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.
Closest to the field:AS 100.0% of AS Andy McDermid, Daytona International Speedway Runoffs 2015 race · FV 103.0% of AS Alex Scaler, Sonoma Raceway Runoffs 2018 race · GTL 99.2% of AS Troy Ermish, Sonoma Raceway Runoffs 2018 race · STL 99.5% of AS Danny Steyn, Sonoma Raceway Runoffs 2018 race
ASFVGTLSTLsolid race · dashed qualifying · slower is lower
ASFVGTLSTLsolid 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%)
2:46.536Zachary Whitston · fastest of 37 · top 5 within 1.7s+2.435s (+1.48%)
2:45.272Brian Farnham · fastest of 34 · top 5 within 1.3s-1.464s (-0.88%)
117.4Rick Shields+0.2 mph (+0.1%)
+16.801squal +19.625s
111.3%qual 113.4%
2:30.537Derek Ketchie · fastest of 16 · top 5 within 2.9s-1.528s (-1.00%)
2:30.657Danny Steyn · fastest of 16 · top 5 within 0.6s-1.470s (-0.97%)
134.8Mike Taylor+2.6 mph (+2.0%)
+2.186squal +3.626s
101.5%qual 102.5%
18 rule changes (AS: 13, GTL: 1, STL: 4)5 cars added · 3 weight · 2 engine · 1 induction · 1 suspension & brakes · 1 tyres & wheels · 3 wording · 2 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. · 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. · STL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019). · AS GM LM7 5.3L must use full prep Holley carburetor as described in 9.1.6.D.c.1, not specifically 4776. · STL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. · 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. · STL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs. · AS Spec Lines reorganized for 2026; detailed chassis, engine, weight, wheelbase, tire and brake specifications moved to main rules and engine build sheets. · GT3U class removed from GCR; GT3U cars now compete in STU. · AS GM LM7 5.3L gains Edelbrock 71187 intake manifold, MSD 6014 ignition box, Holly 4776 carb option under full prep spec line. · AS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm. · STL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs. · AS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft. · AS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs.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 & wheelsaddedtyres & wheelsAS class adds Pirelli P Zero Trofeo Track as permitted tyre option for competition.
AS Change in 9.1.6.D.4.d.5 in Suspension Mounting Points #40094suspension & brakesfastersuspension & 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 #40532weightslowerweightAS Ford Mustang Coupe GT 05-14 Gen3 Coyote minimum weight increases from 3100 to 3400 lbs.
STL Spec Line Clean Up #40344cars addedremovedcars addedSTL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019).
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.
STL Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied.
AS Header Information Update for EFI Engine Build Sheets #39886engineaddedengineAS 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.
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.
GTL Remove GT3U from GCR as it is now in STU #39862cars addedremovedcars addedGT3U class removed from GCR; GT3U cars now compete in STU.
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.
AS Restrictor Plate Change for Gen 2 Ford Coyote Engine #39501inductionslowerinductionAS Ford Mustang and Mercury Capri with Restricted Prep engines get 61 mm restrictor, down from 64 mm.
STL Weight adjustment for STL #39579weightslowerweightSTL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.
AS 1994 Mustang Spec Line Request #39104engineaddedengineAS Ford Mustang GT 94-04 Restricted Prep Engine now permits Ford Motorsport M-6250-F303 camshaft.
AS Cadillac CTS-V BOP Weight Change #38640weight -50 lbsfasterweightAS Cadillac CTS-V 04-07 Restricted Prep minimum weight drops to 3400 lbs.
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%)
2:44.101Andrew Abbott · fastest of 34 · top 5 within 1.3s+1.458s (+0.90%)
2:46.736Zachary Whitston · fastest of 29 · top 5 within 0.6s+1.902s (+1.15%)
117.2Zachary Whitston+0.7 mph (+0.6%)
+17.504squal +17.309s
111.7%qual 111.8%
2:32.065Jose Osiris Pena · fastest of 14 · top 5 within 3.4s+2.002s (+1.33%)
2:32.127Jose Osiris Pena · fastest of 13 · top 5 within 2.4s+1.882s (+1.25%)
132.2Jon Sewell-2.1 mph (-1.5%)
+2.895squal +5.273s
101.9%qual 103.6%
17 rule changes (AS: 11, GTL: 3, STL: 3)5 engine · 2 cars added · 2 weight · 1 induction · 5 wording · 2 other · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · AS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs. · 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. · 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. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed. · 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. · AS removes 'Any ECM maybe used' note from five Cadillac and Chevrolet/Pontiac V8 Restricted Prep models. · 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. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof height limit. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · GTL Toyota G16E-GTS removes direct injection prohibition, allowing direct injection engines. · GTL L16 limited prep gains 32mm choke option at 1910 lbs, compression capped 12.0:1, valve lift .450 max.showhide
STL Lotus Weight Reduction #38772weight -50 lbsfasterweightLotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs.
