BoP Lab / Classes / F5

F5 vs SRF vs F6 vs GTL pace at every track

Lap times across years say as much about the weather as the class. % of F5 is each class's best lap as a share of F5'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-SpecEPF5×vsF6 ×FAFCFE2FFFPFVFXGT1GT2vsGTL ×GTXHPPP2SMSMXvsSRF ×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 World Wide Technology Raceway

Closest to the field: F5 100.0% of F5 Matthew Strand, Daytona International Speedway Runoffs 2015 race · SRF 108.2% of F5 Thomas Kirchman, Indianapolis Motor Speedway Runoffs 2017 qualifying · GTL 99.5% of F5 Michael Lewis, Virginia International Raceway Runoffs 2022 race

% of F5Lap times

F5SRFF6GTLsolid race · dashed qualifying · slower is lower

F5SRFF6GTLsolid race · dashed qualifying · each class's best lap as a share of F5's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	F5			SRF					F6					GTL
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs F5	% of F5	Qual best	Race best	Trap	vs F5	% of F5	Qual best	Race best	Trap	vs F5	% of F5
	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%)
9 rule changes (SRF: 5, GTL: 4)1 aero · 1 engine · 1 removed · 1 suspension & brakes · 1 weight · 4 othershowhide 2026-09-01 SRF GCR Rain/Brake Light Correction #40579suspension & brakes 2026-03-01 GTL Remove GT3U from GCR as it is now in STU #39862removed 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 2025-01-01 GTL Correct language regarding OEM Areo Devices #37137aero 2024-11-01 GTL G16E-GTS Fuel Injection Spec Line Change #36588engine 2024-11-01 GTL GTL Alternate Weight and Choke Option for L16 engine #36653weight
	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			2:30.858Peter Shadowen · fastest of 14 · top 5 within 4.4s-1.085s (-0.71%)	2:30.844Chris Bovis · fastest of 13 · top 5 within 3.7s-0.757s (-0.50%)	133.3Peter Shadowen+1.8 mph (+1.4%)
26 rule changes (SRF: 10, GTL: 16)5 cars added · 5 engine · 4 weight · 3 suspension & brakes · 3 tyres & wheels · 2 induction · 1 aero · 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 GTL Request to Include Toyota GR86 in GTL #36324cars added 2024-09-01 GTL Inclusion of Modified Spec Miata for GTL competition #36325cars added 2024-09-01 GTL Include Mazda MX5 RF 2017- in GTL #36428cars added 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 2024-07-01 GTL Add GTL to GT3 choke option line. #36236induction 2024-05-01 GTL Request for Spec Line 1010 Reconsideration #35009weight +300 lbs 2024-05-01 GTL Allow 34 mm chokes for the Datsun 510 #35661induction +50 lbs 2024-02-01 GTL Rear Blade Spoiler Clarification #35261aero 2024-02-01 GTL GT Direct Injection allowance and rules #35437engine 2024-02-01 GTL GT2/3 remove Direction Injection not allowed in Spec line notes #35439engine 2024-01-01 GTL Rotary Engine 12A Rotor Housings #35131engine 2024-01-01 GTL Request to Include Toyota GR86 in GTL #35198cars added 2024-01-01 GTL Errors and Omissions, GTL engines & Cars #35226engine 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 2023-12-01 GTL Small Engines in GT Lite #34842engine 2023-12-01 GTL Request to Classify Honda Fit body in GTL #35020cars added 2023-12-01 GTL Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453weight 2023-11-01 GTL Weight for Nissan Sentra/200SX A 1400's #34918weight -50 lbs 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			2:09.564Peter Shadowen · fastest of 11 · top 5 within 4.9s+1.775s (+1.39%)	2:11.277Graham Fuller · fastest of 10 · top 5 within 2.4s-9.903s (-7.01%)	142.7Peter Shadowen+6.7 mph (+4.9%)
