BoP Lab / Classes / STL

STL vs AS vs EPx 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.

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vsAS ×B-Spec +EP +vsEPx ×FA +FC +FE2 +FF +FP +FV +FX +GT1 +GT2 +GTX +HP +P +P2 +SM +SMX +SRF3 +STL×STU +T1 +T2 +T3 +T4 +Show 50 inactive classes

Series Runoffs Super Tour Both

Reference · what % is measured against, 12 events

Tracks · untick to narrow Auto Club Speedway Barber Motorsports Park Blackhawk Farms Raceway Buttonwillow Raceway Park Circuit of St. Louis (formerly Gateway Motorsports Circuit of the Americas Daytona International Speedway Grattan Raceway Hallett Motor Racing Circuit Homestead-Miami Speedway Indianapolis Motor Speedway Laguna Seca Michelin Raceway Road Atlanta Mid-Ohio Sports Car Course New Jersey Motorsports Park NOLA Motorsports Park Pacific Raceways Pittsburgh International Race Complex Portland International Raceway Pueblo Motorsports Park Road America Sebring International Raceway Sonoma Raceway Summit Point Raceway Thunderhill Raceway Park Virginia International Raceway Watkins Glen International Willow Springs Raceway World Wide Technology Raceway

Closest to the field: STL 100.0% of STL Kevin Boehm, Daytona International Speedway Runoffs 2015 race · AS 90.1% of STL Gregory Eaton, Indianapolis Motor Speedway Runoffs 2021 race

