Lap times across years say as much about the weather as the class. % of AS is each class's best lap as a share of AS'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.
Quickest here:AS 1:30.651 Tom Sloe, Runoffs 2016 qualifying · T1 1:28.656 Ross Murray, Runoffs 2016 qualifying · SM 1:40.514 Justin Hille, Runoffs 2016 qualifying · STU 1:19.234 Franklin Church, Runoffs 2018 qualifying
AST1SMSTUsolid race · dashed qualifying · slower is lower
AST1SMSTUsolid race · dashed qualifying · each class's best lap as a share of AS's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
2:26.911Andrew McDermid · fastest of 8 · top 5 within 3.4s+0.119s (+0.08%)
2:28.471Andrew McDermid · fastest of 8 · top 5 within 2.4s-0.761s (-0.51%)
151.0Andrew McDermid-0.6 mph (-0.4%)
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%)
+14.254squal +15.262s
109.6%qual 110.4%
2:24.912Richard Astacio · fastest of 17 · top 5 within 2.6s+1.829s (+1.28%)
2:26.416Richard Astacio · fastest of 16 · top 5 within 1.5s+1.919s (+1.33%)
145.1Hugh Stewart+0.8 mph (+0.5%)
-2.055squal -1.999s
98.6%qual 98.6%
42 rule changes (AS: 13, T1: 12, SM: 2, STU: 15)7 cars added · 6 weight · 4 engine · 4 induction · 4 tyres & wheels · 1 aero · 1 removed · 1 suspension & brakes · 11 wording · 3 other · AS Camaro 16+ Spec Line: 1LE front splitter kit permitted, belt tensioner and motor mount parts allowed, spark plug position defined. · AS class adds Pirelli P Zero Trofeo Track as permitted tyre option for competition. · GT3U wheel and tyre options clarified: 15x7 with 225 section at +275 lbs; 15x9 with 245 section at +275 lbs plus 1.5%; 16–18x9 with 245 section at +275 lbs plus 3.0%. · AS class rear trailing arms no longer required to maintain stock length, only to locate rear axle. · AS Ford Mustang GT 4.6L 4-valve regains allowance, minimum weight 3200 lbs. · AS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs. · SM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. · STU cars at or under 2,825 lbs minimum weight limited to 8-inch wheels; over 2,825 lbs limited to 9-inch wheels. · STU GT3U minimum weight increases from GT3 race weight plus 225 to plus 275 pounds; 2.0L unrestricted engines add 75 lbs. · T1 classes now require U-rated or better DOT tires; re-grooving DOT tires banned; shaving and truing only allowed. · AS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776. · STU adds BMW M50B20TU engine, 1991 cc, minimum weight per chart, must meet all STU engine regulations. · STL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. · T1 trunk lid and wing mounting wording clarified; no performance change. · STU Honda K20C1 Turbo I4 turbo restrictor increases from 35mm to 36mm TIR. · STU GT86 Cup car must meet 2022 Toyota GR Cup rules, tires maximum 245 section width. · 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. · AS EFI engine build sheets add dry sump, header, camshaft, and timing chain tensioner options for LS, LT1, Ford, and Mopar engines. · AS LT1 Camaro engine build sheet added with full specs; LT1 weight 3200 lbs, GTO tire to 275, Mustang weight to 3525 lbs, oil catch tanks now required. · SM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. · STU Mazda Renesis Street Port added to Table B with 2450 lbs minimum weight and 70mm throttle body options. · STU eliminates 33 and 34 mm inlet restrictor options, removing minimum weights of 2380 and 2525 lbs. · T1 restrictor requirement removed entirely; no replacement specified. · AS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets. · STU Mazda MZR engines may now use Fab 9 Elite NC MX5 Performance Intake manifold as alternative option. · T1 GT4 Spec Line 4030- permits Wagner Tuning #200001124 intercooler as replacement for OEM heat exchanger. · AS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line. · T1 Chevrolet Corvette C6 LS1/LS6 spec line reinstated: 3200 lbs minimum, 70mm restrictor. · AS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm. · STU Mazda MZR (LF, L3, L5) Turbo added; Goodwin intake removed, Jack Spania Racing 70 mm intake and Fab9 Tuning bottom-mount turbo kit approved. · T1 Spec Line removes 70mm flat plate restrictor option. · AS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft. · STU 36mm restrictor revised to 2830 cc, 37mm to 2980 cc. · STU removes 275 tire option and 2% weight adder for cars over 3150 lbs; maximum section width now 245. · STU Honda K20 and K24 engines lose 2% weight penalty; minimum weight now per chart only. · 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. · AS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs. · STU Honda K24 engine swap weight increases by 2 percent, effective November 1, 2025.showhide
AS 2016+ Camaro Spec Line Full Prep #39646otheraddedAS Camaro 16+ Spec Line: 1LE front splitter kit permitted, belt tensioner and motor mount parts allowed, spark plug position defined.
AS Consideration of Pirelli P Zero Trofeo Track for AS Competition #40495tyres & wheelsadded · tyres & wheelsAS class adds Pirelli P Zero Trofeo Track as permitted tyre option for competition.
STU Wheel and tire requirements for GT3U #40679wordingwordingGT3U wheel and tyre options clarified: 15x7 with 225 section at +275 lbs; 15x9 with 245 section at +275 lbs plus 1.5%; 16–18x9 with 245 section at +275 lbs plus 3.0%.
AS Change in 9.1.6.D.4.d.5 in Suspension Mounting Points #40094suspension & brakesfaster · suspension & brakesAS class rear trailing arms no longer required to maintain stock length, only to locate rear axle.
AS Re-Add 4.6L 4v 96-04 Mustang Cobra #40239cars addedaddedAS Ford Mustang GT 4.6L 4-valve regains allowance, minimum weight 3200 lbs.
AS Errors and Omissions #40532weightslower · weightAS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs.
SM Rear Toe Link #40271wordingwordingSM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361.
STU 9” Wheels #40433tyres & wheelsslower · tyres & wheelsSTU cars at or under 2,825 lbs minimum weight limited to 8-inch wheels; over 2,825 lbs limited to 9-inch wheels.
STU Weight adjustment to former GT3U cars #40474weightslower · weightSTU GT3U minimum weight increases from GT3 race weight plus 225 to plus 275 pounds; 2.0L unrestricted engines add 75 lbs.
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.
AS Clarification for LM7 Holley Carburetor #40167wordingwordingAS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776.
STU Request to allow BMW M50B20TU engine in STU #40202cars addedaddedSTU adds BMW M50B20TU engine, 1991 cc, minimum weight per chart, must meet all STU engine regulations.
STU Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied.
T1 Trunk Lid Wording #40177wordingwordingT1 trunk lid and wing mounting wording clarified; no performance change.
STU Turbo Restrictor Size Increase Request #40008inductionfaster · inductionSTU Honda K20C1 Turbo I4 turbo restrictor increases from 35mm to 36mm TIR.
STU GT86 Cups Car in STU #40028wordingwordingSTU GT86 Cup car must meet 2022 Toyota GR Cup rules, tires maximum 245 section width.
T1 Clarification on Request #39716 T1 (Spec Line #1139) #39924wordingunclearT1 LS1, LS6 removes OEM designation; 70mm restrictor requirement deleted.
T1 Mistake in Line 1430 #39958wordingwordingT1 Spec Line Coyote Boss 302 production years corrected to 11–14, displacement 4957 cc unchanged.
AS Header Information Update for EFI Engine Build Sheets #39886engineadded · engineAS EFI engine build sheets add dry sump, header, camshaft, and timing chain tensioner options for LS, LT1, Ford, and Mopar engines.
AS Errors and Omissions #39933otherfasterAS LT1 Camaro engine build sheet added with full specs; LT1 weight 3200 lbs, GTO tire to 275, Mustang weight to 3525 lbs, oil catch tanks now required.
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.
STU Mazda Rx-8 Renesis - Streetported Variant & Added Weight #39785cars addedaddedSTU Mazda Renesis Street Port added to Table B with 2450 lbs minimum weight and 70mm throttle body options.
STU Eliminate 33 and 34 mm TIRs #39872inductionremoved · inductionSTU eliminates 33 and 34 mm inlet restrictor options, removing minimum weights of 2380 and 2525 lbs.
