lotus/Caterham 7 America Request #30392engine
  • FP Request to classify ITC Plymouth Arrow #30588cars added
  • FP Reclassification of the 1984/85 BMW 318i from FP to HP #30661cars added
  • FP Fiat x1/9 Competition Adjustments #30711weight -50 lbs
  • FP Reclassify Daimler SP 250 #30721cars added
  • T4 Wrong Part Number on 320i Spec Line #30645wording
  • AS Request CTS-V Spec Line Error Correction #30242weight
  • AS Request to consolidate SN95 Mustang '94-'04 Mustang spec lines #30428cars added
  • AS American Sedan Transmission Rule Change Request #30595weight
  • AS Correction to specifications inadvertently deleted #30691wording
  • AS weight adjustments #30700weight +50 lbs
  • FP Move Porsche 924 in Level 1 Prep From EP to FP #30135cars added
  • FP Clarify Application of Percentage Based Weight Penalties #30669weight
  • T4 Civic Type R Brake Rotors #29817suspension & brakes
  • FP Change Classification of 84-87 Mazda 626 from FP to HP #30350cars added
  • FP Fiat X1/9 brake rotors #30423suspension & brakes
  • T4 Mini Cooper Spec Line Anomalies #30478weight
  • T4 Request CAI Mustang in T4 #30562induction
  • FP Please Classify Mazda3 in FP #30165cars added
  • FP Golf MkIII Valve Size Request #30268engine
  • T4 Request consistency review in GCR #30263other
  • AS AS Mustang LP 4.6 3V Classification Transmission Request #29886weight
  • AS Request CF driveshaft on CTS-V for durability improvement #30117engine
  • AS Adjustment to model years of 5th generation RP Camaro #30348engine
  • 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
  • AS Request for 2015 -2017 Ford Mustang Spec Line #29514cars added
  • AS Request Trunk lid / Rear Hatch clarification #29591wording
  • AS Common Weight for CTS-V Tire #29759weight
  • AS Correction to specifications inadvertently deleted #30041cars added
  • FP Alternate Front Brake Rotors and Calipers for EP AH 3000 #29893suspension & brakes
  • FP Request VW weight break #29963weight -50 lbs
  • 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
  • AS Request Additional Engine Options for Dodge Challenger Spec Line #29543engine
  • AS Rule simplification spec line communization #29824weight
  • FP Mk2 VW Consistency and Cleanup of FP and HP Spec Lines #29195weight -50 lbs
  • FP Correct Wording for Level 1 and Level 2 Induction Systems #29406induction
  • FP Weight Reduction for Datsun Roadster #29409weight -75 lbs
  • FP EP TR8 Adjustment #29512weight -100 lbs
  • FP Request to Classify 1996-2000 Honda Civic EX #29515cars added
  • FP FAJS Carburetor #29576other
  • 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 Ho2:31.414Ethan Shippert · fastest of 23 · top 5 within 2.2s2:34.033Kevin Ruck · fastest of 21 · top 5 within 2.3s133.2Sam Henry-3.848squal -5.989s97.6%qual 96.2%2:27.045Gregory Eaton · fastest of 18 · top 5 within 0.6s2:27.668Gregory Eaton · fastest of 15 · top 5 within 1.5s149.2Gregory Eaton-10.213squal -10.358s93.5%qual 93.4%
60 rule changes (T4: 25, FP: 19, AS: 16)10 cars added · 9 weight · 8 engine · 6 induction · 6 suspension & brakes · 5 tyres & wheels · 2 aero · 6 wording · 8 othershowhide
  • FP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458tyres & wheels
  • AS Dodge Challenger AS Spec Line Clarification #28698induction
  • AS Dodge Challenger AS Spec Line Clarification #2 #28699aero
  • FP EP BMW Z3 Rule Clarification #28998engine
  • T4 Scion FRS Solo Spec Coupe Gear Ratio #29021other
  • AS Support for R-Type Specification Tires #27450tyres & wheels
  • AS Spec Tire Request #27519tyres & wheels
  • AS Restrictor Plate Change for RP 2011+ Mustang with Coyote Engine #27675induction
  • AS 2005-2009 Restricted Prep 4.6 3V #27908engine
  • AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909engine
  • AS Request for Full Preparation Classification for 2010-2014 Camaro #28030other
  • AS Cylinder Heads #28696engine
  • AS Request for Max Rotor Diameter Change #28748suspension & brakes
  • AS Request increase rotor diameter #28797other
  • FP Request to Classify Porsche 911 2.0L #28456cars added
  • FP Request to change to Carburetor Spec Line 84-87 Mazda 626 #28926induction
  • 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
  • FP BMW Cylinder Head Casting and Part Numbers #28708engine
  • FP Correct Scirocco Spec line E&O #28892weight
  • T4 Request to Classify 2004 Mercedes Benz 320 CLK #27663cars added
  • AS weight adjustments for 2020 season #28785weight -50 lbs
  • FP Request to Classify 1990-1994 Mazda Protege #28381cars added
  • FP Error in Mini Cooper Spec Line #28713wording