AS RE: Previous Letter 37695 Update #38245weight -75 lbsfasterweightAS Ford Mustang GT 5.0 2018- minimum weight reduced to 3525 lbs.
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.
AS Errors and Omission #38055inductionslowerinductionAS 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.
STL E&O: SMX Allowance in STL #37945wordingunclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed.
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.
AS Increase Coyote Engine Restrictor to 80mm #36177enginefasterengineAS Ford Mustang and Cobra Coyote engine restrictor increases to 80mm from 67mm or 64mm.
AS Performance Pack for 2015+ Mustang #36867enginefasterengineAS 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 #37208engineaddedengineAS LS-engine cars gain ECU freedom: CTS-V, Camaro, Firebird (70–02) and Camaro SS may use any ECM.
GTL Correct language regarding OEM Areo Devices #37137wordingwordingTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof height limit.
STL Request to Remove Miata Hubs from General category #37138cars addedaddedSTL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved.
GTL G16E-GTS Fuel Injection Spec Line Change #36588engineaddedengineGTL Toyota G16E-GTS removes direct injection prohibition, allowing direct injection engines.
GTL GTL Alternate Weight and Choke Option for L16 engine #36653engineaddedengineGTL L16 limited prep gains 32mm choke option at 1910 lbs, compression capped 12.0:1, valve lift .450 max.
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%)
2:42.643Andrew Whitston · fastest of 27 · top 5 within 2.3s-1.351s (-0.82%)
2:44.834Andrew Abbott · fastest of 27 · top 5 within 0.9s-0.982s (-0.59%)
116.5Brian Farnham-0.7 mph (-0.6%)
+18.405squal +16.065s
112.6%qual 111.0%
2:30.858Peter Shadowen · fastest of 14 · top 5 within 4.4s-1.085s (-0.71%)
2:30.844Chris Bovis · fastest of 13 · top 5 within 3.7s-0.757s (-0.50%)
133.3Peter Shadowen+1.8 mph (+1.4%)
+4.415squal +4.280s
103.0%qual 102.9%
2:30.063Joe Moser · fastest of 18 · top 5 within 3.7s-1.357s (-0.90%)
2:30.245Joe Moser · fastest of 16 · top 5 within 4.2s-1.870s (-1.23%)
134.3Joe Moser+1.3 mph (+1.0%)
+3.816squal +3.485s
102.6%qual 102.4%
33 rule changes (AS: 11, FV: 2, GTL: 16, STL: 4)10 cars added · 6 engine · 4 weight · 2 aero · 1 induction · 1 tyres & wheels · 4 wording · 5 other · FV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side. · AS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options. · GTL adds Toyota GR86 2021–2023, 2dr RWD, 101.3 in wheelbase. · GTL adds Spec Miata 1990–2005 with legal Spec Miata engine and intake system. · GTL adds Mazda MX5 RF 2017- model with 91.0 in wheelbase. · GTL added to GT3 choke option line in GCR 9.1.2.E.13.n. · 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. · GT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR. · GTL Datsun 510 Limited Prep fuel induction increased to 34 mm chokes, minimum weight rises to 2000 lbs. · 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. · 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… · GT1-GTX rear blade spoiler: angle 50–75°, max 59.0 wide by 5.0 high inches; total area limit removed. · GT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment. · GT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. · STL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm. · STL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled. · GTL 12A rotary engines may machine and use 13B housing to O.E. 12A spec across all port types. · GTL Toyota DR86 2021–2024 added to class. · GTL BMW Mini model years changed to 2002-2013. · STL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki. · FV front wheel bearings wording clarified; specification unchanged. · GTL small unrestricted engines under 1399cc lose 38–79 lbs across Alfa, AMC, Triumph, Mini, Sprite, Fiat, Ford, Honda, Mazda, Nissan, Subaru, Toyota, Volkswagen. · GTL Honda Fit 2009-13 2-door FWD added with 99.0 in wheelbase, alternate 94.0 and 97.0 in. · GTL spec lines moved contiguous with GT2 and GT3; GTA category and specs renumbered behind GTL; P2 engine tables reorganised with restrictor and weight specifications clarified. · GTL Nissan Sentra/200SX A 1400 minimum weight reduced to 1800 lbs.showhide
FV Disc Brakes #36822wordingwordingFV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side.
AS Mustang transmission ratios #36662otheraddedAS Mustang GT 05-14 Restricted Prep and 2018- gain alternate transmission ratio options.