T1 Spec line #1139 Restrictor Change Request #39922enginefaster · engineT1 restrictor requirement removed entirely; no replacement specified.
AS Re-Organization of AS Spec lines for 2026 #39887wordingwordingAS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets.
STU Fab 9 Racing Intake Manifold in STU #39767cars addedaddedSTU Mazda MZR engines may now use Fab 9 Elite NC MX5 Performance Intake manifold as alternative option.
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.
AS Edelbrock manifold (& timing kit) to Chevy LS Spec Lines Request #39055cars addedaddedAS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line.
T1 LS1 into Corvette C6 Spec Line Request #39716cars addedaddedT1 Chevrolet Corvette C6 LS1/LS6 spec line reinstated: 3200 lbs minimum, 70mm restrictor.
AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501inductionslower · inductionAS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm.
STU Request for Permission on Aftermarket Turbo Kit and Intake #39529cars addedaddedSTU Mazda MZR (LF, L3, L5) Turbo added; Goodwin intake removed, Jack Spania Racing 70 mm intake and Fab9 Tuning bottom-mount turbo kit approved.
AS 1994 Mustang Spec Line Request #39104engineadded · engineAS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft.
STU Turbo Inlet Restrictor Table #38961wordingwordingSTU 36mm restrictor revised to 2830 cc, 37mm to 2980 cc.
STU 275 Tire Rule #38983tyres & wheelsslower · tyres & wheelsSTU removes 275 tire option and 2% weight adder for cars over 3150 lbs; maximum section width now 245.
STU STU Honda Engine weight penalty #39375weightfaster · weightSTU Honda K20 and K24 engines lose 2% weight penalty; minimum weight now per chart only.
2:26.792Andrew McDermid · fastest of 11 · top 5 within 3.9s+0.214s (+0.15%)
2:29.232Gregory Eaton · fastest of 10 · top 5 within 4.0s+2.803s (+1.91%)
151.5Andrew McDermid+1.9 mph (+1.3%)
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%)
-7.620squal -6.115s
94.9%qual 95.8%
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%)
+15.198squal +16.319s
110.2%qual 111.1%
2:23.083Peter Cunningham · fastest of 16 · top 5 within 2.6s-3.144s (-2.15%)
2:24.497Chip Herr · fastest of 15 · top 5 within 3.8s-1.327s (-0.91%)
144.3Chip Herr-1.0 mph (-0.7%)
-4.735squal -3.709s
96.8%qual 97.5%
52 rule changes (AS: 11, T1: 19, SM: 4, STU: 18)12 weight · 10 cars added · 10 engine · 6 tyres & wheels · 2 induction · 1 aero · 8 wording · 3 other · STU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs. · STU-TCR gains GT3 TCR spec lines; 275 tyre option now costs 150 lb adder, up from 100 lb. · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · AS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs. · STU 2.8–3.2L N/A engines now permit 245 max tyre width; over 3150 lbs cars may run 275 with 2% weight penalty. · STU Mazda MZR intake manifold now allows Goodwin 61-2510 or Gato Performance 31972. · STU Honda JDM H23a added, 2259 cc, minimum weight per chart, must meet ST engine regulations. · AS Ford Mustang GT 05-14 Restricted Prep Engine gains additional gear ratio option: 3.66, 2.43, 1.69, 1.32, 1.00, .65. · 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. · AS Ford Mustang GT 5.0L 15-17 flat plate restrictor reduces from 67mm to 64mm. · AS LS1/LS6 intakes added for 5.3L truck engine: part numbers 12561269 and 88894095. · 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. · STU wheels capped at 18 inches diameter; under 2,850 lbs max 8 inches wide, over 2,850 lbs max 9 inches wide. · STU-GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tyre options clarified with weight adjustments. · 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. · AS Flotek head value seat cutting dimensions figure updated for consistency. · AS class notes cleaned: fuel cell and ECM specifications removed from multiple Camaro, Firebird, Challenger and Mustang variants. · T1 Cadillac CT4-V Blackwing added: 3564cc, 3750 lbs minimum, OEM ECU with reprogramming allowed. · AS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models. · STU BMW N54/N55 3.0 classified at chart plus 3% minimum weight; N54 twin turbo not allowed. · STU Mini Cooper S SC pulley diameter reduced to 2.185 inches. · STU Honda K20C1 Turbo I4 exempted from 3% direct injection weight adder. · STU GT3U minimum weight increases 150 pounds to 250 pounds. · 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. · AS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm. · AS Mustang GT 05-14 Restricted loses 300 lbs engine; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively. · AS class: multiple American muscle cars gain additional allowed gear ratio options across model years and prep levels. · AS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM. · STU Audi 1.8T Wagon removed; Porsche 944 1800cc weight to Chart, turbo inlet restrictor deleted. · STU-GT3 reclassified as STU-GT3U, effective 1 January 2026. · STU GT3 TCR may run 275-wide DOT tires with 100 lb weight penalty; A compound prohibited at 275. · 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. · STU BMW N54/N55 turbo inlet restrictors now required per GCR definition; twin turbo conversion to single turbo clarified. · 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. · STU Mini Cooper S SC: 1900 stock pulley spec to 2.565 diameter; 2100 now permits 2.285 diameter pulley.showhide
STU Lotus Weight Reduction E&O #38919weightfaster · weightSTU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs.
STU STU-TCR Adjustments #38723weightslower · weightSTU-TCR gains GT3 TCR spec lines; 275 tyre option now costs 150 lb adder, up from 100 lb.
STU Lotus Weight Reduction #38772weight -50 lbsfaster · weightLotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs.
AS RE: Previous Letter 37695 Update #38245weight -75 lbsfaster · weightAS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs.
STU 2.8-3.2L N/A Engine Allowances #38007tyres & wheelsfaster · tyres & wheelsSTU 2.8–3.2L N/A engines now permit 245 max tyre width; over 3150 lbs cars may run 275 with 2% weight penalty.
STU 2006-2015 Mazda Miata Intake Manifold #38422engineadded · engineSTU Mazda MZR intake manifold now allows Goodwin 61-2510 or Gato Performance 31972.
STU Requesting Approval of the JDM Honda h23a #38489cars addedaddedSTU Honda JDM H23a added, 2259 cc, minimum weight per chart, must meet ST engine regulations.
AS Errors and Omissions #38234otheraddedAS Ford Mustang GT 05-14 Restricted Prep Engine gains additional gear ratio option: 3.66, 2.43, 1.69, 1.32, 1.00, .65.
SM SMX Data Submission - Penalties #38248otheraddedSMX drivers must submit data acquisition files on time or face suspension and $250 fine.
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.
AS Errors and Omission #38055inductionslower · inductionAS Ford Mustang GT 5.0L 15-17 flat plate restrictor reduces from 67mm to 64mm.
AS Request to Add LS1/LS6 Intakes for 5.3L Truck Engine EnO #38197cars addedaddedAS LS1/LS6 intakes added for 5.3L truck engine: part numbers 12561269 and 88894095.
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.
STU Wheel Size Inconsistency #38018tyres & wheelstyres & wheelsSTU wheels capped at 18 inches diameter; under 2,850 lbs max 8 inches wide, over 2,850 lbs max 9 inches wide.
STU Table C: STU-GT3U Clarification #38268weightfaster · weightSTU-GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tyre options clarified with weight adjustments.
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.
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.
T1 DCT Transmission in E46 #37964cars addedaddedT1 BMW E46 M3 permits BMW #GS7D36SG sequential transmission as aftermarket option in SL# 1060 and 1070.
T1 Reduce E92 M3 Minimum Weight to 3050 #38092weightfaster · weightT1 BMW M3 E92 minimum weight reduced to 3300 lbs.
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.
AS Flotek Head Plunge Cut Inconsistencies #37502wordingwordingAS Flotek head value seat cutting dimensions figure updated for consistency.
AS Notes clean up #37693wordingwordingAS class notes cleaned: fuel cell and ECM specifications removed from multiple Camaro, Firebird, Challenger and Mustang variants.
AS Race memo #37902wordingwordingAS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models.
STU BMW N54/N55 Engine Allowance Follow Up #37447cars addedaddedSTU BMW N54/N55 3.0 classified at chart plus 3% minimum weight; N54 twin turbo not allowed.
STU STU Mini Cooper pulley size clarification re: letter #36980 #37717inductionfaster · inductionSTU Mini Cooper S SC pulley diameter reduced to 2.185 inches.
