BoP Lab / Classes / FC

FC vs STL vs SM vs SRF3 pace at every track

Lap times across years say as much about the weather as the class. % of FC is each class's best lap as a share of FC'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-SpecEPFAFC×FE2FFFPFVFXGT1GT2GTXHPPP2vsSM ×SMXvsSRF3 ×vsSTL ×STUT1T2T3T4Show 51 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 World Wide Technology Raceway

Closest to the field: FC 100.0% of FC Yufeng Luo, Daytona International Speedway Runoffs 2015 race · STL 100.0% of FC Danny Steyn, Virginia International Raceway Runoffs 2022 race · SM 108.8% of FC Travis Wiley, Virginia International Raceway Runoffs 2022 race · SRF3 111.1% of FC Franklin Futrelle, Virginia International Raceway Runoffs 2022 race

% of FCLap times

FCSTLSMSRF3solid race · dashed qualifying · slower is lower

FCSTLSMSRF3solid race · dashed qualifying · each class's best lap as a share of FC's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	FC			STL					SM					SRF3
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FC	% of FC	Qual best	Race best	Trap	vs FC	% of FC	Qual best	Race best	Trap	vs FC	% of FC
	Road America Runoffs 20262026-09-28	2:10.686Brandon Dixon · fastest of 10 · top 5 within 4.0s-0.573s (-0.44%)	2:11.389Brandon Dixon · fastest of 10 · top 5 within 2.7s-1.435s (-1.08%)	143.3Dean Kiriluk-1.8 mph (-1.2%)	2:30.537Derek 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%)	+19.268squal +19.851s	114.7%qual 115.2%	2:42.173Brett Kowalski · fastest of 34 · top 5 within 0.3s-0.938s (-0.58%)	2:42.725Francisco Barroso · fastest of 35 · top 5 within 0.2s-1.705s (-1.04%)	119.6Wyatt Couch+0.3 mph (+0.3%)	+31.336squal +31.487s	123.8%qual 124.1%	2:27.443Tyler Stephens · fastest of 44 · top 5 within 0.3s-0.783s (-0.53%)	2:29.257Peyton Long · fastest of 42 · top 5 within 0.3s-0.582s (-0.39%)	134.1Bobby Sak+0.4 mph (+0.3%)	+17.868squal +16.757s	113.6%qual 112.8%
10 rule changes (FC: 2, STL: 4, SM: 2, SRF3: 2)2 cars added · 2 engine · 2 weight · 2 wording · 2 other · SM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. · 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. · SM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. · 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. · FC USF2000 Tube Frame may now use Hewland LD200 4-speed H-pattern as alternative to Hewland JL-200 5-speed sequential. · FC F2000 Metrik ZF2 minimum weight reduced to 1220 lbs. · 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 2026-07-01 SM Rear Toe Link #40271wordingwordingSM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. 2026-07-01 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). 2026-06-01 STL Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. 2026-04-01 SM Part Number Change Request #39914otherunclearSM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. 2026-04-01 STL Classifications #39885cars addedaddedSTL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs. 2026-03-01 SRF3 SRF3 Spark Plugs #39899engineengineSRF3 spark plugs limited to NGK LTR7IX-11 P/N G301041 only; washers and sealing rings prohibited. 2026-01-01 FC F2000 MZR Spec Line Clarity/Revision Requested #38927otheraddedFC USF2000 Tube Frame may now use Hewland LD200 4-speed H-pattern as alternative to Hewland JL-200 5-speed sequential. 2026-01-01 FC Adjust F2000 Metrik ZF2 weight #39612weight -20 lbsfasterweightFC F2000 Metrik ZF2 minimum weight reduced to 1220 lbs. 2026-01-01 STL Weight adjustment for STL #39579weightslowerweightSTL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs. 2025-10-01 SRF3 Add HD Oil Cooler #38979engineaddedengineSRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted.
