BoP Lab / Classes / FB

FB vs F6 vs SRF vs P1 pace at every track

Lap times across years say as much about the weather as the class. % of FB is each class's best lap as a share of FB's on the same day, so the conditions drop out: 100% is level, less is quicker, and a move in it is the class getting faster or slower against the field.

Class · click a class to switch, + to compare alongside (up to 4: remove one to add another)

ASB-SpecEPvsF6 ×FAFB×FCFE2FFFPFVFXGT1GT2GTXHPPvsP1 ×P2SMSMXvsSRF ×SRF3STLSTUT1T2T3T4Show 47 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

Closest to the field: FB 100.0% of FB J R Osborne, Daytona International Speedway Runoffs 2015 race · SRF 119.0% of FB Thomas Kirchman, Indianapolis Motor Speedway Runoffs 2017 qualifying · P1 87.9% of FB Todd Slusher, Virginia International Raceway Runoffs 2019 race

% of FBLap times

FBF6SRFP1solid race · dashed qualifying · slower is lower

FBF6SRFP1solid race · dashed qualifying · each class's best lap as a share of FB's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	FB			F6					SRF					P1
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FB	% of FB	Qual best	Race best	Trap	vs FB	% of FB	Qual best	Race best	Trap	vs FB	% of FB
	Road America Runoffs 20262026-09-28				2:18.489Calvin Stewart · fastest of 13 · top 5 within 4.2s-0.617s (-0.44%)	2:20.255James Weida · fastest of 13 · top 5 within 2.0s+1.415s (+1.02%)	143.0Calvin Stewart-4.5 mph (-3.1%)
5 rule changes (SRF: 5)1 suspension & brakes · 4 othershowhide 2026-09-01 SRF GCR Rain/Brake Light Correction #40579suspension & brakes 2026-03-01 SRF SRF3 Spark Plugs #39899other 2025-10-01 SRF Add HD Oil Cooler #38979other 2025-04-01 SRF Driver Safety & Comfort #37966other 2025-04-01 SRF Update SADEV transmission specs #37992other
	Road America Runoffs 20242024-10-01				2:19.106Calvin Stewart · fastest of 22 · top 5 within 1.3s	2:18.840James Weida · fastest of 22 · top 5 within 1.0s	147.6Calvin Stewart								2:00.476Chip Romer · fastest of 12 · top 5 within 1.5s-0.625s (-0.52%)	2:00.418Matt Romer · fastest of 9 · top 5 within 2.1s-1.452s (-1.19%)	168.3Jason Miller+8.7 mph (+5.4%)
16 rule changes (SRF: 10, P1: 6)3 suspension & brakes · 3 tyres & wheels · 3 weight · 2 engine · 2 induction · 1 wording · 2 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 2024-09-01 SRF Protest Fee Clarification #36540wording 2024-09-01 SRF 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 2024-05-01 P1 Update GCR section 9.1.8.B.J.7 #35907engine 2024-03-01 P1 Remove redundant effective date language in GCR 9.1.8.B.J.4 #35693induction 2024-03-01 P1 Correct engine series terminology #35694engine 2024-01-01 P1 Please correct omitted punctuation #34890weight 2024-01-01 P1 Adjust restrictors and weights for Engine Table lines H and I #35229induction 2024-01-01 P1 Revise Group CN Honda K20A-FD2 Spec Line #35337weight 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 2023-10-01 SRF SRF Radiator Rule Update #34805other
	Virginia International Raceway Runoffs 20232023-09-23				1:57.437Calvin Stewart · fastest of 9 · top 5 within 4.7s	1:58.816Calvin Stewart · fastest of 9 · top 5 within 3.6s	144.0Calvin Stewart								1:42.602Todd Vanacore · fastest of 10 · top 5 within 0.9s+1.001s (+0.99%)	1:44.329Todd Vanacore · fastest of 9 · top 5 within 0.7s-9.766s (-8.56%)	158.5Jason Miller+1.2 mph (+0.8%)