STU Question About a Weight Modifier #37782weightfaster · weightSTU Honda K20C1 Turbo I4 exempted from 3% direct injection weight adder.
STU Increase Minimum Weight #37919weight +100 lbsslower · weightSTU GT3U minimum weight increases 150 pounds to 250 pounds.
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.
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.
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.
T1 C8 Corvette Facts #37400weight -100 lbsfaster · weightT1 Chevrolet Corvette C8 (2020-2023) minimum weight drops to 3500 lbs.
T1 Camaro Gen 5 Competitive Disadvantage #37440enginefaster · engineT1 Chevrolet Camaro Gen 5 required restrictor increases from 75mm to 80mm flat plate.
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.
AS Increase Coyote Engine Restrictor to 80mm #36177enginefaster · engineAS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm.
AS Performance Pack for 2015+ Mustang #36867enginefaster · engineAS Mustang GT 05-14 Restricted loses 300 lbs engine; 15-17 and 2018+ models lose 61mm and 60mm restrictors respectively.
AS Gear Ratios #37131otheraddedAS class: multiple American muscle cars gain additional allowed gear ratio options across model years and prep levels.
AS ECU specs for LS engine #37208engineadded · engineAS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM.
STU Audi 1.8t Wagon STU Table B #36685cars addedremoved · cars addedSTU Audi 1.8T Wagon removed; Porsche 944 1800cc weight to Chart, turbo inlet restrictor deleted.
STU Merger GT3 to STU #37486wordingunclearSTU-GT3 reclassified as STU-GT3U, effective 1 January 2026.
STU GT3 TCR Tire allowance #37494tyres & wheelsadded · tyres & wheelsSTU GT3 TCR may run 275-wide DOT tires with 100 lb weight penalty; A compound prohibited at 275.
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.
STU 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.
STU BMW N54/N55 Engine Allowance #37146wordingwordingSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; twin turbo conversion to single turbo clarified.
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.
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.
T1 Alt. Clutch Allowance #36606engineadded · engineT1 now permits 5.5 inch clutch as engine option.
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.
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.
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.
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.
STU R53 15% Pulley Request #36980enginefaster · engineSTU Mini Cooper S SC: 1900 stock pulley spec to 2.565 diameter; 2100 now permits 2.285 diameter pulley.
2:26.578Gregory Eaton · fastest of 18 · top 5 within 2.6s-0.467s (-0.32%)
2:26.429Gregory Eaton · fastest of 18 · top 5 within 2.5s-1.239s (-0.84%)
149.6Gregory Eaton+0.4 mph (+0.3%)
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%)
-10.298squal -10.000s
93.0%qual 93.2%
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%)
+15.057squal +14.528s
110.3%qual 109.9%
2:26.227Thomas Noble · fastest of 18 · top 5 within 2.3s-1.656s (-1.12%)
2:25.824Thomas Noble · fastest of 17 · top 5 within 2.4s-2.586s (-1.74%)
145.3Thomas Noble+1.1 mph (+0.8%)
-0.605squal -0.351s
99.6%qual 99.8%
32 rule changes (AS: 11, T1: 13, SM: 4, STU: 4)14 cars added · 3 engine · 2 aero · 2 removed · 1 induction · 1 tyres & wheels · 1 weight · 2 wording · 6 other · AS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options. · 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. · STU RWD turbo cars no longer required to reduce inlet restrictor by 1 mm from table minimum. · AS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes. · AS Chevrolet Camaro 1LE (2016-) added with 3600 lbs minimum weight, 275 tires, 60mm restrictor, 345/338mm brakes. · AS Chevrolet/Pontiac Camaro & Firebird 82–92 5.7L LS1 classified: 3200 lbs, 13.1×1.27 disc brakes, 17 in max wheel, 65 mm restrictor, SLP intake lid permitted. · AS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations. · Mercedes AMG-C63 S 2023 added to T1 with 4000 cc, 3700 lb minimum weight, no restrictor. · AS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes. · AS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25. · T1 Honda S2000 classified: 1530 cc max, 2950 lbs minimum, 4.75" supercharger pulley, 6.75" crank pulley. · Chevrolet Camaro, Pontiac Firebird 70–81 Full Prep classified in AS at 3400–3600 lbs with 108.0 wheelbase, specific head castings, and suspension modifications permitted. · AS class adds fuel cell location notes to multiple Cadillac, Chevrolet, Dodge and Ford models: cells within 24 inches of standard tank. · Chevrolet Camaro 6th gen Full Prep added to AS class at 3400 lbs base or 3600 lbs with built engine. · AS class: Ford Mustang GT 05-14 Restricted prep added; Cadillac CTS-V 04-07 to 3450 lbs; Camaro/Firebird variants reconfigured with weight and notes changes; Dodge Challenger 08-20 restrictor 76mm to 80mm; Ford Mustang variants updated wei… · STU Mini Cooper S SC gains alternate LEAP OMICRON hood scoop part LEP-OMICRON3 as permitted option. · STU BMW S54 B32 OEM dry sump oiling system now permitted. · T1 adds Pontiac GTO 2006-2009 LS1 5700cc, 3400 lbs minimum, engine repositioning allowed. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. · 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. · 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. · 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
AS Mustang transmission ratios #36662otheraddedAS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options.
SM SMX Camera Rule Correction #36496wordingwordingSMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification.
SM Committee) AIM ECU Protocol #36556engineadded · engineSM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 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.
SM Committee) Shifter Bushing #36611otheraddedSM and SMX now allow an alternate shifter bushing at the bottom of the shift lever.
STU RWD Turbo Disadvantage #36255inductionfaster · inductionSTU RWD turbo cars no longer required to reduce inlet restrictor by 1 mm from table minimum.
AS Request for Classification of 2018-2023 mustang In #35764cars addedaddedAS adds 2018-23 Ford Mustang GT 5.0L at 3600 lbs, 275 tire, 60mm restrictor, optional Brembo front brakes.
AS 6th gen Camaro limited prep #35733cars addedaddedAS Chevrolet Camaro 1LE (2016-) added with 3600 lbs minimum weight, 275 tires, 60mm restrictor, 345/338mm brakes.
AS Chevrolet/Pontiac Camaro & Firebird (82-92) 5.7L V8 LS1 Alum BLK #35825cars addedaddedAS Chevrolet/Pontiac Camaro & Firebird 82–92 5.7L LS1 classified: 3200 lbs, 13.1×1.27 disc brakes, 17 in max wheel, 65 mm restrictor, SLP intake lid permitted.
AS Full Prep Head #35891engineadded · engineAS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations.
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.
AS Restricted Prep Aftermarket Parts Request #35682otheraddedAS Camaro, Firebird 93-02 and GTO 04-06 add approved LS1 connecting rod part numbers to Notes.
AS Allowance of 11 #35824tyres & wheelsfaster · tyres & wheelsAS Cadillac CTS-V, Chevy Camaro SS V8, Dodge Challenger, Ford Mustang GT 5.0L, Pontiac GTO allowed 11" wheels until 3/1/25.
AS Request to Classify 1970-1981 Camaro and Firebird in AS #33659cars addedaddedChevrolet Camaro, Pontiac Firebird 70–81 Full Prep classified in AS at 3400–3600 lbs with 108.0 wheelbase, specific head castings, and suspension modifications permitted.
AS Fuel Cell 12 #34194otheraddedAS class adds fuel cell location notes to multiple Cadillac, Chevrolet, Dodge and Ford models: cells within 24 inches of standard tank.
AS Please Classify the 6th Gen Into AS. #35448cars addedaddedChevrolet Camaro 6th gen Full Prep added to AS class at 3400 lbs base or 3600 lbs with built engine.
AS spec lines #35713otherunclearAS class: Ford Mustang GT 05-14 Restricted prep added; Cadillac CTS-V 04-07 to 3450 lbs; Camaro/Firebird variants reconfigured with weight and notes changes; Dodge Challenger 08-20 restrictor 76mm to 80mm; Ford Mustang variants updated wei…
STU Letter #35397 addendum #35453aeroadded · aeroSTU Mini Cooper S SC gains alternate LEAP OMICRON hood scoop part LEP-OMICRON3 as permitted option.
STU S54 Drysump #35464otheraddedSTU BMW S54 B32 OEM dry sump oiling system now permitted.
