BoP Lab / Classes / T1

T1 vs SM vs FV vs FF pace at every track

Lap times across years say as much about the weather as the class. % of T1 is each class's best lap as a share of T1'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-SpecEPFAFCFE2vsFF ×FPvsFV ×FXGT1GT2GTXHPPP2vsSM ×SMXSRF3STLSTUT1×T2T3T4Show 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

Quickest here: T1 1:28.656 Ross Murray, Runoffs 2016 qualifying · SM 1:40.514 Justin Hille, Runoffs 2016 qualifying · FV 1:37.942 Alex Scaler, Runoffs 2016 qualifying · FF 1:29.213 Neil Verhagen, Runoffs 2016 qualifying

% of T1Lap times

T1SMFVFFsolid race · dashed qualifying · slower is lower

T1SMFVFFsolid race · dashed qualifying · each class's best lap as a share of T1's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	T1			SM					FV					FF
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs T1	% of T1	Qual best	Race best	Trap	vs T1	% of T1	Qual best	Race best	Trap	vs T1	% of T1
	Road America Runoffs 20262026-09-28				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%)			2:46.536Zachary Whitston · fastest of 37 · top 5 within 1.7s+2.435s (+1.48%)	2:45.272Brian Farnham · fastest of 34 · top 5 within 1.3s-1.464s (-0.88%)	117.4Rick Shields+0.2 mph (+0.1%)			2:23.047David Ybarra · fastest of 20 · top 5 within 1.4s-1.858s (-1.28%)	2:23.686Nathan Down · fastest of 20 · top 5 within 1.6s-1.855s (-1.27%)	138.9Tazio Stefanelli+0.5 mph (+0.3%)
16 rule changes (T1: 12, SM: 2, FF: 2)2 engine · 2 tyres & wheels · 1 aero · 1 cars added · 1 induction · 1 removed · 1 weight · 6 wording · 1 other · FF Kent 1600 compression ratio calculation parameters reorganized: bore size and valve protrusion limits moved to separate subsections for clarity. · SM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. · T1 classes now require U-rated or better DOT tires; re-grooving DOT tires banned; shaving and truing only allowed. · T1 trunk lid and wing mounting wording clarified; no performance change. · T1 LS1, LS6 removes OEM designation; 70mm restrictor requirement deleted. · T1 Spec Line Coyote Boss 302 production years corrected to 11–14, displacement 4957 cc unchanged. · SM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. · T1 restrictor requirement removed entirely; no replacement specified. · T1 GT4 Spec Line 4030- permits Wagner Tuning #200001124 intercooler as replacement for OEM heat exchanger. · T1 Chevrolet Corvette C6 LS1/LS6 spec line reinstated: 3200 lbs minimum, 70mm restrictor. · FF clarifies alternative tire eligibility: homologated 1989 or earlier with rocker or outboard suspension all four corners; push-rod/pull-rod cars may seek approval. · T1 Spec Line removes 70mm flat plate restrictor option. · unclear · T1 non-GT4 cars: multiple restrictor increases 61–80mm range, one weight raise to 3600 lbs, L76 engine clarified, throttle body permission removed. · T1 BMW M3 E92 (08-13) Spec Line 1090 removed entirely.showhide 2026-07-01 FF Clarification in FF Kent 1600 Compression Ratio Paragraph #40293wordingwordingFF Kent 1600 compression ratio calculation parameters reorganized: bore size and valve protrusion limits moved to separate subsections for clarity. 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 T1 Tire Equality #40342tyres & wheelstyres & wheelsT1 classes now require U-rated or better DOT tires; re-grooving DOT tires banned; shaving and truing only allowed. 2026-06-01 T1 Trunk Lid Wording #40177wordingwordingT1 trunk lid and wing mounting wording clarified; no performance change. 2026-05-01 T1 Clarification on Request #39716 T1 (Spec Line #1139) #39924wordingunclearT1 LS1, LS6 removes OEM designation; 70mm restrictor requirement deleted. 2026-05-01 T1 Mistake in Line 1430 #39958wordingwordingT1 Spec Line Coyote Boss 302 production years corrected to 11–14, displacement 4957 cc unchanged. 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 T1 Spec line #1139 Restrictor Change Request #39922enginefaster · engineT1 restrictor requirement removed entirely; no replacement specified. 2026-03-01 T1 Replace OEM Heat Exchanger (Intercooler) With Aftermarket #39542aeroadded · aeroT1 GT4 Spec Line 4030- permits Wagner Tuning #200001124 intercooler as replacement for OEM heat exchanger. 2026-02-01 T1 LS1 into Corvette C6 Spec Line Request #39716cars addedaddedT1 Chevrolet Corvette C6 LS1/LS6 spec line reinstated: 3200 lbs minimum, 70mm restrictor. 2026-01-01 FF Formula F Alternative Tire Rule Proposed Clarifications #39281tyres & wheelsadded · tyres & wheelsFF clarifies alternative tire eligibility: homologated 1989 or earlier with rocker or outboard suspension all four corners; push-rod/pull-rod cars may seek approval. 2026-01-01 T1 additional T1 adjustment #39520engineremoved · engineT1 Spec Line removes 70mm flat plate restrictor option. 2025-12-01 T1 Keep S2000 Classification #39344wordingunclearunclear 2025-12-01 T1 Correcting and updating T1 GT4 spec lines #39394weight 2025-12-01 T1 BOP adjustments to non GT4 T1 cars #39406induction +100 lbsfaster · inductionT1 non-GT4 cars: multiple restrictor increases 61–80mm range, one weight raise to 3600 lbs, L76 engine clarified, throttle body permission removed. 2025-12-01 T1 Remove T1 Spec Line #39407removedremovedT1 BMW M3 E92 (08-13) Spec Line 1090 removed entirely.