10 rule changes (SRF: 3, P1: 7)4 tyres & wheels · 3 induction · 2 aero · 1 suspension & brakesshowhide 2023-07-01 P1 SIR Testing #34354induction 2023-07-01 P1 E&O Single Inlet Restrictor abbreviation, etc. #34369induction 2023-07-01 P1 E&O Clean up ducted air provision #34410tyres & wheels 2023-06-01 SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheels 2023-05-01 SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheels 2023-04-01 P1 E&O - Correct dimensional equivalents #34018tyres & wheels 2023-03-01 P1 November 2022 Rules Clarification for Suspension Covers #33615aero 2023-03-01 SRF Update SRF Brake Rule #33469suspension & brakes 2022-11-01 P1 Clarify body panel coverage of suspension components #33318aero 2022-10-01 P1 E&O clarification regarding forced induction #33123induction
	Virginia International Raceway Runoffs 20222022-09-24														1:41.601Todd Slusher · fastest of 9 · top 5 within 2.3s-1.073s (-1.05%)	1:54.095John Mcaleer · fastest of 9 · top 5 within 1.4s+10.597s (+10.24%)	157.2Jason Miller+1.3 mph (+0.8%)
6 rule changes (SRF: 3, P1: 3)2 tyres & wheels · 2 weight · 1 induction · 1 suspension & brakesshowhide 2022-08-01 P1 Clarify authorization to use flat plate intake restrictor #32964induction 2022-06-01 SRF SRF Tire Rule Update #32614tyres & wheels 2022-06-01 SRF Brake, seal, and air filter clarifications #32670suspension & brakes 2022-05-01 P1 E&O Clarification of Bodywork Rules #32468tyres & wheels 2022-01-01 P1 Displacement & Weight Change Request for 2-Cycle 6 Cylinder #31609weight 2021-12-01 SRF Three Updates to SRF Rules #31523weight
	Indianapolis Motor Speedway Runoffs 20212021-09-25														1:29.011Lee Alexander · fastest of 13 · top 5 within 2.5s-1.783s (-1.96%)	1:29.225Lee Alexander · fastest of 12 · top 5 within 3.5s-2.274s (-2.49%)	160.1Jason Miller
17 rule changes (SRF: 6, P1: 11)7 engine · 5 weight · 1 induction · 1 suspension & brakes · 1 tyres & wheels · 2 othershowhide 2021-09-01 P1 Move 2000cc and 2300cc engine options to individual spec lines #31012engine 2021-09-01 P1 E&O Spec Line B notes #31095weight 2021-08-01 P1 Add 1355cc spec line #30890weight 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 2021-06-01 SRF SRF3 Alternator Pulley #30684weight 2021-05-01 P1 E&O tonneau cover provision in cockpit opening section #30458other 2021-05-01 P1 Update Spec Line B Notes #30498weight 2021-05-01 P1 Update Spec Lines C and G notes #30499weight 2021-05-01 P1 E&O Maximum Valves Per Cylinder #30559engine 2021-04-01 P1 Clean up Spec Line A notes section #30424engine 2021-04-01 P1 Clean up Spec Line H notes section #30425engine 2021-03-01 P1 DP02 Sealed 2ltr Engine Option #30038engine 2021-03-01 P1 E&O restrictor terminology #30285induction 2021-03-01 SRF Mandatory identification: #30223engine 2020-12-01 SRF SRF Shocks, Springs and Ride Height. #29688suspension & brakes
	Road America Runoffs 20202020-10-02														2:01.101James French · fastest of 18 · top 5 within 1.1s	2:01.870James French · fastest of 17 · top 5 within 1.8s	159.7David Locke
9 rule changes (SRF: 5, P1: 4)3 weight · 2 induction · 2 suspension & brakes · 1 tyres & wheels · 1 othershowhide 2020-05-01 P1 E&O minimum weights and intake manifolds #28731induction 2020-05-01 SRF SRF Bump Stop Correction #27019suspension & brakes 2020-02-01 P1 Extend date for removing sealed DP02-spec 2.0L option #28046weight 2020-01-01 P1 Remove sealed DP02-spec 2.0 MZR spec #26753induction 2020-01-01 P1 Update Revised Spec Line F #27745weight 202-01-01 SRF 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
