BoP Lab / Classes / FM

FM vs F6 vs SRF vs P1 pace at every track

Lap times across years say as much about the weather as the class. % of FM is each class's best lap as a share of FM'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 ×FAFCFE2FFFM×FPFVFXGT1GT2GTXHPPvsP1 ×P2SMSMXvsSRF ×SRF3STLSTUT1T2T3T4Show 47 inactive classes

Series Runoffs Super Tour Both

Reference class · the yardstick the % column and chart are 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

Quickest here: FM 1:26.043 Jacob Loomis, Runoffs 2016 qualifying · F6 1:57.437 Calvin Stewart, Runoffs 2023 qualifying · SRF 1:37.344 Mike Miserendino, Runoffs 2016 qualifying · P1 1:17.308 James Devenport, Runoffs 2016 qualifying

% of FMLap times

FMF6SRFP1solid race · dashed qualifying · slower is lower

FMF6SRFP1solid race · dashed qualifying · each class's best lap as a share of FM's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	FM			F6					SRF					P1
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FM	% of FM	Qual best	Race best	Trap	vs FM	% of FM	Qual best	Race best	Trap	vs FM	% of FM
	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)2 engine · 2 wording · 1 other · SRF rain/brake light part number and GCR section reference corrected for original roll hoop mounting. · SRF3 spark plugs limited to NGK LTR7IX-11 P/N G301041 only; washers and sealing rings prohibited. · SRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted. · 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.showhide 2026-09-01 SRF GCR Rain/Brake Light Correction #40579wordingwordingSRF rain/brake light part number and GCR section reference corrected for original roll hoop mounting. 2026-03-01 SRF SRF3 Spark Plugs #39899engineengineSRF3 spark plugs limited to NGK LTR7IX-11 P/N G301041 only; washers and sealing rings prohibited. 2025-10-01 SRF Add HD Oil Cooler #38979engineadded · engineSRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted. 2025-04-01 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. 2025-04-01 SRF Update SADEV transmission specs #37992wordingwordingSRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward.
	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)2 suspension & brakes · 2 weight · 1 tyres & wheels · 8 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. · P1 engine approval process wording clarified; unspecified engines need case-by-case Board review. · P1 removes redundant effective date language from ECU stall prohibition rule. · P1 Honda K20A-FD2 engine terminology corrected from 'spec' to proper series designation; FIA certification documentation requirement removed. · P1 Engine Table line H restrictor grows to 32 mm, weight rises to 1450 lbs; line I restrictor to 31 mm, weight to 1475 lbs. · P1 Group CN Honda K20A-FD2 removes engine modification restrictions; CRB may add intake restrictor if needed. · 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. · SRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.showhide 2024-10-01 SRF Update SRF3 Air Filter Rule #36681wordingremovedSRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only. 2024-10-01 SRF Update SRF Brake Rotor Thickness #36687suspension & brakessuspension & brakesSRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches. 2024-10-01 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. 2024-09-01 SRF Protest Fee Clarification #36540wordingwordingFE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. 2024-09-01 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. 2024-08-01 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. 2024-05-01 P1 Update GCR section 9.1.8.B.J.7 #35907wordingwordingP1 engine approval process wording clarified; unspecified engines need case-by-case Board review. 2024-03-01 P1 Remove redundant effective date language in GCR 9.1.8.B.J.4 #35693wordingwordingP1 removes redundant effective date language from ECU stall prohibition rule. 2024-03-01 P1 Correct engine series terminology #35694wordingwordingP1 Honda K20A-FD2 engine terminology corrected from 'spec' to proper series designation; FIA certification documentation requirement removed. 