	Road America Runoffs 20252025-09-29	2:20.677James Candelaria · fastest of 5 · top 5 within 5.9s+4.099s (+3.00%)	2:21.612Drew Delmonico · fastest of 5 · top 5 within 11.8s+5.481s (+4.03%)	163.6Drew Delmonico+5.7 mph (+3.6%)	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%)	+22.818squal +22.434s	116.1%qual 115.9%	2:44.101Andrew Abbott · fastest of 34 · top 5 within 1.3s+1.458s (+0.90%)	2:46.736Zachary Whitston · fastest of 29 · top 5 within 0.6s+1.902s (+1.15%)	117.2Zachary Whitston+0.7 mph (+0.6%)	+25.124squal +23.424s	117.7%qual 116.7%	2:24.905Jonathan Kotyk · fastest of 17 · top 5 within 1.1s+2.353s (+1.65%)	2:25.541Calvin Kautz · fastest of 16 · top 5 within 0.5s+3.484s (+2.45%)	138.4Tazio Stefanelli-2.3 mph (-1.6%)	+3.929squal +4.228s	102.8%qual 103.0%
27 rule changes (T1: 19, SM: 4, FF: 4)6 engine · 6 weight · 5 cars added · 5 tyres & wheels · 1 aero · 3 wording · 1 other · 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. · FF adds rocker arm and outboard suspension cars option to use Hoosier bias ply slicks or VFF tyres; clarifies mixing rules. · 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. · Porsche 981 GT4 Clubsport added to T1 as Spec Line 4085, minimum weight 3100 lbs, 265/645 front and 305/680 rear tires. · T1 Honda S2000 Spec Line 1530 minimum weight drops 50 lbs to 2900. · T1 BMW E46 M3 permits BMW #GS7D36SG sequential transmission as aftermarket option in SL# 1060 and 1070. · T1 BMW M3 E92 minimum weight reduced to 3300 lbs. · T1 Mustang Darkhorse R tyres widen to 315 front and rear, weight set to 3600 lbs with driver, Runoffs eligibility requires 3 Super Tour events. · T1 Cadillac CT4-V Blackwing added: 3564cc, 3750 lbs minimum, OEM ECU with reprogramming allowed. · FF adds alternative tire options for older cars with rocker arm or outboard suspension: bias ply slicks or VFF radials. · T1 Mustang Spec 1430 restrictor opens 60mm to 65mm; Spec 1460 weight up to 3500 lbs, restrictor 70mm; Corvette 1190 restrictor 67mm to 70mm; BMW 1090 restrictor tightens 40mm to 35mm, expires 12/31/25; BMW 1100 weight up to 3350 lbs. · T1 Mustang weight to 3600 lbs, restrictor to 60mm; Corvette weight to 3500 lbs, restrictor to 67mm; BMW deleted. · T1 E46 M3 Spec Line 1050 throttle body changed from Dinan D760-3400 to VAC Motorsports VAC-TB-S54 on 3.250L engine. · T1 Chevrolet Corvette C8 (2020-2023) minimum weight drops to 3500 lbs. · T1 Chevrolet Camaro Gen 5 required restrictor increases from 75mm to 80mm flat plate. · T1 Audi R8 GT4 Spec Line #4020 max tire size changes to 315 DOT, 305/645, or 30/65-18 (f), 33/68-18 (r) Non-DOT. · 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. · T1 GT4 tire sizes standardized: most cars 315 DOT with 305/660 or 305/645 Non-DOT; Camaro 305/680, Mustang 315/680 Non-DOT. · BMW M4 GT4 (G82) added to T1 as spec line 4031, 3525 lbs minimum, red power stick; F82 model switched to red power stick. · T1 now permits 5.5 inch clutch as engine option. · T1 GT4 Spec Line 4020 restrictor opens to 45mm and minimum weight drops to 3400 lbs with driver. · T1 adds Mustang Darkhorse R homologated car, 305/315 tyres, 10.5/11 in wheels, minimum weight TBD. · T1 Corvette may roll or flatten wheel opening lips, remove composite fender lips and liners, and add fender vents for tire clearance. · T1 E46 M3 S54 now allows Dinan Throttle Body #D760-3400 on the 3.250L engine. · FF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition. · FF Honda Fit pistons: OEM 0.25mm oversize PN 13020-RB7-Z00 or Fast Forward PN FF800-110 now both allowed; standard diameter 73.240mm (2.8835 inches), minimum weight 198.0g.showhide 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 FF Page 228, FF tire rule 9.1.1.10.e #38251tyres & wheelsadded · tyres & wheelsFF adds rocker arm and outboard suspension cars option to use Hoosier bias ply slicks or VFF tyres; clarifies mixing rules. 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 T1 Acceptance of Porsche 981 GT4 Clubsport into T1 #36664cars addedaddedPorsche 981 GT4 Clubsport added to T1 as Spec Line 4085, minimum weight 3100 lbs, 265/645 front and 305/680 rear tires. 2025-05-01 T1 Request to Restore T1 Honda S2000 to Proper Weights #37644weight -50 lbsfaster · weightT1 Honda S2000 Spec Line 1530 minimum weight drops 50 lbs to 2900. 2025-05-01 T1 DCT Transmission in E46 #37964cars addedaddedT1 BMW E46 M3 permits BMW #GS7D36SG sequential transmission as aftermarket option in SL# 1060 and 1070. 2025-05-01 T1 Reduce E92 M3 Minimum Weight to 3050 #38092weightfaster · weightT1 BMW M3 E92 minimum weight reduced to 3300 lbs. 2025-05-01 T1 Finalize Spec Line for T1 Darkhorse #38106tyres & wheelsfaster · tyres & wheelsT1 Mustang Darkhorse R tyres widen to 315 front and rear, weight set to 3600 lbs with driver, Runoffs eligibility requires 3 Super Tour events. 2025-04-01 T1 Cadillac CT4-V Blackwing #38003cars addedaddedT1 Cadillac CT4-V Blackwing added: 3564cc, 3750 lbs minimum, OEM ECU with reprogramming allowed. 2025-03-01 FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change #37802tyres & wheelsadded · tyres & wheelsFF adds alternative tire options for older cars with rocker arm or outboard suspension: bias ply slicks or VFF radials. 2025-03-01 T1 Correct and make new T1 BOP adjustments. #37737weight +75 lbsslower · weightT1 Mustang Spec 1430 restrictor opens 60mm to 65mm; Spec 1460 weight up to 3500 lbs, restrictor 70mm; Corvette 1190 restrictor 67mm to 70mm; BMW 1090 restrictor tightens 40mm to 35mm, expires 12/31/25; BMW 1100 weight up to 3350 lbs. 2025-02-01 T1 T1 Parity Compared to GT4 #37170weight +125 lbsslower · weightT1 Mustang weight to 3600 lbs, restrictor to 60mm; Corvette weight to 3500 lbs, restrictor to 67mm; BMW deleted. 2025-02-01 T1 Clarification of Request Approval #37273 #37399engineengineT1 E46 M3 Spec Line 1050 throttle body changed from Dinan D760-3400 to VAC Motorsports VAC-TB-S54 on 3.250L engine. 2025-02-01 T1 C8 Corvette Facts #37400weight -100 lbsfaster · weightT1 Chevrolet Corvette C8 (2020-2023) minimum weight drops to 3500 lbs. 2025-02-01 T1 Camaro Gen 5 Competitive Disadvantage #37440enginefaster · engineT1 Chevrolet Camaro Gen 5 required restrictor increases from 75mm to 80mm flat plate. 2025-02-01 T1 Tire Changes in the Rules for GT4 #37497tyres & wheelstyres & wheelsT1 Audi R8 GT4 Spec Line #4020 max tire size changes to 315 DOT, 305/645, or 30/65-18 (f), 33/68-18 (r) Non-DOT. 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 T1 Changes to T1 Tires for GT4 and Other Cars #35383tyres & wheelsunclearT1 GT4 tire sizes standardized: most cars 315 DOT with 305/660 or 305/645 Non-DOT; Camaro 305/680, Mustang 315/680 Non-DOT. 2024-12-01 T1 G82 M4 GT4 inclusion in T1 #35864cars addedaddedBMW M4 GT4 (G82) added to T1 as spec line 4031, 3525 lbs minimum, red power stick; F82 model switched to red power stick. 2024-12-01 T1 Alt. Clutch Allowance #36606engineadded · engineT1 now permits 5.5 inch clutch as engine option. 2024-12-01 T1 BOP Changes Need Updates #36667engine -150 lbsfaster · engineT1 GT4 Spec Line 4020 restrictor opens to 45mm and minimum weight drops to 3400 lbs with driver. 2024-12-01 T1 Request Ford Performance Darkhorse R in T1 #37136cars addedaddedT1 adds Mustang Darkhorse R homologated car, 305/315 tyres, 10.5/11 in wheels, minimum weight TBD. 2024-12-01 T1 Car Mods for T1 Corvette under line item 1150 #37173aeroadded · aeroT1 Corvette may roll or flatten wheel opening lips, remove composite fender lips and liners, and add fender vents for tire clearance. 2024-12-01 T1 Increased Bore Throttle Bodies for E46 M3 S54 Engine #37273engineadded · engineT1 E46 M3 S54 now allows Dinan Throttle Body #D760-3400 on the 3.250L engine. 2024-11-01 FF Change FF/FC Weight with Sequential Gearbox #36651weightfaster · weightFF and FC sequential gearbox weight penalty reduces from 25 lbs to 10 lbs minimum weight addition. 2024-11-01 FF Alternative Oversize Honda Fit Pistons #37064engineadded · engineFF Honda Fit pistons: OEM 0.25mm oversize PN 13020-RB7-Z00 or Fast Forward PN FF800-110 now both allowed; standard diameter 73.240mm (2.8835 inches), minimum weight 198.0g.