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.
STU ST Electric-Assisted Steering Systems #35066aeroadded · aeroSTL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems.
T1 C8 Corvette T1 Restrictor Plate Request #35213enginefaster · engineT1 Chevrolet Corvette C8 (2020–23) restrictor plate increases from 70mm to 72mm flat plate.
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.
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.
T1 Remove T1 spec lines #35192removedremovedT1 removes 27 spec line numbers entirely, including engine, suspension, brake and aero specifications.
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.
T1 C7 Corvette Rule Change Request #34897cars addedaddedT1 adds Chevrolet Corvette C7 (14–19) including Z51, Grandsport as homologated car.
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.
T1 Addendum to Letter #35022: Drivetrain Rule #35105cars addedaddedT1 Aston Martin Vantage gains OEM Sportshift II transmission as permitted option.
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.
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.
2:03.082Daniel Richardson · fastest of 11 · top 5 within 2.2s+0.920s (+0.75%)
2:04.120Gregory Eaton · fastest of 9 · top 5 within 3.0s-0.458s (-0.37%)
154.6James Jost+3.7 mph (+2.5%)
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%)
-8.632squal -8.562s
93.0%qual 93.0%
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%)
+12.109squal +11.904s
109.8%qual 109.7%
2:00.389Johan Schwartz · fastest of 13 · top 5 within 2.3s-0.226s (-0.19%)
2:02.302Mark Liller · fastest of 14 · top 5 within 1.6s-30.055s (-19.73%)
144.0Mark Liller+0.1 mph (+0.1%)
-1.818squal -2.693s
98.5%qual 97.8%
27 rule changes (AS: 4, T1: 19, SM: 1, STU: 3)6 cars added · 5 engine · 4 weight · 3 tyres & wheels · 1 aero · 1 induction · 1 removed · 5 wording · 1 other · AS crate motor part number specification clarified; both CT400 P/N-19370604 and 19370604 engine assemblies permitted for GM vehicles. · AS Ford Mustang GT 5.0L (15-17) Restricted maximum wheel diameter increases to 19.0 inches. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front upper control arms; SPC-66045 spec part removed. · AS Dodge Challenger 5.7L/6.1L/6.4L V8 now allows alternate front brake calipers with adaptor brackets for component compatibility. · 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. · STU adds 2022 Toyota GR Cup and GR86 Cup, both 2387cc, 2700 lbs, 18-inch wheels, 245/620R18 slicks. · 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. · STU Mazda BP5A now classified at 1839 cc displacement, 2510 lbs minimum weight, alternate intake manifold permitted. · T1 Chevrolet Camaro Gen 5 LS3-6160 adds new Spec Line 1135 with 70mm flat plate restrictor, 3550 lbs minimum weight. · STU minimum weights adjusted: 2450 cc to 2595 lbs, 2600 cc to 2710 lbs. · 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
AS Crate Motor Part Numbers #32944wordingwordingAS crate motor part number specification clarified; both CT400 P/N-19370604 and 19370604 engine assemblies permitted for GM vehicles.
AS Request wheel size change #33007tyres & wheelsfaster · tyres & wheelsAS Ford Mustang GT 5.0L (15-17) Restricted maximum wheel diameter increases to 19.0 inches.
AS Alternative Upper Front Control Arms for Dodge Challenger #33352wordingwordingAS Dodge Challenger 5.7L/6.1L/6.4L V8 allows alternate front upper control arms; SPC-66045 spec part removed.
AS Front Brake Caliper Adapters for Dodge Challenger #33353otherotherAS Dodge Challenger 5.7L/6.1L/6.4L V8 now allows alternate front brake calipers with adaptor brackets for component compatibility.
T1 Why no Camaro? #34421cars addedaddedChevrolet Camaro GT4-R added to T1 GT4 Spec Line 4035, 315 tires, 3375 lbs minimum, ineligible for Runoffs.
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.
T1 Remove #34475cars addedaddedT1 GT4 McLaren 570S, Mercedes AMG GT4, and Porsche 718 Cayman GT4 CS MR now eligible for Runoffs competition.
T1 Error in T1 GT4 numbering scheme- #34578wordingwordingT1 GT4 BMW M4 spec line number changed from 4050 to 4030.
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.
STU 2022 Toyota GR Cup for STU #34449cars addedaddedSTU adds 2022 Toyota GR Cup and GR86 Cup, both 2387cc, 2700 lbs, 18-inch wheels, 245/620R18 slicks.
T1 Viper Cleanup #34107inductionfaster · inductionT1 Dodge Viper ACR/ACR-X restrictor increases from 50mm to 60mm flat plate.
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.
T1 Ford Mustang S197 (05-14) Clarification #34450wordingwordingT1 Ford Mustang S197 (05-14) must use OEM 8.8 differential housing.
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.
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.
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.
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.
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.
STU Alternate OEM Miata Intake Manifold #33827engineadded · engineSTU Mazda BP5A now classified at 1839 cc displacement, 2510 lbs minimum weight, alternate intake manifold permitted.
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.
STU E&O STU NA Weight Chart. #33737weightfaster · weightSTU minimum weights adjusted: 2450 cc to 2595 lbs, 2600 cc to 2710 lbs.
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.
T1 T1 GT4 adjustments #33786weightfaster · weightT1 GT4 all nine cars lose 125 lbs minimum weight with driver across the range.
T1 Sunset of pre 2023 Touring 1 Rules. #33916removedremovedT1 pre-2023 rules and spec lines removed entirely, effective 2023-03-01.
T1 Corrections to T1 Spec Lines #33678tyres & wheelstyres & wheelsGT4 McLaren 570S maximum tyre size set to 285 front, 315 rear.
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.
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.
2:02.162Kurt Rezzetano · fastest of 13 · top 5 within 2.3s-0.776s (-0.63%)
2:04.578Gregory Eaton · fastest of 11 · top 5 within 2.9s+0.678s (+0.55%)
150.9James Jost-3.0 mph (-2.0%)
1:54.890Andrew 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%)
+11.489squal -7.272s
109.2%qual 94.0%
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%)
+14.529squal +12.502s
111.7%qual 110.2%
2:00.615Johan Schwartz · fastest of 21 · top 5 within 2.6s+0.667s (+0.56%)
2:32.357Mark Liller · fastest of 19 · top 5 within 4.3s+31.874s (+26.46%)
143.9Johan Schwartz+0.1 mph (+0.1%)
+27.779squal -1.547s
122.3%qual 98.7%
42 rule changes (AS: 9, T1: 11, SM: 1, STU: 21)12 weight · 7 cars added · 7 engine · 3 tyres & wheels · 2 aero · 1 suspension & brakes · 9 wording · 1 other · AS adds Hoosier W2 wet tyre option alongside R7, R6, WET/H20. · AS Dodge Challenger 08-20 gains two transmission ratio options: 2.97–0.50 or 2.26–0.63. · STU Mazda 13B Turbo added as Chart Limited displacement, streetport only, alternative turbos only. · STU OEM louver vents no longer count against vent allowance or 200 square inch limit. · STU non-4-valve engines gain 9% base engine weight reduction allowance; 2400cc minimum weight drops 1 lb to 2595. · T1 Camaro, CTS, Firebird, GTO minimum weight reduced to 3475 lbs from 3500 lbs. · AS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty. · STU normally-aspirated engines 2976cc–3200cc with single throttle body lose 10% base engine weight reduction allowance. · ST removes redundant language about engine balance shaft removal and alternate pulley installation. · 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. · STU cars that qualified for 9 inch wheels in 2021 may continue running them through 2022 only. · STU splitter definition clarified: must attach to lowest point of front, have no vertical deviations. · SM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation. · STU BMW E36 M3 (95-99) S52B32 minimum weight cut to 3110 lbs from 3200, displacement to 3152 cc. · STU BMW S50B32 Euro maximum displacement 3201 cc, minimum weight 3300 lbs, permits 0.040 overbore and 0.5 compression increase. · ST engine swap origin rule narrowed: North America changed to United States only for case-by-case approval. · STU Honda CRX 84-91 and Civic Del Sol 93-97 both ineligible for front-wheel-drive weight reductions. · STU wheel width rule clarified: under 2950 lbs uses max 8.0 inches, 2950 lbs and over uses max 9.0 inches. · STU single-throttle body cars get lower minimum weights: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs. · 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. · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STU Audi A4 1.8T minimum weight fixed to 3050 lbs, K04 turbo removed, VF30 with 35mm restrictor required; Porsche 944 1800 weight fixed to 3050 lbs, VW/Audi 1.8L engine removed, 35mm inlet restrictor required. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · 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. · STU engines may delete balance shafts and plug openings; alternate pulleys or gears allowed only for timing belt or chain operation. · STU hood vents now allow louvers within 200 square inches. · SMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000. · AS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line. · AS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes. · AS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180. · STU adds Honda K23 with 2354 cc displacement and chart minimum weight, K24 block allowed with K23 internals and head. · STU Honda K23 relaxes internal engine requirement, now needs only K23 crankshaft. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · 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. · AS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms. · AS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.showhide
AS Request to add Hoosier W2 #33031tyres & wheelsadded · tyres & wheelsAS adds Hoosier W2 wet tyre option alongside R7, R6, WET/H20.