	Road America Runoffs 20252025-09-29	2:11.259Brandon Dixon · fastest of 10 · top 5 within 2.7s-0.367s (-0.28%)	2:12.824Brandon Dixon · fastest of 9 · top 5 within 2.3s+1.290s (+0.98%)	145.1Brandon Dixon+0.9 mph (+0.6%)	2:32.065Jose 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%)	+19.303squal +20.806s	114.5%qual 115.9%	2:43.111Bobby Gossett · fastest of 32 · top 5 within 0.3s+2.005s (+1.24%)	2:44.430Kyle Greenhill · fastest of 28 · top 5 within 0.3s+2.944s (+1.82%)	119.3Francisco Barroso-0.6 mph (-0.5%)	+31.606squal +31.852s	123.8%qual 124.3%	2:28.226Bobby Sak · fastest of 43 · top 5 within 0.6s+0.453s (+0.31%)	2:29.839Morgan Burkhard · fastest of 42 · top 5 within 0.3s+1.710s (+1.15%)	133.7Bobby Sak-1.5 mph (-1.1%)	+17.015squal +16.967s	112.8%qual 112.9%
12 rule changes (FC: 2, STL: 3, SM: 4, SRF3: 3)2 weight · 1 cars added · 6 wording · 3 other · SRF3 adds oil cooler options P/N G480503 and P/N G1148500; brake rule restructured to list Hawk Blue pads, Wilwood rotor, caliper kit, master cylinder options. · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · SMX drivers must submit data acquisition files on time or face suspension and $250 fine. · SMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fines, level 2 and 4 may carry $500 fines. · SM tire marking rules clarified: one Hoosier SM 7.5 P205/50/ZR17 set per Super Tour weekend, impound after first dry session, damaged tires may be replaced with used tires only. · 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. · SMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · FC tire rule clarified: four dry and four wet tires for Regionals and Majors, eight each for Runoffs; marking and declaration timing adjusted. · FF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition.showhide 2025-09-01 SRF3 SRF Rule Updates #38853otheraddedSRF3 adds oil cooler options P/N G480503 and P/N G1148500; brake rule restructured to list Hawk Blue pads, Wilwood rotor, caliper kit, master cylinder options. 2025-08-01 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. 2025-06-01 SM SMX Data Submission - Penalties #38248otheraddedSMX drivers must submit data acquisition files on time or face suspension and $250 fine. 2025-06-01 SM Committee) SMX Penaly Clarification updated language #38337wordingwordingSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fines, level 2 and 4 may carry $500 fines. 2025-05-01 SM Clarify Tire Marking Regs #38005wordingwordingSM tire marking rules clarified: one Hoosier SM 7.5 P205/50/ZR17 set per Super Tour weekend, impound after first dry session, damaged tires may be replaced with used tires only. 2025-05-01 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. 2025-04-01 SRF3 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 SRF3 Update SADEV transmission specs #37992wordingwordingSRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward. 2024-12-01 SM E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingwordingSMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation. 2024-12-01 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. 2024-11-01 FC 9.1.1.10.h. FC Tire Rule #36533wordingwordingFC tire rule clarified: four dry and four wet tires for Regionals and Majors, eight each for Runoffs; marking and declaration timing adjusted. 2024-11-01 FC Change FF/FC Weight with Sequential Gearbox #36651weightfasterweightFF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition.
	Road America Runoffs 20242024-10-01	2:11.626Timothy Minor · fastest of 10 · top 5 within 1.3s-1.018s (-0.77%)	2:11.534Michael Varacins · fastest of 9 · top 5 within 1.8s-2.074s (-1.55%)	144.2Michael Varacins+1.8 mph (+1.2%)	2:30.063Joe 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%)	+18.711squal +18.437s	114.2%qual 114.0%	2:41.106Ethan Goulart · fastest of 49 · top 5 within 0.5s-1.103s (-0.68%)	2:41.486Brett Kowalski · fastest of 43 · top 5 within 0.3s-2.262s (-1.38%)	119.9Alex Bertagnoli-1.4 mph (-1.2%)	+29.952squal +29.480s	122.8%qual 122.4%	2:27.773Denny Stripling · fastest of 57 · top 5 within 0.3s-2.013s (-1.34%)	2:28.129S Sandy Satullo III · fastest of 52 · top 5 within 0.7s-2.909s (-1.93%)	135.2Denny Stripling+3.4 mph (+2.6%)	+16.595squal +16.147s	112.6%qual 112.3%
