FF vs FA vs GT2 vs T2 pace at Buttonwillow Raceway Park
Quickest here:FF 1:51.118 Eric Poulsen, Cal Club 2025 race · FA 1:14.588 Greg Labadie, Cal Club 2023 qualifying · GT2 1:42.698 Tim Carroll, Cal Club 2026 qualifying · T2 1:51.198 Rylan Hazelton, Cal Club 2026 qualifying
FFFAGT2T2solid race · dashed qualifying · slower is lower
FFFAGT2T2solid race · dashed qualifying · each class's best lap as a share of FF's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
FF
FA
GT2
T2
Qual best
Race best
Trap
Qual best
Race best
Trap
vs FF
% of FF
Qual best
Race best
Trap
vs FF
% of FF
Qual best
Race best
Trap
vs FF
% of FF
Cal Club 2026 CALCL262026-02-21
1:53.098Edward Erlandson · fastest of 2+1.054s (+0.94%)
1:54.741Edward Erlandson · fastest of 2+3.623s (+3.26%)
133.7Edward Erlandson+19.0 mph (+16.5%)
1:35.792Greg Labadie · only car-3.750s (-3.77%)
1:37.275Greg Labadie · only car-2.623s (-2.63%)
163.8Greg Labadie+36.4 mph (+28.6%)
-17.466squal -17.306s
84.8%qual 84.7%
1:42.698Tim Carroll · fastest of 8 · top 5 within 7.4s-3.120s (-2.95%)
1:44.128Tim Carroll · fastest of 8 · top 5 within 4.3s-2.798s (-2.62%)
155.7Rocky Crocker+37.8 mph (+32.1%)
-10.613squal -10.400s
90.8%qual 90.8%
1:51.198Rylan Hazelton · fastest of 10 · top 5 within 2.5s-2.867s (-2.51%)
1:51.454Rylan Hazelton · fastest of 10 · top 5 within 3.0s-1.304s (-1.16%)
146.6Patrick Howe+32.2 mph (+28.1%)
-3.287squal -1.900s
97.1%qual 98.3%
45 rule changes (FF: 3, FA: 7, GT2: 8, T2: 27)8 cars added · 6 induction · 5 engine · 5 weight · 4 suspension & brakes · 4 tyres & wheels · 3 aero · 9 wording · 1 other · FA Pro Mazda: lower intake manifold now unrestricted, throttle body raised to 80mm, wing height must not exceed 99cm, bodywork width must not exceed 132cm. · GT2 Porsche 911 SC gains option of 4.0L 4V engine at 2350 lbs or 4.0L 2V at 2275 lbs. · M3 E92 classified in GT2 with 3999cc V8, 35mm restrictor, 3300 lbs minimum weight. · BMW 435i (2014-2017) added to T2 with 40mm restrictor, 3400 lbs minimum weight. · Nissan Z including Nismo added to T2 with 38mm restrictor, 3600 lbs base and 3650 lbs Nismo. · T2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously prohibited except in specified examples. · T2-TCR adds Link & Co 03 TCR and MG6 TCR, both 3000 lbs, 90% power, 275 max tire width. · FA MZR gains alternate Noor P/N 0088-8-00 intake manifold with AT Power runners as option to Elan or Mazda Speed Elite. · FA Formula 1000 motorcycle-based engine loses maximum compression ratio 14.5:1 limit. · FA Formula 1000 allows carbon fiber external panels, forward-facing gaps, raises floor to 125mm, adds eight 75×125mm rub blocks, expands diffuser to 110cm with 75mm radius transitions. · FF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners. · GT2 adds Cadillac CTS, Chevrolet Impala/Malibu/Monte Carlo/SS, Dodge Intrepid, Ford Fusion/Taurus, Lincoln MKS, Pontiac G8/GTO/Grand Prix, Toyota Camry, and Gen late Model Stock Car bodies. · GT2 Mazda BP engine 1839cc classified with 46mm turbo inlet restrictor, 2250 lbs minimum weight. · 991.2 GT3 Cup throttle body restrictor increases from 65mm to 70mm; 997.2 loses 100 lbs to 2800; Corvette LS engines get larger restrictors across multiple displacements and model years; LS3 and LT1 weight reduced 100 lbs each to 3150. · T2, T3, T4 cars may