GTL Request to Include Toyota GR86 in GTL #36324cars addedaddedGTL adds Toyota GR86 2021–2023, 2dr RWD, 101.3 in wheelbase.
GTL Inclusion of Modified Spec Miata for GTL competition #36325cars addedaddedGTL adds Spec Miata 1990–2005 with legal Spec Miata engine and intake system.
GTL Include Mazda MX5 RF 2017- in GTL #36428cars addedaddedGTL adds Mazda MX5 RF 2017- model with 91.0 in wheelbase.
GTL Add GTL to GT3 choke option line. #36236otheraddedGTL added to GT3 choke option line in GCR 9.1.2.E.13.n.
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 #35891engineaddedengineAS Chevrolet Camaro, Firebird, and Ford Mustang now permit Flo Tek cylinder heads in multiple generations.
GTL Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerweightGT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR.
GTL Allow 34 mm chokes for the Datsun 510 #35661induction +50 lbsfasterinductionGTL Datsun 510 Limited Prep fuel induction increased to 34 mm chokes, minimum weight rises to 2000 lbs.
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 & wheelsfastertyres & 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…
GTL Rear Blade Spoiler Clarification #35261aeroaeroGT1-GTX rear blade spoiler: angle 50–75°, max 59.0 wide by 5.0 high inches; total area limit removed.
GTL GT Direct Injection allowance and rules #35437engineaddedengineGT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment.
GTL GT2/3 remove Direction Injection not allowed in Spec line notes #35439engineaddedengineGT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E.
STL ST Electric-Assisted Steering Systems #35066aeroaddedaeroSTL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems.
STL BOP Adjustments #35112weightfasterweightSTL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm.
STL Mazda 12A #35320engineremovedengineSTL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled.
GTL Rotary Engine 12A Rotor Housings #35131engineaddedengineGTL 12A rotary engines may machine and use 13B housing to O.E. 12A spec across all port types.
GTL Request to Include Toyota GR86 in GTL #35198cars addedaddedGTL Toyota DR86 2021–2024 added to class.
GTL Errors and Omissions, GTL engines & Cars #35226wordingwordingGTL BMW Mini model years changed to 2002-2013.
STL Alternate Carburetor Request for 79-85 RX7 12a #35181engineaddedengineSTL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki.
GTL Small Engines in GT Lite #34842weightfasterweightGTL small unrestricted engines under 1399cc lose 38–79 lbs across Alfa, AMC, Triumph, Mini, Sprite, Fiat, Ford, Honda, Mazda, Nissan, Subaru, Toyota, Volkswagen.
GTL Request to Classify Honda Fit body in GTL #35020cars addedaddedGTL Honda Fit 2009-13 2-door FWD added with 99.0 in wheelbase, alternate 94.0 and 97.0 in.
GTL Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingwordingGTL spec lines moved contiguous with GT2 and GT3; GTA category and specs renumbered behind GTL; P2 engine tables reorganised with restrictor and weight specifications clarified.
GTL Weight for Nissan Sentra/200SX A 1400's #34918weight -50 lbsfasterweightGTL Nissan Sentra/200SX A 1400 minimum weight reduced to 1800 lbs.
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%)
2:15.639Andrew Whitston · fastest of 27 · top 5 within 1.4s+0.523s (+0.39%)
2:16.611Andrew Abbott · fastest of 23 · top 5 within 1.6s-1.482s (-1.07%)
115.6Brian Farnham-0.2 mph (-0.2%)
+12.491squal +12.557s
110.1%qual 110.2%
2:09.564Peter Shadowen · fastest of 11 · top 5 within 4.9s+1.775s (+1.39%)
2:11.277Graham Fuller · fastest of 10 · top 5 within 2.4s-9.903s (-7.01%)
142.7Peter Shadowen+6.7 mph (+4.9%)
+7.157squal +6.482s
105.8%qual 105.3%
2:05.779Danny Steyn · fastest of 22 · top 5 within 3.4s+0.305s (+0.24%)
2:06.682Joe Moser · fastest of 20 · top 5 within 1.5s-1.150s (-0.90%)
131.8Danny Steyn+0.1 mph (+0.1%)
+2.562squal +2.697s
102.1%qual 102.2%
13 rule changes (AS: 4, GTL: 7, STL: 2)5 cars added · 1 engine · 1 tyres & wheels · 1 weight · 4 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. · STL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2. · Fields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection. · GTL 3K, 4K, 5K Toyota engines may now use 4Y block only. · GT2 and GTL add Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines as permitted options. · Spec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules. · GTL Fiat X1/9 1500 Limited Prep minimum weight increases to 2000 lbs from 1835 lbs. · GT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870. · GTL adds Ford Festiva 1988-1993 FWD hatchback with Mazda B3 1324cc engine. · GTL adds Toyota G16E-GTS 1618cc DOHC 3-cyl engine, 1945 lbs, SIR, no turbo or direct injection.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 & wheelsfastertyres & 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.