  • T4 Request to change allowed header part # for T4 06-15 Miata #28223wording
  • T4 Z3M Roadster Weight #28437weight
  • FP Caterham 7 Spec Line #28498engine
  • FP Request to classify SOHC 1989-90 240SX in F prod L2 #28553cars added
  • FP VW Weight and Valve Size Request #27886weight
  • FP Request to allow 40 DCOE carb for the Datsun 510 #28195induction
  • FP Request to classify Porsche 914 2L in LPrep FProd #28231cars added
  • FP Request Ford Fiesta Weight Adjustment #28336weight
  • 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
  • AS Rear Trailing Arms #28007suspension & brakes
  • AS Weight reduction for cars running iron heads #28010weight
  • AS 05-10 Mustang with HR cam classification #28226cars added
  • AS 10-15 Camaro Full Prep classification #28227cars added
  • FP Request for Help for Datsun 1200 #27934induction
  • 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
  • FP Request to List Mazda Miata Throttle Body Size #27907induction
  • FP Request to Classify 2001-2003 Mazda Protege ES in FP #27922cars added
  • 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
  • FP Request to Correct Track of 1988-91 Honda Civic #27487wording
  • FP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661engine
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 Boileau2:07.436Eric Prill · fastest of 19 · top 5 within 0.6s2:08.076Eric Prill · fastest of 18 · top 5 within 0.8s131.4Ken Kannard-2.883squal -3.821s97.8%qual 97.1%2:02.938Gregory Eaton · fastest of 17 · top 5 within 0.8s2:03.900James Jost · fastest of 16 · top 5 within 2.1s153.9James Jost-7.059squal -8.319s94.6%qual 93.7%
28 rule changes (T4: 15, FP: 9, AS: 4)6 weight · 5 suspension & brakes · 4 cars added · 3 induction · 2 tyres & wheels · 1 engine · 3 wording · 4 othershowhide
  • AS Request to add SMG to 9.1.6.B.1 AS Intent #27140other
  • FP Request bodywork for Austin Healey Bugeye Sprite MK1 #27106other
  • FP Request to classify the GMX5 2019 #27263cars added
  • FP level one susp. component rule #27270suspension & brakes
  • FP Clarification of Carb Rules - Prep 1 #27300induction
  • FP Clarification of Carb Rules - Prep 2 #27301induction
  • T4 Request spare tire/wheel clarification #27012tyres & wheels
  • T4 Research E&O Mazda MX5 #27112weight
  • AS Request Ride Height Clarification #26598suspension & brakes
  • FP Request Miata Eligibility - 2003 #27121other
  • T4 MR2 Spyder Year Correction #26936wording
  • AS Request to Revert to 2017 Weights #25885weight
  • T4 Request to allow piggy back ECU on 2000 Mazda Protégé #26085engine
  • T4 Request helper spring as optional #26678suspension & brakes
  • FP Rollcenter Correction Clarification #25873tyres & wheels
  • FP Hardtops #26476wording
  • T4 Request to classify 2000 - 2001 BMW 323 #25096cars added
  • FP Request Classification of Dodge Daytona in F Production #26259weight -150 lbs
  • 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
  • AS SMG Mustang eligibility in American sedan #26224cars added
  • T4 2012-2015 Honda Civic Si Performance Request #26129suspension & brakes
  • 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 Murray1:47.588Joe Huffaker · fastest of 15 · top 5 within 3.0s1:48.481Joe Huffaker · fastest of 14 · top 5 within 2.2s109.1Joe Huffaker-5.549squal -4.751s95.1%qual 95.8%1:47.782Andrew McDermid · fastest of 12 · top 5 within 1.9s1:50.345John Heinricy · fastest of 10 · top 5 within 2.3s105.0Kevin Fandozzi-3.685squal -4.557s96.8%qual 95.9%
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 1.1s1:52.091Eric Prill · fastest of 42 · top 5 within 1.2s1:53.007Eric Prill · fastest of 40 · top 5 within 0.7s-3.916squal -4.475s96.7%qual 96.2%1:45.220James Jost · fastest of 29 · top 5 within 6.7s1:51.507Bryan Long · fastest of 28 · top 5 within 0.9s-5.416squal -11.346s95.4%qual 90.3%
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 0.8s1:35.938John Walker · fastest of 33 · top 5 within 0.4s1:36.399John Walker · fastest of 27 · top 5 within 0.3s-3.998squal -2.875s96.0%qual 97.1%1:30.651Tom Sloe · fastest of 22 · top 5 within 3.6s1:33.424Edward Hosni · fastest of 20 · top 5 within 1.0s-6.973squal -8.162s93.1%qual 91.7%
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 1.6s2:11.009Kevin Ruck · fastest of 20 · top 5 within 1.6s2:12.419Kevin Ruck · fastest of 18 · top 5 within 1.1s-3.575squal -4.877s97.4%qual 96.4%2:01.746Tom Sloe · fastest of 22 · top 5 within 2.6s2:02.922Andy McDermid · fastest of 19 · top 5 within 2.2s-13.072squal -14.140s90.4%qual 89.6%

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.