relocate under-dash electronics and fuse boxes for access after roll cage installation. · T2 Cadillac CT4-V Blackwing minimum weight drops 50 lbs to 3750. · T2 C6 Corvette LS2 restrictor increases from 67mm to 80mm FPR. · T2 Dodge Viper SRT10 coupe weight reduced from 3675 lbs to 3650 lbs. · T2 Ford Mustang GT 5.0L 15-23 permits Ford Track/Performance Package aero parts M-16600-FP and M-16601-MPP. · T4 Performance now permits 1-piece alternative rotors matching spec line sizes; alternate brake kits allowed same. · T2 Ford Mustang Boss 302 restrictor opens 56mm to 63mm; Mustang GT 5.0L 60mm to 65mm. · T2 Chevrolet Camaro SS/1LE (10-15) minimum weight reduced to 3575 lbs. · T2 Ford Mustang Challenge Dark Horse R (2024-) weight increases to 3825 lbs, displacement grows to 5038cc, tire width expands to 315. · FA class adds USF Pro 2000 car eligibility for Formula Atlantic racing. · T3 and T4 Mazda MX-5 Miata models add approved gear kit PT#-0000-02-6100 to notes. · T4 Mazda MX-5 Miata/Club/RF (19-24) and (16-18) remove discontinued hardtop part #0000-07-5901; T3 MX-5 Miata (16-18) and Global Cup ND (16-21) same. · T2 Spec Corvette to 3200 lbs; Mustang 11-14 restrictor 60→62mm; Mustang 2015-23 tyre 295→315; 996 weights down to 3050/3000 lbs; 997.2 models restrictor 60→65mm, weights reduced 50 lbs. · T2 Spec Corvette rev limit set to 7100 rpm. · GT2 Porsche 911 Coupe & Targa may use 993 3.8 RSR rear deck lid or approved aftermarket reproductions. · T2, T3, T4 Spec Lines table header changed from T2 to ET. · BMW M2 CS Cup 2020 must run Red power stick part #8324085, not Purple #8324089. · T2 Chevrolet Corvette C5 Z06 and C6 brake allowances clarified; stock calipers and rotors only for C5, specific sizes for C6. · T2 Chevrolet Corvette C5 LS1 restrictor reduced from 59mm to 58mm FPR. · FA Ligier JS F3 front tires may be Hoosier 43363 240/580R13 MS, rear 43368 300/590R13 MS. · FF adds rocker arm and outboard suspension cars optional bias ply and VFF tires; removes front-as-rear rule, adds mixing restrictions. · T2 C6 Corvette LS2 restrictor increases from 63mm to 67mm FPR. · T2 Nissan 370Z max wheel size increases to 19 x 10.5 inches; mid link replacement for true coil overs now permitted. · T2 Cadillac CT4-V Blackwing maximum tire size increases from 295 to 315. · Ford Mustang Challenge Darkhorse R newly classified in T2 with 58 mm restrictor, 3775 lbs minimum weight. · T2 350Z (03-08) removes detailed OEM part numbers and consolidates permitted modifications into simplified allowance list. · FA Formula Renault 2.0 (10-17) spec notes clarified: engine sealed, manual compliance required, tire choice unrestricted, no alterations except repairs. · FF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials. · GT2 Pontiac Fiero changes from FWD to RWD; hood bulge permitted for front engine relocation. · TA2 and STO OEM wings no longer exempt from rear wing height rule at roof peak. · T2 BMW M2 CS Cup requires Red power stick #8324085 instead of Purple #8324089; Corvette C5 Z06 restrictor reduces to 58mm from 59mm.showhide
FA Pro Mazda Classification and Performance Enhancement Proposal #39411inductionfasterFA Pro Mazda: lower intake manifold now unrestricted, throttle body raised to 80mm, wing height must not exceed 99cm, bodywork width must not exceed 132cm.