STL Clarify STL table B - IT spec notes on Tires #34187wordingwordingSTL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2.
GTL Please classify Fields Cardinal V8 #33784cars addedaddedFields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection.
GTL Toyota 4Y Engine Classification Request #33562engineaddedengineGTL 3K, 4K, 5K Toyota engines may now use 4Y block only.
GTL Toyota 4A-F and 4A-FE 1.6L DOHC 16V Engine Request #33415cars addedaddedGT2 and GTL add Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines as permitted options.
STL Spec MX5 in STL #33473cars addedaddedSpec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules.
GTL Fiat HP Limited Prep X1/9 Weight in GTL #33297weightslowerweightGTL Fiat X1/9 1500 Limited Prep minimum weight increases to 2000 lbs from 1835 lbs.
GTL GT2 (TA2)/GTA Part Number Update #33315wordingwordingGT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870.
GTL Request to add Ford Festiva to GTL #33335cars addedaddedGTL adds Ford Festiva 1988-1993 FWD hatchback with Mazda B3 1324cc engine.
GTL Engine Request #33064cars addedaddedGTL adds Toyota G16E-GTS 1618cc DOHC 3-cyl engine, 1945 lbs, SIR, no turbo or direct injection.
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%)
2:15.116Brian Farnham · fastest of 29 · top 5 within 1.1s-0.596s (-0.44%)
2:18.093Andrew Whitston · fastest of 28 · top 5 within 1.2s-0.196s (-0.14%)
115.8Jonathan Weisheit+1.1 mph (+0.9%)
+13.515squal +12.954s
110.8%qual 110.6%
2:07.789Peter Shadowen · fastest of 14 · top 5 within 2.2s+0.792s (+0.62%)
2:21.180Michael Lewis · fastest of 13 · top 5 within 2.1s+13.343s (+10.44%)
136.0Peter Shadowen+4.9 mph (+3.7%)
+16.602squal +5.627s
113.3%qual 104.6%
2:05.474Danny Steyn · fastest of 24 · top 5 within 2.3s-1.729s (-1.36%)
2:07.832Danny Steyn · fastest of 22 · top 5 within 1.9s+0.559s (+0.44%)
131.7Trever Degioanni-3.2 mph (-2.3%)
+3.254squal +3.312s
102.6%qual 102.7%
21 rule changes (AS: 9, FV: 4, GTL: 3, STL: 5)4 cars added · 4 engine · 3 weight · 2 tyres & wheels · 7 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. · GT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps. · AS Cadillac CTS-V 6.0L V8 Restricted Prep removes 295 tire size 50 lb penalty. · FV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077. · FV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs. · Ginetta G40 added to GTL with Ford Zetec 1796cc engine, 2050 lbs minimum weight, 22.5mm SIR. · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · 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. · FV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · STL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. · STL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb. · FV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight. · 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. · GT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight.showhide
AS Request to add Hoosier W2 #33031tyres & wheelsaddedtyres & 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.
GTL Tail lights on all GT category race cars. #32799wordingwordingGT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps.
FV Connecting Rod Update Request for 9.1.1.C Formula Vee (FV) 5.C.6 #32160engineaddedengineFV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077.
FV E&O clarification of connecting rod center-to-center length #32183wordingwordingFV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs.
GTL Request to Classify Ginetta G40 in GTL #31599cars addedaddedGinetta G40 added to GTL with Ford Zetec 1796cc engine, 2050 lbs minimum weight, 22.5mm SIR.
STL Single TB Weight Modifiers #31449weightfasterweightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs.
STL Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels.
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 addedremovedcars 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 #31851engineaddedengineAS Camaro, Firebird, Mustang full prep engines: alternate GM and Ford Performance cylinder heads permitted regionally with Allstar restrictor ALL26180.
FV Update direct replacement connecting rod information #31843wordingwordingFV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight.
STL Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed.
STL Mazda Renesis Restriction #31467enginefasterengineSTL Mazda Renesis flat plate restrictor increases from 55mm to 60mm.
STL Clarification of 79-85 RX7 Spec line #31621wordingwordingSTL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb.
FV Formula V Connecting Rod Replacement #31448engineaddedengineFV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight.
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 #30881weightslowerweightAS Pontiac GTO 04-06 Restricted Prep minimum weight rises: LS1 to 3300 lbs, LS2 to 3350 lbs on 295 tires.
GTL Request car classification #31032cars addedaddedGT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight.