20 rule changes (FC: 2, STL: 4, SM: 4, SRF3: 10)3 engine · 3 weight · 2 suspension & brakes · 1 aero · 1 cars added · 1 tyres & wheels · 5 wording · 4 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. · SMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification. · SM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01. · SMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only. · SM and SMX now allow an alternate shifter bushing at the bottom of the shift lever. · 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. · SRF3 alternator pulley minimum weight drops from 12 to 11 oz, adds P/N G902131 six-row option. · FC F2000 Metrik ZF2 added as spec line car with Brembo 4-piston calipers and vented rotors permitted. · 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 2024-10-01 SRF3 Update SRF3 Air Filter Rule #36681wordingremovedSRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only. 2024-10-01 SRF3 Update SRF Brake Rotor Thickness #36687suspension & brakessuspension & brakesSRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches. 2024-10-01 SRF3 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 SM SMX Camera Rule Correction #36496wordingwordingSMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification. 2024-09-01 SM Committee) AIM ECU Protocol #36556engineaddedengineSM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01. 2024-09-01 SM Committee) OE versus OEM Definitons #36608wordingwordingSMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only. 2024-09-01 SM Committee) Shifter Bushing #36611otheraddedSM and SMX now allow an alternate shifter bushing at the bottom of the shift lever. 2024-09-01 SRF3 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 SRF3 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. 2024-06-01 SRF3 SRF3 Alternator Pulley Update In #36095weightfasterweightSRF3 alternator pulley minimum weight drops from 12 to 11 oz, adds P/N G902131 six-row option. 2024-04-01 FC Four Pot Calipers #35481cars addedaddedFC F2000 Metrik ZF2 added as spec line car with Brembo 4-piston calipers and vented rotors permitted. 2024-02-01 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. 2024-02-01 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. 2024-02-01 STL Mazda 12A #35320engineremovedengineSTL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled. 2024-01-01 FC Please correct omitted punctuation #34890weight 2024-01-01 SRF3 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 SRF3 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 SRF3 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. 2024-01-01 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. 2023-10-01 SRF3 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	1:50.281Nolan Allaer · fastest of 11 · top 5 within 2.3s+0.386s (+0.35%)	1:51.169Nolan Allaer · fastest of 11 · top 5 within 2.5s-16.690s (-13.05%)	143.5Robert Allaer+2.3 mph (+1.7%)	2:05.779Danny 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%)	+15.513squal +15.498s	114.0%qual 114.1%	2:14.986Danny Steyn · fastest of 52 · top 5 within 0.1s+0.322s (+0.24%)	2:16.229Julian DaCosta · fastest of 46 · top 5 within 0.3s-2.878s (-2.07%)	120.3Jim Drago+1.1 mph (+0.9%)	+25.060squal +24.705s	122.5%qual 122.4%	2:03.842Morgan Burkhard · fastest of 40 · top 5 within 0.2s+0.126s (+0.10%)	2:04.911David Ogburn · fastest of 39 · top 5 within 0.3s-17.155s (-12.08%)	134.5Bobby Sak+0.1 mph (+0.0%)	+13.742squal +13.561s	112.4%qual 112.3%
10 rule changes (FC: 3, STL: 2, SM: 1, SRF3: 4)2 cars added · 2 tyres & wheels · 1 engine · 1 weight · 4 wording · FC tire marking rule clarified: four dry and four wet tires for Regional/Major/Super Tour, eight each for Runoffs; undeclared tire penalty removed. · USF2000 Van Diemen with Mazda MZR LF-DE 2.0L added to FC as spec line car; removed from FX. · 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. · SRF3 alternate dash panel P/N 180100 or 180101 moved from optional to required bodywork section. · FC/FF PE3-8400 ECU tune-file firmware version changes from V3.04.50 to V3.04.35. · SM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore. · 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 2023-07-01 FC Review FC Runoffs Tire Marking Rule #34274wordingwordingFC tire marking rule clarified: four dry and four wet tires for Regional/Major/Super Tour, eight each for Runoffs; undeclared tire penalty removed. 2023-06-01 FC USF2000 Van Diemen with Mazda MZR LF-DE 2.0L in FC #34329cars addedaddedUSF2000 Van Diemen with Mazda MZR LF-DE 2.0L added to FC as spec line car; removed from FX. 2023-06-01 SRF3 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. 2023-06-01 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. 