2024-01-01 P1 Please correct omitted punctuation #34890weight 2024-01-01 P1 Adjust restrictors and weights for Engine Table lines H and I #35229weightslower · weightP1 Engine Table line H restrictor grows to 32 mm, weight rises to 1450 lbs; line I restrictor to 31 mm, weight to 1475 lbs. 2024-01-01 P1 Revise Group CN Honda K20A-FD2 Spec Line #35337wordingunclearP1 Group CN Honda K20A-FD2 removes engine modification restrictions; CRB may add intake restrictor if needed. 2024-01-01 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. 2024-01-01 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. 2024-01-01 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. 2023-10-01 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 20232023-09-23				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)2 aero · 2 engine · 2 tyres & wheels · 4 wording · P1 SIR testing: vehicle deemed compliant if it stalls within 3 seconds of the stall test. · P1 intake restrictor rule clarified: flat plate, venturi, or Single Inlet Restrictor required; all intake air must pass through. · P1 ducted air rule clarified: top-exit ducted air must pass through heat exchanger, except cockpit opening and engine bay vents. · SRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance. · SRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13. · P1 aero height limit, front/rear overhang, and cockpit dimensions corrected to metric-inch equivalents. · P1 suspension covers must have symmetrical upper and lower surfaces, no airfoil cross-sections or angled downforce. · 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. · P1 aerodynamic devices may not extend more than 1cm below lower surfaces rear of front axle; body panels covering suspension must not be airfoil-shaped or create downforce. · P1 forced induction prohibited: turbocharging and supercharging not allowed.showhide 2023-07-01 P1 SIR Testing #34354wordingwordingP1 SIR testing: vehicle deemed compliant if it stalls within 3 seconds of the stall test. 2023-07-01 P1 E&O Single Inlet Restrictor abbreviation, etc. #34369wordingwordingP1 intake restrictor rule clarified: flat plate, venturi, or Single Inlet Restrictor required; all intake air must pass through. 2023-07-01 P1 E&O Clean up ducted air provision #34410wordingwordingP1 ducted air rule clarified: top-exit ducted air must pass through heat exchanger, except cockpit opening and engine bay vents. 2023-06-01 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. 2023-05-01 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. 2023-04-01 P1 E&O - Correct dimensional equivalents #34018wordingwordingP1 aero height limit, front/rear overhang, and cockpit dimensions corrected to metric-inch equivalents. 2023-03-01 P1 November 2022 Rules Clarification for Suspension Covers #33615aeroslower · aeroP1 suspension covers must have symmetrical upper and lower surfaces, no airfoil cross-sections or angled downforce. 2023-03-01 SRF Update SRF Brake Rule #33469enginefaster · engineSRF 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. 2022-11-01 P1 Clarify body panel coverage of suspension components #33318aeroaeroP1 aerodynamic devices may not extend more than 1cm below lower surfaces rear of front axle; body panels covering suspension must not be airfoil-shaped or create downforce. 2022-10-01 P1 E&O clarification regarding forced induction #33123engineremoved · engineP1 forced induction prohibited: turbocharging and supercharging not allowed.
	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 engine · 2 wording · 2 other · P1 motorcycle-based engines with individual throttle bodies must use flat plate intake restrictors within 4 inches of primary butterfly. · 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. · P1 bodywork rules clarified: cycle fenders prohibited, side body minimum height at front axle centerline, air ducting for downforce banned. · P1 2-cycle 6-cylinder maximum displacement increases to 1725 cc, restrictor shrinks to 40mm, minimum weight drops to 1275 lbs. · 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 2022-08-01 P1 Clarify authorization to use flat plate intake restrictor #32964engineadded · engineP1 motorcycle-based engines with individual throttle bodies must use flat plate intake restrictors within 4 inches of primary butterfly. 2022-06-01 SRF SRF Tire Rule Update #32614wordingwordingSRF tire rule wording clarified: tires must be run as delivered. 2022-06-01 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. 