GT2 Allow Larger Air Cooled Engines in Porsche 911 GT2 #39249enginefasterGT2 Porsche 911 SC gains option of 4.0L 4V engine at 2350 lbs or 4.0L 2V at 2275 lbs.
GT2 Classify T1 BMW in GT2 #39408cars addedcars addedM3 E92 classified in GT2 with 3999cc V8, 35mm restrictor, 3300 lbs minimum weight.
T2 Request to Add 2014-2017 435i to T2 #38991cars addedcars addedBMW 435i (2014-2017) added to T2 with 40mm restrictor, 3400 lbs minimum weight.
T2 Consideration for Nissan Z & NISMO Z to Touring 2 Class #39296cars addedcars addedNissan Z including Nismo added to T2 with 38mm restrictor, 3600 lbs base and 3650 lbs Nismo.
T2 Allow Alt Bushing Material in Toe Links #39607suspension & brakesfasterT2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously prohibited except in specified examples.
T2 Request for Classification of MG6 TCR in T2-TCR Class #39702cars addedcars addedT2-TCR adds Link & Co 03 TCR and MG6 TCR, both 3000 lbs, 90% power, 275 max tire width.
FA Alternate Intake Manifold for MZR #38223inductionunclearFA MZR gains alternate Noor P/N 0088-8-00 intake manifold with AT Power runners as option to Elan or Mazda Speed Elite.
FA Engine Compression Rule Change Request #39302enginefasterFA Formula 1000 motorcycle-based engine loses maximum compression ratio 14.5:1 limit.
FA Change Formula 1000 allowances #39608aerofasterFA Formula 1000 allows carbon fiber external panels, forward-facing gaps, raises floor to 125mm, adds eight 75×125mm rub blocks, expands diffuser to 110cm with 75mm radius transitions.
FF Formula F Alternative Tire Rule Proposed Clarifications #39281wordingwordingFF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners.
GT2 Additional Body Options to Replace Older Stock Car Bodies #39086cars addedcars addedGT2 adds Cadillac CTS, Chevrolet Impala/Malibu/Monte Carlo/SS, Dodge Intrepid, Ford Fusion/Taurus, Lincoln MKS, Pontiac G8/GTO/Grand Prix, Toyota Camry, and Gen late Model Stock Car bodies.
GT2 GT3 Turbo to GT2? #39365cars addedcars addedGT2 Mazda BP engine 1839cc classified with 46mm turbo inlet restrictor, 2250 lbs minimum weight.
GT2 Tech Bulletins for GT2 and GT2-ST #39537induction -100 lbsslower991.2 GT3 Cup throttle body restrictor increases from 65mm to 70mm; 997.2 loses 100 lbs to 2800; Corvette LS engines get larger restrictors across multiple displacements and model years; LS3 and LT1 weight reduced 100 lbs each to 3150.
T2 Alternate Placement of Fuse Panel and Electronics Request #39370wordingwordingT2, T3, T4 cars may relocate under-dash electronics and fuse boxes for access after roll cage installation.
T2 Rebalance Blackwing Cadillac T2 for 2026 #39426weight -50 lbsfasterT2 Cadillac CT4-V Blackwing minimum weight drops 50 lbs to 3750.
T2 C6 LS2 Corvette Parity Request #39472inductionfasterT2 C6 Corvette LS2 restrictor increases from 67mm to 80mm FPR.
T2 T2 Tire Sizing #39490weight -25 lbsfasterT2 Dodge Viper SRT10 coupe weight reduced from 3675 lbs to 3650 lbs.