2023-05-01 SRF3 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. 2023-03-01 SRF3 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. 2023-03-01 SRF3 Update SRF Bodywork Fitment Rule #33765wordingwordingSRF3 alternate dash panel P/N 180100 or 180101 moved from optional to required bodywork section. 2023-01-01 FC E&O 9.1.1.B.16.j #33634wordingwordingFC/FF PE3-8400 ECU tune-file firmware version changes from V3.04.50 to V3.04.35. 2023-01-01 SM BOP for NB1 and NB2 #32309weightslowerweightSM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore. 2023-01-01 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 20222022-09-24	1:49.895Nolan Allaer · fastest of 12 · top 5 within 1.5s-1.305s (-1.17%)	2:07.859Nolan Allaer · fastest of 13 · top 5 within 3.8s+15.685s (+13.98%)	141.2Tim Minor-0.6 mph (-0.4%)	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%)	-0.027squal +15.579s	100.0%qual 114.2%	2:14.664Danny Steyn · fastest of 60 · top 5 within 0.2s+0.112s (+0.08%)	2:19.107Travis Wiley · fastest of 58 · top 5 within 0.9s+2.648s (+1.94%)	119.2Jonathan Neudorf-0.6 mph (-0.5%)	+11.248squal +24.769s	108.8%qual 122.5%	2:03.716Franklin Futrelle · fastest of 44 · top 5 within 0.6s-0.908s (-0.73%)	2:22.066Franklin Futrelle · fastest of 40 · top 5 within 1.2s+17.311s (+13.88%)	134.5David Ogburn+2.1 mph (+1.6%)	+14.207squal +13.821s	111.1%qual 112.6%
14 rule changes (FC: 5, STL: 5, SM: 1, SRF3: 3)1 engine · 1 tyres & wheels · 1 weight · 9 wording · 2 other · FC Zetec ECU: Performance Electronics model designation changed from PE-3 to PE3-8400; monitor firmware updated to V3.04.50. · 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. · SM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation. · 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. · FC chassis/frame section cleaned up: panels between main tubes must prevent cockpit intrusion; suspension cannot mount to exterior panels; engine/gearbox exempt from load-bearing restrictions. · 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. · FC Zetec ECU requirements clarified: Pectel T2 or PE-3 required with specified communications ports and SCCA tune-file/map from official website. · 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… · FC composite anti-intrusion panels of non-uniform thickness limited to eight fasteners per side. · FC tire marking requirements clarified: competitor must ensure tires declared, marked, and logged by Tech before qualifying or race use.showhide 2022-07-01 FC Add Specification to Performance Electronics ECU for Ford Zetec #32761wordingwordingFC Zetec ECU: Performance Electronics model designation changed from PE-3 to PE3-8400; monitor firmware updated to V3.04.50. 2022-06-01 SRF3 SRF Tire Rule Update #32614wordingwordingSRF tire rule wording clarified: tires must be run as delivered. 2022-06-01 SRF3 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. 2022-04-01 SM Update GCR Section 9.1.7.3.A.1. #32217wordingwordingSM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation. 2022-03-01 STL Single TB Weight Modifiers #31449weightfasterweightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. 2022-03-01 STL Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. 2022-01-01 FC Clean up Chassis/Frame section #31867wordingwordingFC chassis/frame section cleaned up: panels between main tubes must prevent cockpit intrusion; suspension cannot mount to exterior panels; engine/gearbox exempt from load-bearing restrictions. 2022-01-01 STL Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. 2022-01-01 STL Mazda Renesis Restriction #31467enginefasterengineSTL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. 2022-01-01 STL Clarification of 79-85 RX7 Spec line #31621wordingwordingSTL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb. 2021-12-01 FC Clarify Zetec ECU requirements #31554wordingwordingFC Zetec ECU requirements clarified: Pectel T2 or PE-3 required with specified communications ports and SCCA tune-file/map from official website. 2021-12-01 SRF3 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… 2021-11-01 FC Clarify composite anti-intrusion panel language #31426wordingwordingFC composite anti-intrusion panels of non-uniform thickness limited to eight fasteners per side. 2021-11-01 FC Clarify tire marking requirements #31455wordingwordingFC tire marking requirements clarified: competitor must ensure tires declared, marked, and logged by Tech before qualifying or race use.
