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BoP Lab / Classes / FB

FB vs SRF vs F5 vs STL 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-SpecEPvsF5×FAFB×FCFE2FFFPFVFXGT1GT2GTXHPPP2SMSMXvsSRF×SRF3vsSTL×STUT1T2T3T4Show 48 inactive classes
Series
Reference class · the yardstick the % column and chart are measured against
Tracks · untick to narrow

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 · F5 99.9% of FB Wiley Mcmahan, Virginia International Raceway Runoffs 2019 race · STL 108.1% of FB Cliff Ira, Virginia International Raceway Runoffs 2019 race

1:402:002:2013 rule changes between Runoffs 2018 and Runoffs 201913 ▾22 rule changes between Runoffs 2019 and Runoffs 202022 ▾24 rule changes between Runoffs 2020 and Runoffs 202124 ▾14 rule changes between Runoffs 2021 and Runoffs 202214 ▾5 rule changes between Runoffs 2022 and Runoffs 20235 ▾14 rule changes between Runoffs 2023 and Runoffs 202414 ▾5 rule changes between Runoffs 2024 and Runoffs 20255 ▾7 rule changes between Runoffs 2025 and Runoffs 20267 ▾FB race best at Runoffs 2015: 1:51.616 (J R Osborne)FB race best at Runoffs 2016: 1:21.015 (Jeremy Hill)FB race best at Runoffs 2017: 1:33.702 (Alex Mayer)FB race best at Runoffs 2018: 1:31.189 (J R Osborne)FB race best at Runoffs 2019: 1:57.688 (Pete Frost)FB qualifying best at Runoffs 2015: 1:50.711 (J R Osborne)Off the chart: FB qualifying best at Runoffs 2016: 1:19.886 (Alex Mayer)FB qualifying best at Runoffs 2017: 1:33.746 (Gary Hickman)FB qualifying best at Runoffs 2018: 1:28.612 (J R Osborne)FB qualifying best at Runoffs 2019: 1:54.469 (Pete Frost)SRF race best at Runoffs 2015: 2:16.700 (Cliff White)SRF race best at Runoffs 2016: 1:37.621 (Todd Harris)SRF race best at Runoffs 2017: 1:53.769 (Todd Harris)SRF qualifying best at Runoffs 2015: 2:14.306 (Cliff White)SRF qualifying best at Runoffs 2016: 1:37.344 (Mike Miserendino)SRF qualifying best at Runoffs 2017: 1:51.573 (Thomas Kirchman)F5 race best at Runoffs 2015: 2:03.298 (Matthew Strand)F5 race best at Runoffs 2016: 1:29.853 (Steven Thompson)F5 race best at Runoffs 2017: 1:42.860 (Wiley Clinton McMahan)F5 race best at Runoffs 2018: 1:42.491 (David Lapham)F5 race best at Runoffs 2019: 1:57.572 (Wiley Mcmahan)F5 race best at Runoffs 2020: 2:21.391 (James Weida)F5 race best at Runoffs 2021: 1:43.140 (Sven de Vries)F5 race best at Runoffs 2022: 2:21.862 (Sven de Vries)F5 qualifying best at Runoffs 2015: 2:01.824 (W. Clint McMahan)F5 qualifying best at Runoffs 2016: 1:28.528 (Calvin Stewart)F5 qualifying best at Runoffs 2017: 1:43.136 (Wiley Clinton McMahan)F5 qualifying best at Runoffs 2018: 1:41.807 (Jeff Jorgenson)F5 qualifying best at Runoffs 2019: 1:57.361 (Wiley Mcmahan)F5 qualifying best at Runoffs 2020: 2:20.954 (Calvin Stewart)F5 qualifying best at Runoffs 2021: 1:42.619 (Ryan Mayfield)F5 qualifying best at Runoffs 2022: 1:57.689 (James Weida)STL race best at Runoffs 2015: 2:10.269 (Kevin Boehm)STL race best at Runoffs 2016: 1:36.625 (Kevin Boehm)STL race best at Runoffs 2017: 1:52.589 (Eric Kutil)STL race best at Runoffs 2018: 1:49.754 (Danny Steyn)STL race best at Runoffs 2019: 2:07.273 (Cliff Ira)STL race best at Runoffs 2020: 2:32.115 (Joe Moser)STL race best at Runoffs 2021: 