10 rule changes (SRF: 3, GTL: 7)3 engine · 2 tyres & wheels · 2 weight · 1 cars added · 1 induction · 1 suspension & brakesshowhide 2023-06-01 SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheels 2023-05-01 GTL Please classify Fields Cardinal V8 #33784cars added 2023-05-01 SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheels 2023-03-01 SRF Update SRF Brake Rule #33469suspension & brakes 2023-02-01 GTL Toyota 4Y Engine Classification Request #33562engine 2023-01-01 GTL Toyota 4A-F and 4A-FE 1.6L DOHC 16V Engine Request #33415engine 2022-12-01 GTL Fiat HP Limited Prep X1/9 Weight in GTL #33297weight 2022-12-01 GTL GT2 (TA2)/GTA Part Number Update #33315induction 2022-12-01 GTL Request to add Ford Festiva to GTL #33335weight 2022-11-01 GTL Engine Request #33064engine
	Virginia International Raceway Runoffs 20222022-09-24	1:57.689James Weida · fastest of 11 · top 5 within 3.9s+0.328s (+0.28%)	2:21.862Sven de Vries · fastest of 10 · top 5 within 14.3s+24.290s (+20.66%)	142.9Calvin Stewart+0.1 mph (+0.1%)											2:07.789Peter Shadowen · fastest of 14 · top 5 within 2.2s+0.792s (+0.62%)	2:21.180Michael Lewis · fastest of 13 · top 5 within 2.1s+13.343s (+10.44%)	136.0Peter Shadowen+4.9 mph (+3.7%)	-0.682squal +10.100s	99.5%qual 108.6%
12 rule changes (F5: 6, SRF: 3, GTL: 3)2 cars added · 2 engine · 2 induction · 2 suspension & brakes · 1 tyres & wheels · 1 weight · 2 othershowhide 2022-09-01 F5 Intake Boots Correction #33028induction 2022-09-01 GTL Tail lights on all GT category race cars. #32799suspension & brakes 2022-08-01 F5 Ensure availability of ECU for Rotax engines #32695engine 2022-07-01 F5 Clarify stepped exhaust header references #32743engine 2022-06-01 F5 593 carb boot availability and oil pump clarification #32527induction 2022-06-01 SRF SRF Tire Rule Update #32614tyres & wheels 2022-06-01 SRF Brake, seal, and air filter clarifications #32670suspension & brakes 2022-03-01 F5 E&O class name #32194other 2022-03-01 GTL Request to Classify Ginetta G40 in GTL #31599cars added 2022-01-01 F5 Data Box Mounting Plate #31638other 2021-12-01 SRF Three Updates to SRF Rules #31523weight 2021-10-01 GTL Request car classification #31032cars added
	Indianapolis Motor Speedway Runoffs 20212021-09-25	1:42.619Ryan Mayfield · fastest of 22 · top 5 within 1.6s-0.517s (-0.50%)	1:43.140Sven de Vries · fastest of 20 · top 5 within 1.7s+0.280s (+0.27%)	144.4James Weida											1:51.819Christopher Bovis · fastest of 22 · top 5 within 1.8s+1.488s (+1.35%)	1:51.952Scott Twomey · fastest of 19 · top 5 within 1.7s-0.116s (-0.10%)	129.5Brian Linn	+8.812squal +9.200s	108.5%qual 109.0%