	Indianapolis Motor Speedway Runoffs 20212021-09-25	1:36.787Trent Walko · fastest of 31 · top 5 within 1.7s+0.451s (+0.47%)	1:36.980Simon Sikes · fastest of 31 · top 5 within 2.0s+0.090s (+0.09%)	141.6Tim Minor	1:51.665Danny 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	+25.731squal +14.878s	126.5%qual 115.4%	1:57.695Brian Henderson · fastest of 90 · top 5 within 0.5s-0.611s (-0.52%)	1:58.837Brian Henderson · fastest of 88 · top 5 within 0.3s-0.263s (-0.22%)	119.8Kyle Greenhill	+21.857squal +20.908s	122.5%qual 121.6%	1:49.520Franklin Futrelle · fastest of 84 · top 5 within 0.5s-0.304s (-0.28%)	1:50.095John Black · fastest of 82 · top 5 within 0.2s+0.313s (+0.29%)	132.1Matthew Horst	+13.115squal +12.733s	113.5%qual 113.2%
23 rule changes (FC: 1, STL: 15, SM: 1, SRF3: 6)4 engine · 3 cars added · 3 weight · 2 aero · 1 induction · 1 suspension & brakes · 1 tyres & wheels · 5 wording · 3 other · STL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. · 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. · 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. · SM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · FC Pinto engine loses 10 lbs to 1190; Pinto aluminum head loses 10 lbs to 1190; Zetec loses 10 lbs to 1210. · 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 2021-09-01 STL Request to clean up Spec MX-5 Redundancy #31069wordingwordingSTL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. 2021-08-01 SRF3 SRF Wet Tires #30849tyres & wheelsaddedtyres & wheelsSRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021. 2021-08-01 SRF3 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 SRF3 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 SRF3 SRF3 Alternator Pulley #30684engineaddedengineSRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. 2021-06-01 STL VW Engine Request #30625engineaddedengineSTL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. 2021-05-01 STL Solstice Ride Height #30183otheraddedSTL Pontiac Solstice/Saturn Sky allowed 4 inch ride height. 2021-05-01 STL Request Mazda B5 DOHC #30420cars addedaddedSTL Mazda B5 DOHC added to class; must meet all STL regulations. 2021-05-01 STL Honda B16A (JDM) Restrictor change #30531engineslowerengineSTL Honda B16A (JDM) restrictor reduced from 54mm to 53mm. 2021-04-01 SM Updates - Obsolete Parts & BOP Parts #30438wordingaddedSM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture. 2021-04-01 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. 2021-03-01 FC Request for FC Weight Change #30171weightfasterweightFC Pinto engine loses 10 lbs to 1190; Pinto aluminum head loses 10 lbs to 1190; Zetec loses 10 lbs to 1210. 2021-03-01 SRF3 Mandatory identification: #30223wordingwordingSRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. 2021-03-01 STL GM Ecotec engines in STL #30247engineaddedengineSTL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor. 2021-03-01 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. 2021-02-01 STL Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. 2021-02-01 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. 2021-02-01 STL Transmission Options #30118otheraddedSTL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment. 2021-01-01 STL Request for FWD and RWD Parity #29728weightfasterweightSTL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity. 2021-01-01 STL Request to Remove Honda F20C 2% Weight Penalty #29815weightfasterweightSTL Honda F20C drops 2% weight penalty, minimum weight reduced. 2021-01-01 STL Request for FWD and RWD Parity #30023inductionslowerinductionSTL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm. 2020-12-01 SRF3 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. 2020-12-01 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 20202020-10-02	2:12.644Robert Allaer · fastest of 13 · top 5 within 2.1s	2:13.608Robert Allaer · fastest of 11 · top 5 within 1.2s	142.4Robert Allaer	2:31.420Danny Steyn · fastest of 33 · top 5 within 3.1s	2:32.115Joe Moser · fastest of 30 · top 5 within 1.5s	132.9Darin Treakle	+18.507squal +18.776s	113.9%qual 114.2%	2:42.209Kyle Greenhill · fastest of 77 · top 5 within 0.5s	2:43.748Preston Pardus · fastest of 75 · top 5 within 1.0s	121.3Kyle Greenhill	+30.140squal +29.565s	122.6%qual 122.3%	2:29.786TJ Acker · fastest of 59 · top 5 within 0.5s	2:31.038Justin Hille · fastest of 55 · top 5 within 0.2s	131.9Charles Russell Turner	+17.430squal +17.142s	113.0%qual 112.9%