T2 Rear Spoiler for Mustang GT S550 (15-23) #39499aerounclearT2 Ford Mustang GT 5.0L 15-23 permits Ford Track/Performance Package aero parts M-16600-FP and M-16601-MPP.
T2 Clarify T4 Brake Rotor Allowance #39503suspension & brakessuspension & brakesT4 Performance now permits 1-piece alternative rotors matching spec line sizes; alternate brake kits allowed same.
T2 Help the 2011-2014 s197Mustang GT and Boss302 Less Restriction #38523inductionfasterT2 Ford Mustang Boss 302 restrictor opens 56mm to 63mm; Mustang GT 5.0L 60mm to 65mm.
T2 Improving Competitiveness of Gen 5 Camaro SS #39021weight -50 lbsfasterT2 Chevrolet Camaro SS/1LE (10-15) minimum weight reduced to 3575 lbs.
T2 Adjust T2 Darkhorse R #39346weightslowerT2 Ford Mustang Challenge Dark Horse R (2024-) weight increases to 3825 lbs, displacement grows to 5038cc, tire width expands to 315.
FA Re-Consider USF Pro 2000 Car for Formula Atlantic Class #38783cars addedcars addedFA class adds USF Pro 2000 car eligibility for Formula Atlantic racing.
T2 ND Gearset Request for T4 #39166wordingwordingT3 and T4 Mazda MX-5 Miata models add approved gear kit PT#-0000-02-6100 to notes.
T2 ND Spec Lines Wrong PT#'s #39170wordingwordingT4 Mazda MX-5 Miata/Club/RF (19-24) and (16-18) remove discontinued hardtop part #0000-07-5901; T3 MX-5 Miata (16-18) and Global Cup ND (16-21) same.
T2 Touring 2 Post-Runoffs BOP Adjustments and Changes #39274weight -50 lbsfasterT2 Spec Corvette to 3200 lbs; Mustang 11-14 restrictor 60→62mm; Mustang 2015-23 tyre 295→315; 996 weights down to 3050/3000 lbs; 997.2 models restrictor 60→65mm, weights reduced 50 lbs.
T2 Adjust rev limit on Spec Corvette in T2 #39282engineslowerT2 Spec Corvette rev limit set to 7100 rpm.
GT2 Rear Deck Lid for Older Air-Cooled Porsche #38506wordingwordingGT2 Porsche 911 Coupe & Targa may use 993 3.8 RSR rear deck lid or approved aftermarket reproductions.
T2 Incorrect Touring Heading #38451wordingwordingT2, T3, T4 Spec Lines table header changed from T2 to ET.
T2 Clarifications needed to BMW M2 CS cup line #38536engineunclearBMW M2 CS Cup 2020 must run Red power stick part #8324085, not Purple #8324089.
T2 Fix brake allowance supersessions. #38554suspension & brakesslowerT2 Chevrolet Corvette C5 Z06 and C6 brake allowances clarified; stock calipers and rotors only for C5, specific sizes for C6.
T2 C5 Corvette correction #38782engineslowerT2 Chevrolet Corvette C5 LS1 restrictor reduced from 59mm to 58mm FPR.
FA Ligier JS F3 Tire Choice #38434tyres & wheelstyres & wheelsFA Ligier JS F3 front tires may be Hoosier 43363 240/580R13 MS, rear 43368 300/590R13 MS.
T2 C6 T-2 Corvette 6 Liter Engine Restrictor #37490inductionfasterT2 C6 Corvette LS2 restrictor increases from 63mm to 67mm FPR.
T2 370Z Mid link Replacement for True Coil Overs and OEM Wheel Size #38014suspension & brakesfasterT2 Nissan 370Z max wheel size increases to 19 x 10.5 inches; mid link replacement for true coil overs now permitted.
T2 T2 Cadillac tire #38210tyres & wheelsfasterT2 Cadillac CT4-V Blackwing maximum tire size increases from 295 to 315.