	Virginia International Raceway Runoffs 20192019-10-05	1:54.469Pete Frost · only car	1:57.688Pete Frost · only car	145.9Pete Frost											1:42.674Todd Slusher · fastest of 14 · top 5 within 1.5s	1:43.498Todd Slusher · fastest of 13 · top 5 within 1.0s	155.9Jim Devenport	-14.190squal -11.795s	87.9%qual 89.7%
15 rule changes (SRF: 1, P1: 14)5 engine · 3 induction · 1 removed · 1 tyres & wheels · 2 wording · 3 othershowhide 2019-08-01 P1 E&O Transmissions #27098other 2019-07-01 P1 E&O Transmissions #27005tyres & wheels 2019-07-01 P1 Move minimum height provision to #27031removed 2019-07-01 P1 Remove duplicative fender louver provision #27033induction 2019-07-01 SRF SRF Dash Windscreen Kit #27028other 2019-05-31 P1 Missing word E&O #26919other 2019-05-31 P1 E&O correction to GCR 9.1.8.C.C. #26927wording 2019-05-01 P1 Clean up reference to engine table #26648engine 2019-05-01 P1 Remove redundant spec line #26692engine 2019-04-01 P1 Clean Up Engine Table Language #26590engine 2019-03-01 P1 Move single-seat closed cockpit provision to #26376wording 2019-02-01 P1 Correct errors in GCR section 9.1.8.C.J #26144engine 2019-01-01 P1 Remove redundant inlet restrictor provisions #25877induction 2019-01-01 P1 Clarify Honda K20A-FD2 parts requirement #25949engine 2019-01-01 P1 Correct GCR section 9.1.8.C.J errors #25966induction
	Sonoma Raceway Runoffs 20182018-10-10	1:28.612J R Osborne · fastest of 7 · top 5 within 3.3s	1:31.189J R Osborne · fastest of 7 · top 5 within 3.7s	140.5J R Osborne											1:27.714Todd Slusher · fastest of 19 · top 5 within 2.1s	1:28.786Perry Richardson · fastest of 19 · top 5 within 0.9s	144.0Johnnie Crean	-2.403squal -0.898s	97.4%qual 99.0%
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:33.746Gary Hickman · fastest of 18 · top 5 within 3.3s	1:33.702Alex Mayer · fastest of 17 · top 5 within 3.0s							1:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s	1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s		+20.067squal +17.827s	121.4%qual 119.0%	1:30.794Jim Devenport · fastest of 19 · top 5 within 2.8s	1:31.499Jim Devenport · fastest of 16 · top 5 within 2.2s		-2.203squal -2.952s	97.6%qual 96.9%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:19.886Alex Mayer · fastest of 10 · top 5 within 1.5s	1:21.015Jeremy Hill · fastest of 10 · top 5 within 1.2s							1:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s	1:37.621Todd Harris · fastest of 27 · top 5 within 0.6s		+16.606squal +17.458s	120.5%qual 121.9%	1:17.308James Devenport · fastest of 14 · top 5 within 2.7s	1:19.407Gianpaolo Ciancimino · fastest of 13 · top 5 within 1.8s		-1.608squal -2.578s	98.0%qual 96.8%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	1:50.711J R Osborne · fastest of 20 · top 5 within 1.1s	1:51.616J R Osborne · fastest of 19 · top 5 within 2.1s							2:14.306Cliff White · fastest of 39 · top 5 within 1.2s	2:16.700Cliff White · fastest of 38 · top 5 within 0.5s		+25.084squal +23.595s	122.5%qual 121.3%	1:49.219Jim Downing · fastest of 9 · top 5 within 2.2s	1:49.792Gianpaolo Ciancimino · fastest of 10 · top 5 within 1.7s		-1.824squal -1.492s	98.4%qual 98.7%

By track

Track	Events	Typical % of FB	Best	Latest
Road America	3	0 of 3 with FB
Virginia International Raceway	3	100.0%1 of 3 with FB	100.0%Runoffs 2019	100.0%Runoffs 2019
Indianapolis Motor Speedway	2	100.0%1 of 2 with FB	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	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 FB'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.