24 rule changes (FC: 4, STL: 11, SM: 2, SRF3: 7)6 engine · 4 cars added · 2 suspension & brakes · 2 weight · 1 tyres & wheels · 9 wording · FC ECU maps clarified: SCCA Club or 2013 Pro map required, available on SCCA website; 1.340 restrictor reminder. · SM allows aftermarket radiators in original location with stock OEM cooling fan, and permits 1990-1997 cars to install upper radiator seal NA75-50-OK7A. · FC Zetec engine minimum weight increases 20 lbs to 1220 lbs. · SM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure. · 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. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · SRF3 shocks no longer require the same brand in all positions; only SCCA P/N 280407 bump stops allowed, one per shock, all must be sealed by Enterprises. · 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. · SRF3 bump stop must be SCCA P/N 280407, no modifications, optional, maximum one per shock. · 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. · SRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. · FC allows Eagle #CRS5483F3D connecting rods alongside original Ford; crankshaft replacement clarified to original Ford only. · FC allows Mahle #930169439 piston as new option alongside Ford original, Sealed Power #H872cp, United Engine and Machine #SO2763. · 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 2020-10-01 FC Urgent: SCCA PE3 map unsuitable #29475wordingwordingFC ECU maps clarified: SCCA Club or 2013 Pro map required, available on SCCA website; 1.340 restrictor reminder. 2020-10-01 SM Radiator E&O Clarifications #29294wordingwordingSM allows aftermarket radiators in original location with stock OEM cooling fan, and permits 1990-1997 cars to install upper radiator seal NA75-50-OK7A. 2020-08-01 FC Request for weight adjustments to equalize FC competition. #28888weightslowerweightFC Zetec engine minimum weight increases 20 lbs to 1220 lbs. 2020-08-01 SM Modifications to prevent failures of Rear Brake Caliper Pin #28953suspension & brakessuspension & brakesSM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure. 2020-08-01 STL Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds. 2020-08-01 STL ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules. 2020-07-01 STL Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. 2020-06-01 SRF3 SRF Shocks #28791wordingwordingSRF3 shocks no longer require the same brand in all positions; only SCCA P/N 280407 bump stops allowed, one per shock, all must be sealed by Enterprises. 2020-06-01 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. 2020-06-01 STL Request to update PN for MX-5 #28622cars addedaddedSTL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC. 2020-06-01 STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873wordingwordingSTL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants. 2020-05-01 SRF3 Update Bump Stop Rule #28712suspension & brakessuspension & brakesSRF3 bump stop must be SCCA P/N 280407, no modifications, optional, maximum one per shock. 2020-05-01 SRF3 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. 2020-05-01 STL STL Honda B18 restrictor changes #28794enginefasterengineSTL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. 2020-04-01 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. 2020-04-01 STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663engineslowerengineSTL Mazda MZR restrictor reduced from 54 mm to 53 mm. 2020-04-01 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. 2020-03-01 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. 202-01-01 SRF3 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 FC Request for Better Zetec Connecting Rods #27710engineaddedengineFC allows Eagle #CRS5483F3D connecting rods alongside original Ford; crankshaft replacement clarified to original Ford only. 2019-12-01 FC Add Alternate Piston #27795engineaddedengineFC allows Mahle #930169439 piston as new option alongside Ford original, Sealed Power #H872cp, United Engine and Machine #SO2763. 