T2 Please class the Darkhorse R in T2 #37295cars addedcars addedFord Mustang Challenge Darkhorse R newly classified in T2 with 58 mm restrictor, 3775 lbs minimum weight.
T2 T2 350Z Spec Line Cleanup #37603wordingwordingT2 350Z (03-08) removes detailed OEM part numbers and consolidates permitted modifications into simplified allowance list.
FA Update Formula Renault 2.0 spec line notes #37853wordingwordingFA Formula Renault 2.0 (10-17) spec notes clarified: engine sealed, manual compliance required, tire choice unrestricted, no alterations except repairs.
FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change #37802tyres & wheelsfasterFF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials.
GT2 Hood Bulge allowed #37000wordingunclearGT2 Pontiac Fiero changes from FWD to RWD; hood bulge permitted for front engine relocation.
GT2 OEM Wing Adjustment #37590aeroslowerTA2 and STO OEM wings no longer exempt from rear wing height rule at roof peak.
T2 T2 BOP #37312otherslowerT2 BMW M2 CS Cup requires Red power stick #8324085 instead of Purple #8324089; Corvette C5 Z06 restrictor reduces to 58mm from 59mm.
Cal Club 2025 CALCL252025-02-22
1:52.044Eric Poulsen · only car
1:51.118Eric Poulsen · only car
114.7Eric Poulsen
1:39.542Greg Labadie · only car+24.954s (+33.46%)
1:39.898Greg Labadie · only car
127.4Greg Labadie
-11.220squal -12.502s
89.9%qual 88.8%
1:45.818Brad McAllister · fastest of 6 · top 5 within 14.6s
1:46.926Brad McAllister · fastest of 6 · top 5 within 13.3s
117.9Guy Laidig
-4.192squal -6.226s
96.2%qual 94.4%
1:54.065Oli Thordarson · fastest of 2
1:52.758Oli Thordarson · fastest of 2
114.4Oli Thordarson
+1.640squal +2.021s
101.5%qual 101.8%
93 rule changes (FF: 5, FA: 4, GT2: 23, T2: 61)17 weight · 13 cars added · 10 induction · 7 suspension & brakes · 7 tyres & wheels · 3 aero · 3 engine · 2 removed · 27 wording · 4 other · FA adds Tatuus F.3 T-318 or FR-19 as spec line car in Table 2 for Formula Regional European Championship. · GT2 STO aftermarket ABS weight penalty reduced from 100 lbs to 50 lbs. · T2 Mustang GT 5.0L combines 2015-17 and 2018-23 with different restrictors: 63mm for Gen 2, 60mm for Gen 3. · T2 Chevrolet Camaro 1LE gains 100 lbs to 3600, restrictor increases to 62mm FPR. · T2 BMW M235iR (-2016) now permits oil cooler, radiator per touring rules, and silicone charge pipe. · Ford SCCA Club Spec Mustang classified T3 at 3350 lbs with driver; Mazda SCCA Club Spec MX-5 classified T4 at 2500 lbs with driver. · GT2 Panoz Esperante GTS adds 2013-2016 Ford EcoBoost Twin Turbo V-6 3496cc engine, 2600 lbs. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · GT2 Sunbeam Tiger gains Holly 650 cfm carburetor alternate options PN #80541-1 and #80541-2. · T2, T3, T4 remove nine, nine, and thirty-six expired spec lines respectively, effective 2025-01-01. · T2 Ford Mustang GT 5.0L (11-14) weight reduced from 3575 to 3525 lbs. · T2 Spec Corvette clarifies braking, tires, cooling, suspension, and Spec+ upgrades; SC-3200, SC+-3300 lbs. · T2 and T3 Mustang spec lines remove redundant driveshaft alternate/aluminum allowance wording. · T2 Chevrolet Corvette C6 LS3 restrictor increases from 53mm to 56mm flat plate. · T2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors. · T2, T3, T4 brake component wording clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter. · T2, T3, T4 fuel cell cars may remove charcoal canisters, emissions