	Road America Runoffs 20242024-10-01	2:16.578Andrew Aquilante · fastest of 8 · top 5 within 4.8s-1.068s (-0.78%)	2:16.131Andrew Aquilante · fastest of 7 · top 5 within 4.0s-2.570s (-1.85%)	157.9Andrew Aquilante-0.8 mph (-0.5%)	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%)	+25.355squal +24.528s	118.6%qual 118.0%	2:42.643Andrew Whitston · fastest of 27 · top 5 within 2.3s-1.351s (-0.82%)	2:44.834Andrew Abbott · fastest of 27 · top 5 within 0.9s-0.982s (-0.59%)	116.5Brian Farnham-0.7 mph (-0.6%)	+28.703squal +26.065s	121.1%qual 119.1%	2:22.552Calvin Kautz · fastest of 13 · top 5 within 1.1s-0.364s (-0.25%)	2:22.057Sebastian Mateo Naranjo · fastest of 13 · top 5 within 0.6s-2.211s (-1.53%)	140.7Calvin Kautz+2.6 mph (+1.9%)	+5.926squal +5.974s	104.4%qual 104.4%
21 rule changes (T1: 13, SM: 4, FV: 2, FF: 2)9 cars added · 3 engine · 2 removed · 1 weight · 5 wording · 1 other · FF EGR blanking plate rule clarified: VTEC activation valve must be retained and functioning, no modifications permitted. · FV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side. · 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. · Mercedes AMG-C63 S 2023 added to T1 with 4000 cc, 3700 lb minimum weight, no restrictor. · T1 Honda S2000 classified: 1530 cc max, 2950 lbs minimum, 4.75" supercharger pulley, 6.75" crank pulley. · T1 adds Pontiac GTO 2006-2009 LS1 5700cc, 3400 lbs minimum, engine repositioning allowed. · T1 Chevrolet Corvette C8 (2020–23) restrictor plate increases from 70mm to 72mm flat plate. · T1 category removes 23 car spec lines including NSX, Viper, Ferrari, Mazda, Nissan, Porsche, Subaru, Toyota; Porsche 997 spec line 1680 expiration removed. · FF Honda Fit gains Fast Forward oversize piston ring option PN FF800-100 as alternative to Riken or Nippon. · T1 GT4 cars gain Runoffs eligibility; weights and power maps adjusted across six models; tire rules now allow IMSA or SRO GT4 slicks. · T1 removes 27 spec line numbers entirely, including engine, suspension, brake and aero specifications. · FV front wheel bearings wording clarified; specification unchanged. · T1 Chevrolet Corvette C5 LS2 added: 6000 cc, 3300 lbs minimum, 72mm restrictor, carbon aero option −50 lbs. · T1 adds Chevrolet Corvette C7 (14–19) including Z51, Grandsport as homologated car. · T1 Gen 5 Camaro minimum weight cut 75 lbs to 3475; restrictor opens from 70mm to 75mm flat plate. · T1 Aston Martin Vantage gains OEM Sportshift II transmission as permitted option. · Pontiac GTO 2006-2009 re-integrated to T1 with LS2 at 3400 lbs, 72mm restrictor, or LS3 at 3500 lbs, 61mm restrictor. · T1 Porsche 997-1 GT3 Cup added as spec line 4210, minimum weight 3050 lbs, 996 spec line 1670 removed.showhide 2024-10-01 FF Update to FF EGR Blanking Plate Rule #36633wordingwordingFF EGR blanking plate rule clarified: VTEC activation valve must be retained and functioning, no modifications permitted. 2024-10-01 FV Disc Brakes #36822wordingwordingFV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side. 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 #36556engineadded · engineSM 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. 2024-05-01 T1 Please Expedite classing the C63 Mercedes #35987cars addedaddedMercedes AMG-C63 S 2023 added to T1 with 4000 cc, 3700 lb minimum weight, no restrictor. 2024-04-01 T1 Honda S2000 #35582cars addedaddedT1 Honda S2000 classified: 1530 cc max, 2950 lbs minimum, 4.75" supercharger pulley, 6.75" crank pulley. 2024-03-01 T1 9.1.9.1 T1 new category item/ line 26 rule to expire Jan 1 2023 #35411cars addedaddedT1 adds Pontiac GTO 2006-2009 LS1 5700cc, 3400 lbs minimum, engine repositioning allowed. 2024-02-01 T1 C8 Corvette T1 Restrictor Plate Request #35213enginefaster · engineT1 Chevrolet Corvette C8 (2020–23) restrictor plate increases from 70mm to 72mm flat plate. 2024-02-01 T1 The Cars Have Expired #35379removedremovedT1 category removes 23 car spec lines including NSX, Viper, Ferrari, Mazda, Nissan, Porsche, Subaru, Toyota; Porsche 997 spec line 1680 expiration removed. 2024-01-01 FF Honda Fit Oversize Piston Rings #35305engineadded · engineFF Honda Fit gains Fast Forward oversize piston ring option PN FF800-100 as alternative to Riken or Nippon. 2024-01-01 T1 GT4 batch adjustment in T1 #35162cars added -85 lbsaddedT1 GT4 cars gain Runoffs eligibility; weights and power maps adjusted across six models; tire rules now allow IMSA or SRO GT4 slicks. 2024-01-01 T1 Remove T1 spec lines #35192removedremovedT1 removes 27 spec line numbers entirely, including engine, suspension, brake and aero specifications. 2023-12-01 FV FV Wheel Bearing Clarification #35150wordingwordingFV front wheel bearings wording clarified; specification unchanged. 2023-12-01 T1 New T1 add spec line for C5 corvette LS2 engines (Copy from C6) #33764cars addedaddedT1 Chevrolet Corvette C5 LS2 added: 6000 cc, 3300 lbs minimum, 72mm restrictor, carbon aero option −50 lbs. 2023-12-01 T1 C7 Corvette Rule Change Request #34897cars addedaddedT1 adds Chevrolet Corvette C7 (14–19) including Z51, Grandsport as homologated car. 2023-12-01 T1 Camaro Gen 5 Weight Reduction Due to Competitive Disadvantage #35092weight -75 lbsfaster · weightT1 Gen 5 Camaro minimum weight cut 75 lbs to 3475; restrictor opens from 70mm to 75mm flat plate. 2023-12-01 T1 Addendum to Letter #35022: Drivetrain Rule #35105cars addedaddedT1 Aston Martin Vantage gains OEM Sportshift II transmission as permitted option. 2023-12-01 T1 2004 - 2006 Pontiac GTO Re-Integration Back Into T1 #34403cars addedaddedPontiac GTO 2006-2009 re-integrated to T1 with LS2 at 3400 lbs, 72mm restrictor, or LS3 at 3500 lbs, 61mm restrictor. 2023-12-01 T1 Request to Classify Porsche 997-1 GT3 Cup #34561cars addedaddedT1 Porsche 997-1 GT3 Cup added as spec line 4210, minimum weight 3050 lbs, 996 spec line 1670 removed.