2:02.711 (Joe Moser)STL race best at Runoffs 2022: 2:07.832 (Danny Steyn)STL race best at Runoffs 2023: 2:06.682 (Joe Moser)STL race best at Runoffs 2024: 2:30.245 (Joe Moser)STL race best at Runoffs 2025: 2:32.127 (Jose Osiris Pena)STL race best at Runoffs 2026: 2:30.657 (Danny Steyn)STL qualifying best at Runoffs 2015: 2:09.672 (Kevin Boehm)STL qualifying best at Runoffs 2016: 1:35.439 (John Schmitt)STL qualifying best at Runoffs 2017: 1:52.647 (Adam Roberts)STL qualifying best at Runoffs 2018: 1:49.138 (Danny Steyn)STL qualifying best at Runoffs 2019: 2:07.203 (Danny Steyn)STL qualifying best at Runoffs 2020: 2:31.420 (Danny Steyn)STL qualifying best at Runoffs 2021: 1:51.665 (Danny Steyn)STL qualifying best at Runoffs 2022: 2:05.474 (Danny Steyn)STL qualifying best at Runoffs 2023: 2:05.779 (Danny Steyn)STL qualifying best at Runoffs 2024: 2:30.063 (Joe Moser)STL qualifying best at Runoffs 2025: 2:32.065 (Jose Osiris Pena)STL qualifying best at Runoffs 2026: 2:30.537 (Derek Ketchie)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2025R2025Road America · Runoffs 2026R2026
FBSRFF5STLsolid race · dashed qualifying · slower is lower
100%105%110%115%120%125%13 rule changes between Runoffs 2018 and Runoffs 201913 ▾22 rule changes between Runoffs 2019 and Runoffs 202022 ▾24 rule changes between Runoffs 2020 and Runoffs 202124 ▾14 rule changes between Runoffs 2021 and Runoffs 202214 ▾5 rule changes between Runoffs 2022 and Runoffs 20235 ▾14 rule changes between Runoffs 2023 and Runoffs 202414 ▾5 rule changes between Runoffs 2024 and Runoffs 20255 ▾7 rule changes between Runoffs 2025 and Runoffs 20267 ▾FB race best at Runoffs 2015: 100.0% of FB's (J R Osborne)FB race best at Runoffs 2016: 100.0% of FB's (Jeremy Hill)FB race best at Runoffs 2017: 100.0% of FB's (Alex Mayer)FB race best at Runoffs 2018: 100.0% of FB's (J R Osborne)FB race best at Runoffs 2019: 100.0% of FB's (Pete Frost)FB qualifying best at Runoffs 2015: 100.0% of FB's (J R Osborne)FB qualifying best at Runoffs 2016: 100.0% of FB's (Alex Mayer)FB qualifying best at Runoffs 2017: 100.0% of FB's (Gary Hickman)FB qualifying best at Runoffs 2018: 100.0% of FB's (J R Osborne)FB qualifying best at Runoffs 2019: 100.0% of FB's (Pete Frost)SRF race best at Runoffs 2015: 122.5% of FB's (Cliff White)SRF race best at Runoffs 2016: 120.5% of FB's (Todd Harris)SRF race best at Runoffs 2017: 121.4% of FB's (Todd Harris)SRF qualifying best at Runoffs 2015: 121.3% of FB's (Cliff White)SRF qualifying best at Runoffs 2016: 121.9% of FB's (Mike Miserendino)SRF qualifying best at Runoffs 2017: 119.0% of FB's (Thomas Kirchman)F5 race best at Runoffs 2015: 110.5% of FB's (Matthew Strand)F5 race best at Runoffs 2016: 110.9% of FB's (Steven Thompson)F5 race best at Runoffs 2017: 109.8% of FB's (Wiley Clinton McMahan)F5 race best at Runoffs 2018: 112.4% of FB's (David Lapham)F5 race best at Runoffs 2019: 99.9% of FB's (Wiley Mcmahan)F5 qualifying best at Runoffs 2015: 110.0% of FB's (W. Clint McMahan)F5 qualifying best at Runoffs 2016: 110.8% of FB's (Calvin Stewart)F5 qualifying best at Runoffs 2017: 110.0% of FB's (Wiley Clinton McMahan)F5 qualifying best at Runoffs 2018: 114.9% of FB's (Jeff Jorgenson)F5 qualifying best at