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
1:57.479Andrew Whitston · fastest of 48 · top 5 within 0.8s+1.720s (+1.49%)
1:57.234Alex Scaler · fastest of 47 · top 5 within 1.0s+1.311s (+1.13%)
124.0Mark Edwards
+6.628squal +7.052s
106.0%qual 106.4%
1:51.819Christopher Bovis · fastest of 22 · top 5 within 1.8s+1.488s (+1.35%)
1:51.952Scott Twomey · fastest of 19 · top 5 within 1.7s-0.116s (-0.10%)
129.5Brian Linn
+1.346squal +1.392s
101.2%qual 101.3%
1:51.665Danny Steyn · fastest of 42 · top 5 within 1.7s-0.982s (-0.87%)
2:02.711Joe Moser · fastest of 37 · top 5 within 3.2s+10.122s (+8.99%)
131.8Max Gee
+12.105squal +1.238s
110.9%qual 101.1%
37 rule changes (AS: 14, GTL: 8, STL: 15)10 cars added · 5 engine · 5 weight · 3 aero · 3 induction · 1 suspension & brakes · 6 wording · 4 other · STL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix. · GTL Honda B18 split into B18A/B at 1797 cc 2050 lbs and B18C at 1834 cc 2065 lbs. · GTL Nissan B13 Sentra may have hood bulge maximum 1.5 inches high by 10.0 long by 6.0 wide. · unclear · 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. · STL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. · STL Pontiac Solstice/Saturn Sky allowed 4 inch ride height. · STL Mazda B5 DOHC added to class; must meet all STL regulations. · STL Honda B16A (JDM) restrictor reduced from 54mm to 53mm. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · 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. · GTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs, 28mm SIR option with 175 lb penalty removed. · STL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · GTL adds FIAT X-1/9 Bertone 1500 SOHC, 1498 cc, 2000 lbs, fuel injection or carburetors permitted. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork. · STL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment. · 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. · GTL Nissan MRA8DE 1.8L engine added, 1797 cc, DOHC, 2050 lbs minimum weight. · GTL Mazda 13B SIR increases from 26 mm to 28 mm; 27 mm option with 175 lbs removed. · STL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity. · STL Honda F20C drops 2% weight penalty, minimum weight reduced. · STL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm. · 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.showhide
STL Request to clean up Spec MX-5 Redundancy #31069wordingwordingSTL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations.
GTL Request to Update GTA Obsolete Part Numbers #30615wordingwordingGTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix.
GTL Request clarification for the Honda B18a,bVS B18c #30482cars addedaddedGTL Honda B18 split into B18A/B at 1797 cc 2050 lbs and B18C at 1834 cc 2065 lbs.
GTL Request to Allow Hood Bulge on Nissan B13 Sentra #30504aeroaddedaeroGTL Nissan B13 Sentra may have hood bulge maximum 1.5 inches high by 10.0 long by 6.0 wide.
GTL Request BMW E21 Classing #30582otherunclearunclear
AS Request CTS-V Spec Line Error Correction #30242weightfasterweightAS 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 #30595enginefasterengineAS 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 lbsslowerweightAS Camaro, Firebird, Mustang, and Capri all gain 50 lbs minimum weight across seven model year variants.
STL VW Engine Request #30625engineaddedengineSTL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs.
STL Request Mazda B5 DOHC #30420cars addedaddedSTL Mazda B5 DOHC added to class; must meet all STL regulations.
STL Honda B16A (JDM) Restrictor change #30531engineslowerengineSTL Honda B16A (JDM) restrictor reduced from 54mm to 53mm.
STL ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingwordingST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section.
AS AS Mustang LP 4.6 3V Classification Transmission Request #29886enginefasterengineAS 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.
GTL Request for Help for Mazda 12A #29754induction +50 lbsslowerinductionGTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs, 28mm SIR option with 175 lb penalty removed.
STL GM Ecotec engines in STL #30247engineaddedengineSTL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor.
STL Super Touring Alternate Miata Hubs #30345cars addedaddedST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1.
GTL Request LP HP Fiat X1/9 & Bertone 1500 to GTL #30058cars addedaddedGTL adds FIAT X-1/9 Bertone 1500 SOHC, 1498 cc, 2000 lbs, fuel injection or carburetors permitted.
STL Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment.
STL Super Touring Wing Clarification #30111aeroaeroSTL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork.
STL Transmission Options #30118otheraddedSTL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment.
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 #29759weightfasterweightAS 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.
STL Request for FWD and RWD Parity #30023inductionslowerinductionSTL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm.
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.