AS correction of Dodge Challenger specification line #33151cars addedaddedAS Dodge Challenger 08-20 gains two transmission ratio options: 2.97–0.50 or 2.26–0.63.
STU Request Mazda 13 B turbo #32668cars addedaddedSTU Mazda 13B Turbo added as Chart Limited displacement, streetport only, alternative turbos only.
STU Hood Vents and Intercooler Scoops #32733aeroadded · aeroSTU OEM louver vents no longer count against vent allowance or 200 square inch limit.
STU Non 4 valve weight reduction removed #32808weightfaster · weightSTU non-4-valve engines gain 9% base engine weight reduction allowance; 2400cc minimum weight drops 1 lb to 2595.
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.
STU Error in new minimum weight table when combined with other text #32711engineslower · engineSTU normally-aspirated engines 2976cc–3200cc with single throttle body lose 10% base engine weight reduction allowance.
STU Redundant Language in May GCR #32713wordingwordingST removes redundant language about engine balance shaft removal and alternate pulley installation.
T1 Fix FP350S limited prep and Shelby 350 full prep issues #31680enginefaster · engineT1-LP Ford Mustang FP350S restrictor increases from 70mm to 75mm.
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.
STU Opposed to the Proposed STU Weight Chart #32381tyres & wheelsadded · tyres & wheelsSTU cars that qualified for 9 inch wheels in 2021 may continue running them through 2022 only.
STU Clarification request for GCR 9.1.4.D.3.a Splitter Definition #32414wordingwordingSTU splitter definition clarified: must attach to lowest point of front, have no vertical deviations.
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.
STU Request Adjustment to Min Weight for STU BMW E36 M3 (95-99) #31535weight -90 lbsfaster · weightSTU BMW E36 M3 (95-99) S52B32 minimum weight cut to 3110 lbs from 3200, displacement to 3152 cc.
STU BMW E36 M3 Canadian (North American) S50B32 engine #31866engineadded · engineSTU BMW S50B32 Euro maximum displacement 3201 cc, minimum weight 3300 lbs, permits 0.040 overbore and 0.5 compression increase.
STU Engine Swap Origin Country #32209wordingwordingST engine swap origin rule narrowed: North America changed to United States only for case-by-case approval.
STU CRX/Civic Del Sol #32214weightslower · weightSTU Honda CRX 84-91 and Civic Del Sol 93-97 both ineligible for front-wheel-drive weight reductions.
STU Error correction #32383wordingwordingSTU wheel width rule clarified: under 2950 lbs uses max 8.0 inches, 2950 lbs and over uses max 9.0 inches.
STU Single TB Weight Modifiers Add to Chart #32393weightfaster · weightSTU single-throttle body cars get lower minimum weights: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs.
T1 Viper/Z06 Parity #31942engine -50 lbsfaster · engineT1 Dodge Viper ACR displacement rises to 8400 cc OEM, minimum weight drops to 3550 lbs.
T1 Discrepancy in T1 allowances #32293wordingwordingT1 Limited T1 specification reference removed; all T1 cars now have unified allowances.
STU Single TB Weight Modifiers #31449weightfaster · weightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs.
STU Request to Remove A4 1.8t from STU Spec Line Tables #31465weightslower · weightSTU Audi A4 1.8T minimum weight fixed to 3050 lbs, K04 turbo removed, VF30 with 35mm restrictor required; Porsche 944 1800 weight fixed to 3050 lbs, VW/Audi 1.8L engine removed, 35mm inlet restrictor required.
STU Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels.
STU Request Allowance for Balance Shaft Delete in STU #31434enginefaster · engineSTU engines may delete balance shafts and plug openings; alternate pulleys or gears allowed only for timing belt or chain operation.
STU Request Louvers in hood vents #31916aeroadded · aeroSTU hood vents now allow louvers within 200 square inches.
AS Proposed Revisions to SCCA GCR 2021 Appendix M, Part 3 #30295wordingwordingSMG Long Tube Headers: Borla PN 17237 discontinued, approved alternatives American Racing MT3-05134300LSNC or Kooks PN 11312000.
AS specification line consolidation and correction #31846cars addedremoved · cars addedAS Mercury Capri 79-86 removed as separate spec line, merged into Ford Mustang 79-93 spec line.
AS correction of SMG specification line #31847wordingremovedAS Spec Mustang SMG Restricted Prep removes 3.73 gear ratio and 355/300 brake disc sizes.
AS Alternate cylinder heads for full prep engine builds - Evaluation #31851engineadded · engineAS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180.
STU Request to Add Honda K23 Spec Line #30682cars addedaddedSTU adds Honda K23 with 2354 cc displacement and chart minimum weight, K24 block allowed with K23 internals and head.
STU RE: Aug FT letter 30682 #31060enginefaster · engineSTU Honda K23 relaxes internal engine requirement, now needs only K23 crankshaft.
STU Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed.
T1 Turbo Miata Help #31315weight +200 lbsslower · weightT1 Mazda MX-5 Miata MazdaSpeed minimum weight rises to 2550 lbs, restrictor grows to 42mm.
T1 Fix the T1 Corvette heading #31528cars addedaddedT1 Chevrolet Corvette Cadillac XLR classified as model year 2019 and earlier.
AS Request for adjustable Front Upper Control Arms on 4th Gen F-Body #30457otheraddedAS Chevrolet/Pontiac Camaro & Firebird 93-02 gains BMR AA004 or UMI 2310 adjustable front upper control arms.
AS Request Pontiac GTO tire size change #30881weightslower · weightAS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.