% of STLLap times

STLASEPxsolid race · dashed qualifying · slower is lower

STLASEPxsolid 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

	Event	STL			AS					EPx
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs STL	% of STL	Qual best	Race best	Trap	vs STL	% of STL
	Road America Runoffs 20262026-09-28	2:30.537Derek 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%)	2:26.911Andrew 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%)	-2.186squal -3.626s	98.5%qual 97.6%
17 rule changes (STL: 4, AS: 13)8 weight · 3 engine · 2 removed · 2 tyres & wheels · 1 induction · 1 othershowhide 2026-09-01 AS 2016+ Camaro Spec Line Full Prep #39646tyres & wheels 2026-09-01 AS Consideration of Pirelli P Zero Trofeo Track for AS Competition #40495tyres & wheels 2026-08-01 AS Change in 9.1.6.D.4.d.5 in Suspension Mounting Points #40094other 2026-08-01 AS Re-Add 4.6L 4v 96-04 Mustang Cobra #40239weight 2026-08-01 AS Errors and Omissions #40532weight 2026-07-01 STL Spec Line Clean Up #40344removed 2026-06-01 AS Clarification for LM7 Holley Carburetor #40167engine 2026-06-01 STL Calculating Weight #40224weight 2026-04-01 AS Header Information Update for EFI Engine Build Sheets #39886engine 2026-04-01 AS Errors and Omissions #39933weight 2026-04-01 STL Classifications #39885weight 2026-03-01 AS Re-Organization of AS Spec lines for 2026 #39887removed 2026-02-01 AS Edelbrock manifold (& timing kit) to Chevy LS Spec Lines Request #39055weight 2026-01-01 AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501induction 2026-01-01 STL Weight adjustment for STL #39579weight 2025-12-01 AS 1994 Mustang Spec Line Request #39104engine 2025-11-01 AS Cadillac CTS-V BOP Weight Change #38640weight -50 lbs
	Road America Runoffs 20252025-09-29	2:32.065Jose 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%)	2:26.792Andrew 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%)	-2.895squal -5.273s	98.1%qual 96.5%
14 rule changes (STL: 3, AS: 11)5 engine · 5 weight · 2 induction · 1 tyres & wheels · 1 othershowhide 2025-08-01 STL Lotus Weight Reduction #38772weight -50 lbs 2025-07-01 AS RE: Previous Letter 37695 Update #38245weight -75 lbs 2025-06-01 AS Errors and Omissions #38234engine 2025-05-01 AS Errors and Omission #38055induction 2025-05-01 AS Request to Add LS1/LS6 Intakes for 5.3L Truck Engine EnO #38197engine 2025-05-01 STL E&O: SMX Allowance in STL #37945weight 2025-04-01 AS Flotek Head Plunge Cut Inconsistencies #37502other 2025-04-01 AS Notes clean up #37693weight 2025-03-01 AS Race memo #37902engine 2025-01-01 AS Increase Coyote Engine Restrictor to 80mm #36177induction 2025-01-01 AS Performance Pack for 2015+ Mustang #36867weight 2025-01-01 AS Gear Ratios #37131engine 2025-01-01 AS ECU specs for LS engine #37208engine 2024-12-01 STL Request to Remove Miata Hubs from General category #37138tyres & wheels
	Road America Runoffs 20242024-10-01	2:30.063Joe 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%)	2:26.578Gregory 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%)	-3.816squal -3.485s	97.5%qual 97.7%
15 rule changes (STL: 4, AS: 11)6 cars added · 2 induction · 1 engine · 1 tyres & wheels · 1 weight · 4 othershowhide 2024-09-01 AS Mustang transmission ratios #36662engine 2024-06-01 AS Request for Classification of 2018-2023 mustang In #35764cars added 2024-05-01 AS 6th gen Camaro limited prep #35733cars added 2024-05-01 AS Chevrolet/Pontiac Camaro & Firebird (82-92) 5.7L V8 LS1 Alum BLK #35825cars added 2024-05-01 AS Full Prep Head #35891other 2024-04-01 AS Restricted Prep Aftermarket Parts Request #35682other 2024-04-01 AS Allowance of 11 #35824tyres & wheels 2024-03-01 AS Request to Classify 1970-1981 Camaro and Firebird in AS #33659cars added 2024-03-01 AS Fuel Cell 12 #34194other 2024-03-01 AS Please Classify the 6th Gen Into AS. #35448cars added 2024-03-01 AS spec lines #35713cars added 2024-02-01 STL ST Electric-Assisted Steering Systems #35066other 2024-02-01 STL BOP Adjustments #35112weight 2024-02-01 STL Mazda 12A #35320induction 2024-01-01 STL Alternate Carburetor Request for 79-85 RX7 12a #35181induction
	Virginia International Raceway Runoffs 20232023-09-23	2:05.779Danny Steyn · fastest of 22 · top 5 within 3.4s+0.305s (+0.24%)	2:06.682Joe Moser · fastest of 20 · top 5 within 1.5s-1.150s (-0.90%)	131.8Danny Steyn+0.1 mph (+0.1%)	2:03.082Daniel 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%)	-2.562squal -2.697s	98.0%qual 97.9%
6 rule changes (STL: 2, AS: 4)3 tyres & wheels · 2 engine · 1 suspension & brakesshowhide 2023-08-01 AS Crate Motor Part Numbers #32944engine 2023-08-01 AS Request wheel size change #33007tyres & wheels 2023-08-01 AS Alternative Upper Front Control Arms for Dodge Challenger #33352engine 2023-08-01 AS Front Brake Caliper Adapters for Dodge Challenger #33353suspension & brakes 2023-06-01 STL Clarify STL table B - IT spec notes on Tires #34187tyres & wheels 2023-01-01 STL Spec MX5 in STL #33473tyres & wheels