17 rule changes (F5: 3, SRF: 6, GTL: 8)4 engine · 3 tyres & wheels · 3 weight · 1 cars added · 1 induction · 1 suspension & brakes · 2 wording · 2 othershowhide 2021-08-01 F5 Clarify allowable assisted shifting systems #30871wording 2021-08-01 F5 Request to correct terminology #30976tyres & wheels 2021-08-01 GTL Request to Update GTA Obsolete Part Numbers #30615wording 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 2021-07-01 GTL Request clarification for the Honda B18a,bVS B18c #30482weight 2021-07-01 GTL Request to Allow Hood Bulge on Nissan B13 Sentra #30504other 2021-07-01 GTL Request BMW E21 Classing #30582tyres & wheels 2021-06-01 F5 Request to Allow Rotax 593 HO Engine #30712engine 2021-06-01 SRF SRF3 Alternator Pulley #30684weight 2021-03-01 GTL Request for Help for Mazda 12A #29754weight +50 lbs 2021-03-01 SRF Mandatory identification: #30223engine 2021-02-01 GTL Request LP HP Fiat X1/9 & Bertone 1500 to GTL #30058cars added 2021-01-01 GTL Please Add GTL Nissan 1.8L Engine MRA8DE #29805engine 2021-01-01 GTL Increase 13b SIR size #29867induction 2020-12-01 SRF SRF Shocks, Springs and Ride Height. #29688suspension & brakes
	Road America Runoffs 20202020-10-02	2:20.954Calvin Stewart · fastest of 16 · top 5 within 1.8s	2:21.391James Weida · fastest of 14 · top 5 within 1.5s	143.2Aaron Ellis											2:31.943Chris Bovis · fastest of 14 · top 5 within 6.3s	2:31.601Peter Shadowen · fastest of 14 · top 5 within 7.2s	131.4Peter Shadowen	+10.210squal +10.989s	107.2%qual 107.8%
28 rule changes (F5: 6, SRF: 5, GTL: 17)7 aero · 5 induction · 3 cars added · 3 weight · 2 engine · 2 suspension & brakes · 1 tyres & wheels · 5 othershowhide 2020-10-01 F5 Request to Update Suzuki Engine Years for F500 #29453engine 2020-09-01 GTL GT Category Wording #29193induction 2020-08-01 GTL Request to change the Mazda 13b restrictor size #28518induction +175 lbs 2020-07-01 F5 Request for Cockpit Adjustment of External Jetting Devices #28359other 2020-07-01 F5 Two Stroke Motors (reply to #28359 WDYT) #28816engine 2020-07-01 F5 Re letter requesting driver adjustable carb mixture #28840other 2020-07-01 F5 #28359 WDYT Request for Cockpit Adjustment #28875other 2020-07-01 GTL Request to classify 1999-2007 Toyota MR2 Spyder body #28870cars added 2020-07-01 GTL TA2 Gurney flap wicker clarification #28874aero 2020-07-01 GTL STO Gurney flap wicker clarification #28883aero 2020-07-01 GTL GT Gurney flap wicker clarification #28909aero 2020-07-01 GTL Mazda 13b Restrictor Size Follow up to Letter 28518 #29015induction 2020-06-01 GTL Stall Test #28709induction 2020-05-01 GTL GTL Wing Rule #28754aero 2020-05-01 SRF SRF Bump Stop Correction #27019suspension & brakes 2020-03-01 GTL Wing Mounting Upright Size #27641aero 2020-03-01 GTL Wing Mounting Upright Size #27641aero 2020-03-01 GTL GTL wing end plates addition #28243aero 2020-03-01 GTL Clarification to letter #27406 #28309weight -50 lbs 2020-02-01 GTL Windshield Clips #27323other 2020-01-01 F5 Change 600cc restrictor size #27883induction 2020-01-01 GTL Request Factory Five Daytona coupe classification #26308cars added 2020-01-01 GTL Request to Classify the MK1 two door Jetta #27648cars added 202-01-01 SRF SRF Rain / Brake Rule - BoD approved as follows #34958suspension & brakes 2019-12-01 GTL 88-91 Honda CRX Spec Line Correction #27233weight 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	1:57.361Wiley Mcmahan · fastest of 15 · top 5 within 3.8s	1:57.572Wiley Mcmahan · fastest of 15 · top 5 within 4.0s	142.8Eric McRee											2:06.997Peter Shadowen · fastest of 19 · top 5 within 4.0s	2:07.837Bill Ball · fastest of 18 · top 5 within 4.2s	131.1Peter Shadowen	+10.265squal +9.636s	108.7%qual 108.2%