	Virginia International Raceway Runoffs 20232023-09-23	1:54.520Andrew Aquilante · fastest of 12 · top 5 within 3.7s-0.370s (-0.32%)	1:55.488Andrew Aquilante · fastest of 12 · top 5 within 2.7s-20.579s (-15.12%)	159.2James Candelaria+1.6 mph (+1.0%)	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%)	+20.741squal +20.466s	118.0%qual 117.9%	2:15.639Andrew Whitston · fastest of 27 · top 5 within 1.4s+0.523s (+0.39%)	2:16.611Andrew Abbott · fastest of 23 · top 5 within 1.6s-1.482s (-1.07%)	115.6Brian Farnham-0.2 mph (-0.2%)	+21.123squal +21.119s	118.3%qual 118.4%	1:59.249Nolan Allaer · fastest of 8 · top 5 within 2.8s+0.034s (+0.03%)	2:00.583Jonathan Kotyk · fastest of 8 · top 5 within 0.4s-17.775s (-12.85%)	138.4Calvin Kautz+0.1 mph (+0.1%)	+5.095squal +4.729s	104.4%qual 104.1%
21 rule changes (T1: 19, SM: 1, FF: 1)5 cars added · 5 engine · 3 weight · 2 tyres & wheels · 1 aero · 1 induction · 1 removed · 3 wording · Chevrolet Camaro GT4-R added to T1 GT4 Spec Line 4035, 315 tires, 3375 lbs minimum, ineligible for Runoffs. · T1 Dodge Viper ACR / SRT RT-10 and ACR/ACR-X spec lines 1350 and 1370 remove 12/23 expiration dates. · T1 GT4 McLaren 570S, Mercedes AMG GT4, and Porsche 718 Cayman GT4 CS MR now eligible for Runoffs competition. · T1 GT4 BMW M4 spec line number changed from 4050 to 4030. · T1 Chevrolet Corvette C5 rear spoiler to 5 inches above bumper allowed, plus 50 lbs; carbon aero parts permitted with 50 lb decrease. · T1 Dodge Viper ACR/ACR-X restrictor increases from 50mm to 60mm flat plate. · T1 Dodge Viper ACR/ACR-X Spec Line 1370 restrictor increases to 55mm; Spec Line 1390 decreases to 55mm flat plates. · T1 Ford Mustang S197 (05-14) must use OEM 8.8 differential housing. · T1 Chevrolet Camaro Gen 5 LS7 gains two spec lines with 70mm and 53mm restrictors, both 3450 lbs minimum. · T1 Chevrolet Camaro Gen 5, Corvette C5 and C6: resleeve restricted to stock parameters for engine repair or replacement, not LS3 bore/stroke. · T1 Ford Mustang S197 (05-14) reinstated with 5.0L Voodoo engine, 3550 lbs minimum, 75mm restrictor. · T1-GT4 minimum weights set: Aston Martin Vantage AMR 3575 lbs, Audi R8 3550, BMW M4 3500, Ford Mustang 3550, McLaren 570S 3450, Mercedes AMG 3450, Porsche 718 Cayman CS MR 3200, Porsche 718 RS 3450, Toyota Supra 3350. · T1-GT4 McLaren 570S front tyre widens from 285 to 315; Mercedes AMG GT4 front tyre widens from 275 to 315. · T1 Chevrolet Camaro Gen 5 LS3-6160 adds new Spec Line 1135 with 70mm flat plate restrictor, 3550 lbs minimum weight. · FF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. · T1 aftermarket sequential gearbox cars must have 1:1 or greater top gear ratio, OEM location, max 10 inch bellhousing; non-sequential cars gain 100 lbs weight break. · T1 GT4 all nine cars lose 125 lbs minimum weight with driver across the range. · T1 pre-2023 rules and spec lines removed entirely, effective 2023-03-01. · GT4 McLaren 570S maximum tyre size set to 285 front, 315 rear. · SM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore. · T1 adds eight GT4 cars: Aston Martin, Audi, BMW, Ford, McLaren, Mercedes, two Porsches, Toyota, minimum weights 3200–3575 lbs, restricted by SRO 2022 rules.showhide 2023-08-01 T1 Why no Camaro? #34421cars addedaddedChevrolet Camaro GT4-R added to T1 GT4 Spec Line 4035, 315 tires, 3375 lbs minimum, ineligible for Runoffs. 2023-08-01 T1 Request to Remove Expiration from T1 spec lines #1350 & #1370 #34470wordingwordingT1 Dodge Viper ACR / SRT RT-10 and ACR/ACR-X spec lines 1350 and 1370 remove 12/23 expiration dates. 2023-08-01 T1 Remove #34475cars addedaddedT1 GT4 McLaren 570S, Mercedes AMG GT4, and Porsche 718 Cayman GT4 CS MR now eligible for Runoffs competition. 2023-08-01 T1 Error in T1 GT4 numbering scheme- #34578wordingwordingT1 GT4 BMW M4 spec line number changed from 4050 to 4030. 2023-08-01 T1 C5 Approved Aero That Was Mistakenly Deleted #34374aeroslower · aeroT1 Chevrolet Corvette C5 rear spoiler to 5 inches above bumper allowed, plus 50 lbs; carbon aero parts permitted with 50 lb decrease. 2023-07-01 T1 Viper Cleanup #34107inductionfaster · inductionT1 Dodge Viper ACR/ACR-X restrictor increases from 50mm to 60mm flat plate. 2023-07-01 T1 Viper 8300 OEM FPR Size #34268engineunclearT1 Dodge Viper ACR/ACR-X Spec Line 1370 restrictor increases to 55mm; Spec Line 1390 decreases to 55mm flat plates. 2023-07-01 T1 Ford Mustang S197 (05-14) Clarification #34450wordingwordingT1 Ford Mustang S197 (05-14) must use OEM 8.8 differential housing. 2023-07-01 T1 Gen 5 Camaro Engine #33875cars addedaddedT1 Chevrolet Camaro Gen 5 LS7 gains two spec lines with 70mm and 53mm restrictors, both 3450 lbs minimum. 2023-07-01 T1 Inquiry to letter #33682 #34071engineslower · engineT1 Chevrolet Camaro Gen 5, Corvette C5 and C6: resleeve restricted to stock parameters for engine repair or replacement, not LS3 bore/stroke. 2023-06-01 T1 Request to reinstate T1 S197 Mustang #34048cars addedaddedT1 Ford Mustang S197 (05-14) reinstated with 5.0L Voodoo engine, 3550 lbs minimum, 75mm restrictor. 2023-05-01 T1 T1 GT4 adjustments #33786weightunclearT1-GT4 minimum weights set: Aston Martin Vantage AMR 3575 lbs, Audi R8 3550, BMW M4 3500, Ford Mustang 3550, McLaren 570S 3450, Mercedes AMG 3450, Porsche 718 Cayman CS MR 3200, Porsche 718 RS 3450, Toyota Supra 3350. 2023-05-01 T1 Touring 1 Tire Sizes #34191tyres & wheelsfaster · tyres & wheelsT1-GT4 McLaren 570S front tyre widens from 285 to 315; Mercedes AMG GT4 front tyre widens from 275 to 315. 2023-04-01 T1 Clarification for Camaro Gen5 2010-2015 #33739engineslower · engineT1 Chevrolet Camaro Gen 5 LS3-6160 adds new Spec Line 1135 with 70mm flat plate restrictor, 3550 lbs minimum weight. 2023-03-01 FF Add Fast Forward Part Numbers for Honda Fit Engine #33752engineadded · engineFF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. 2023-03-01 T1 Sequential Gearbox Limitations in T1 #33691engineadded · engineT1 aftermarket sequential gearbox cars must have 1:1 or greater top gear ratio, OEM location, max 10 inch bellhousing; non-sequential cars gain 100 lbs weight break. 2023-03-01 T1 T1 GT4 adjustments #33786weightfaster · weightT1 GT4 all nine cars lose 125 lbs minimum weight with driver across the range. 2023-03-01 T1 Sunset of pre 2023 Touring 1 Rules. #33916removedremovedT1 pre-2023 rules and spec lines removed entirely, effective 2023-03-01. 2023-02-01 T1 Corrections to T1 Spec Lines #33678tyres & wheelstyres & wheelsGT4 McLaren 570S maximum tyre size set to 285 front, 315 rear. 2023-01-01 SM BOP for NB1 and NB2 #32309weightslower · weightSM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore. 2023-01-01 T1 GT4 section to Current T1 Rules. #33632cars addedaddedT1 adds eight GT4 cars: Aston Martin, Audi, BMW, Ford, McLaren, Mercedes, two Porsches, Toyota, minimum weights 3200–3575 lbs, restricted by SRO 2022 rules.