Runoffs 2019: 102.5% of FB's (Wiley Mcmahan)STL race best at Runoffs 2015: 116.7% of FB's (Kevin Boehm)STL race best at Runoffs 2016: 119.3% of FB's (Kevin Boehm)STL race best at Runoffs 2017: 120.2% of FB's (Eric Kutil)STL race best at Runoffs 2018: 120.4% of FB's (Danny Steyn)STL race best at Runoffs 2019: 108.1% of FB's (Cliff Ira)STL qualifying best at Runoffs 2015: 117.1% of FB's (Kevin Boehm)STL qualifying best at Runoffs 2016: 119.5% of FB's (John Schmitt)STL qualifying best at Runoffs 2017: 120.2% of FB's (Adam Roberts)STL qualifying best at Runoffs 2018: 123.2% of FB's (Danny Steyn)STL qualifying best at Runoffs 2019: 111.1% of FB's (Danny Steyn)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2025R2025Road America · Runoffs 2026R2026
FBSRFF5STLsolid 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
EventFBSRFF5STL
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 20262026-09-282:30.537Derek Ketchie · fastest of 16 · top 5 within 2.9s-1.528s (-1.00%)2:30.657Danny Steyn · fastest of 16 · top 5 within 0.6s-1.470s (-0.97%)134.8Mike Taylor+2.6 mph (+2.0%)
7 rule changes (SRF: 3, STL: 4)2 cars added · 2 engine · 1 weight · 2 wording · SRF rain/brake light part number and GCR section reference corrected for original roll hoop mounting. · STL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019). · STL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. · STL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs. · SRF3 spark plugs limited to NGK LTR7IX-11 P/N G301041 only; washers and sealing rings prohibited. · STL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs. · SRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted.showhide
  • SRF GCR Rain/Brake Light Correction #40579wordingwordingSRF rain/brake light part number and GCR section reference corrected for original roll hoop mounting.
  • STL Spec Line Clean Up #40344cars addedremovedcars addedSTL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019).
  • STL Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied.
  • STL Classifications #39885cars addedaddedSTL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs.
  • SRF SRF3 Spark Plugs #39899engineengineSRF3 spark plugs limited to NGK LTR7IX-11 P/N G301041 only; washers and sealing rings prohibited.
  • STL Weight adjustment for STL #39579weightslowerweightSTL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.
  • SRF Add HD Oil Cooler #38979engineaddedengineSRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted.
Road America Runoffs 20252025-09-292:32.065Jose Osiris Pena · fastest of 14 · top 5 within 3.4s+2.002s (+1.33%)2:32.127Jose Osiris Pena · fastest of 13 · top 5 within 2.4s+1.882s (+1.25%)132.2Jon Sewell-2.1 mph (-1.5%)
5 rule changes (SRF: 2, STL: 3)1 cars added · 1 weight · 2 wording · 1 other · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed. · SRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only. · SRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved.showhide
  • STL Lotus Weight Reduction #38772weight -50 lbsfasterweightLotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs.
  • STL E&O: SMX Allowance in STL #37945wordingunclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed.