2019-12-01 SRF3 SRF Tire Warmer Rule #27622tyres & wheelstyres & wheelsSRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers. 2019-12-01 SRF3 SRF / SRF3 Nose Weight Reduction #27706weightfasterweightSRF front nose weight minimum reduced from 35 to 32 lbs. 2019-12-01 SRF3 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	1:51.200Robert Allaer · fastest of 10 · top 5 within 3.1s	1:52.174Robert Allaer · fastest of 9 · top 5 within 2.7s	141.8Robert Allaer	2:07.203Danny Steyn · fastest of 36 · top 5 within 1.8s	2:07.273Cliff Ira · fastest of 35 · top 5 within 1.4s	134.8Cliff Ira	+15.099squal +16.003s	113.5%qual 114.4%	2:14.552Todd Buras · fastest of 60 · top 5 within 0.2s	2:16.459Elivan Goulart · fastest of 56 · top 5 within 0.4s	119.8Jim Drago	+24.285squal +23.352s	121.6%qual 121.0%	2:04.624Brian Schofield · fastest of 54 · top 5 within 0.6s	2:04.755Bobby Sak · fastest of 53 · top 5 within 0.3s	132.4Bobby Sak	+12.581squal +13.424s	111.2%qual 112.1%
20 rule changes (FC: 2, STL: 11, SM: 4, SRF3: 3)3 cars added · 3 engine · 2 aero · 1 weight · 6 wording · 5 other · STL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components. · 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. · SRF3 multi-piece nose assembly approved for use; no other nose modifications allowed. · STL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. · FC Wiseco piston and Crower rod part numbers updated; minimum weight unchanged at 976 grams. · SRF3 brakes now accept Hawk Blue 9012 pads P/N 801993 only; Wilwood vented rotor P/N 800065 minimum 13.25mm as delivered; caliper bushings P/N 1196185 A or B permitted. Shock absorbers: Penske P/N 280396 only, sealed, with SCCA bump rubber… · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · SM fuel pump and filter now permitted as Mazda or OEM equivalent part. · 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. · SM allows factory Mazda ECU and injector harnesses (P/N 0000-10-020E-99, 0000-10-080D-99) on 1999–2000 model year cars, unmodified. · SM electrical rules reorganized and clarified; alternator now externally regulated only by OEM ECU or master kill switch; harness repair by splicing permitted. · SM tire tread protrusion language removed from GCR 9.1.7.C.5. · FC Wiseco piston and connecting rod minimum weight corrected to 976 grams. · 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 2019-10-01 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. 2019-07-01 SRF3 SRF Dash Windscreen Kit #27028aeroaddedaeroSRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. 2019-07-01 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. 2019-05-31 SRF3 New SRF Sectional Nose Rule Addition #26914aeroaddedaeroSRF3 multi-piece nose assembly approved for use; no other nose modifications allowed. 2019-05-31 STL Request Restrictor Plate correction #26779enginefasterengineSTL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. 2019-05-01 FC E&O Wiseco piston and Crower connecting rod #26659wordingwordingFC Wiseco piston and Crower rod part numbers updated; minimum weight unchanged at 976 grams. 2019-05-01 SRF3 SRF Brakes and Shock Rule Changes #26629otherotherSRF3 brakes now accept Hawk Blue 9012 pads P/N 801993 only; Wilwood vented rotor P/N 800065 minimum 13.25mm as delivered; caliper bushings P/N 1196185 A or B permitted. Shock absorbers: Penske P/N 280396 only, sealed, with SCCA bump rubber… 2019-05-01 STL Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. 2019-03-01 SM Request to allow aftermarket fuel filters. #26370otheraddedSM fuel pump and filter now permitted as Mazda or OEM equivalent part. 2019-03-01 STL Request to Allow VW 1.8L Engine #25614cars addedaddedSTL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only. 2019-03-01 STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbsfasterweightSTL Mazda Renesis minimum weight reduced to 2700 lbs. 2019-03-01 STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821otheraddedSTL Mazda MX-5 Cup brake pad compound now open. 2019-03-01 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. 