	Virginia International Raceway Runoffs 20222022-09-24	1:54.890Andrew Aquilante · fastest of 10 · top 5 within 3.2s+0.119s (+0.10%)	2:16.067Andrew Aquilante · fastest of 8 · top 5 within 15.9s+1.654s (+1.23%)	157.5Mark Boden+1.3 mph (+0.8%)	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%)	+3.040squal +19.774s	102.2%qual 117.2%	2:15.116Brian Farnham · fastest of 29 · top 5 within 1.1s-0.596s (-0.44%)	2:18.093Andrew Whitston · fastest of 28 · top 5 within 1.2s-0.196s (-0.14%)	115.8Jonathan Weisheit+1.1 mph (+0.9%)	+2.026squal +20.226s	101.5%qual 117.6%	1:59.215Jonathan Kotyk · fastest of 13 · top 5 within 1.2s-0.348s (-0.29%)	2:18.358Jonathan Kotyk · fastest of 12 · top 5 within 2.4s-2.116s (-1.51%)	138.3Tim Kautz+2.2 mph (+1.6%)	+2.291squal +4.325s	101.7%qual 103.8%
16 rule changes (T1: 11, SM: 1, FV: 4)4 engine · 4 weight · 3 cars added · 1 suspension & brakes · 4 wording · T1 Camaro, CTS, Firebird, GTO minimum weight reduced to 3475 lbs from 3500 lbs. · T1-LP Ford Mustang FP350S restrictor increases from 70mm to 75mm. · Mercedes-Benz AMG GT4 (2017-2021) added to T1 with 3400 lb minimum weight, SRO Power Level 2 engine control. · SM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation. · T1 Dodge Viper ACR displacement rises to 8400 cc OEM, minimum weight drops to 3550 lbs. · T1 Limited T1 specification reference removed; all T1 cars now have unified allowances. · T1 Mazda RX-7 added: 2700 lbs minimum weight, 44mm restrictor, 13B rotary with single Garrett Turbo #3076. · FV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077. · FV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO LS3 minimum weight reduced to 3475 lbs. · T1 Camaro, CTS, Firebird, GTO with 7011 max displacement loses 50 lbs, to 3500. · T1 brake rotors no longer limited to 33mm thickness maximum. · FV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight. · FV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight. · T1 Mazda MX-5 Miata MazdaSpeed minimum weight rises to 2550 lbs, restrictor grows to 42mm. · T1 Chevrolet Corvette Cadillac XLR classified as model year 2019 and earlier.showhide 2022-08-01 T1 Correct Camaro Spec Line From Letter #30791 response to 3475lbs #32824weight -25 lbsfaster · weightT1 Camaro, CTS, Firebird, GTO minimum weight reduced to 3475 lbs from 3500 lbs. 2022-06-01 T1 Fix FP350S limited prep and Shelby 350 full prep issues #31680enginefaster · engineT1-LP Ford Mustang FP350S restrictor increases from 70mm to 75mm. 2022-06-01 T1 Request to Classify AMG GT4 #32610cars addedaddedMercedes-Benz AMG GT4 (2017-2021) added to T1 with 3400 lb minimum weight, SRO Power Level 2 engine control. 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. 2022-04-01 T1 Viper/Z06 Parity #31942engine -50 lbsfaster · engineT1 Dodge Viper ACR displacement rises to 8400 cc OEM, minimum weight drops to 3550 lbs. 2022-04-01 T1 Discrepancy in T1 allowances #32293wordingwordingT1 Limited T1 specification reference removed; all T1 cars now have unified allowances. 2022-04-01 T1 T1 RX7 classification #32352cars addedaddedT1 Mazda RX-7 added: 2700 lbs minimum weight, 44mm restrictor, 13B rotary with single Garrett Turbo #3076. 2022-03-01 FV Connecting Rod Update Request for 9.1.1.C Formula Vee (FV) 5.C.6 #32160engineadded · engineFV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077. 2022-03-01 FV E&O clarification of connecting rod center-to-center length #32183wordingwordingFV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs. 2022-03-01 T1 Weight reduction E&O #30791weight -25 lbsfaster · weightT1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO LS3 minimum weight reduced to 3475 lbs. 2022-03-01 T1 Performance Adjustment Request for Camaro #31521weight -50 lbsfaster · weightT1 Camaro, CTS, Firebird, GTO with 7011 max displacement loses 50 lbs, to 3500. 2022-03-01 T1 Remove 33m Brake rotor thickness rule #31954suspension & brakessuspension & brakesT1 brake rotors no longer limited to 33mm thickness maximum. 2022-01-01 FV Update direct replacement connecting rod information #31843wordingwordingFV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight. 2021-12-01 FV Formula V Connecting Rod Replacement #31448engineadded · engineFV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight. 2021-12-01 T1 Turbo Miata Help #31315weight +200 lbsslower · weightT1 Mazda MX-5 Miata MazdaSpeed minimum weight rises to 2550 lbs, restrictor grows to 42mm. 2021-12-01 T1 Fix the T1 Corvette heading #31528cars addedaddedT1 Chevrolet Corvette Cadillac XLR classified as model year 2019 and earlier.
	Indianapolis Motor Speedway Runoffs 20212021-09-25	1:42.292Andrew Aquilante · fastest of 22 · top 5 within 1.3s+0.499s (+0.49%)	1:43.752Mark Boden · fastest of 22 · top 5 within 1.0s+0.881s (+0.86%)	159.2Mark Boden	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	+15.085squal +15.403s	114.5%qual 115.1%	1:57.479Andrew Whitston · fastest of 48 · top 5 within 0.8s+1.720s (+1.49%)	1:57.234Alex Scaler · fastest of 47 · top 5 within 1.0s+1.311s (+1.13%)	124.0Mark Edwards	+13.482squal +15.187s	113.0%qual 114.8%	1:44.359Jonathan Kotyk · fastest of 24 · top 5 within 1.1s-0.242s (-0.23%)	1:55.676Jonathan Kotyk · fastest of 23 · top 5 within 1.8s+11.152s (+10.67%)	141.6Nicholas Sheppard	+11.924squal +2.067s	111.5%qual 102.0%
22 rule changes (T1: 18, SM: 1, FF: 3)7 cars added · 5 weight · 4 engine · 1 induction · 4 wording · 1 other · T1 BMW E46, E36, Z3 minimum weight raised to 2700 lbs; 3.4L engine car to 2750 lbs. · T1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm. · T1 Corvette and Cadillac XLR: Casting #799 heads now permitted on LS6 engines, no other head modifications allowed. · T1 Mustang GT5.0L 18+ Performance Pack, Bullet, Mach 1 allowed with 100 lb penalty; Shelby/GT350/GT500 restrictor opens 65 mm to 70 mm. · T1 Dodge Viper SRT-10 Incl. Coupe 08-10 restrictor increases from 45mm to 57mm. · T1 Corvette C7 Grand Sport now included; intake restrictor increases from 70 mm to 73 mm. · T1 Corvette Z06 06-13 now allows aluminum chassis replacement with equivalent OE steel chassis. · T1 Chevrolet Camaro with 6162 displacement minimum weight reduced to 3500 lbs. · T1-LP Chevrolet Corvette C5 Z06, C6 Grand Sport, and Z06 dry sump kit notes clarified to remove duplicates. · FF block relief permitted only as needed to fit an allowed crankshaft. · SM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture. · T1 LP aero adjustments: removed 50 lb weight allowance for stock OEM manifold/headers, reorganised aero and engine durability allowances into numbered list. · T1 Ford Mustang Challenge maximum displacement changes to 4600 cc for 3-valve engines, 5000 cc for others. · T1 BMW E46 allows carbon or fiberglass OEM-style dashboards with 25 pound weight penalty instead of requiring stock dash pad. · T1 Ford Mustang/Thunderbird specification removed Thunderbird model; now Shelby/Shelby GT350/GT500 only through 2018. · T1 Dodge Viper ACR 8400cc OEM added with 3600 lb minimum weight, 55mm flat-plate restrictor. · BMW M2CS Club Sport added to T1 Spec Lines classification. · Porsche 997.1 GT3 Cup (2006–2011) classified in T1 at 3600cc displacement, 3150 lbs minimum weight, no restrictor. · T1 Limited Prep Chevrolet Corvette Z06 years extend to 2013, from 2012. · FF class cylinder head now permits optional coolant bleed line pipe thread fitting to swirl tower. · FF Honda LC1 ECU supplied by HPD is permitted effective 12/1/2020 with HPD lambda sensor. · T1 Corvette C8 Z51 gets wider wheels and tyres, loses 100 lbs to 3550.showhide 2021-08-01 T1 T1 E46 BOP E&O for Letter # 29970 #30934weight +100 lbsslower · weightT1 BMW E46, E36, Z3 minimum weight raised to 2700 lbs; 3.4L engine car to 2750 lbs. 2021-07-01 T1 Request BoP for the Viper in 1 LP #29968enginefaster · engineT1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm. 2021-07-01 T1 LS6 Alternative Head Question #30074cars addedaddedT1 Corvette and Cadillac XLR: Casting #799 heads now permitted on LS6 engines, no other head modifications allowed. 