15 rule changes (F5: 1, SRF: 1, GTL: 13)5 weight · 4 cars added · 2 engine · 1 induction · 1 suspension & brakes · 1 tyres & wheels · 1 othershowhide 2019-08-31 F5 Request for Weight Increase for Motorcycle Powered Cars #27214weight +25 lbs 2019-08-31 GTL Fun Cup Beetle #27334weight 2019-08-01 GTL GTL #26960weight 2019-07-01 GTL Request CRZ wheelbase change #26896tyres & wheels 2019-07-01 SRF SRF Dash Windscreen Kit #27028other 2019-05-01 GTL Request to Classify VW Fun Cup Beetle #25986cars added 2019-05-01 GTL Request GTX Fuel injection for previous GT-1 tube frame cars #26141engine 2019-05-01 GTL Request to Classify Ligier JS2 R #26535cars added 2019-05-01 GTL Request for GTL Mazda 13B SIR Increase with Penalty #26572engine 2019-04-01 GTL Request Ride Height Clarification #26600suspension & brakes 2019-03-01 GTL Request Mazda 12a Rotary SIR Increase #26081induction 2019-03-01 GTL Request to Classify Mustang 2 Body in GTL #26222cars added 2019-01-01 GTL Request for GTL Mini Adjustments #25754weight 2019-01-01 GTL BMC thru Rover Group remove long inactive mini #25771weight 2019-01-01 GTL GTX Homologation table update #26034cars added
	Sonoma Raceway Runoffs 20182018-10-10	1:41.807Jeff Jorgenson · fastest of 5 · top 5 within 6.6s	1:42.491David Lapham · fastest of 5 · top 5 within 9.5s	113.3David Lapham											1:47.885Troy Ermish · fastest of 20 · top 5 within 4.5s	1:49.458Troy Ermish · fastest of 19 · top 5 within 3.6s	109.3Charles Leonard	+6.967squal +6.078s	106.8%qual 106.0%
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:43.136Wiley Clinton McMahan · fastest of 38 · top 5 within 1.4s	1:42.860Wiley Clinton McMahan · fastest of 37 · top 5 within 1.6s		1:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s	1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s		+10.909squal +8.437s	110.6%qual 108.2%						1:50.331Christopher Bovis · fastest of 26 · top 5 within 1.5s	1:52.068Christopher Bovis · fastest of 20 · top 5 within 1.0s		+9.208squal +7.195s	109.0%qual 107.0%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:28.528Calvin Stewart · fastest of 14 · top 5 within 3.9s	1:29.853Steven Thompson · fastest of 12 · top 5 within 4.5s		1:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s	1:37.621Todd Harris · fastest of 27 · top 5 within 0.6s		+7.768squal +8.816s	108.6%qual 110.0%						1:35.377Wilson Wright · fastest of 28 · top 5 within 1.2s	1:35.912Kyle Disque · fastest of 28 · top 5 within 1.1s		+6.059squal +6.849s	106.7%qual 107.7%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	2:01.824W. Clint McMahan · fastest of 16 · top 5 within 3.0s	2:03.298Matthew Strand · fastest of 15 · top 5 within 4.9s		2:14.306Cliff White · fastest of 39 · top 5 within 1.2s	2:16.700Cliff White · fastest of 38 · top 5 within 0.5s		+13.402squal +12.482s	110.9%qual 110.2%						2:11.387Jim Dentici · fastest of 10 · top 5 within 2.2s	2:13.564Jim Dentici · fastest of 9 · top 5 within 2.0s		+10.266squal +9.563s	108.3%qual 107.8%

By track

Track	Events	Typical % of F5	Best	Latest
Road America	3	100.0%1 of 3 with F5	100.0%Runoffs 2020	100.0%Runoffs 2020
Virginia International Raceway	3	100.0%2 of 3 with F5	100.0%Runoffs 2019	100.0%Runoffs 2022
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 F5'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.