1:50.427Drew Cattell · fastest of 31 · top 5 within 1.9s+5.207s (+4.95%)
1:50.606Gregory Eaton · fastest of 28 · top 5 within 1.7s-0.901s (-0.81%)
153.8James Jost
1:42.292Andrew 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
-6.854squal -8.135s
93.8%qual 92.6%
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
+8.231squal +7.268s
107.4%qual 106.6%
1:47.078Joe Moser · fastest of 30 · top 5 within 2.0s-1.843s (-1.69%)
1:47.441Joe Moser · fastest of 28 · top 5 within 1.8s-1.946s (-1.78%)
146.9Kip VanSteenburg
-3.165squal -3.349s
97.1%qual 97.0%
45 rule changes (AS: 14, T1: 18, SM: 1, STU: 12)14 cars added · 9 weight · 7 engine · 1 aero · 1 induction · 1 suspension & brakes · 10 wording · 2 other · T1 BMW E46, E36, Z3 minimum weight raised to 2700 lbs; 3.4L engine car to 2750 lbs. · STU fender flare wording clarified: flare of exterior contour may not change wheel opening size, location or shape from side view. · STU Mazda 12A Bridgeport weight reduced from 2550 lbs to 2350 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. · AS Cadillac CTS-V 6.0L LS6 removes 295-tire 50 lb penalty. · AS consolidates seven SN95 Mustang '94-'04 spec lines into three unified lines by model year and engine. · AS Camaro/Firebird LT1 and LS1 transmission changed to TUET1 6362; Mustang GT 4.6L/5spd to TUKT16901, loses 300 lbs. · AS Camaro & Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted. · AS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants. · 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. · STU fender flare rules clarified: maximum 2 inches total, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry. · 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. · SM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture. · STU Honda S2000 now allows F20/F22 K24 crankshaft with chart weight for achieved displacement. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · AS Mustang 4.6L 5spd gains cold air intake freedom; 5.0L 6spd now requires 56mm flat plate restrictor. · AS CTS-V 5.7L LS6 and 6.0L LS2 may use Driveshaft Shop P/N GMCTSV2-C carbon fiber driveshaft. · AS Chevrolet Camaro SS V8 6.2L Restricted Prep model years extended from 10–13 to 10–15. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · T1 LP aero adjustments: removed 50 lb weight allowance for stock OEM manifold/headers, reorganised aero and engine durability allowances into numbered list. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STU Porsche PDK automatic transmission limited to 8 forward speeds; sequential DCT systems require 3.5% minimum weight increase. · STU Mazda 13B Street Port 2400 removes choke location rule, allows auto-type 2bbl with any dual-Y manifold. · STU driveshaft and half-shafts now explicitly permitted in steel or aluminum, removing OEM material requirement. · 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. · AS Ford Mustang GT 5.0L 15-17 Restricted added to Spec Line with 3600 lbs minimum weight, 55mm restrictor, 18×10 wheels, 295 tires. · AS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed. · AS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 and Challenger 08-20 specs removed. · AS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with weight minimums 3250–3500 and 3350–3600 lbs respectively. · STU Mazda 13B Spec and Bridge Port removed; Street Port added at 2400 lbs minimum weight. · T1 Limited Prep Chevrolet Corvette Z06 years extend to 2013, from 2012. · AS Dodge Challenger gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres; compression to 10.9:1 max. · AS Camaro & Firebird (93-02) and Ford Mustang Coupe GT (05-14) spec lines consolidated; Camaro/Firebird now allows both LT1 and LS1 engines; Mustang now allows both 4.6L 3-valve and 5.0L 4-valve engines with restrictor. · ST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion. · T1 Corvette C8 Z51 gets wider wheels and tyres, loses 100 lbs to 3550.showhide
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.
STU STU Fender flares #30696wordingwordingSTU fender flare wording clarified: flare of exterior contour may not change wheel opening size, location or shape from side view.
STU Request weight reduction for 12A bridgeport motor in Miata #30751weight -200 lbsfaster · weightSTU Mazda 12A Bridgeport weight reduced from 2550 lbs to 2350 lbs.
T1 Request BoP for the Viper in 1 LP #29968enginefaster · engineT1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm.
T1 LS6 Alternative Head Question #30074cars addedaddedT1 Corvette and Cadillac XLR: Casting #799 heads now permitted on LS6 engines, no other head modifications allowed.
AS Request CTS-V Spec Line Error Correction #30242weightfaster · weightAS Cadillac CTS-V 6.0L LS6 removes 295-tire 50 lb penalty.
AS Request to consolidate SN95 Mustang '94-'04 Mustang spec lines #30428wordingwordingAS consolidates seven SN95 Mustang '94-'04 spec lines into three unified lines by model year and engine.
AS American Sedan Transmission Rule Change Request #30595enginefaster · engineAS Camaro/Firebird LT1 and LS1 transmission changed to TUET1 6362; Mustang GT 4.6L/5spd to TUKT16901, loses 300 lbs.
AS Correction to specifications inadvertently deleted #30691wordingwordingAS Camaro & Firebird and Mustang GT gear ratio specifications restored with alternate sets permitted.
AS weight adjustments #30700weight +50 lbsslower · weightAS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants.
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.
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.
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.
STU Request for Fender Flare Clarification #30375wordingwordingSTU fender flare rules clarified: maximum 2 inches total, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry.
T1 Request For Reduction in Weight/Penalties for Camaro #30443weightfaster · weightT1 Chevrolet Camaro with 6162 displacement minimum weight reduced to 3500 lbs.
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.
SM Updates - Obsolete Parts & BOP Parts #30438wordingaddedSM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture.
STU Provision for Interchangeable Engine Components Already Allowed #30342engineadded · engineSTU Honda S2000 now allows F20/F22 K24 crankshaft with chart weight for achieved displacement.
STU 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.
AS AS Mustang LP 4.6 3V Classification Transmission Request #29886enginefaster · engineAS Mustang 4.6L 5spd gains cold air intake freedom; 5.0L 6spd now requires 56mm flat plate restrictor.
AS Request CF driveshaft on CTS-V for durability improvement #30117otheraddedAS CTS-V 5.7L LS6 and 6.0L LS2 may use Driveshaft Shop P/N GMCTSV2-C carbon fiber driveshaft.
AS Adjustment to model years of 5th generation RP Camaro #30348cars addedaddedAS Chevrolet Camaro SS V8 6.2L Restricted Prep model years extended from 10–13 to 10–15.
STU Super Touring Alternate Miata Hubs #30345cars addedaddedST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1.
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.
STU Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment.
STU Porsche PDK #30081wordingwordingSTU Porsche PDK automatic transmission limited to 8 forward speeds; sequential DCT systems require 3.5% minimum weight increase.
STU Reference Letter #29333 Proposed STU 13B Spec Line Changes #30086wordingwordingSTU Mazda 13B Street Port 2400 removes choke location rule, allows auto-type 2bbl with any dual-Y manifold.
STU Drive Shaft Request #30087otherotherSTU driveshaft and half-shafts now explicitly permitted in steel or aluminum, removing OEM material requirement.
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.
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.
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.
T1 Class BMW M2CS Club Sport #30195cars addedaddedBMW M2CS Club Sport added to T1 Spec Lines classification.
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.
AS Request for 2015 -2017 Ford Mustang Spec Line #29514cars addedaddedAS Ford Mustang GT 5.0L 15-17 Restricted added to Spec Line with 3600 lbs minimum weight, 55mm restrictor, 18×10 wheels, 295 tires.
AS Request Trunk lid / Rear Hatch clarification #29591wordingwordingAS underhood bracing on stock hoods, trunks, and rear decks may be modified or removed.
AS Common Weight for CTS-V Tire #29759weightfaster · weightAS Cadillac CTS-V 04-07 with 295 tire drops to 3450 lbs; Camaro SS V8 10-13 and Challenger 08-20 specs removed.
AS Correction to specifications inadvertently deleted #30041cars addedaddedAS Camaro & Firebird (93-02) and Mustang GT (05-14) specifications restored with weight minimums 3250–3500 and 3350–3600 lbs respectively.
STU 13B Rules Adjustment #29333cars addedremoved · cars addedSTU Mazda 13B Spec and Bridge Port removed; Street Port added at 2400 lbs minimum weight.
T1 Correct T1 Limited Prep Years #29708cars addedaddedT1 Limited Prep Chevrolet Corvette Z06 years extend to 2013, from 2012.
AS Request Additional Engine Options for Dodge Challenger Spec Line #29543cars addedaddedAS Dodge Challenger gains 6.1L and 6.4L V8 options; 5.7L weight rises to 3500 lbs on 295 tyres, 3600 on 315 tyres; compression to 10.9:1 max.
AS Rule simplification spec line communization #29824cars addedcars addedAS Camaro & Firebird (93-02) and Ford Mustang Coupe GT (05-14) spec lines consolidated; Camaro/Firebird now allows both LT1 and LS1 engines; Mustang now allows both 4.6L 3-valve and 5.0L 4-valve engines with restrictor.
STU Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
T1 Changes to Corvette C8 #29898weight -100 lbsfaster · weightT1 Corvette C8 Z51 gets wider wheels and tyres, loses 100 lbs to 3550.