2021-06-01 T1 T1-LP - Add Performance Pack, Bullet, Mach 1 to 18+ Mustang #29849enginefaster · engineT1 Mustang GT5.0L 18+ Performance Pack, Bullet, Mach 1 allowed with 100 lb penalty; Shelby/GT350/GT500 restrictor opens 65 mm to 70 mm. 2021-06-01 T1 Request BoP for the Viper in 1 LP #29968enginefaster · engineT1 Dodge Viper SRT-10 Incl. Coupe 08-10 restrictor increases from 45mm to 57mm. 2021-06-01 T1 Request to classify C7 and 13Viper in T1 LP #29969inductionfaster · inductionT1 Corvette C7 Grand Sport now included; intake restrictor increases from 70 mm to 73 mm. 2021-06-01 T1 Request LP Z06 steel chassis #30589cars addedaddedT1 Corvette Z06 06-13 now allows aluminum chassis replacement with equivalent OE steel chassis. 2021-05-01 T1 Request For Reduction in Weight/Penalties for Camaro #30443weightfaster · weightT1 Chevrolet Camaro with 6162 displacement minimum weight reduced to 3500 lbs. 2021-05-01 T1 Fix dry sump Contradictions in T1-LP vs T2 #30596wordingwordingT1-LP Chevrolet Corvette C5 Z06, C6 Grand Sport, and Z06 dry sump kit notes clarified to remove duplicates. 2021-04-01 FF Kent crankshaft clarification #30426wordingwordingFF block relief permitted only as needed to fit an allowed crankshaft. 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. 2021-03-01 T1 T1 LP Aero adjustments #30196weightslower · weightT1 LP aero adjustments: removed 50 lb weight allowance for stock OEM manifold/headers, reorganised aero and engine durability allowances into numbered list. 2021-02-01 T1 Request to Clarify Miller Mustang Classification #28728engineengineT1 Ford Mustang Challenge maximum displacement changes to 4600 cc for 3-valve engines, 5000 cc for others. 2021-02-01 T1 BMW E46 Carbon Dash #29806weightslower · weightT1 BMW E46 allows carbon or fiberglass OEM-style dashboards with 25 pound weight penalty instead of requiring stock dash pad. 2021-02-01 T1 Request to Update T1 Mustang Spec Line #30001cars addedremoved · cars addedT1 Ford Mustang/Thunderbird specification removed Thunderbird model; now Shelby/Shelby GT350/GT500 only through 2018. 2021-02-01 T1 Dodge Viper 8400 OEM??? #30174cars addedaddedT1 Dodge Viper ACR 8400cc OEM added with 3600 lb minimum weight, 55mm flat-plate restrictor. 2021-02-01 T1 Class BMW M2CS Club Sport #30195cars addedaddedBMW M2CS Club Sport added to T1 Spec Lines classification. 2021-02-01 T1 997.1 GT3 Cup #30229cars addedaddedPorsche 997.1 GT3 Cup (2006–2011) classified in T1 at 3600cc displacement, 3150 lbs minimum weight, no restrictor. 2021-01-01 T1 Correct T1 Limited Prep Years #29708cars addedaddedT1 Limited Prep Chevrolet Corvette Z06 years extend to 2013, from 2012. 2020-12-01 FF Allow Optional Coolant Bleed Line to Correct a Known Problem #29673otheraddedFF class cylinder head now permits optional coolant bleed line pipe thread fitting to swirl tower. 2020-12-01 FF Clarification regarding Honda LC1 ECU implementation date #29684wordingwordingFF Honda LC1 ECU supplied by HPD is permitted effective 12/1/2020 with HPD lambda sensor. 2020-12-01 T1 Changes to Corvette C8 #29898weight -100 lbsfaster · weightT1 Corvette C8 Z51 gets wider wheels and tyres, loses 100 lbs to 3550.
	Road America Runoffs 20202020-10-02	2:17.646Andrew Aquilante · fastest of 15 · top 5 within 3.7s	2:18.701Mark Boden · fastest of 14 · top 5 within 3.0s	158.8James Candelaria	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	+25.047squal +24.563s	118.1%qual 117.8%	2:43.994Hunter Phelps-Barron · fastest of 28 · top 5 within 0.6s	2:45.816Alex Scaler · fastest of 24 · top 5 within 1.5s	117.1Hunter Phelps-Barron	+27.115squal +26.348s	119.5%qual 119.1%	2:22.916Simon Sikes · fastest of 14 · top 5 within 1.6s	2:24.268Jeffrey Bartz · fastest of 14 · top 5 within 0.4s	138.1Jeffrey Bartz	+5.567squal +5.270s	104.0%qual 103.8%
25 rule changes (T1: 13, SM: 2, FV: 6, FF: 4)6 tyres & wheels · 5 cars added · 3 engine · 3 suspension & brakes · 2 aero · 1 weight · 4 wording · 1 other · 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. · FF Honda LC1 ECU implementation date clarified to pending, contingent on SCCA receiving sufficient support materials. · SM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure. · T1 rear wing wording clarifies Gurney flap terminology in chord length and mounting height rules. · FV now permits 4 bolt wheels in addition to existing specifications. · FV now allows 4-bolt pattern wheels in addition to existing specifications. · T1 and T2 Corvettes now allow coilover suspension with 800 lb max coil springs; T1 Z06 conversion no longer T1-only. · T1 Porsche 996 GT3 Cup eligible model years changed from 02-05 to 98-04. · T1 Chevrolet Corvette Cadillac XLR may install SCRSPLR-001 rear spoiler with OE bodywork. · T1 Camaro OEM 366mm rear rotor and caliper allowed without weight penalty. · FF Kent Engine alternator becomes optional instead of not required. · T1 Porsche 996 Spec Lines: 996 Cup Replica Rear deck lid now allowed. · T1 Acura NSX Turbo and Audi TTRS now require DOT tires per GCR section 9.3. · FF permits HPD LC1 ECU with lambda sensor; E1 ECU no longer supported but existing units may continue. · FF rain tyres now allow Hoosier W3 Radial 185/60R13 front and 205/60R13 rear. · FV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. · T1 BMW E46 and E36 models permitted with S54 engine; displacement corrected to 3250 cc from 3200 cc. · T1 adds Subaru WRX, WRX STI 2005-2020: 2457 cc, 3000 lbs minimum, 46 mm restrictor, alternate turbo permitted. · T1-LP Ford Mustang FP350S restrictor enlarged to 70mm; GT and GT5.0L weights increased to 3500 lbs, Brembo BBK at no penalty, restrictors removed from notes. · Ford Mustang/Thunderbird 5000 Coyote OEM added to T1; 2015-17 at 3450 lbs, 2018+ at 3450 lbs with 65mm flat plate restrictor. · T1 BMW M3 E92 (08-13) carbon dash allowed with 25 lb penalty added. · T1 Corvette C5 Z06, C6 coupe and Grand Sport, C6 Z06 may convert leaf springs to coilover suspension. · FV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020. · Formula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020. · FV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.showhide 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 FF Clarification regarding Honda LC1 ECU implementation #29135wordingwordingFF Honda LC1 ECU implementation date clarified to pending, contingent on SCCA receiving sufficient support materials. 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 T1 Touring Gurney flap wicker clarification #29013wordingwordingT1 rear wing wording clarifies Gurney flap terminology in chord length and mounting height rules. 2020-07-01 FV Support for Recommended Item - 4 bolt wheels in FV #29084cars addedaddedFV now permits 4 bolt wheels in addition to existing specifications. 2020-07-01 FV Support for 4-bolt pattern wheels #28955 #29118tyres & wheelsadded · tyres & wheelsFV now allows 4-bolt pattern wheels in addition to existing specifications. 