  • SRF Driver Safety & Comfort #37966otheraddedSRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only.
  • SRF Update SADEV transmission specs #37992wordingwordingSRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward.
  • STL Request to Remove Miata Hubs from General category #37138cars addedaddedSTL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved.
Road America Runoffs 20242024-10-012:30.063Joe Moser · fastest of 18 · top 5 within 3.7s-1.357s (-0.90%)2:30.245Joe Moser · fastest of 16 · top 5 within 4.2s-1.870s (-1.23%)134.3Joe Moser+1.3 mph (+1.0%)
14 rule changes (SRF: 10, STL: 4)2 engine · 2 suspension & brakes · 1 aero · 1 tyres & wheels · 1 weight · 4 wording · 3 other · SRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only. · SRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches. · SRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front. · FE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. · SRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement. · SRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. · STL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm. · STL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled. · SRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch. · SRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit. · SRF adds mandatory front brake ducts 12–36 inches, throttle pedal heel-toe extension, braided stainless flex lines, camber limit 5.0 degrees, radiator opening height 3½ ± ½ inches, rear shift cable clamp P/N WM302007A. · STL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki. · SRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.showhide
  • SRF Update SRF3 Air Filter Rule #36681wordingremovedSRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only.
  • SRF Update SRF Brake Rotor Thickness #36687suspension & brakessuspension & brakesSRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches.
  • SRF Hoosier Tire Decal Placement #36739wordingwordingSRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front.
  • SRF Protest Fee Clarification #36540wordingwordingFE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure.
  • SRF Update to Letter 36619 with new Hoosier Contingency Decal Info #36624wordingwordingSRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement.
  • SRF Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheelstyres & wheelsSRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified.
  • STL ST Electric-Assisted Steering Systems #35066aeroaddedaeroSTL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems.
  • STL BOP Adjustments #35112weightfasterweightSTL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm.
  • STL Mazda 12A #35320engineremovedengineSTL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled.
  • SRF Update SRF Rain / Brake Rule #34706otherotherSRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch.
  • SRF Update SRF Brake Light Rule v1 #34853otherotherSRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit.
  • SRF SRF / SRF3 Rule Updates #35268suspension & brakessuspension & brakesSRF adds mandatory front brake ducts 12–36 inches, throttle pedal heel-toe extension, braided stainless flex lines, camber limit 5.0 degrees, radiator opening height 3½ ± ½ inches, rear shift cable clamp P/N WM302007A.
  • STL Alternate Carburetor Request for 79-85 RX7 12a #35181engineaddedengineSTL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki.
  • SRF SRF Radiator Rule Update #34805otheraddedSRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.
Virginia International Raceway Runoffs 20232023-09-232:05.779Danny Steyn · fastest of 22 · top 5 within 3.4s+0.305s (+0.24%)2:06.682Joe Moser · fastest of 20 · top 5 within 1.5s-1.150s (-0.90%)131.8Danny Steyn+0.1 mph (+0.1%)
5 rule changes (SRF: 3, STL: 2)2 tyres & wheels · 1 cars added · 1 engine · 1 wording · SRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance. · STL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2. · SRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13. · SRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs. · Spec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules.showhide
  • SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheelstyres & wheelsSRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance.
  • STL Clarify STL table B - IT spec notes on Tires #34187wordingwordingSTL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2.
  • SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheelstyres & wheelsSRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13.
  • SRF Update SRF Brake Rule #33469enginefasterengineSRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs.
  • STL Spec MX5 in STL #33473cars addedaddedSpec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules.