valves, and sensors. · Porsche Spec Boxster moves to T4, minimum weight 2750 lbs, requires 3 Super Tour events before Runoffs eligibility. · T2 Chevrolet Corvette C6 Coupe/Grand Sport wheels widened to 18×11 or 19×13. · T4 BMW 320i 14-15 Spec Line expires 12/31/24 removed; Turner Motorsports intercooler #024703TMS02 allowed. · Cadillac CTS 02-07 3.6L classified in T3. · T2 Corvette C5 Z06 restrictor split by engine: LS1 59mm, LS2 63mm, LS3 56mm FPR. · T2 Chevrolet Corvette Z06 (06-12) Spec Line deleted entirely. · FF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs. · FF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches. · T2 Spec Corvette now allows 295 R compound DOT tires as alternative to Nankang NS-2R. · FF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers. · T2 Corvette C6 LS2 restrictor increases to 63mm; Camaro 1LE weight drops to 3500 lbs, restrictor tightens to 58mm FRP. · T2 Subaru Impreza WRX STi (03-07) and (08-11) expiration notes removed. · T2 Ford Mustang 5.0L gets 100 lb weight reduction with 4-piston Brembo brakes and 355mm rotors; EcoBoost brake note removed. · GT2-ST allows aftermarket replacement differential housings if exact equivalents. · GT4 cars now permitted in GT2-ST with factory restrictor, must comply with 2012 STO rules, slicks allowed with 100-pound penalty. · Ford Mustang GT 5.0L and V6 now permit Track/Performance Package parts in T2 and T3. · T2 Ford Mustang S550 5.0 Gen2/Gen3 gains 100 lbs with stock or Brembo 355mm brakes. · T2-T4 Ford Mustangs: remove 25 lbs penalty for non-OEM driveshaft, clarify alternate driveshaft allowances. · T2 Corvette C5, Camaro SS, Firebird, Solstice GXP, C6 allow four or six piston front calipers. · Audi S4 (2000-2002) moves to T3 with 3400 lbs minimum weight, 38mm turbo inlet restrictor required. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR. · GT2-ST Corvette 14-19 LS2 restrictor increases from 78mm to 80mm flat plate. · T3 and T4 Mazda RX-8 may remove or disable factory oil injection system. · T2 BMW M3 01-06 max wheel size increases from 18 x 9 to 18 x 10 inch. · T2, T3, T4 driveshafts may use alternative materials or one-piece units; non-OEM adds 25 lbs. · T2 Porsche Cayman S 06-09 allows StopTech ST60/ST40 brake kit with 50 lb penalty. · Chevrolet Corvette C8 (2020–) classified into GT2-ST with 6162cc displacement, 3300 lbs minimum weight, 71mm restrictor. · 2015 Mitjet ST added to GT2, must run per VTS specifications with complete FIA form CdM008. · T2-T4 Spec Lines remove wheelbase requirement, replace with Required Restrictor specification. · T2 and T3 Nissan 370Z brake rotors enlarged: front 320x28 to 355x32mm, rear 320x16 to 350x20mm vented. · T2 Mustang GT 5.0L 2018+ now permits BMR rear upper control arm camber links part #UTCA064. · GT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed. · GT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors. · GT2 Chevrolet Corvette 7011 OEM 7 liter weight reduced 150 lbs, to 3125 lbs. · GT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E. · T2 Mustang GT 5.0L 15-17 now permits BMR rear upper control arm camber links part #UTCA064. · T2 Chevrolet Camaro SS, 1LE, Corvette C5/C6, Z06, and Pontiac Firebird, Solstice GXP now allow four or six piston front calipers. · T2 Cadillac CT4-V Blackwing Runoffs qualification requirement removed. · T2, T3, T4 battery replacement wording simplified; OEM