BoP Lab / Classes / SRF

SRF vs AS vs SRF3 pace at every track

Lap times across years say as much about the weather as the class. % of SRF is each class's best lap as a share of SRF'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 +FA +FC +FE2 +FF +FP +FV +FX +GT1 +GT2 +GTX +HP +P +P2 +SM +SMX +SRF×vsSRF3 ×STL +STU +T1 +T2 +T3 +T4 +Show 50 inactive classes

Series Runoffs Super Tour Both

Reference · what % is measured against

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: SRF 100.0% of SRF Cliff White, Daytona International Speedway Runoffs 2015 race · AS 89.9% of SRF Andy McDermid, Daytona International Speedway Runoffs 2015 race · SRF3 95.3% of SRF Chad Galloway, Daytona International Speedway Runoffs 2015 race

% of SRFLap times

SRFASSRF3solid race · dashed qualifying · slower is lower

SRFASSRF3solid race · dashed qualifying · each class's best lap as a share of SRF's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	SRF			AS					SRF3
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs SRF	% of SRF	Qual best	Race best	Trap	vs SRF	% of SRF
	Road America Runoffs 20262026-09-28				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%)			2:27.443Tyler Stephens · fastest of 44 · top 5 within 0.3s-0.783s (-0.53%)	2:29.257Peyton Long · fastest of 42 · top 5 within 0.3s-0.582s (-0.39%)	134.1Bobby Sak+0.4 mph (+0.3%)
18 rule changes (SRF: 3, AS: 13, SRF3: 2)5 weight · 3 engine · 2 tyres & wheels · 1 induction · 1 removed · 1 suspension & brakes · 5 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 2026-09-01 SRF GCR Rain/Brake Light Correction #40579suspension & brakes 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 2026-06-01 AS Clarification for LM7 Holley Carburetor #40167engine 2026-04-01 AS Header Information Update for EFI Engine Build Sheets #39886engine 2026-04-01 AS Errors and Omissions #39933weight 2026-03-01 AS Re-Organization of AS Spec lines for 2026 #39887removed 2026-03-01 SRF SRF3 Spark Plugs #39899other 2026-03-01 SRF3 SRF3 Spark Plugs #39899other 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 2025-12-01 AS 1994 Mustang Spec Line Request #39104engine 2025-11-01 AS Cadillac CTS-V BOP Weight Change #38640weight -50 lbs 2025-10-01 SRF Add HD Oil Cooler #38979other 2025-10-01 SRF3 Add HD Oil Cooler #38979other
	Road America Runoffs 20252025-09-29				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%)			2:28.226Bobby Sak · fastest of 43 · top 5 within 0.6s+0.453s (+0.31%)	2:29.839Morgan Burkhard · fastest of 42 · top 5 within 0.3s+1.710s (+1.15%)	133.7Bobby Sak-1.5 mph (-1.1%)
16 rule changes (SRF: 2, AS: 11, SRF3: 3)5 engine · 4 weight · 2 induction · 5 othershowhide 2025-09-01 SRF3 SRF Rule Updates #38853weight 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 2025-04-01 AS Flotek Head Plunge Cut Inconsistencies #37502other 2025-04-01 AS Notes clean up #37693weight 2025-04-01 SRF Driver Safety & Comfort #37966other 2025-04-01 SRF Update SADEV transmission specs #37992other 2025-04-01 SRF3 Driver Safety & Comfort #37966other 2025-04-01 SRF3 Update SADEV transmission specs #37992other 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
	Road America Runoffs 20242024-10-01				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%)			2:27.773Denny Stripling · fastest of 57 · top 5 within 0.3s-2.013s (-1.34%)	2:28.129S Sandy Satullo III · fastest of 52 · top 5 within 0.7s-2.909s (-1.93%)	135.2Denny Stripling+3.4 mph (+2.6%)
31 rule changes (SRF: 10, AS: 11, SRF3: 10)7 tyres & wheels · 6 cars added · 6 suspension & brakes · 3 weight · 1 engine · 1 wording · 7 othershowhide 2024-10-01 SRF Update SRF3 Air Filter Rule #36681other 2024-10-01 SRF Update SRF Brake Rotor Thickness #36687suspension & brakes 2024-10-01 SRF Hoosier Tire Decal Placement #36739tyres & wheels 2024-10-01 SRF3 Update SRF3 Air Filter Rule #36681other 2024-10-01 SRF3 Update SRF Brake Rotor Thickness #36687suspension & brakes 2024-10-01 SRF3 Hoosier Tire Decal Placement #36739tyres & wheels 2024-09-01 AS Mustang transmission ratios #36662engine 2024-09-01 SRF Protest Fee Clarification #36540wording 2024-09-01 SRF Update to Letter 36619 with new Hoosier Contingency Decal Info #36624tyres & wheels 