Virginia International Raceway Runoffs 20222022-09-241:57.689James 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%)2:05.474Danny Steyn · fastest of 24 · top 5 within 2.3s-1.729s (-1.36%)2:07.832Danny Steyn · fastest of 22 · top 5 within 1.9s+0.559s (+0.44%)131.7Trever Degioanni-3.2 mph (-2.3%)
14 rule changes (SRF: 3, F5: 6, STL: 5)2 engine · 1 tyres & wheels · 1 weight · 6 wording · 4 other · 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. · 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. · SRF tire rule wording clarified: tires must be run as delivered. · SRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified. · F500 Majors and Runoffs cars must install AIM part #X47KPFSOLO2R0 data box mount for Solo or Solo 2. · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · F5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · STL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. · STL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb. · SRF wet tyres front P185/65R13 W2 option added; air box clarified as-delivered; SRF3 restrictor plate G301048 mandatory Jan 1 2022; P2 motorcycle engines up to 1005cc with 35mm restrictor, 2009+ stock 1075 lbs, 2008 stock 1025 lbs, modifie…showhide
  • F5 Intake Boots Correction #33028wordingwordingF500 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.
  • F5 Ensure availability of ECU for Rotax engines #32695engineaddedengineF500 Rotax engines now permit Ingi Tech Sparker ignition DCP-CDI-P2 as alternate ECU.
  • F5 Clarify stepped exhaust header references #32743wordingwordingF500 clarifies stepped diameter exhaust headers prohibited except at cylinder head flange area.
  • F5 593 carb boot availability and oil pump clarification #32527wordingwordingF500 Rotax 593 intake boot options clarified; oil injection pump removal now permitted.
  • SRF SRF Tire Rule Update #32614wordingwordingSRF tire rule wording clarified: tires must be run as delivered.
  • SRF Brake, seal, and air filter clarifications #32670otherfasterSRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified.
  • F5 E&O class name #32194otheraddedF500 Majors and Runoffs cars must install AIM part #X47KPFSOLO2R0 data box mount for Solo or Solo 2.
  • STL Single TB Weight Modifiers #31449weightfasterweightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs.
  • STL Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels.
  • F5 Data Box Mounting Plate #31638otheraddedF5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs.
  • STL Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed.
  • STL Mazda Renesis Restriction #31467enginefasterengineSTL Mazda Renesis flat plate restrictor increases from 55mm to 60mm.
  • STL Clarification of 79-85 RX7 Spec line #31621wordingwordingSTL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb.
  • SRF Three Updates to SRF Rules #31523otherotherSRF wet tyres front P185/65R13 W2 option added; air box clarified as-delivered; SRF3 restrictor plate G301048 mandatory Jan 1 2022; P2 motorcycle engines up to 1005cc with 35mm restrictor, 2009+ stock 1075 lbs, 2008 stock 1025 lbs, modifie…
Indianapolis Motor Speedway Runoffs 20212021-09-251:42.619Ryan 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 Weida1:51.665Danny Steyn · fastest of 42 · top 5 within 1.7s-0.982s (-0.87%)2:02.711Joe Moser · fastest of 37 · top 5 within 3.2s+10.122s (+8.99%)131.8Max Gee
24 rule changes (SRF: 6, F5: 3, STL: 15)4 cars added · 4 engine · 2 aero · 2 weight · 1 induction · 1 suspension & brakes · 1 tyres & wheels · 6 wording · 3 other · STL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. · 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. · SRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021. · SRF adds SADEV-SRF3 6-speed sequential transmission option with ratios 3.0–0.92:1 and 3.20 final drive. · SRF seal requirements clarified: seals now must be on driveline components in designated locations; unsealed components removed and inspected by CSR or Enterprises rather than engine shipped for testing. · F500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required. · SRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. · STL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. · STL Pontiac Solstice/Saturn Sky allowed 4 inch ride height. · STL Mazda B5 DOHC added to class; must meet all STL regulations. · STL Honda B16A (JDM) restrictor reduced from 54mm to 53mm. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · SRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. · STL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork. · STL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment. · STL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity. · STL Honda F20C drops 2% weight penalty, minimum weight reduced. · STL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm. · SRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified. · ST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.showhide
  • STL Request to clean up Spec MX-5 Redundancy #31069wordingwordingSTL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations.