weight tolerance requirement removed. · T4 now permits C-Spec cars to compete alongside B-Spec cars. · T2-T4 spec lines for 46 cars expire 12/31/24; appeal required to continue. · T2 Chevrolet Camaro 1LE minimum weight increases to 3575 lbs, restrictor plate widens to 60mm. · FF Honda Fit gains Fast Forward FF800-100 oversize piston ring pack option. · GT2-ST Dodge Viper hybrid kit restrictor reduced from 50mm to 45mm flat plates. · T2 Cadillac CT4-V Blackwing rear wheels widen from 18 x 10 to 18 x 11. · T2 BMW M2 CS Cup drops 50 lbs to 3550; M235iR drops 50 lbs to 3300. · T2 Spec Corvette minimum weight drops 175 lbs to 3200, tire rules tighten to Nankang NS-2R only. · T2 Dodge Viper SRT-10 rear tyre narrowed from 345/30 to 335/30. · T2 Ford Mustang GT 5.0L three generations gain 50-75 lbs minimum weight; restrictors increase to 58-60mm. · T2 Chevrolet Camaro 1LE minimum weight drops 50 lbs to 3500, restrictor opens to 58mm flat plate. · T2 C5 Z06 removes restrictor note from weight; C5/C6 Corvettes increase restrictors to 59mm, 63mm LS2, 53mm LS3. · T3 Nissan 370Z model years expanded to include NISMO Edition through 2022. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · T2 BMW M2 CS Cup 2020- permitted to add hood vents conforming to 9.1.9.2.D.8.a.7. · GT2-ST Dodge Viper including Comp Coupe, ACR/ACR-X with VRL front fascia loses 100 lbs. · GT2 Mazda 20B 3 rotor loses 220 lbs, to 2280, consolidating two spec lines. · T2 Chevrolet Corvette C6 LS2 restrictor plate increases from 58mm to 60mm flat plate. · T2 Cadillac CT4-V Blackwing permitted to use Radium fuel surge tank behind fireproof bulkhead. · T3 Mazda RX-8 removes transmission/final drive pairing requirement; T4 removes same requirement, adds Mazdaspeed radiator and coil spring kit. · T3 BMW 320i (14-15) gains aftermarket intercooler permission; T4 loses it. · T3 Pontiac Solstice GXP minimum ride height set to 3 inches. · GT2 BMW engines: 3.4L 6-cyl at 2575 lbs, 4.0L V8 at 2900 lbs, 4.5L V8 at 2950 lbs, 5.0L V8 at 3000 lbs; S54 with 97mm stroke permitted at 2800 lbs. · GT2 Corvette C7 restrictor increases from 73mm to 77mm flat plate, removing weight penalty. · T2 Nissan 370Z allows NISMO suspension alternatives to SPL parts; rear toe arms removed from permitted list. · FA Pro Formula Mazda front wheels widen to 10 in. max; rear wheels narrow to 14 in. min. · T2 Porsche Cayman S model year range extended from 06-08 to 06-09. · FA Pro Formula Mazda maximum bodywork width behind front wheels increases to 51.97 inches. · FA MSR Formula Mazda FMzR added to Table 2 classification. · 2009-2012 Porsche Cayman S classified in GT2, 3.4L, RWD, no PDK transmission allowed. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · T2 Chevrolet Corvette C5 Z06 restrictor increases from 53mm to 56mm; 58mm option removed. · GT2 Ginetta G56 GTA may now use Factory installed ProMap ECU Map. · T2 upper and lower control arm bushings can now use polyurethane, delrin, or alternate synthetic materials. · T2 Cadillac CT4-V Blackwing now permits adjustable sway bar end links. · FF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. · T2 Honda Civic Type-R tire size increases from 275 to 295.showhide
FA Classify FR European Championship car as spec line car in Table 2 #37658cars addedcars addedFA adds Tatuus F.3 T-318 or FR-19 as spec line car in Table 2 for Formula Regional European Championship.
