BoP Lab / Classes / FB
FB vs AS vs F5 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.
Closest to the field: FB 100.0% of FB J R Osborne, Daytona International Speedway Runoffs 2015 race · AS 105.3% of FB James Jost, Virginia International Raceway Runoffs 2019 race · F5 99.9% of FB Wiley Mcmahan, Virginia International Raceway Runoffs 2019 race
| Event | FB | AS | F5 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Qual best | Race best | Trap | Qual best | Race best | Trap | vs FB | % of FB | Qual best | Race best | Trap | vs FB | % of FB | |||
| Road America Runoffs 20262026-09-28 | 2:26.911Andrew 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%) | ||||||||||||
13 rule changes (AS: 13)2 cars added · 2 engine · 2 weight · 1 induction · 1 suspension & brakes · 1 tyres & wheels · 2 wording · 2 other · AS Camaro 16+ Spec Line: 1LE front splitter kit permitted, belt tensioner and motor mount parts allowed, spark plug position defined. · AS class adds Pirelli P Zero Trofeo Track as permitted tyre option for competition. · AS class rear trailing arms no longer required to maintain stock length, only to locate rear axle. · AS Ford Mustang GT 4.6L 4-valve regains allowance, minimum weight 3200 lbs. · AS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs. · AS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776. · AS EFI engine build sheets add dry sump, header, camshaft, and timing chain tensioner options for LS, LT1, Ford, and Mopar engines. · AS LT1 Camaro engine build sheet added with full specs; LT1 weight 3200 lbs, GTO tire to 275, Mustang weight to 3525 lbs, oil catch tanks now required. · AS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets. · AS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line. · AS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm. · AS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft. · AS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs.show
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| 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%) | ||||||||||||
11 rule changes (AS: 11)3 engine · 1 cars added · 1 induction · 1 weight · 3 wording · 2 other · AS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs. · AS Ford Mustang GT 05-14 Restricted Prep Engine gains additional gear ratio option: 3.66, 2.43, 1.69, 1.32, 1.00, .65. · AS Ford Mustang GT 5.0L 15-17 flat plate restrictor reduces from 67mm to 64mm. · AS LS1/LS6 intakes added for 5.3L truck engine: part numbers 12561269 and 88894095. · AS Flotek head value seat cutting dimensions figure updated for consistency. · AS class notes cleaned: fuel cell and ECM specifications removed from multiple Camaro, Firebird, Challenger and Mustang variants. · AS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models. · AS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm. · AS Mustang GT 05-14 Restricted loses 300 lbs engine; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively. · AS class: multiple American muscle cars gain additional allowed gear ratio options across model years and prep levels. · AS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM.show
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| 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%) | ||||||||||||
11 rule changes (AS: 11)5 cars added · 1 engine · 1 tyres & wheels · 4 other · AS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options. · AS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes. · AS Chevrolet Camaro 1LE (2016-) added with 3600 lbs minimum weight, 275 tires, 60mm restrictor, 345/338mm brakes. · AS Chevrolet/Pontiac Camaro & Firebird 82–92 5.7L LS1 classified: 3200 lbs, 13.1×1.27 disc brakes, 17 in max wheel, 65 mm restrictor, SLP intake lid permitted. · AS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations. · AS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes. · AS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25. · Chevrolet Camaro, Pontiac Firebird 70–81 Full Prep classified in AS at 3400–3600 lbs with 108.0 wheelbase, specific head castings, and suspension modifications permitted. · AS class adds fuel cell location notes to multiple Cadillac, Chevrolet, Dodge and Ford models: cells within 24 inches of standard tank. · Chevrolet Camaro 6th gen Full Prep added to AS class at 3400 lbs base or 3600 lbs with built engine. · AS class: Ford Mustang GT 05-14 Restricted prep added; Cadillac CTS-V 04-07 to 3450 lbs; Camaro/Firebird variants reconfigured with weight and notes changes; Dodge Challenger 08-20 restrictor 76mm to 80mm; Ford Mustang variants updated wei…show