2020-06-01 T1 Consider coil spring conversion Corvette in T2 #28824suspension & brakesadded · suspension & brakesT1 and T2 Corvettes now allow coilover suspension with 800 lb max coil springs; T1 Z06 conversion no longer T1-only. 2020-05-01 T1 Additional Clarification on 996 Cup in T1 From Letter #28040 #28060cars addedaddedT1 Porsche 996 GT3 Cup eligible model years changed from 02-05 to 98-04. 2020-05-01 T1 Request SPEC Corvette Rear Spolier #28182aeroadded · aeroT1 Chevrolet Corvette Cadillac XLR may install SCRSPLR-001 rear spoiler with OE bodywork. 2020-05-01 T1 T1 Rear Brake Rotor Size Exemption for Gen 5 Camaro #28402cars addedaddedT1 Camaro OEM 366mm rear rotor and caliper allowed without weight penalty. 2020-04-01 FF E&O FF Kent Engine alternator language #28204engineadded · engineFF Kent Engine alternator becomes optional instead of not required. 2020-04-01 T1 Request 996 GT3 Trunk for Wing Allowance. #28153aeroadded · aeroT1 Porsche 996 Spec Lines: 996 Cup Replica Rear deck lid now allowed. 2020-04-01 T1 All Touring, Change DOT Tire Language 9.1.9.1, 9.3.45 #28452wordingwordingT1 Acura NSX Turbo and Audi TTRS now require DOT tires per GCR section 9.3. 2020-03-01 FF Honda Racing HPD low cost ECU proposal #27563engineadded · engineFF permits HPD LC1 ECU with lambda sensor; E1 ECU no longer supported but existing units may continue. 2020-03-01 FF Update rain tire designation #28443tyres & wheelsadded · tyres & wheelsFF rain tyres now allow Hoosier W3 Radial 185/60R13 front and 205/60R13 rear. 2020-03-01 FV Update rain tire designation #28444tyres & wheelstyres & wheelsFV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. 2020-03-01 T1 Request for E46 wagon with S54 engine in T1 #27427enginefaster · engineT1 BMW E46 and E36 models permitted with S54 engine; displacement corrected to 3250 cc from 3200 cc. 2020-02-01 T1 Request to include Subaru WRX/STI 02-18 in T1 #24916cars addedaddedT1 adds Subaru WRX, WRX STI 2005-2020: 2457 cc, 3000 lbs minimum, 46 mm restrictor, alternate turbo permitted. 2020-02-01 T1 Request Ford Mustang FP350S T1-LP weight and restrictor change #26662weight +100 lbsfaster · weightT1-LP Ford Mustang FP350S restrictor enlarged to 70mm; GT and GT5.0L weights increased to 3500 lbs, Brembo BBK at no penalty, restrictors removed from notes. 2020-02-01 T1 Request to classify Ford Coyote 3rd Gen OEM #27145cars addedaddedFord Mustang/Thunderbird 5000 Coyote OEM added to T1; 2015-17 at 3450 lbs, 2018+ at 3450 lbs with 65mm flat plate restrictor. 2020-02-01 T1 Request alternate dashboard #27276otheraddedT1 BMW M3 E92 (08-13) carbon dash allowed with 25 lb penalty added. 2020-02-01 T1 Request for Allowance of Coil Springs on Limited Prep C6 Corvette #27713suspension & brakesadded · suspension & brakesT1 Corvette C5 Z06, C6 coupe and Grand Sport, C6 Z06 may convert leaf springs to coilover suspension. 2020-01-01 FV FV Allow non-spec tire in Regional competition #26284tyres & wheelsadded · tyres & wheelsFV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020. 2020-01-01 FV Request to Allow Rear Tires on the Front of Formula Vee #26537tyres & wheelsadded · tyres & wheelsFormula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020. 2019-12-01 FV Clarification on Wheel Bolt Pattern #27603tyres & wheelsadded · tyres & wheelsFV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.
	Virginia International Raceway Runoffs 20192019-10-05	1:54.771Andrew Aquilante · fastest of 19 · top 5 within 3.1s	2:14.413Andrew Aquilante · fastest of 15 · top 5 within 4.8s	156.2Mark Boden	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	+2.046squal +19.781s	101.5%qual 117.2%	2:15.712Andrew Whitston · fastest of 26 · top 5 within 1.5s	2:18.289Zachary Whitston · fastest of 19 · top 5 within 0.4s	114.8Roger Siebenaler	+3.876squal +20.941s	102.9%qual 118.2%	1:59.563Tyler O'Connor · fastest of 14 · top 5 within 1.4s	2:20.474Jonathan Kotyk · fastest of 14 · top 5 within 6.3s	136.2Derek Ketchie	+6.061squal +4.792s	104.5%qual 104.2%
32 rule changes (T1: 19, SM: 4, FV: 6, FF: 3)6 cars added · 5 weight · 3 suspension & brakes · 2 aero · 1 engine · 1 induction · 1 tyres & wheels · 11 wording · 2 other · FV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body. · FV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions. · T1-LP Chevrolet Camaro 1LE 2016+ minimum weight reduced to 3500 lbs, restrictor increased to 70mm. · Ford Mustang Challenge added to T1 as E&O with 4600cc displacement, 3300 lbs minimum weight, no restrictor. · T1 Chevrolet Corvette Cadillac XLR model year range removed from specification. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird and GTO intake restrictor increases from 67 mm to 70 mm. · FV exhaust outlet opening max distance from body rear increased from 3 to 4 inches. · T2-T4 touring tires must be DOT certified with minimum U speed rating; TCS line size is maximum unless noted. · FV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed. · Ford Mustang with 3.5 EcoBoost engine added to T1: 3496 cc displacement, 3300 lb minimum weight, 31 mm restrictor. · T1 Corvette C5 body allowed C7 carbon aero parts, adds fifty pounds. · T1 Audi TTRS must conform to July 24th, 2015 revision 7 GTS rules, not December 14th, 2011 revision 3. · T1 minimum ride height set to 3.5 inches, measured at rocker panel without driver. · T1 Porsche 928 S4/GTS-R minimum weight drops from 3500 to 3200 lbs; 60mm flat plate restrictor removed. · FV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed. · Porsche 928 S4/928 GTS-R added to T1 at 5400cc, 3500 lbs minimum, 60mm restrictor. · SM fuel pump and filter now permitted as Mazda or OEM equivalent part. · T1-LP Ford Mustang GT 5.0L 2018- classified at 3400 lbs with 65mm restrictor, T2 and T3 Mustangs limited to 2015-2017. · FF Honda Fit cylinder honing increased to 73.315mm and oversize pistons PN 13020-RB7-Z00 now permitted with matching ring packs. · FF intake manifold thermal wrap now permitted if easily removable for inspection; no coating allowed. · FF clarifies coolant and oil catch tank capacity requirements: coolant minimum one U.S. pint, oil minimum one U.S. quart per system. · FV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text. · 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. · T1-LP Mustang GT350(R) spec line replaced with complete dimensions, gearing, brakes, weight 3650 lbs curb, carbon wheels standard. · Ford Mustang FP350S (2017) classified in T1-LP with 3600 lbs minimum weight, 18×11 wheels, 315 tires, 6-speed gears. · T1 suspension rules clarified: spherical bearings, solid or spherical bushings, and alternate control arms now permitted. · T1 Porsche 996 and 996 GT3 Cup lose 150–200 lbs to 3000; 997 loses 50 lbs to 3100. · Porsche 997 T1 Maximum gains PDK transmission option; GT3 Cup engine remains not allowed. · T1 Acura NSX Turbo World Challenge weight rises to 3100 lbs, restrictor shrinks to 44mm. · T1–T4 spec car classifications clarified with permitted parts, rule conformance versions, and exclusions of other touring modifications.showhide 2019-10-01 FV Allowed Modifications E&O #27398wordingwordingFV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body. 2019-08-31 FV E&O Wheels #27230tyres & wheelsadded · tyres & wheelsFV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions. 2019-08-31 T1 T1 LP 2016 Camaro and Later #27198weight -100 lbsfaster · weightT1-LP Chevrolet Camaro 1LE 2016+ minimum weight reduced to 3500 lbs, restrictor increased to 70mm. 2019-08-01 T1 Request to return Ford Mustang Challenge Car to T1 #26751cars addedaddedFord Mustang Challenge added to T1 as E&O with 4600cc displacement, 3300 lbs minimum weight, no restrictor. 