2:27.045Gregory Eaton · fastest of 18 · top 5 within 0.6s
2:27.668Gregory Eaton · fastest of 15 · top 5 within 1.5s
149.2Gregory Eaton
2:17.646Andrew Aquilante · fastest of 15 · top 5 within 3.7s
2:18.701Mark Boden · fastest of 14 · top 5 within 3.0s
158.8James Candelaria
-8.967squal -9.399s
93.9%qual 93.6%
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
+16.080squal +15.164s
110.9%qual 110.3%
2:27.883David Fiorelli · fastest of 14 · top 5 within 4.1s
2:28.410Anthony Geraci · fastest of 14 · top 5 within 3.1s
144.2David Fiorelli
+0.742squal +0.838s
100.5%qual 100.6%
48 rule changes (AS: 16, T1: 13, SM: 2, STU: 17)8 cars added · 8 engine · 5 weight · 4 suspension & brakes · 3 aero · 16 wording · 4 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. · STU fender flare rule reworded: now per-corner up to 2" total, 1% weight penalty applies to entire modification. · AS Dodge Challenger 5.7L V8 now requires iron block instead of aluminum, compression to 10.5:1 max, intake valve 12.7 mm, exhaust 12.3 mm, intake timing 188 degrees, exhaust timing 205 degrees. · AS Dodge Challenger 08-14 rear spoiler: 1GL20RXF replaced with 1GL20TZZAB; 82211606 still permitted. · 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. · T1 rear wing wording clarifies Gurney flap terminology in chord length and mounting height rules. · AS class pursuing specified list of eligible tires; list details unclear from text provided. · AS class tire eligibility list under development; no specifications changed yet. · AS Coyote Mustang restrictor plate under review for 2021; no change effective yet. · AS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration. · AS Ford Mustang Coupe GT 4.6L 3V Restricted Prep now permits Ford Performance camshaft kit P/N M-6550-3V. · 2010-2014 Camaro remains classified in AS; no specification changes. · AS class cylinder head supplier discontinuation; replacement option pending for 2021 season. · AS Mustang, Capri, Camaro, and Firebird maximum brake rotor diameter increased from 12.2 to 13.1 inches. · unclear · STU request for alternate intake manifold denied; no change to rules. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · STU large displacement turbo engines limited by GCR turbo list; no BoP change granted. · STU sequential shifters referred to Board of Directors for approval; no rule change effective. · STU Mazda 13B Bridge Port and Street Port added with 2550 lbs and 2250 lbs minimum weight respectively. · 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. · STU Honda S2000 gains HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed options. · STU Lotus Elise Cup R and SC Exige SC gain 100 lbs minimum weight to 2300, 2500. · STU Volkswagen GTI/GLI MK5 and Jetta Mk4 may now install turbo inlet restrictor in OEM housing, per TIR spec. · STU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates to original. · 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. · STU vehicles over 2951 lbs base weight may use 9 inch wide wheels, changed from 2950 lbs. · STU turbocharged engines now use base weight instead of minimum weight; DFI cars add 3% to base weight. · T1 BMW E46 and E36 models permitted with S54 engine; displacement corrected to 3250 cc from 3200 cc. · AS rear trailing arms may be replaced with tubular arms maintaining stock length and axle location purpose only. · AS Ford and GM full prep cars get increased weight reduction from 150 to 200 lbs. · 05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam permitted. · 10-15 Camaro Full Prep classified AS with 3400 lbs base weight, 3700 lbs over 313 CID, specific head castings and Edelbrock heads permitted. · 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. · STU allows OEM electronic throttle bodies, manual conversion, cam changes, and manual-to-electronic conversion with same inner diameter.showhide
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.
STU Request for Advanced Aero Rule Wording Clarification. #29124wordingwordingSTU fender flare rule reworded: now per-corner up to 2" total, 1% weight penalty applies to entire modification.
AS Dodge Challenger AS Spec Line Clarification #28698engineslower · engineAS Dodge Challenger 5.7L V8 now requires iron block instead of aluminum, compression to 10.5:1 max, intake valve 12.7 mm, exhaust 12.3 mm, intake timing 188 degrees, exhaust timing 205 degrees.
AS Dodge Challenger AS Spec Line Clarification #2 #28699aeroaeroAS Dodge Challenger 08-14 rear spoiler: 1GL20RXF replaced with 1GL20TZZAB; 82211606 still permitted.
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.
STU Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds.
STU ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules.
AS Support for R-Type Specification Tires #27450wordingunclearAS class pursuing specified list of eligible tires; list details unclear from text provided.
AS Spec Tire Request #27519wordingunclearAS class tire eligibility list under development; no specifications changed yet.
AS Restrictor Plate Change for RP 2011+ Mustang with Coyote Engine #27675wordingunclearAS Coyote Mustang restrictor plate under review for 2021; no change effective yet.
AS 2005-2009 Restricted Prep 4.6 3V #27908engineadded · engineAS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration.
AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909engineadded · engineAS Ford Mustang Coupe GT 4.6L 3V Restricted Prep now permits Ford Performance camshaft kit P/N M-6550-3V.
AS Request for Full Preparation Classification for 2010-2014 Camaro #28030wordingunclear2010-2014 Camaro remains classified in AS; no specification changes.
AS Cylinder Heads #28696wordingunclearAS class cylinder head supplier discontinuation; replacement option pending for 2021 season.
AS Request for Max Rotor Diameter Change #28748otherfasterAS Mustang, Capri, Camaro, and Firebird maximum brake rotor diameter increased from 12.2 to 13.1 inches.
AS Request increase rotor diameter #28797wordingunclearunclear
STU Request for Alternate Intake Manifold #26514wordingunclearSTU request for alternate intake manifold denied; no change to rules.
STU Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
STU Request BoP for my Car #29004wordingunclearSTU large displacement turbo engines limited by GCR turbo list; no BoP change granted.
STU Sequential Shifters in STU #29031wordingunclearSTU sequential shifters referred to Board of Directors for approval; no rule change effective.
STU Rotary Help #27833cars addedaddedSTU Mazda 13B Bridge Port and Street Port added with 2550 lbs and 2250 lbs minimum weight respectively.
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.
AS weight adjustments for 2020 season #28785weight -50 lbs
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.
T1 Request SPEC Corvette Rear Spolier #28182aeroadded · aeroT1 Chevrolet Corvette Cadillac XLR may install SCRSPLR-001 rear spoiler with OE bodywork.
T1 T1 Rear Brake Rotor Size Exemption for Gen 5 Camaro #28402cars addedaddedT1 Camaro OEM 366mm rear rotor and caliper allowed without weight penalty.
STU Request to approve Honda S2000 HKS supercharger #27281otheraddedSTU Honda S2000 gains HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed options.
STU Request BoP on the Lotus #27637weight +100 lbsslower · weightSTU Lotus Elise Cup R and SC Exige SC gain 100 lbs minimum weight to 2300, 2500.
STU Turbo Inlet Restrictor On MK5 Volkswagen #27704otherslowerSTU Volkswagen GTI/GLI MK5 and Jetta Mk4 may now install turbo inlet restrictor in OEM housing, per TIR spec.
STU Honda K20C1 removal #27732engineslower · engineSTU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm.
STU Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineadded · engineSTU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs.
STU Alternate Engine for Porsche 944 #28259engineadded · engineSTU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates to original.
T1 Request 996 GT3 Trunk for Wing Allowance. #28153aeroadded · aeroT1 Porsche 996 Spec Lines: 996 Cup Replica Rear deck lid now allowed.
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.
STU Please Modify the STU Wheel Size Rule for Clarity #27694weightfaster · weightSTU vehicles over 2951 lbs base weight may use 9 inch wide wheels, changed from 2950 lbs.
STU Turbo Engine Cars Base Weight #28032wordingwordingSTU turbocharged engines now use base weight instead of minimum weight; DFI cars add 3% to base weight.
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.
AS Rear Trailing Arms #28007suspension & brakesadded · suspension & brakesAS rear trailing arms may be replaced with tubular arms maintaining stock length and axle location purpose only.
AS Weight reduction for cars running iron heads #28010weightfaster · weightAS Ford and GM full prep cars get increased weight reduction from 150 to 200 lbs.
AS 05-10 Mustang with HR cam classification #28226cars addedadded05-10 Ford Mustang Coupe GT 4.6L OHC classified AS with 3200 lbs minimum weight, HR cam permitted.
AS 10-15 Camaro Full Prep classification #28227cars addedadded10-15 Camaro Full Prep classified AS with 3400 lbs base weight, 3700 lbs over 313 CID, specific head castings and Edelbrock heads permitted.
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.
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.
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.
T1 Request alternate dashboard #27276otheraddedT1 BMW M3 E92 (08-13) carbon dash allowed with 25 lb penalty added.
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.
STU Request for an electronic throttle body #27342engineadded · engineSTU allows OEM electronic throttle bodies, manual conversion, cam changes, and manual-to-electronic conversion with same inner diameter.