2024-09-01 SRF3 Update to Letter 36619 with new Hoosier Contingency Decal Info #36624tyres & wheels 2024-08-01 SRF Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheels 2024-08-01 SRF3 Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheels 2024-06-01 AS Request for Classification of 2018-2023 mustang In #35764cars added 2024-06-01 SRF3 SRF3 Alternator Pulley Update In #36095weight 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 2024-01-01 SRF Update SRF Rain / Brake Rule #34706suspension & brakes 2024-01-01 SRF Update SRF Brake Light Rule v1 #34853suspension & brakes 2024-01-01 SRF SRF / SRF3 Rule Updates #35268weight 2024-01-01 SRF3 Update SRF Rain / Brake Rule #34706suspension & brakes 2024-01-01 SRF3 Update SRF Brake Light Rule v1 #34853suspension & brakes 2024-01-01 SRF3 SRF / SRF3 Rule Updates #35268weight 2023-10-01 SRF SRF Radiator Rule Update #34805other 2023-10-01 SRF3 SRF Radiator Rule Update #34805other
	Virginia International Raceway Runoffs 20232023-09-23				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%)			2:03.842Morgan Burkhard · fastest of 40 · top 5 within 0.2s+0.126s (+0.10%)	2:04.911David Ogburn · fastest of 39 · top 5 within 0.3s-17.155s (-12.08%)	134.5Bobby Sak+0.1 mph (+0.0%)
11 rule changes (SRF: 3, AS: 4, SRF3: 4)6 tyres & wheels · 3 suspension & brakes · 2 engineshowhide 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 SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheels 2023-06-01 SRF3 Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheels 2023-05-01 SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheels 2023-05-01 SRF3 Update SRF Front W2 Rain Tire Part Number #34118tyres & wheels 2023-03-01 SRF Update SRF Brake Rule #33469suspension & brakes 2023-03-01 SRF3 Update SRF Brake Rule #33469suspension & brakes 2023-03-01 SRF3 Update SRF Bodywork Fitment Rule #33765tyres & wheels
	Virginia International Raceway Runoffs 20222022-09-24				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%)			2:03.716Franklin Futrelle · fastest of 44 · top 5 within 0.6s-0.908s (-0.73%)	2:22.066Franklin Futrelle · fastest of 40 · top 5 within 1.2s+17.311s (+13.88%)	134.5David Ogburn+2.1 mph (+1.6%)
15 rule changes (SRF: 3, AS: 9, SRF3: 3)4 weight · 3 suspension & brakes · 2 tyres & wheels · 1 engine · 2 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 2022-06-01 SRF SRF Tire Rule Update #32614tyres & wheels 2022-06-01 SRF Brake, seal, and air filter clarifications #32670suspension & brakes 2022-06-01 SRF3 SRF Tire Rule Update #32614tyres & wheels 2022-06-01 SRF3 Brake, seal, and air filter clarifications #32670suspension & brakes 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 2021-12-01 SRF Three Updates to SRF Rules #31523weight 2021-12-01 SRF3 Three Updates to SRF Rules #31523weight 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				1:50.427Drew 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			1:49.520Franklin Futrelle · fastest of 84 · top 5 within 0.5s-0.304s (-0.28%)	1:50.095John Black · fastest of 82 · top 5 within 0.2s+0.313s (+0.29%)	132.1Matthew Horst
26 rule changes (SRF: 6, AS: 14, SRF3: 6)8 weight · 7 engine · 3 cars added · 2 suspension & brakes · 2 tyres & wheels · 2 wording · 2 othershowhide 2021-08-01 SRF SRF Wet Tires #30849tyres & wheels 2021-08-01 SRF SADEV-SRF3 Transmission #30926other 2021-08-01 SRF SRF Update Maintenance, Repairs and Seals #30961engine 2021-08-01 SRF3 SRF Wet Tires #30849tyres & wheels 2021-08-01 SRF3 SADEV-SRF3 Transmission #30926other 2021-08-01 SRF3 SRF Update Maintenance, Repairs and Seals #30961engine 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 SRF SRF3 Alternator Pulley #30684weight 2021-06-01 SRF3 SRF3 Alternator Pulley #30684weight 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 SRF Mandatory identification: #30223engine 2021-03-01 SRF3 Mandatory identification: #30223engine 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 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 SRF SRF Shocks, Springs and Ride Height. #29688suspension & brakes 2020-12-01 SRF3 SRF Shocks, Springs and Ride Height. #29688suspension & brakes