  • F5 Clarify allowable assisted shifting systems #30871wordingwordingF5 clarifies mechanical shifting only; throttle-cut and flat-shifter devices permitted if driver retains full control.
  • F5 Request to correct terminology #30976wordingwordingF5 single-seat open-wheel cars: rigid suspension becomes limited suspension in class definition.
  • SRF SRF Wet Tires #30849tyres & wheelsaddedtyres & wheelsSRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021.
  • SRF SADEV-SRF3 Transmission #30926cars addedaddedSRF adds SADEV-SRF3 6-speed sequential transmission option with ratios 3.0–0.92:1 and 3.20 final drive.
  • SRF SRF Update Maintenance, Repairs and Seals #30961wordingwordingSRF seal requirements clarified: seals now must be on driveline components in designated locations; unsealed components removed and inspected by CSR or Enterprises rather than engine shipped for testing.
  • F5 Request to Allow Rotax 593 HO Engine #30712cars addedaddedF500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required.
  • SRF SRF3 Alternator Pulley #30684engineaddedengineSRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz.
  • STL VW Engine Request #30625engineaddedengineSTL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs.
  • STL Solstice Ride Height #30183otheraddedSTL Pontiac Solstice/Saturn Sky allowed 4 inch ride height.
  • STL Request Mazda B5 DOHC #30420cars addedaddedSTL Mazda B5 DOHC added to class; must meet all STL regulations.
  • STL Honda B16A (JDM) Restrictor change #30531engineslowerengineSTL Honda B16A (JDM) restrictor reduced from 54mm to 53mm.
  • STL ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingwordingST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section.
  • SRF Mandatory identification: #30223wordingwordingSRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement.
  • STL GM Ecotec engines in STL #30247engineaddedengineSTL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor.
  • STL Super Touring Alternate Miata Hubs #30345cars addedaddedST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1.
  • STL Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment.
  • STL Super Touring Wing Clarification #30111aeroaeroSTL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork.
  • STL Transmission Options #30118otheraddedSTL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment.
  • STL Request for FWD and RWD Parity #29728weightfasterweightSTL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity.
  • STL Request to Remove Honda F20C 2% Weight Penalty #29815weightfasterweightSTL Honda F20C drops 2% weight penalty, minimum weight reduced.
  • STL Request for FWD and RWD Parity #30023inductionslowerinductionSTL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm.
  • SRF SRF Shocks, Springs and Ride Height. #29688otherotherSRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified.
  • STL Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
Road America Runoffs 20202020-10-022:20.954Calvin Stewart · fastest of 16 · top 5 within 1.8s2:21.391James Weida · fastest of 14 · top 5 within 1.5s143.2Aaron Ellis2:31.420Danny Steyn · fastest of 33 · top 5 within 3.1s2:32.115Joe Moser · fastest of 30 · top 5 within 1.5s132.9Darin Treakle
22 rule changes (SRF: 5, F5: 6, STL: 11)6 engine · 4 cars added · 1 induction · 1 tyres & wheels · 1 weight · 9 wording · F500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019. · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds. · STL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules. · 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. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · STL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum. · STL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC. · STL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants. · SRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020. · STL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STL Mazda MZR restrictor reduced from 54 mm to 53 mm. · STL Mazda MZR restrictor reduces from 55 mm to 53 mm. · STL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes. · F500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm. · SRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. · SRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers. · SRF front nose weight minimum reduced from 35 to 32 lbs. · SRF2 becomes Regional Only; SRF3 nomenclature changed from GEN3 to Ford 1.6L conversion; SRF and SRF3 no longer compete together for points.showhide
  • F5 Request to Update Suzuki Engine Years for F500 #29453engineaddedengineF500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019.
  • STL Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds.
  • STL ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules.