	Virginia International Raceway Runoffs 20222022-09-24	2:05.474Danny Steyn · fastest of 24 · top 5 within 2.3s-1.729s (-1.36%)	2:07.832Danny Steyn · fastest of 22 · top 5 within 1.9s+0.559s (+0.44%)	131.7Trever Degioanni-3.2 mph (-2.3%)	2:02.162Kurt 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%)	-3.254squal -3.312s	97.5%qual 97.4%
14 rule changes (STL: 5, AS: 9)3 weight · 2 induction · 1 engine · 1 suspension & brakes · 1 tyres & wheels · 3 wording · 3 othershowhide 2022-09-01 AS Request to add Hoosier W2 #33031other 2022-09-01 AS correction of Dodge Challenger specification line #33151wording 2022-07-01 AS Request CTS-V Spec Line Error Correction #30242weight 2022-03-01 STL Single TB Weight Modifiers #31449weight 2022-03-01 STL Improved Touring Tires #32063tyres & wheels 2022-01-01 AS Proposed Revisions to SCCA GCR 2021 Appendix M, Part 3 #30295other 2022-01-01 AS specification line consolidation and correction #31846wording 2022-01-01 AS correction of SMG specification line #31847suspension & brakes 2022-01-01 AS Alternate cylinder heads for full prep engine builds - Evaluation #31851engine 2022-01-01 STL Throttling Device Clarification #31323induction 2022-01-01 STL Mazda Renesis Restriction #31467induction 2022-01-01 STL Clarification of 79-85 RX7 Spec line #31621wording 2021-10-01 AS Request for adjustable Front Upper Control Arms on 4th Gen F-Body #30457other 2021-10-01 AS Request Pontiac GTO tire size change #30881weight
	Indianapolis Motor Speedway Runoffs 20212021-09-25	1:51.665Danny 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 Gee	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	-12.105squal -1.238s	90.1%qual 98.9%
29 rule changes (STL: 15, AS: 14)8 weight · 5 engine · 4 cars added · 2 aero · 2 induction · 2 suspension & brakes · 1 tyres & wheels · 3 wording · 2 othershowhide 2021-09-01 STL Request to clean up Spec MX-5 Redundancy #31069other 2021-06-01 AS Request CTS-V Spec Line Error Correction #30242weight 2021-06-01 AS Request to consolidate SN95 Mustang '94-'04 Mustang spec lines #30428cars added 2021-06-01 AS American Sedan Transmission Rule Change Request #30595weight 2021-06-01 AS Correction to specifications inadvertently deleted #30691wording 2021-06-01 AS weight adjustments #30700weight +50 lbs 2021-06-01 STL VW Engine Request #30625engine 2021-05-01 STL Solstice Ride Height #30183suspension & brakes 2021-05-01 STL Request Mazda B5 DOHC #30420cars added 2021-05-01 STL Honda B16A (JDM) Restrictor change #30531induction 2021-04-01 STL ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wording 2021-03-01 AS AS Mustang LP 4.6 3V Classification Transmission Request #29886weight 2021-03-01 AS Request CF driveshaft on CTS-V for durability improvement #30117engine 2021-03-01 AS Adjustment to model years of 5th generation RP Camaro #30348engine 2021-03-01 STL GM Ecotec engines in STL #30247engine 2021-03-01 STL Super Touring Alternate Miata Hubs #30345tyres & wheels 2021-02-01 STL Brake Component Relocation #29990suspension & brakes 2021-02-01 STL Super Touring Wing Clarification #30111aero 2021-02-01 STL Transmission Options #30118other 2021-01-01 AS Request for 2015 -2017 Ford Mustang Spec Line #29514cars added 2021-01-01 AS Request Trunk lid / Rear Hatch clarification #29591wording 2021-01-01 AS Common Weight for CTS-V Tire #29759weight 2021-01-01 AS Correction to specifications inadvertently deleted #30041cars added 2021-01-01 STL Request for FWD and RWD Parity #29728weight 2021-01-01 STL Request to Remove Honda F20C 2% Weight Penalty #29815weight 2021-01-01 STL Request for FWD and RWD Parity #30023induction 2020-12-01 AS Request Additional Engine Options for Dodge Challenger Spec Line #29543engine 2020-12-01 AS Rule simplification spec line communization #29824weight 2020-12-01 STL Request clarification on wing measurement #29640aero
	Road America Runoffs 20202020-10-02	2:31.420Danny Steyn · fastest of 33 · top 5 within 3.1s	2:32.115Joe Moser · fastest of 30 · top 5 within 1.5s	132.9Darin Treakle	2:27.045Gregory Eaton · fastest of 18 · top 5 within 0.6s	2:27.668Gregory Eaton · fastest of 15 · top 5 within 1.5s	149.2Gregory Eaton	-4.447squal -4.375s	97.1%qual 97.1%
27 rule changes (STL: 11, AS: 16)6 induction · 5 engine · 3 cars added · 3 tyres & wheels · 3 weight · 2 aero · 2 suspension & brakes · 1 wording · 2 othershowhide 2020-08-01 AS Dodge Challenger AS Spec Line Clarification #28698induction 2020-08-01 AS Dodge Challenger AS Spec Line Clarification #2 #28699aero 2020-08-01 STL Minimum Weight Determination #27695weight 2020-08-01 STL ST Gurney flap Wicker clarification #29012aero 2020-07-01 AS Support for R-Type Specification Tires #27450tyres & wheels 2020-07-01 AS Spec Tire Request #27519tyres & wheels 2020-07-01 AS Restrictor Plate Change for RP 2011+ Mustang with Coyote Engine #27675induction 2020-07-01 AS 2005-2009 Restricted Prep 4.6 3V #27908engine 2020-07-01 AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909engine 2020-07-01 AS Request for Full Preparation Classification for 2010-2014 Camaro #28030other 2020-07-01 AS Cylinder Heads #28696engine 2020-07-01 AS Request for Max Rotor Diameter Change #28748suspension & brakes 2020-07-01 AS Request increase rotor diameter #28797other 2020-07-01 STL Request for Addition to GT3 Approved Turbo List #27576induction 2020-06-01 STL Request to add 2016-2019 GMX-5 Spec line #28604cars added 2020-06-01 STL Request to update PN for MX-5 #28622wording 2020-06-01 STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873engine 2020-05-01 AS weight adjustments for 2020 season #28785weight -50 lbs 2020-05-01 STL STL Honda B18 restrictor changes #28794induction 2020-04-01 STL Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engine 2020-04-01 STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663induction 2020-04-01 STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664induction 2020-03-01 STL Request to add wheel part numbers #28342tyres & wheels 2020-02-01 AS Rear Trailing Arms #28007suspension & brakes 2020-02-01 AS Weight reduction for cars running iron heads #28010weight 2020-02-01 AS 05-10 Mustang with HR cam classification #28226cars added 2020-02-01 AS 10-15 Camaro Full Prep classification #28227cars added
	Virginia International Raceway Runoffs 20192019-10-05	2:07.203Danny Steyn · fastest of 36 · top 5 within 1.8s	2:07.273Cliff Ira · fastest of 35 · top 5 within 1.4s	134.8Cliff Ira	2:02.938Gregory Eaton · fastest of 17 · top 5 within 0.8s	2:03.900James Jost · fastest of 16 · top 5 within 2.1s	153.9James Jost	-3.373squal -4.265s	97.3%qual 96.6%
15 rule changes (STL: 11, AS: 4)5 weight · 3 suspension & brakes · 2 cars added · 2 induction · 1 engine · 1 wording · 1 othershowhide 2019-10-01 AS Request to add SMG to 9.1.6.B.1 AS Intent #27140other 2019-10-01 STL Request to Classify Spec MX-5 Challenge in STL #27399cars added 2019-08-01 AS Request Ride Height Clarification #26598suspension & brakes 2019-07-01 STL Request clarification for manifold and throttle in STU #27004induction 2019-05-31 AS Request to Revert to 2017 Weights #25885weight 2019-05-31 STL Request Restrictor Plate correction #26779induction 2019-05-01 STL Request Ride Height Clarification #26597suspension & brakes 2019-03-01 STL Request to Allow VW 1.8L Engine #25614engine 2019-03-01 STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbs 2019-03-01 STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821suspension & brakes 2019-03-01 STL Request to clarify B18C1 GSR Honda B motor table #26209weight 2019-03-01 STL Port Matching #26415wording 2019-02-01 AS SMG Mustang eligibility in American sedan #26224cars added 2019-01-01 STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746weight 2019-01-01 STL Request E&O for Mazda Miata Spec Line #25955weight
	Sonoma Raceway Runoffs 20182018-10-10	1:49.138Danny Steyn · fastest of 19 · top 5 within 2.5s	1:49.754Danny Steyn · fastest of 17 · top 5 within 2.5s	103.2Craig McHaffie	1:47.782Andrew McDermid · fastest of 12 · top 5 within 1.9s	1:50.345John Heinricy · fastest of 10 · top 5 within 2.3s	105.0Kevin Fandozzi	+0.591squal -1.356s	100.5%qual 98.8%
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:52.647Adam Roberts · fastest of 57 · top 5 within 0.8s	1:52.589Eric Kutil · fastest of 50 · top 5 within 1.2s		1:45.220James Jost · fastest of 29 · top 5 within 6.7s	1:51.507Bryan Long · fastest of 28 · top 5 within 0.9s		-1.082squal -7.427s	99.0%qual 93.4%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:35.439John Schmitt · fastest of 34 · top 5 within 1.5s	1:36.625Kevin Boehm · fastest of 31 · top 5 within 0.6s		1:30.651Tom Sloe · fastest of 22 · top 5 within 3.6s	1:33.424Edward Hosni · fastest of 20 · top 5 within 1.0s		-3.201squal -4.788s	96.7%qual 95.0%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	2:09.672Kevin Boehm · fastest of 37 · top 5 within 2.5s	2:10.269Kevin Boehm · fastest of 37 · top 5 within 2.1s		2:01.746Tom Sloe · fastest of 22 · top 5 within 2.6s	2:02.922Andy McDermid · fastest of 19 · top 5 within 2.2s		-7.347squal -7.926s	94.4%qual 93.9%

By track

Track	Events	Typical % of STL	Best	Latest
Road America	4	100.0%	100.0%Runoffs 2020	100.0%Runoffs 2026
Virginia International Raceway	3	100.0%	100.0%Runoffs 2019	100.0%Runoffs 2023
Indianapolis Motor Speedway	2	100.0%	100.0%Runoffs 2017	100.0%Runoffs 2021
Daytona International Speedway	1	100.0%	100.0%Runoffs 2015	100.0%Runoffs 2015
Mid-Ohio Sports Car Course	1	100.0%	100.0%Runoffs 2016	100.0%Runoffs 2016
Sonoma Raceway	1	100.0%	100.0%Runoffs 2018	100.0%Runoffs 2018

About this data

Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of STL's best on the same day: the weather and the day cancel out, so one figure compares across years where lap times cannot; a class that suits one track more than another still reads differently there. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.