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| 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%) | ||||||||||||
4 rule changes (AS: 4)1 tyres & wheels · 2 wording · 1 other · AS crate motor part number specification clarified; both CT400 P/N-19370604 and 19370604 engine assemblies permitted for GM vehicles. · AS Ford Mustang GT 5.0L (15-17) Restricted maximum wheel diameter increases to 19.0 inches. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front upper control arms; SPC-66045 spec part removed. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 now allows alternate front brake calipers with adaptor brackets for component compatibility.show
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| 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%) | 1:57.689James 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%) | |||||||||
15 rule changes (AS: 9, F5: 6)2 cars added · 2 engine · 2 weight · 1 tyres & wheels · 5 wording · 3 other · AS adds Hoosier W2 wet tyre option alongside R7, R6, WET/H20. · AS Dodge Challenger 08-20 gains two transmission ratio options: 2.97–0.50 or 2.26–0.63. · F500 Rotax 493 and 593 intake boots: removed Moto Tassinari V3124-873B-2 from 493/593 non-HO allowance, added Moto Tassinari V3120-794A-2 option for non-HO. · F500 Rotax engines now permit Ingi Tech Sparker ignition DCP-CDI-P2 as alternate ECU. · AS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty. · F500 clarifies stepped diameter exhaust headers prohibited except at cylinder head flange area. · F500 Rotax 593 intake boot options clarified; oil injection pump removal now permitted. · F500 Majors and Runoffs cars must install AIM part #X47KPFSOLO2R0 data box mount for Solo or Solo 2. · SMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000. · AS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line. · AS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes. · AS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180. · F5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. · AS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms. · AS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.show
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| 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 | 1:42.619Ryan 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 | |||||||||
17 rule changes (AS: 14, F5: 3)6 cars added · 3 weight · 2 engine · 5 wording · 1 other · F5 clarifies mechanical shifting only; throttle-cut and flat-shifter devices permitted if driver retains full control. · F5 single-seat open-wheel cars: rigid suspension becomes limited suspension in class definition. · AS Cadillac CTS-V 6.0L LS6 removes 295-tire 50 lb penalty. · AS consolidates seven SN95 Mustang '94-'04 spec lines into three unified lines by model year and engine. · AS Camaro/Firebird LT1 and LS1 transmission changed to TUET1 6362; Mustang GT 4.6L/5spd to TUKT16901, loses 300 lbs. · AS Camaro & Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted. · AS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants. · F500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required. · AS Mustang 4.6L 5spd gains cold air intake freedom; 5.0L 6spd now requires 56mm flat plate restrictor. · AS CTS-V 5.7L LS6 and 6.0L LS2 may use Driveshaft Shop P/N GMCTSV2-C carbon fiber driveshaft. · AS Chevrolet Camaro SS V8 6.2L Restricted Prep model years extended from 10–13 to 10–15. · AS Ford Mustang GT 5.0L 15-17 Restricted added to Spec Line with 3600 lbs minimum weight, 55mm restrictor, 18×10 wheels, 295 tires. · AS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed. · AS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 and Challenger 08-20 specs removed. · AS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with weight minimums 3250–3500 and 3350–3600 lbs respectively. · AS Dodge Challenger gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres; compression to 10.9:1 max. · AS Camaro & Firebird (93-02) and Ford Mustang Coupe GT (05-14) spec lines consolidated; Camaro/Firebird now allows both LT1 and LS1 engines; Mustang now allows both 4.6L 3-valve and 5.0L 4-valve engines with restrictor.show