STL Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
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
2:43.994Hunter Phelps-Barron · fastest of 28 · top 5 within 0.6s
2:45.816Alex Scaler · fastest of 24 · top 5 within 1.5s
117.1Hunter Phelps-Barron
+18.148squal +16.949s
112.3%qual 111.5%
2:31.943Chris Bovis · fastest of 14 · top 5 within 6.3s
2:31.601Peter Shadowen · fastest of 14 · top 5 within 7.2s
131.4Peter Shadowen
+3.933squal +4.898s
102.7%qual 103.3%
2:31.420Danny Steyn · fastest of 33 · top 5 within 3.1s
2:32.115Joe Moser · fastest of 30 · top 5 within 1.5s
132.9Darin Treakle
+4.447squal +4.375s
103.0%qual 103.0%
50 rule changes (AS: 16, FV: 6, GTL: 17, STL: 11)10 cars added · 7 engine · 5 aero · 5 tyres & wheels · 3 weight · 2 suspension & brakes · 1 induction · 15 wording · 2 other · GT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line. · 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. · GTL Mazda 13B restrictor increases from 24mm to 26mm SIR, minimum weight rises to 2125 lbs, alternative 27mm SIR option adds 175 lbs. · 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. · 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 · FV now permits 4 bolt wheels in addition to existing specifications. · FV now allows 4-bolt pattern wheels in addition to existing specifications. · GTL: Toyota MR2 Spyder 1999–2007 newly classified for GTL competition. · TA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications. · STO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change. · GT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b. · GTL Mazda 13B restrictor size addressed in response to letter 28518; see that letter for details. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · GTL SIR stall test procedure clarified: system tested as raced, competitor must prevent air bypass behind restrictor. · STL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum. · STL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC. · STL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants. · GTL wing mount openings excluded from square inch area limit. · STL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STL Mazda MZR restrictor reduced from 54 mm to 53 mm. · STL Mazda MZR restrictor reduces from 55 mm to 53 mm. · FV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. · GTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side view. · GTL wing mounting posts limited to 85 square inches each, measured flat from side view. · GTL wing endplates maximum area increased to 64 square inches from 8.5 by 3.0 inches rectangle. · GTL Mazda 12A street port minimum weight drops to 1950 lbs. · STL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes. · 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. · GT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications. · FV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020. · Formula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020. · GTX Misc. adds Factory Five Type 65 Coupe R Ford 302/351 and 5.0/5.2L NA at 2600 lbs, plus Ferrari 458/488 Challenge, Ford FP350S, Chevrolet C6, Lamborghini Super Trofeo. · GTL adds Jetta Mk1 two-door classification effective 2020-01-01. · FV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits. · GTL Honda CRX 84-87 and 88-91 lose permission to use IRS with 2.5% weight penalty.showhide
GTL GT Category Wording #29193wordingaddedGT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line.
AS Dodge Challenger AS Spec Line Clarification #28698engineslowerengineAS 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.
GTL Request to change the Mazda 13b restrictor size #28518induction +175 lbsfasterinductionGTL Mazda 13B restrictor increases from 24mm to 26mm SIR, minimum weight rises to 2125 lbs, alternative 27mm SIR option adds 175 lbs.
STL Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds.
STL ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules.
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 #27908engineaddedengineAS Restricted Prep 4.6 3V now permits conversion to 2 valve configuration.
AS Request for 2005-2009 Restricted Prep 4.6 3V Parts #27909engineaddedengineAS 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
FV Support for Recommended Item - 4 bolt wheels in FV #29084cars addedaddedFV now permits 4 bolt wheels in addition to existing specifications.
FV Support for 4-bolt pattern wheels #28955 #29118tyres & wheelsaddedtyres & wheelsFV now allows 4-bolt pattern wheels in addition to existing specifications.
GTL Request to classify 1999-2007 Toyota MR2 Spyder body #28870cars addedaddedGTL: Toyota MR2 Spyder 1999–2007 newly classified for GTL competition.
GTL TA2 Gurney flap wicker clarification #28874wordingwordingTA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications.
GTL STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change.
GTL GT Gurney flap wicker clarification #28909wordingwordingGT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b.
GTL Mazda 13b Restrictor Size Follow up to Letter 28518 #29015wordingunclearGTL Mazda 13B restrictor size addressed in response to letter 28518; see that letter for details.
STL Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
GTL Stall Test #28709wordingwordingGTL SIR stall test procedure clarified: system tested as raced, competitor must prevent air bypass behind restrictor.
STL Request to add 2016-2019 GMX-5 Spec line #28604cars addedaddedSTL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum.
STL Request to update PN for MX-5 #28622cars addedaddedSTL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC.
STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873wordingwordingSTL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants.
AS weight adjustments for 2020 season #28785weight -50 lbs
GTL GTL Wing Rule #28754aeroaddedaeroGTL wing mount openings excluded from square inch area limit.
STL STL Honda B18 restrictor changes #28794enginefasterengineSTL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants.