2022-05-01 P1 E&O Clarification of Bodywork Rules #32468wordingwordingP1 bodywork rules clarified: cycle fenders prohibited, side body minimum height at front axle centerline, air ducting for downforce banned. 2022-01-01 P1 Displacement & Weight Change Request for 2-Cycle 6 Cylinder #31609enginefaster · engineP1 2-cycle 6-cylinder maximum displacement increases to 1725 cc, restrictor shrinks to 40mm, minimum weight drops to 1275 lbs. 2021-12-01 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 20212021-09-25														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)3 cars added · 3 engine · 1 tyres & wheels · 9 wording · 1 other · P1 creates separate spec lines H and I for 2000cc and 2300cc engines at 1400 and 1445 lbs minimum weight respectively. · P1 Staudacher may run 950 lbs minimum weight with 38.5mm flat plate intake restrictor, removing prior weight-linked restrictor rule. · P1 adds 1355cc motorcycle-based engine line C at 1075 lbs minimum weight, no restrictor required. · 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. · SRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. · P1 cockpit opening section allows tonneau covers to meet minimum dimensions; wording clarified on equipment attachment. · P1 Staudacher 1005cc homologated before 1-1-2014 may run 38.5mm flat plate intake restrictor at 950 lbs minimum weight. · P1 Spec Line C: FPIR not required at 1150 lbs, 1355cc max may run without FPIR at 1075 lbs. Spec Line G: up to 2000cc runs 30mm SIR at 1400 lbs, 2300cc runs 30mm SIR at 1445 lbs. · P1 classes B, C, D maximum valves per cylinder set to 4, previously unspecified. · P1 Spec Line A clarifies carburetor induction only, one per cylinder, balance tubes not allowed. · P1 Spec Line H notes clarify peripheral port or bridgeport allowed; wording only. · P1 Elan DP02-spec Mazda MZR sealed engine option removed effective 3/1/2021. · P1 Engine Table Spec Lines C and G change 'inlet restrictor' to 'intake restrictor' terminology. · SRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. · SRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified.showhide 2021-09-01 P1 Move 2000cc and 2300cc engine options to individual spec lines #31012cars addedaddedP1 creates separate spec lines H and I for 2000cc and 2300cc engines at 1400 and 1445 lbs minimum weight respectively. 2021-09-01 P1 E&O Spec Line B notes #31095wordingwordingP1 Staudacher may run 950 lbs minimum weight with 38.5mm flat plate intake restrictor, removing prior weight-linked restrictor rule. 2021-08-01 P1 Add 1355cc spec line #30890cars addedaddedP1 adds 1355cc motorcycle-based engine line C at 1075 lbs minimum weight, no restrictor required. 2021-08-01 SRF SRF Wet Tires #30849tyres & wheelsadded · tyres & wheelsSRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021. 2021-08-01 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. 2021-08-01 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. 2021-06-01 SRF SRF3 Alternator Pulley #30684engineadded · engineSRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. 2021-05-01 P1 E&O tonneau cover provision in cockpit opening section #30458wordingwordingP1 cockpit opening section allows tonneau covers to meet minimum dimensions; wording clarified on equipment attachment. 2021-05-01 P1 Update Spec Line B Notes #30498wordingwordingP1 Staudacher 1005cc homologated before 1-1-2014 may run 38.5mm flat plate intake restrictor at 950 lbs minimum weight. 2021-05-01 P1 Update Spec Lines C and G notes #30499wordingwordingP1 Spec Line C: FPIR not required at 1150 lbs, 1355cc max may run without FPIR at 1075 lbs. Spec Line G: up to 2000cc runs 30mm SIR at 1400 lbs, 2300cc runs 30mm SIR at 1445 lbs. 2021-05-01 P1 E&O Maximum Valves Per Cylinder #30559engineengineP1 classes B, C, D maximum valves per cylinder set to 4, previously unspecified. 2021-04-01 P1 Clean up Spec Line A notes section #30424wordingwordingP1 Spec Line A clarifies carburetor induction only, one per cylinder, balance tubes not allowed. 2021-04-01 P1 Clean up Spec Line H notes section #30425wordingwordingP1 Spec Line H notes clarify peripheral port or bridgeport allowed; wording only. 2021-03-01 P1 DP02 Sealed 2ltr Engine Option #30038engineremoved · engineP1 Elan DP02-spec Mazda MZR sealed engine option removed effective 3/1/2021. 2021-03-01 P1 E&O restrictor terminology #30285wordingwordingP1 Engine Table Spec Lines C and G change 'inlet restrictor' to 'intake restrictor' terminology. 2021-03-01 SRF Mandatory identification: #30223wordingwordingSRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. 2020-12-01 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.