2019-03-01 STL Port Matching #26415enginefasterengineSTL Mazda 12 and 13B now permit port matching; porting ban removed. 2019-02-01 SM Request 99-00 replacement Wire harnesses #25602otheraddedSM allows factory Mazda ECU and injector harnesses (P/N 0000-10-020E-99, 0000-10-080D-99) on 1999–2000 model year cars, unmodified. 2019-02-01 SM Organize and Clarify 9.1.7.C.1.o. #25913wordingwordingSM electrical rules reorganized and clarified; alternator now externally regulated only by OEM ECU or master kill switch; harness repair by splicing permitted. 2019-02-01 SM Strike Tire Tread Language #26123wordingremovedSM tire tread protrusion language removed from GCR 9.1.7.C.5. 2019-01-01 FC Correct Wiseco piston and connecting rod #25809wordingwordingFC Wiseco piston and connecting rod minimum weight corrected to 976 grams. 2019-01-01 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. 2019-01-01 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 20182018-10-10	1:32.571Timothy de Silva · fastest of 16 · top 5 within 1.8s	1:34.053Mitch Egner · fastest of 12 · top 5 within 1.6s	133.1Robert Armington	1:49.138Danny Steyn · fastest of 19 · top 5 within 2.5s	1:49.754Danny Steyn · fastest of 17 · top 5 within 2.5s	103.2Craig McHaffie	+15.701squal +16.567s	116.7%qual 117.9%	1:54.355Ken Sutherland · fastest of 48 · top 5 within 0.7s	1:55.278Michael Carter · fastest of 48 · top 5 within 0.3s	102.2Danny Steyn	+21.225squal +21.784s	122.6%qual 123.5%	1:46.117Robeson Clay Russell · fastest of 36 · top 5 within 0.5s	1:47.053TJ Acker · fastest of 35 · top 5 within 0.2s	110.2Steve Fogg	+13.000squal +13.546s	113.8%qual 114.6%
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:36.336Austin McCusker · fastest of 14 · top 5 within 2.3s	1:36.890Tim Minor · fastest of 14 · top 5 within 3.8s		1:52.647Adam Roberts · fastest of 57 · top 5 within 0.8s	1:52.589Eric Kutil · fastest of 50 · top 5 within 1.2s		+15.699squal +16.311s	116.2%qual 116.9%	1:58.306Chris Haldeman · fastest of 86 · top 5 within 0.5s	1:59.100Michael Gagliardo · fastest of 83 · top 5 within 0.6s		+22.210squal +21.970s	122.9%qual 122.8%	1:49.824John Black · fastest of 101 · top 5 within 0.5s	1:49.782Tray Ayres · fastest of 94 · top 5 within 0.4s		+12.892squal +13.488s	113.3%qual 114.0%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:21.962John LaRue · fastest of 7 · top 5 within 2.6s	1:22.049Nigel Saurino · fastest of 7 · top 5 within 3.0s		1:35.439John Schmitt · fastest of 34 · top 5 within 1.5s	1:36.625Kevin Boehm · fastest of 31 · top 5 within 0.6s		+14.576squal +13.477s	117.8%qual 116.4%	1:40.514Justin Hille · fastest of 45 · top 5 within 0.3s	1:40.764Michael Carter · fastest of 44 · top 5 within 0.3s		+18.715squal +18.552s	122.8%qual 122.6%	1:34.363John Black · fastest of 41 · top 5 within 0.5s	1:34.947Cliff White · fastest of 39 · top 5 within 0.3s		+12.898squal +12.401s	115.7%qual 115.1%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	1:54.477Yufeng Luo · fastest of 11 · top 5 within 2.5s	1:55.135Yufeng Luo · fastest of 10 · top 5 within 2.1s		2:09.672Kevin Boehm · fastest of 37 · top 5 within 2.5s	2:10.269Kevin Boehm · fastest of 37 · top 5 within 2.1s		+15.134squal +15.195s	113.1%qual 113.3%	2:18.661Andrew Carbonell · fastest of 62 · top 5 within 0.6s	2:24.067Todd Lamb · fastest of 59 · top 5 within 0.8s		+28.932squal +24.184s	125.1%qual 121.1%	2:08.557Kerry Jacobsen · fastest of 29 · top 5 within 1.1s	2:10.215Chad Galloway · fastest of 29 · top 5 within 0.3s		+15.080squal +14.080s	113.1%qual 112.3%

By track

Track	Events	Typical % of FC	Best	Latest
Road America	4	100.0%	100.0%Runoffs 2020	100.0%Runoffs 2026
Virginia International Raceway	3	100.0%	100.0%Runoffs 2019	100.0%Runoffs 2023
Indianapolis Motor Speedway	2	100.0%	100.0%Runoffs 2017	100.0%Runoffs 2021
Daytona International Speedway	1	100.0%	100.0%Runoffs 2015	100.0%Runoffs 2015
Mid-Ohio Sports Car Course	1	100.0%	100.0%Runoffs 2016	100.0%Runoffs 2016
Sonoma Raceway	1	100.0%	100.0%Runoffs 2018	100.0%Runoffs 2018

About this data

Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of FC'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.