STL Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineaddedengineSTU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs.
STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663engineslowerengineSTL Mazda MZR restrictor reduced from 54 mm to 53 mm.
STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664engineslowerengineSTL Mazda MZR restrictor reduces from 55 mm to 53 mm.
FV Update rain tire designation #28444tyres & wheelstyres & wheelsFV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3.
GTL Wing Mounting Upright Size #27641aeroaeroGTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side view.
GTL Wing Mounting Upright Size #27641aeroaeroGTL wing mounting posts limited to 85 square inches each, measured flat from side view.
GTL GTL wing end plates addition #28243aerofasteraeroGTL wing endplates maximum area increased to 64 square inches from 8.5 by 3.0 inches rectangle.
GTL Clarification to letter #27406 #28309weight -50 lbsfasterweightGTL Mazda 12A street port minimum weight drops to 1950 lbs.
STL Request to add wheel part numbers #28342cars addedaddedSTL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes.
AS Rear Trailing Arms #28007suspension & brakesaddedsuspension & 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 #28010weightfasterweightAS 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.
GTL Windshield Clips #27323otheraddedGT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications.
FV FV Allow non-spec tire in Regional competition #26284tyres & wheelsaddedtyres & wheelsFV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020.
FV Request to Allow Rear Tires on the Front of Formula Vee #26537tyres & wheelsaddedtyres & wheelsFormula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020.
GTL Request Factory Five Daytona coupe classification #26308cars addedaddedGTX Misc. adds Factory Five Type 65 Coupe R Ford 302/351 and 5.0/5.2L NA at 2600 lbs, plus Ferrari 458/488 Challenge, Ford FP350S, Chevrolet C6, Lamborghini Super Trofeo.
GTL Request to Classify the MK1 two door Jetta #27648cars addedaddedGTL adds Jetta Mk1 two-door classification effective 2020-01-01.
FV Clarification on Wheel Bolt Pattern #27603tyres & wheelsaddedtyres & wheelsFV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.
GTL 88-91 Honda CRX Spec Line Correction #27233suspension & brakesremovedsuspension & brakesGTL Honda CRX 84-87 and 88-91 lose permission to use IRS with 2.5% weight penalty.
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
2:15.712Andrew Whitston · fastest of 26 · top 5 within 1.5s
2:18.289Zachary Whitston · fastest of 19 · top 5 within 0.4s
114.8Roger Siebenaler
+14.389squal +12.774s
111.6%qual 110.4%
2:06.997Peter Shadowen · fastest of 19 · top 5 within 4.0s
2:07.837Bill Ball · fastest of 18 · top 5 within 4.2s
131.1Peter Shadowen
+3.937squal +4.059s
103.2%qual 103.3%
2:07.203Danny Steyn · fastest of 36 · top 5 within 1.8s
2:07.273Cliff Ira · fastest of 35 · top 5 within 1.4s
134.8Cliff Ira
+3.373squal +4.265s
102.7%qual 103.5%
34 rule changes (AS: 4, FV: 6, GTL: 13, STL: 11)9 cars added · 5 engine · 4 weight · 1 induction · 1 removed · 1 suspension & brakes · 1 tyres & wheels · 9 wording · 3 other · AS Spec Mustang (SMG) added as Restricted Prep class. · FV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body. · STL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components. · FV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions. · GTL Fun Cup Beetle engine weight set to 1850 lbs with Weber DMTL 32/34 induction. · AS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects. · GTL Fun Cup Beetle removes reference to VW engine table; Fun Cup engines only permitted. · GTL Honda CRZ 10-14, CRZ 15-16, and Insight 00-06 gain alternate wheelbase option of 90.6 inches. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · AS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450. · FV exhaust outlet opening max distance from body rear increased from 3 to 4 inches. · STL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. · FV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed. · GTL Fun Cup Beetle added, all model years, 2-door RWD, 94.5 in wheelbase, VW Fun Cup spec chassis. · GTX tube frame cars now allowed fuel injection with maximum 90mm throttle body. · GTX adds Ligier JS2 R classification with restrictor and minimum weight. · GTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · FV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed. · GT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate. · GTL Mazda 12A may use 28mm SIR plus 175 lbs. · GTL: Ford Mustang 94-04 body newly classified for GTL racing. · STL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only. · STL Mazda Renesis minimum weight reduced to 2700 lbs. · STL Mazda MX-5 Cup brake pad compound now open. · STL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited. · STL Mazda 12 and 13B now permit port matching; porting ban removed. · AS adds Spec Mustang SMG classification with 107.1 wheelbase, 3.73 gears, 355mm front and 300mm rear brakes. · FV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text. · GTL Mini 1275–1399 Iron and Aluminum Crossflow with OE common sump gearbox reduce weight by 125 lbs, up from 50 lbs. · GTL BMC thru Rover Group removes four long inactive Mini engines: 948, 970, 1071, 1098. · GTX FIA GT3: Audi R8 now 40 mm restrictor and 2900 lbs; BMW Z4 now 70 mm restrictor and 2800 lbs; Ferrari 488 now 35 mm restrictor, TIR, and 3025 lbs. · STL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline. · STL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.showhide
AS Request to add SMG to 9.1.6.B.1 AS Intent #27140cars addedaddedAS Spec Mustang (SMG) added as Restricted Prep class.
