BoP Lab / Classes / AS

AS vs FX pace at every track

Lap times across years say as much about the weather as the class. % of AS is each class's best lap as a share of AS'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)

AS×B-Spec +EP +FA +FC +FE2 +FF +FP +FV +vsFX ×GT1 +GT2 +GTX +HP +P +P2 +SM +SMX +SRF3 +STL +STU +T1 +T2 +T3 +T4 +Show 51 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 Pittsburgh International Race Complex Portland International Raceway 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: AS 100.0% of AS Andy McDermid, Daytona International Speedway Runoffs 2015 race · FX 89.3% of AS Vaughn Glace, Indianapolis Motor Speedway Runoffs 2021 qualifying

% of ASLap times

ASFXsolid race · dashed qualifying · slower is lower

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

	Event	AS			FX
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs AS	% of AS
	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%)
14 rule changes (AS: 13, FX: 1)5 weight · 4 engine · 2 tyres & wheels · 1 induction · 1 removed · 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 2026-08-01 FX Update sealed engine teardown section #40622engine 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 2026-02-01 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
	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%)
12 rule changes (AS: 11, FX: 1)5 engine · 4 weight · 2 induction · 1 othershowhide 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 2025-03-01 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 FX Request to Change to Weight for Ligier JS F422 #37124weight -15 lbs
	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%)
15 rule changes (AS: 11, FX: 4)6 cars added · 2 tyres & wheels · 1 engine · 1 weight · 5 othershowhide 2024-09-01 AS Mustang transmission ratios #36662engine 2024-07-01 FX Adjust minimum weights to align with pro F4 rules #36221weight -15 lbs 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 2024-04-01 FX Add Classification for 2nd Gen Ligier JS F422 #35844other 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 2024-03-01 FX Clarify Formula 4 Rules in FX #35700tyres & wheels 2023-11-01 FX FM Rules Update #34841other
	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%)
7 rule changes (AS: 4, FX: 3)2 engine · 2 weight · 1 suspension & brakes · 1 tyres & wheels · 1 othershowhide 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 FX USF2000 Van Diemen with Mazda MZR LF-DE 2.0L in FC #34329weight 2023-02-01 FX E&O - Remove references to FB and FM in GCR section 1.4.2.D #33725other 2022-12-01 FX Reclassify 2010-2017 Formula Renault 2.0 as a spec line car in FA #33395weight
	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%)	1:51.480Trevor A Russell · fastest of 5 · top 5 within 9.7s	2:08.711Dimitrios Tsesmetzis · fastest of 4 · top 4 within 6.8s	137.2Trevor A Russell	+4.133squal -10.682s	103.3%qual 91.3%
18 rule changes (AS: 9, FX: 9)4 tyres & wheels · 4 weight · 3 engine · 1 induction · 1 suspension & brakes · 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 2022-08-01 FX Pro Formula F2000/USF2000 Transmission E&O #32823weight 2022-08-01 FX Formula Mazda Minimum Weight #33010weight 2022-08-01 FX Formula Mazda Spec Line E&O Corrections #33011engine 2022-07-01 AS Request CTS-V Spec Line Error Correction #30242weight 2022-07-01 FX Formula Renault 2.0 (10-17) Intake Restrictor #32745induction 2022-07-01 FX Allow Performance Electronics PE3-8400 for USF2000 MZR #32767engine 2022-02-01 FX FM Rule Set Clarification #31881tyres & wheels 2022-02-01 FX E&O F4 Tires #31940tyres & wheels 2022-02-01 FX E&O USF2000 Tube Frame #31951tyres & wheels 2022-02-01 FX URGENT - FX- Formula Renault Tire #32058tyres & 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 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	1:38.596Vaughn Glace · fastest of 15 · top 5 within 4.1s	1:38.833Vaughn Glace · fastest of 15 · top 5 within 4.3s	138.6Vaughn Glace	-11.773squal -11.831s	89.4%qual 89.3%
19 rule changes (AS: 14, FX: 5)6 weight · 5 cars added · 3 engine · 2 tyres & wheels · 1 induction · 2 wordingshowhide 2021-08-01 FX Rules Adjustment #30950tyres & wheels 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 FX FX/FRP Tire Rule #30723tyres & wheels 2021-05-01 FX Classify the 2000-2009 Formula Renault 2.0 / Fran-Am 2000 #30460cars added 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 2021-01-01 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 FX Request for Car Classification to Compete in Formula X #29933cars 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 FX Update specifications for FormulaSPEED cars #29674induction
	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	2:16.968Jacob Loomis · fastest of 12 · top 5 within 2.7s	2:17.553Jacob Loomis · fastest of 11 · top 5 within 3.5s	139.3Brad Drew	-10.115squal -10.077s	93.2%qual 93.1%
22 rule changes (AS: 16, FX: 6)5 cars added · 3 engine · 3 induction · 3 tyres & wheels · 2 suspension & brakes · 2 weight · 1 aero · 3 othershowhide 2020-09-01 FX Follow up to to Letter#28991 Request for FX classification #29281cars added 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 2020-07-01 FX Request to be added to FX group #28991other 2020-05-01 AS weight adjustments for 2020 season #28785weight -50 lbs 2020-04-01 FX Request to classify FSV in FX #28057cars added 2020-04-01 FX Classify FormulaSPEED in FX #28715cars added 2020-03-01 FX Request to remove tire marking language from FM #28415tyres & 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 2020-02-01 FX Change to FX Table 1 #28322induction
	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
4 rule changes (AS: 4)1 cars added · 1 suspension & brakes · 1 weight · 1 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 2019-05-31 AS Request to Revert to 2017 Weights #25885weight 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
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:45.220James Jost · fastest of 29 · top 5 within 6.7s	1:51.507Bryan Long · fastest of 28 · top 5 within 0.9s
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:30.651Tom Sloe · fastest of 22 · top 5 within 3.6s	1:33.424Edward Hosni · fastest of 20 · top 5 within 1.0s
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	2:01.746Tom Sloe · fastest of 22 · top 5 within 2.6s	2:02.922Andy McDermid · fastest of 19 · top 5 within 2.2s

By track

Track	Events	Typical % of AS	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 AS'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.