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| 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 | 2:20.954Calvin Stewart · fastest of 16 · top 5 within 1.8s | 2:21.391James Weida · fastest of 14 · top 5 within 1.5s | 143.2Aaron Ellis | |||||||||
22 rule changes (AS: 16, F5: 6)5 engine · 2 cars added · 2 weight · 1 aero · 1 induction · 1 suspension & brakes · 9 wording · 1 other · F500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019. · AS Dodge Challenger 5.7L V8 now requires iron block instead of aluminum, compression to 10.5:1 max, intake valve 12.7 mm, exhaust 12.3 mm, intake timing 188 degrees, exhaust timing 205 degrees. · AS Dodge Challenger 08-14 rear spoiler: 1GL20RXF replaced with 1GL20TZZAB; 82211606 still permitted. · AS class pursuing specified list of eligible tires; list details unclear from text provided. · AS class tire eligibility list under development; no specifications changed yet. · AS Coyote Mustang restrictor plate under review for 2021; no change effective yet. · AS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration. · AS Ford Mustang Coupe GT 4.6L 3V Restricted Prep now permits Ford Performance camshaft kit P/N M-6550-3V. · 2010-2014 Camaro remains classified in AS; no specification changes. · AS class cylinder head supplier discontinuation; replacement option pending for 2021 season. · AS Mustang, Capri, Camaro, and Firebird maximum brake rotor diameter increased from 12.2 to 13.1 inches. · unclear · F5 request to adjust external jetting device cockpit control denied; no rule change made. · F5 driver adjustable carburettor mixture: refer to separate Fastrack letter #28359 for ruling. · F5 cockpit adjustment request response published in Fastrack letter 28359. · AS rear trailing arms may be replaced with tubular arms maintaining stock length and axle location purpose only. · AS Ford and GM full prep cars get increased weight reduction from 150 to 200 lbs. · 05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam permitted. · 10-15 Camaro Full Prep classified AS with 3400 lbs base weight, 3700 lbs over 313 CID, specific head castings and Edelbrock heads permitted. · F500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm.show
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| Virginia International Raceway Runoffs 20192019-10-05 | 1:54.469Pete Frost · only car | 1:57.688Pete Frost · only car | 145.9Pete Frost | 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 | +6.212squal +8.469s | 105.3%qual 107.4% | 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 | -0.116squal +2.892s | 99.9%qual 102.5% | ||
5 rule changes (AS: 4, F5: 1)2 cars added · 2 weight · 1 wording · AS Spec Mustang (SMG) added as Restricted Prep class. · F500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs. · AS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects. · AS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450. · AS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes.show
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| 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 | 1:47.782Andrew McDermid · fastest of 12 · top 5 within 1.9s | 1:50.345John Heinricy · fastest of 10 · top 5 within 2.3s | 105.0Kevin Fandozzi | +19.156squal +19.170s | 121.0%qual 121.6% | 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 | +11.302squal +13.195s | 112.4%qual 114.9% | ||
| 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 | 1:45.220James Jost · fastest of 29 · top 5 within 6.7s | 1:51.507Bryan Long · fastest of 28 · top 5 within 0.9s | +17.805squal +11.474s | 119.0%qual 112.2% | 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 | +9.158squal +9.390s | 109.8%qual 110.0% | |||||
| 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 | 1:30.651Tom Sloe · fastest of 22 · top 5 within 3.6s | 1:33.424Edward Hosni · fastest of 20 · top 5 within 1.0s | +12.409squal +10.765s | 115.3%qual 113.5% | 1:28.528Calvin Stewart · fastest of 14 · top 5 within 3.9s | 1:29.853Steven Thompson · fastest of 12 · top 5 within 4.5s | +8.838squal +8.642s | 110.9%qual 110.8% | |||||
| 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 | 2:01.746Tom Sloe · fastest of 22 · top 5 within 2.6s | 2:02.922Andy McDermid · fastest of 19 · top 5 within 2.2s | +11.306squal +11.035s | 110.1%qual 110.0% | 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 | +11.682squal +11.113s | 110.5%qual 110.0% | |||||
By track
| Track | Events | Typical % of FB | Best | Latest |
|---|---|---|---|---|
| Road America | 4 | 0 of 4 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.