FV Allowed Modifications E&O #27398wordingwordingFV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body.
STL Request to Classify Spec MX-5 Challenge in STL #27399cars addedaddedSTL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components.
FV E&O Wheels #27230tyres & wheelsaddedtyres & wheelsFV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions.
GTL Fun Cup Beetle #27334wordingwordingGTL Fun Cup Beetle engine weight set to 1850 lbs with Weber DMTL 32/34 induction.
AS Request Ride Height Clarification #26598wordingwordingAS class ride height minimum clarified: five inches measured at rocker panel, excluding seams and stock effects.
GTL GTL #26960wordingwordingGTL Fun Cup Beetle removes reference to VW engine table; Fun Cup engines only permitted.
GTL Request CRZ wheelbase change #26896cars addedaddedGTL Honda CRZ 10-14, CRZ 15-16, and Insight 00-06 gain alternate wheelbase option of 90.6 inches.
STL Request clarification for manifold and throttle in STU #27004wordingwordingSTU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required.
AS Request to Revert to 2017 Weights #25885weightfasterweightAS Ford Mustang 79-93 non-Cobra drops 100 lbs to 3150; over 313 CID Cobra drops 100 lbs to 3450.
FV Exhaust termination rule E&O #26702wordingwordingFV exhaust outlet opening max distance from body rear increased from 3 to 4 inches.
STL Request Restrictor Plate correction #26779enginefasterengineSTL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate.
FV E&O Dimensions #26674suspension & brakessuspension & brakesFV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed.
GTL Request to Classify VW Fun Cup Beetle #25986cars addedaddedGTL Fun Cup Beetle added, all model years, 2-door RWD, 94.5 in wheelbase, VW Fun Cup spec chassis.
GTL Request GTX Fuel injection for previous GT-1 tube frame cars #26141engineaddedengineGTX tube frame cars now allowed fuel injection with maximum 90mm throttle body.
GTL Request to Classify Ligier JS2 R #26535cars addedaddedGTX adds Ligier JS2 R classification with restrictor and minimum weight.
GTL Request for GTL Mazda 13B SIR Increase with Penalty #26572engineaddedengineGTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added.
STL Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.
FV Request to clarify Disc Brake rules bearing retainer & weights #26262weightslowerweightFV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed.
GTL Request Ride Height Clarification #26600wordingfasterGT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate.
GTL Request Mazda 12a Rotary SIR Increase #26081inductionaddedinductionGTL Mazda 12A may use 28mm SIR plus 175 lbs.
GTL Request to Classify Mustang 2 Body in GTL #26222cars addedaddedGTL: Ford Mustang 94-04 body newly classified for GTL racing.
STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbsfasterweightSTL Mazda Renesis minimum weight reduced to 2700 lbs.
STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821otheraddedSTL Mazda MX-5 Cup brake pad compound now open.
STL Request to clarify B18C1 GSR Honda B motor table #26209cars addedaddedSTL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited.
STL Port Matching #26415enginefasterengineSTL Mazda 12 and 13B now permit port matching; porting ban removed.
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.
FV FV Intake Manifold Clarification #26008wordingwordingFV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text.
GTL Request for GTL Mini Adjustments #25754weightfasterweightGTL Mini 1275–1399 Iron and Aluminum Crossflow with OE common sump gearbox reduce weight by 125 lbs, up from 50 lbs.
GTL BMC thru Rover Group remove long inactive mini #25771removedremovedGTL BMC thru Rover Group removes four long inactive Mini engines: 948, 970, 1071, 1098.
GTL GTX Homologation table update #26034otherunclearGTX FIA GT3: Audi R8 now 40 mm restrictor and 2900 lbs; BMW Z4 now 70 mm restrictor and 2800 lbs; Ferrari 488 now 35 mm restrictor, TIR, and 3025 lbs.
STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746enginefasterengineSTL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline.
STL Request E&O for Mazda Miata Spec Line #25955otherunclearSTL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.
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 and the day cancel out, so one figure compares across years where lap times cannot; a class that suits one track more than another still reads differently there. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.