	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)1 engine · 1 induction · 1 removed · 1 tyres & wheels · 1 weight · 4 wording · P1 intake manifolds unrestricted unless engine requires flat plate restrictor; no plenums or balance pipes on restricted individual runner manifolds. · SRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020. · P1 sealed 2.0L Elan DP02-spec Mazda option removal date extended from 1/1/2020 to 1/1/2021. · P1 sealed 2.0 MZR engine removed effective 1/1/2020; competitors may run it under Spec Line G. · P1 Spec Line F: Restricted 2.0L Group becomes CN-spec Honda K20A-FD2, 2000cc, 1400 lbs minimum. · 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 2020-05-01 P1 E&O minimum weights and intake manifolds #28731inductioninductionP1 intake manifolds unrestricted unless engine requires flat plate restrictor; no plenums or balance pipes on restricted individual runner manifolds. 2020-05-01 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. 2020-02-01 P1 Extend date for removing sealed DP02-spec 2.0L option #28046wordingunclearP1 sealed 2.0L Elan DP02-spec Mazda option removal date extended from 1/1/2020 to 1/1/2021. 2020-01-01 P1 Remove sealed DP02-spec 2.0 MZR spec #26753removedremovedP1 sealed 2.0 MZR engine removed effective 1/1/2020; competitors may run it under Spec Line G. 2020-01-01 P1 Update Revised Spec Line F #27745engineengineP1 Spec Line F: Restricted 2.0L Group becomes CN-spec Honda K20A-FD2, 2000cc, 1400 lbs minimum. 202-01-01 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. 2019-12-01 SRF SRF Tire Warmer Rule #27622tyres & wheelstyres & wheelsSRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers. 2019-12-01 SRF SRF / SRF3 Nose Weight Reduction #27706weightfaster · weightSRF front nose weight minimum reduced from 35 to 32 lbs. 2019-12-01 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 20192019-10-05	1:55.124Bryce Cornet · fastest of 8 · top 5 within 2.3s	2:15.816Bryce Cornet · fastest of 8 · top 5 within 4.9s	135.7Bryce Cornet											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	-32.318squal -12.450s	76.2%qual 89.2%
15 rule changes (SRF: 1, P1: 14)1 aero · 1 cars added · 12 wording · 1 other · P1 traction control prohibited. · P1 permits mechanical, solenoid, and air-shifters; prohibits electronic pre-selection and multi-wheel power. · P1 minimum bodywork height rule moved and restated with new 115cm aerodynamic part height limit. · P1 consolidates fender louver rules into one section; removes duplicate allowance for louvers and clarifies brake and engine air ducts are permitted. · SRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. · P1 anti-intrusion panels now allowed anywhere on chassis sides instead of specified locations. · P1 bodywork wording clarified: comfort and safety for driver and passenger or driver only. · P1 Engine Table reference cleaned up; no performance change. · P1 Mazda Renesis Rotary engine spec line removed from Engine Table. · P1 Staudacher and Honda K20A-FD2 engine table wording clarified; no performance change. · P1 closed cockpit single-seat cars remain prohibited; rule moved from subsection J.5 to B.4. · P1 engine table reference corrected from 'above' to 'below'; ETC/FBW/DBW throttle wording clarified on sensor and fail-safe requirements. · P1 removes TIR inlet restrictor option; deletes requirement for single turbo/supercharger unit with single restrictor. · P1 CN-spec Honda K20A-FD2 clarified: stock OEM parts required, no machining allowed. · P1 engine rules correct grammar and remove head designs from specification table.showhide 2019-08-01 P1 E&O Transmissions #27098wordingwordingP1 traction control prohibited. 2019-07-01 P1 E&O Transmissions #27005otheraddedP1 permits mechanical, solenoid, and air-shifters; prohibits electronic pre-selection and multi-wheel power. 