2:02.938Gregory Eaton · fastest of 17 · top 5 within 0.8s
2:03.900James Jost · fastest of 16 · top 5 within 2.1s
153.9James Jost
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
+10.513squal -8.167s
108.5%qual 93.4%
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
+12.559squal +11.614s
110.1%qual 109.4%
1:59.948Kevin Boehm · fastest of 25 · top 5 within 3.5s
2:00.483Kevin Boehm · fastest of 25 · top 5 within 2.5s
143.8Kevin Boehm
-3.417squal -2.990s
97.2%qual 97.6%
49 rule changes (AS: 4, T1: 19, SM: 4, STU: 22)13 cars added · 5 weight · 4 aero · 4 engine · 4 induction · 2 suspension & brakes · 14 wording · 3 other · AS Spec Mustang (SMG) added as Restricted Prep class. · STU wing assembly wording corrected: no part may be higher than roof height. · T1-LP Chevrolet Camaro 1LE 2016+ minimum weight reduced to 3500 lbs, restrictor increased to 70mm. · AS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects. · 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. · STU Nissan SR20DET removes -2mm penalty from Table B. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird and GTO intake restrictor increases from 67 mm to 70 mm. · AS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450. · STU aftermarket side skirts now allowed if they meet 3-inch ride height, lack ducts except jacks or exhaust, don't exceed fascia width, stay below door bottom, and don't reinforce chassis. · STU wheel flare wording clarified: each fender may be flared to 2" with 1% weight penalty, maintaining OEM profile. · T2-T4 touring tires must be DOT certified with minimum U speed rating; TCS line size is maximum unless noted. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · 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. · STU Mazda 13B Bridge Port now permits ELITE ROTARY SHOP FD V2.0 intake manifold; stock throttle body requirement removed. · STU Mazda MZR gains alternate Goodwin intake manifold option with stock or Acura throttle body. · STU alternate suspension components rule moved from section E to section D. · STU Honda/Acura B20 now permits B16 or B18 VTEC cylinder head and matching intake manifold. · STU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero. · STU Honda Civic Si TCA 2017- requires 37mm TIR throttle as of June 1, 2019. · STU BMW S54B32 OEM classified separately from E46, displacement 3246 cc, minimum weight 3300 lbs, OEM engine mandatory. · 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. · Honda Civic Si 2017- added to STU with 1500cc displacement, 2800 lbs minimum weight, OEM engine and bodywork, specific HPD parts allowed. · STU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum; no Super Touring allowances, OEM intake and cams, 1mm overbore, compression +0.5 permitted. · STU Mazda 13B and 13B Bridge Port may use 13B RE or REW housings and intake with turbo removed. · STU Honda K24 may use intake part numbers 17100-RRB-A00 or 17100-PRB-A10. · STU Mazda 12A Bridge Port added, minimum weight 2550 lbs, Nikki or Auto-type carburettor with specified modifications. · STU World Challenge car weight rule deleted; no replacement specified. · STU AWD/RWD cars no longer must reduce restrictor 1 mm from table. · STU rear wing maximum 12" cord, 72 sq in end plates each, roof height max, body width limit. · T1-LP Ford Mustang GT 5.0L 2018- classified at 3400 lbs with 65mm restrictor, T2 and T3 Mustangs limited to 2015-2017. · AS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes. · 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. · STU adds Honda K20C1 Turbo I4, 1996 cc, 3025 lbs minimum weight, 36mm TIR required. · 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
AS Request to add SMG to 9.1.6.B.1 AS Intent #27140cars addedaddedAS Spec Mustang (SMG) added as Restricted Prep class.
STU Request to correct E&O advanced aerodynamics #27290wordingwordingSTU wing assembly wording corrected: no part may be higher than roof height.
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.
AS Request Ride Height Clarification #26598wordingwordingAS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects.
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.
T1 Correct years in T1 FP Corvette spec #27023wordingwordingT1 Chevrolet Corvette Cadillac XLR model year range removed from specification.
STU Remove -2mm penalty from SR20DET Nissan #26982enginefaster · engineSTU Nissan SR20DET removes -2mm penalty from Table B.
STU 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.
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.
AS Request to Revert to 2017 Weights #25885weightfaster · weightAS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450.
STU Request to clarify afterrmarket side skirts exhaust exit #26814aeroadded · aeroSTU aftermarket side skirts now allowed if they meet 3-inch ride height, lack ducts except jacks or exhaust, don't exceed fascia width, stay below door bottom, and don't reinforce chassis.
STU Wheel Flare wording #26872wordingwordingSTU wheel flare wording clarified: each fender may be flared to 2" with 1% weight penalty, maintaining OEM profile.
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.
STU Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.
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.
T1 Request Corvette aerodynamic aids #26265aeroslower · aeroT1 Corvette C5 body allowed C7 carbon aero parts, adds fifty pounds.
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.
T1 Request Ride Height Clarification #26599suspension & brakessuspension & brakesT1 minimum ride height set to 3.5 inches, measured at rocker panel without driver.
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.
STU Request to Use Japanese Mazda 13b Intake Manifold #25790engineadded · engineSTU Mazda 13B Bridge Port now permits ELITE ROTARY SHOP FD V2.0 intake manifold; stock throttle body requirement removed.
STU Request Alternate Intake for Mazda MZR In a Rear Wheel Drive App. #26352inductionadded · inductionSTU Mazda MZR gains alternate Goodwin intake manifold option with stock or Acura throttle body.
STU E&O Suspension #26424wordingwordingSTU alternate suspension components rule moved from section E to section D.
STU Revisit B20 VTEC #26530engineadded · engineSTU Honda/Acura B20 now permits B16 or B18 VTEC cylinder head and matching intake manifold.
STU Move Flared Fenders to STU Advanced Aero #26564aeroaeroSTU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero.
STU TCA Civic SI E&O #26606inductionslower · inductionSTU Honda Civic Si TCA 2017- requires 37mm TIR throttle as of June 1, 2019.
STU S54 Spec line #26620cars addedcars addedSTU BMW S54B32 OEM classified separately from E46, displacement 3246 cc, minimum weight 3300 lbs, OEM engine mandatory.
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.
SM Request to allow aftermarket fuel filters. #26370otheraddedSM fuel pump and filter now permitted as Mazda or OEM equivalent part.
STU Request to Class Assignment for 2017 Civic #24287cars addedaddedHonda Civic Si 2017- added to STU with 1500cc displacement, 2800 lbs minimum weight, OEM engine and bodywork, specific HPD parts allowed.
STU Request to run E46 3246cc in STU #25126cars addedaddedSTU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum; no Super Touring allowances, OEM intake and cams, 1mm overbore, compression +0.5 permitted.
STU Engine Classification for Rotary #25564engineadded · engineSTU Mazda 13B and 13B Bridge Port may use 13B RE or REW housings and intake with turbo removed.
STU K24/K20 Head Swap Clarification/Amendment #25899otheraddedSTU Honda K24 may use intake part numbers 17100-RRB-A00 or 17100-PRB-A10.
STU Request to Classify 12a Bridge Ported Rotary Engine #25985cars addedaddedSTU Mazda 12A Bridge Port added, minimum weight 2550 lbs, Nikki or Auto-type carburettor with specified modifications.
STU World Challenge Car Eligibility #26387wordingunclearSTU World Challenge car weight rule deleted; no replacement specified.
STU Request a phone call for discussion regarding weight #26398inductionfaster · inductionSTU AWD/RWD cars no longer must reduce restrictor 1 mm from table.
STU Advanced Aero E&O #26413aeroadded · aeroSTU rear wing maximum 12" cord, 72 sq in end plates each, roof height max, body width limit.
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.
AS SMG Mustang eligibility in American sedan #26224cars addedaddedAS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes.
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.
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.
SM Strike Tire Tread Language #26123wordingremovedSM tire tread protrusion language removed from GCR 9.1.7.C.5.
STU Request to Equalize Direct Injected Turbo Cars #24890cars addedaddedSTU adds Honda K20C1 Turbo I4, 1996 cc, 3025 lbs minimum weight, 36mm TIR required.
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.
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.
T1 Amendment to Request #25555 #25556suspension & brakessuspension & brakesT1 suspension rules clarified: spherical bearings, solid or spherical bushings, and alternate control arms now permitted.
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.
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.
T1 T1 World Challenge/Grand AM Spec Cars #25687weightslower · weightT1 Acura NSX Turbo World Challenge weight rises to 3100 lbs, restrictor shrinks to 44mm.
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.
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 AS'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.