	Road America Runoffs 20202020-10-02				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			2:29.786TJ Acker · fastest of 59 · top 5 within 0.5s	2:31.038Justin Hille · fastest of 55 · top 5 within 0.2s	131.9Charles Russell Turner
28 rule changes (SRF: 5, AS: 16, SRF3: 7)8 suspension & brakes · 4 tyres & wheels · 4 weight · 3 engine · 2 cars added · 2 induction · 1 aero · 4 othershowhide 2020-08-01 AS Dodge Challenger AS Spec Line Clarification #28698induction 2020-08-01 AS Dodge Challenger AS Spec Line Clarification #2 #28699aero 2020-07-01 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 2020-06-01 SRF3 SRF Shocks #28791suspension & brakes 2020-05-01 AS weight adjustments for 2020 season #28785weight -50 lbs 2020-05-01 SRF SRF Bump Stop Correction #27019suspension & brakes 2020-05-01 SRF3 Update Bump Stop Rule #28712suspension & brakes 2020-05-01 SRF3 SRF Bump Stop Correction #27019suspension & brakes 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 202-01-01 SRF SRF Rain / Brake Rule - BoD approved as follows #34958suspension & brakes 202-01-01 SRF3 SRF Rain / Brake Rule - BoD approved as follows #34958suspension & brakes 2019-12-01 SRF SRF Tire Warmer Rule #27622tyres & wheels 2019-12-01 SRF SRF / SRF3 Nose Weight Reduction #27706weight 2019-12-01 SRF SRF / SRF3 Majors & Regional Class Updates #27723other 2019-12-01 SRF3 SRF Tire Warmer Rule #27622tyres & wheels 2019-12-01 SRF3 SRF / SRF3 Nose Weight Reduction #27706weight 2019-12-01 SRF3 SRF / SRF3 Majors & Regional Class Updates #27723other
	Virginia International Raceway Runoffs 20192019-10-05				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			2:04.624Brian Schofield · fastest of 54 · top 5 within 0.6s	2:04.755Bobby Sak · fastest of 53 · top 5 within 0.3s	132.4Bobby Sak
8 rule changes (SRF: 1, AS: 4, SRF3: 3)2 suspension & brakes · 1 cars added · 1 weight · 4 othershowhide 2019-10-01 AS Request to add SMG to 9.1.6.B.1 AS Intent #27140other 2019-08-01 AS Request Ride Height Clarification #26598suspension & brakes 2019-07-01 SRF SRF Dash Windscreen Kit #27028other 2019-07-01 SRF3 SRF Dash Windscreen Kit #27028other 2019-05-31 AS Request to Revert to 2017 Weights #25885weight 2019-05-31 SRF3 New SRF Sectional Nose Rule Addition #26914other 2019-05-01 SRF3 SRF Brakes and Shock Rule Changes #26629suspension & brakes 2019-02-01 AS SMG Mustang eligibility in American sedan #26224cars added
	Sonoma Raceway Runoffs 20182018-10-10				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			1:46.117Robeson Clay Russell · fastest of 36 · top 5 within 0.5s	1:47.053TJ Acker · fastest of 35 · top 5 within 0.2s	110.2Steve Fogg
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s	1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s		1:45.220James Jost · fastest of 29 · top 5 within 6.7s	1:51.507Bryan Long · fastest of 28 · top 5 within 0.9s		-2.262squal -6.353s	98.0%qual 94.3%	1:49.824John Black · fastest of 101 · top 5 within 0.5s	1:49.782Tray Ayres · fastest of 94 · top 5 within 0.4s		-3.987squal -1.749s	96.5%qual 98.4%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s	1:37.621Todd Harris · fastest of 27 · 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		-4.197squal -6.693s	95.7%qual 93.1%	1:34.363John Black · fastest of 41 · top 5 within 0.5s	1:34.947Cliff White · fastest of 39 · top 5 within 0.3s		-2.674squal -2.981s	97.3%qual 96.9%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	2:14.306Cliff White · fastest of 39 · top 5 within 1.2s	2:16.700Cliff White · fastest of 38 · top 5 within 0.5s		2:01.746Tom Sloe · fastest of 22 · top 5 within 2.6s	2:02.922Andy McDermid · fastest of 19 · top 5 within 2.2s		-13.778squal -12.560s	89.9%qual 90.6%	2:08.557Kerry Jacobsen · fastest of 29 · top 5 within 1.1s	2:10.215Chad Galloway · fastest of 29 · top 5 within 0.3s		-6.485squal -5.749s	95.3%qual 95.7%

By track

Track	Events	Typical % of SRF	Best	Latest
Road America	4	0 of 4 with SRF
Virginia International Raceway	3	0 of 3 with SRF
Indianapolis Motor Speedway	2	100.0%1 of 2 with SRF	100.0%Runoffs 2017	100.0%Runoffs 2017
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	0 of 1 with SRF

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 SRF'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.