2019-07-01 P1 Move minimum height provision to #27031wordingwordingP1 minimum bodywork height rule moved and restated with new 115cm aerodynamic part height limit. 2019-07-01 P1 Remove duplicative fender louver provision #27033wordingwordingP1 consolidates fender louver rules into one section; removes duplicate allowance for louvers and clarifies brake and engine air ducts are permitted. 2019-07-01 SRF SRF Dash Windscreen Kit #27028aeroadded · aeroSRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. 2019-05-31 P1 Missing word E&O #26919wordingwordingP1 anti-intrusion panels now allowed anywhere on chassis sides instead of specified locations. 2019-05-31 P1 E&O correction to GCR 9.1.8.C.C. #26927wordingwordingP1 bodywork wording clarified: comfort and safety for driver and passenger or driver only. 2019-05-01 P1 Clean up reference to engine table #26648wordingwordingP1 Engine Table reference cleaned up; no performance change. 2019-05-01 P1 Remove redundant spec line #26692cars addedremoved · cars addedP1 Mazda Renesis Rotary engine spec line removed from Engine Table. 2019-04-01 P1 Clean Up Engine Table Language #26590wordingwordingP1 Staudacher and Honda K20A-FD2 engine table wording clarified; no performance change. 2019-03-01 P1 Move single-seat closed cockpit provision to #26376wordingwordingP1 closed cockpit single-seat cars remain prohibited; rule moved from subsection J.5 to B.4. 2019-02-01 P1 Correct errors in GCR section 9.1.8.C.J #26144wordingwordingP1 engine table reference corrected from 'above' to 'below'; ETC/FBW/DBW throttle wording clarified on sensor and fail-safe requirements. 2019-01-01 P1 Remove redundant inlet restrictor provisions #25877wordingwordingP1 removes TIR inlet restrictor option; deletes requirement for single turbo/supercharger unit with single restrictor. 2019-01-01 P1 Clarify Honda K20A-FD2 parts requirement #25949wordingwordingP1 CN-spec Honda K20A-FD2 clarified: stock OEM parts required, no machining allowed. 2019-01-01 P1 Correct GCR section 9.1.8.C.J errors #25966wordingwordingP1 engine rules correct grammar and remove head designs from specification table.
	Sonoma Raceway Runoffs 20182018-10-10	1:37.598Bryce Cornet · fastest of 13 · top 5 within 0.9s	1:37.909Bryce Cornet · fastest of 12 · top 5 within 1.3s	124.1Melvin David Kemper Jr											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	-9.123squal -9.884s	90.7%qual 89.9%
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:41.231Jarret Voorhies · fastest of 16 · top 5 within 1.7s	1:41.146Jarret Voorhies · fastest of 16 · top 5 within 1.2s							1:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s	1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s		+12.623squal +10.342s	112.5%qual 110.2%	1:30.794Jim Devenport · fastest of 19 · top 5 within 2.8s	1:31.499Jim Devenport · fastest of 16 · top 5 within 2.2s		-9.647squal -10.437s	90.5%qual 89.7%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:26.043Jacob Loomis · fastest of 8 · top 5 within 3.1s	1:27.922Jacob Loomis · fastest of 8 · top 5 within 2.7s							1:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s	1:37.621Todd Harris · fastest of 27 · top 5 within 0.6s		+9.699squal +11.301s	111.0%qual 113.1%	1:17.308James Devenport · fastest of 14 · top 5 within 2.7s	1:19.407Gianpaolo Ciancimino · fastest of 13 · top 5 within 1.8s		-8.515squal -8.735s	90.3%qual 89.8%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	1:57.804Joseph Burton-Harris · fastest of 10 · top 5 within 2.3s	1:58.029Joseph Burton-Harris · fastest of 10 · top 5 within 1.7s							2:14.306Cliff White · fastest of 39 · top 5 within 1.2s	2:16.700Cliff White · fastest of 38 · top 5 within 0.5s		+18.671squal +16.502s	115.8%qual 114.0%	1:49.219Jim Downing · fastest of 9 · top 5 within 2.2s	1:49.792Gianpaolo Ciancimino · fastest of 10 · top 5 within 1.7s		-8.237squal -8.585s	93.0%qual 92.7%

By track

Track	Events	Typical % of FM	Best	Latest
Road America	3	0 of 3 with FM
Virginia International Raceway	3	100.0%1 of 3 with FM	100.0%Runoffs 2019	100.0%Runoffs 2019
Indianapolis Motor Speedway	2	100.0%1 of 2 with FM	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 FM's best on the same day: the weather, the track and its configuration cancel out, so one figure compares across tracks and years where lap times cannot. 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.