2019-08-01 T1 Correct years in T1 FP Corvette spec #27023wordingwordingT1 Chevrolet Corvette Cadillac XLR model year range removed from specification. 2019-07-01 T1 Request BoP Baten - T1 Camaro - Follow up to Letter # 26145 #26900inductionfaster · inductionT1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird and GTO intake restrictor increases from 67 mm to 70 mm. 2019-05-31 FV Exhaust termination rule E&O #26702wordingwordingFV exhaust outlet opening max distance from body rear increased from 3 to 4 inches. 2019-05-31 T1 Clarify DOT tires touring #26556wordingwordingT2-T4 touring tires must be DOT certified with minimum U speed rating; TCS line size is maximum unless noted. 2019-05-01 FV E&O Dimensions #26674suspension & brakessuspension & brakesFV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed. 2019-05-01 T1 Request to Classify EcoBoost Mustang #25841cars addedaddedFord Mustang with 3.5 EcoBoost engine added to T1: 3496 cc displacement, 3300 lb minimum weight, 31 mm restrictor. 2019-05-01 T1 Request Corvette aerodynamic aids #26265aeroslower · aeroT1 Corvette C5 body allowed C7 carbon aero parts, adds fifty pounds. 2019-05-01 T1 Audi TTRS VTS Documentation Revision #26578wordingwordingT1 Audi TTRS must conform to July 24th, 2015 revision 7 GTS rules, not December 14th, 2011 revision 3. 2019-05-01 T1 Request Ride Height Clarification #26599suspension & brakessuspension & brakesT1 minimum ride height set to 3.5 inches, measured at rocker panel without driver. 2019-05-01 T1 Opposes Unfair weight and throttle restrictor #26719weight -300 lbsfaster · weightT1 Porsche 928 S4/GTS-R minimum weight drops from 3500 to 3200 lbs; 60mm flat plate restrictor removed. 2019-04-01 FV Request to clarify Disc Brake rules bearing retainer & weights #26262weightslower · weightFV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed. 2019-04-01 T1 Request to classify the Porsche 928GTS/S4 in Touring 1 #26315cars addedaddedPorsche 928 S4/928 GTS-R added to T1 at 5400cc, 3500 lbs minimum, 60mm restrictor. 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 T1 Request Mustang GT Limited Prep 2018 Classification #24431cars addedaddedT1-LP Ford Mustang GT 5.0L 2018- classified at 3400 lbs with 65mm restrictor, T2 and T3 Mustangs limited to 2015-2017. 2019-02-01 FF Request for Oversize Honda Fit Pistons #25810enginefaster · engineFF Honda Fit cylinder honing increased to 73.315mm and oversize pistons PN 13020-RB7-Z00 now permitted with matching ring packs. 2019-02-01 FF Heat Shield - Fit Intake #26102aeroadded · aeroFF intake manifold thermal wrap now permitted if easily removable for inspection; no coating allowed. 2019-02-01 FF Request catch cans/tanks clarification #26158wordingwordingFF clarifies coolant and oil catch tank capacity requirements: coolant minimum one U.S. pint, oil minimum one U.S. quart per system. 2019-02-01 FV FV Intake Manifold Clarification #26008wordingwordingFV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text. 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 T1 Class 2015+ Mustang GT350(R) #21466wordingwordingT1-LP Mustang GT350(R) spec line replaced with complete dimensions, gearing, brakes, weight 3650 lbs curb, carbon wheels standard. 2019-01-01 T1 Request to Classify Ford FP350S in T1-LP #25341cars addedaddedFord Mustang FP350S (2017) classified in T1-LP with 3600 lbs minimum weight, 18×11 wheels, 315 tires, 6-speed gears. 2019-01-01 T1 Amendment to Request #25555 #25556suspension & brakessuspension & brakesT1 suspension rules clarified: spherical bearings, solid or spherical bushings, and alternate control arms now permitted. 2019-01-01 T1 Request to balance 996 v 997 T1 weight #25658weightfaster · weightT1 Porsche 996 and 996 GT3 Cup lose 150–200 lbs to 3000; 997 loses 50 lbs to 3100. 2019-01-01 T1 Request to Add PDK Transmission to 997 Porsche Spec Line #25668cars addedaddedPorsche 997 T1 Maximum gains PDK transmission option; GT3 Cup engine remains not allowed. 2019-01-01 T1 T1 World Challenge/Grand AM Spec Cars #25687weightslower · weightT1 Acura NSX Turbo World Challenge weight rises to 3100 lbs, restrictor shrinks to 44mm. 2019-01-01 T1 Add Clarification to Spec Car Classifications Vehicle Spec #25774wordingwordingT1–T4 spec car classifications clarified with permitted parts, rule conformance versions, and exclusions of other touring modifications.
	Sonoma Raceway Runoffs 20182018-10-10	1:39.970Kristofer Olson · fastest of 16 · top 5 within 3.8s	1:41.125Kristofer Olson · fastest of 15 · top 5 within 3.0s	108.6Brad McCall	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	+14.153squal +14.385s	114.0%qual 114.4%	1:52.637Skip Streets · fastest of 29 · top 5 within 1.6s	1:53.639Alex Scaler · fastest of 28 · top 5 within 0.4s	106.3Skip Streets	+12.514squal +12.667s	112.4%qual 112.7%	1:41.612Jonathon Kotyk · fastest of 22 · top 5 within 1.7s	1:42.049Jonathon Kotyk · fastest of 22 · top 5 within 1.3s	115.7Denny Renfrow	+0.924squal +1.642s	100.9%qual 101.6%
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:41.793Andrew Aquilante · fastest of 22 · top 5 within 2.9s	1:42.871Andrew Aquilante · fastest of 21 · top 5 within 2.9s		1:58.306Chris Haldeman · fastest of 86 · top 5 within 0.5s	1:59.100Michael Gagliardo · fastest of 83 · top 5 within 0.6s		+16.229squal +16.513s	115.8%qual 116.2%	1:55.759Michael Varacins · fastest of 39 · top 5 within 1.0s	1:55.923Michael Varacins · fastest of 32 · top 5 within 1.3s		+13.052squal +13.966s	112.7%qual 113.7%	1:44.601Zach Holden · fastest of 36 · top 5 within 1.2s	1:44.524Jonathon Kotyk · fastest of 36 · top 5 within 0.5s		+1.653squal +2.808s	101.6%qual 102.8%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:28.656Ross Murray · fastest of 17 · top 5 within 1.4s	1:29.309Ross Murray · fastest of 15 · top 5 within 1.1s		1:40.514Justin Hille · fastest of 45 · top 5 within 0.3s	1:40.764Michael Carter · fastest of 44 · top 5 within 0.3s		+11.455squal +11.858s	112.8%qual 113.4%	1:37.942Alex Scaler · fastest of 41 · top 5 within 0.3s	1:38.066Flinn Lazier · fastest of 38 · top 5 within 0.7s		+8.757squal +9.286s	109.8%qual 110.5%	1:29.213Neil Verhagen · fastest of 14 · top 5 within 2.1s	1:30.133Neil Verhagen · fastest of 14 · top 5 within 1.4s		+0.824squal +0.557s	100.9%qual 100.6%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	1:53.562Andrew Aquilante · fastest of 12 · top 5 within 2.5s	1:55.494Andrew Aquilante · fastest of 12 · top 5 within 2.1s		2:18.661Andrew Carbonell · fastest of 62 · top 5 within 0.6s	2:24.067Todd Lamb · fastest of 59 · top 5 within 0.8s		+28.573squal +25.099s	124.7%qual 122.1%	2:21.167Roger Siebenaler · fastest of 31 · top 5 within 0.8s	2:21.142Andrew Whitston · fastest of 30 · top 5 within 1.1s		+25.648squal +27.605s	122.2%qual 124.3%	2:02.489Tim Kautz · fastest of 25 · top 5 within 1.1s	2:03.383Rick Payne · fastest of 22 · top 5 within 0.8s		+7.889squal +8.927s	106.8%qual 107.9%

By track

Track	Events	Typical % of T1	Best	Latest
Road America	4	100.0%3 of 4 with T1	100.0%Runoffs 2020	100.0%Runoffs 2025
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 T1'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.