  • F5 Request for Cockpit Adjustment of External Jetting Devices #28359wordingunclearF5 request to adjust external jetting device cockpit control denied; no rule change made.
  • F5 Two Stroke Motors (reply to #28359 WDYT) #28816engine
  • F5 Re letter requesting driver adjustable carb mixture #28840wordingunclearF5 driver adjustable carburettor mixture: refer to separate Fastrack letter #28359 for ruling.
  • F5 #28359 WDYT Request for Cockpit Adjustment #28875wordingunclearF5 cockpit adjustment request response published in Fastrack letter 28359.
  • STL Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
  • STL Request to add 2016-2019 GMX-5 Spec line #28604cars addedaddedSTL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum.
  • STL Request to update PN for MX-5 #28622cars addedaddedSTL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC.
  • STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873wordingwordingSTL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants.
  • SRF SRF Bump Stop Correction #27019wordingwordingSRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020.
  • STL STL Honda B18 restrictor changes #28794enginefasterengineSTL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants.
  • STL Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineaddedengineSTU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs.
  • STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663engineslowerengineSTL Mazda MZR restrictor reduced from 54 mm to 53 mm.
  • STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664engineslowerengineSTL Mazda MZR restrictor reduces from 55 mm to 53 mm.
  • STL Request to add wheel part numbers #28342cars addedaddedSTL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes.
  • F5 Change 600cc restrictor size #27883inductionslowerinductionF500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm.
  • SRF SRF Rain / Brake Rule - BoD approved as follows #34958wordingwordingSRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024.
  • SRF SRF Tire Warmer Rule #27622tyres & wheelstyres & wheelsSRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers.
  • SRF SRF / SRF3 Nose Weight Reduction #27706weightfasterweightSRF front nose weight minimum reduced from 35 to 32 lbs.
  • SRF SRF / SRF3 Majors & Regional Class Updates #27723wordingwordingSRF2 becomes Regional Only; SRF3 nomenclature changed from GEN3 to Ford 1.6L conversion; SRF and SRF3 no longer compete together for points.
Virginia International Raceway Runoffs 20192019-10-051:54.469Pete Frost · only car1:57.688Pete Frost · only car145.9Pete Frost1:57.361Wiley Mcmahan · fastest of 15 · top 5 within 3.8s1:57.572Wiley Mcmahan · fastest of 15 · top 5 within 4.0s142.8Eric McRee-0.116squal +2.892s99.9%qual 102.5%2:07.203Danny Steyn · fastest of 36 · top 5 within 1.8s2:07.273Cliff Ira · fastest of 35 · top 5 within 1.4s134.8Cliff Ira+9.585squal +12.734s108.1%qual 111.1%
13 rule changes (SRF: 1, F5: 1, STL: 11)3 cars added · 3 engine · 2 weight · 1 aero · 2 wording · 2 other · STL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components. · F500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs. · SRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · STL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · STL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only. · STL Mazda Renesis minimum weight reduced to 2700 lbs. · STL Mazda MX-5 Cup brake pad compound now open. · STL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited. · STL Mazda 12 and 13B now permit port matching; porting ban removed. · STL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline. · STL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.showhide
  • STL Request to Classify Spec MX-5 Challenge in STL #27399cars addedaddedSTL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components.
  • F5 Request for Weight Increase for Motorcycle Powered Cars #27214weight +25 lbsslowerweightF500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs.
  • SRF SRF Dash Windscreen Kit #27028aeroaddedaeroSRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102.
  • STL Request clarification for manifold and throttle in STU #27004wordingwordingSTU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required.
  • STL Request Restrictor Plate correction #26779enginefasterengineSTL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate.
  • STL Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.
  • STL Request to Allow VW 1.8L Engine #25614cars addedaddedSTL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only.
  • STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbsfasterweightSTL Mazda Renesis minimum weight reduced to 2700 lbs.
  • STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821otheraddedSTL Mazda MX-5 Cup brake pad compound now open.
  • STL Request to clarify B18C1 GSR Honda B motor table #26209cars addedaddedSTL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited.
  • STL Port Matching #26415enginefasterengineSTL Mazda 12 and 13B now permit port matching; porting ban removed.
  • STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746enginefasterengineSTL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline.
  • STL Request E&O for Mazda Miata Spec Line #25955otherunclearSTL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.
Sonoma Raceway Runoffs 20182018-10-101:28.612J R Osborne · fastest of 7 · top 5 within 3.3s1:31.189J R Osborne · fastest of 7 · top 5 within 3.7s140.5J R Osborne1:41.807Jeff Jorgenson · fastest of 5 · top 5 within 6.6s1:42.491David Lapham · fastest of 5 · top 5 within 9.5s113.3David Lapham+11.302squal +13.195s112.4%qual 114.9%1:49.138Danny Steyn · fastest of 19 · top 5 within 2.5s1:49.754Danny Steyn · fastest of 17 · top 5 within 2.5s103.2Craig McHaffie+18.565squal +20.526s120.4%qual 123.2%
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:33.746Gary Hickman · fastest of 18 · top 5 within 3.3s1:33.702Alex Mayer · fastest of 17 · top 5 within 3.0s1:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s+20.067squal +17.827s121.4%qual 119.0%1:43.136Wiley Clinton McMahan · fastest of 38 · top 5 within 1.4s1:42.860Wiley Clinton McMahan · fastest of 37 · top 5 within 1.6s+9.158squal +9.390s109.8%qual 110.0%1:52.647Adam Roberts · fastest of 57 · top 5 within 0.8s1:52.589Eric Kutil · fastest of 50 · top 5 within 1.2s+18.887squal +18.901s120.2%qual 120.2%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:19.886Alex Mayer · fastest of 10 · top 5 within 1.5s1:21.015Jeremy Hill · fastest of 10 · top 5 within 1.2s1:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s1:37.621Todd Harris · fastest of 27 · top 5 within 0.6s+16.606squal +17.458s120.5%qual 121.9%1:28.528Calvin Stewart · fastest of 14 · top 5 within 3.9s1:29.853Steven Thompson · fastest of 12 · top 5 within 4.5s+8.838squal +8.642s110.9%qual 110.8%1:35.439John Schmitt · fastest of 34 · top 5 within 1.5s1:36.625Kevin Boehm · fastest of 31 · top 5 within 0.6s+15.610squal +15.553s119.3%qual 119.5%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-211:50.711J R Osborne · fastest of 20 · top 5 within 1.1s1:51.616J R Osborne · fastest of 19 · top 5 within 2.1s2:14.306Cliff White · fastest of 39 · top 5 within 1.2s2:16.700Cliff White · fastest of 38 · top 5 within 0.5s+25.084squal +23.595s122.5%qual 121.3%2:01.824W. Clint McMahan · fastest of 16 · top 5 within 3.0s2:03.298Matthew Strand · fastest of 15 · top 5 within 4.9s+11.682squal +11.113s110.5%qual 110.0%2:09.672Kevin Boehm · fastest of 37 · top 5 within 2.5s2:10.269Kevin Boehm · fastest of 37 · top 5 within 2.1s+18.653squal +18.961s116.7%qual 117.1%

By track

TrackEvents Typical % of FB Best Latest 
Road America40 of 4 with FB
Virginia International Raceway3100.0%1 of 3 with FB100.0%Runoffs 2019100.0%Runoffs 2019
Indianapolis Motor Speedway2100.0%1 of 2 with FB100.0%Runoffs 2017100.0%Runoffs 2017
Daytona International Speedway1100.0%100.0%Runoffs 2015100.0%Runoffs 2015
Mid-Ohio Sports Car Course1100.0%100.0%Runoffs 2016100.0%Runoffs 2016
Sonoma Raceway1100.0%100.0%Runoffs 2018100.0%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.