GT2 GT2/ST - Remove Aftermarket/Racing ABS penalty #36538weightfasterGT2 STO aftermarket ABS weight penalty reduced from 100 lbs to 50 lbs.
T2 Mustang Update backdate #37275inductionunclearT2 Mustang GT 5.0L combines 2015-17 and 2018-23 with different restrictors: 63mm for Gen 2, 60mm for Gen 3.
T2 BOP Adjustment for 2016 - Camaro SS/1LE #37434weight +100 lbsslowerT2 Chevrolet Camaro 1LE gains 100 lbs to 3600, restrictor increases to 62mm FPR.
T2 BMW M235iR TCS CHANGE REQUEST #37470wordingwordingT2 BMW M235iR (-2016) now permits oil cooler, radiator per touring rules, and silicone charge pipe.
T2 Request to Classify Club Spec in Appropriate Touring Classes #37523cars addedcars addedFord SCCA Club Spec Mustang classified T3 at 3350 lbs with driver; Mazda SCCA Club Spec MX-5 classified T4 at 2500 lbs with driver.
T2 Remove spec lines that have expired #37269removedremovedT2, T3, T4 remove nine, nine, and thirty-six expired spec lines respectively, effective 2025-01-01.
T2 BoP for the Various Mustangs #37185weight -50 lbsfasterT2 Ford Mustang GT 5.0L (11-14) weight reduced from 3575 to 3525 lbs.
T2 Spec Corvette Line Clarification. #37441wordingwordingT2 Spec Corvette clarifies braking, tires, cooling, suspension, and Spec+ upgrades; SC-3200, SC+-3300 lbs.
T2 Redundant Verbiage Regarding Mustang Spec Lines for Driveshaft #36484wordingwordingT2 and T3 Mustang spec lines remove redundant driveshaft alternate/aluminum allowance wording.
T2 Request Less Restriction for Ls-3 Engined C6 Corvette #36810inductionfasterT2 Chevrolet Corvette C6 LS3 restrictor increases from 53mm to 56mm flat plate.
T2 Fuel Emissions Components #37076wordingwordingT2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors.
T2 fix brake wording #37129wordingwordingT2, T3, T4 brake component wording clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter.
T2 Evaporative emissions systems #37130wordingwordingT2, T3, T4 fuel cell cars may remove charcoal canisters, emissions valves, and sensors.
T2 Move Spec Boxster to T4 #37158cars addedcars addedPorsche Spec Boxster moves to T4, minimum weight 2750 lbs, requires 3 Super Tour events before Runoffs eligibility.
T2 Corvette Wheels #37169tyres & wheelsfasterT2 Chevrolet Corvette C6 Coupe/Grand Sport wheels widened to 18×11 or 19×13.
T2 BMW 320i Spec Line #37204wordingwordingT4 BMW 320i 14-15 Spec Line expires 12/31/24 removed; Turner Motorsports intercooler #024703TMS02 allowed.
T2 Classification for a 2005 Cadillac CTS 3.6 liter 6 speed manual #37224cars addedcars addedCadillac CTS 02-07 3.6L classified in T3.
T2 Please Consider Allowing Update to the C5 Corvette #37298engineunclearT2 Corvette C5 Z06 restrictor split by engine: LS1 59mm, LS2 63mm, LS3 56mm FPR.
T2 Major error in lane, but nobody ran it. #37302removedremovedT2 Chevrolet Corvette Z06 (06-12) Spec Line deleted entirely.
FF Change FF/FC Weight with Sequential Gearbox #36651weightfasterFF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs.
FF Alternative Oversize Honda Fit Pistons #37064wordingwordingFF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches.
T2 Spec Corvette Change for T2 #37127tyres & wheelstyres & wheelsT2 Spec Corvette now allows 295 R compound DOT tires as alternative to Nankang NS-2R.
FF Update to FF EGR Blanking Plate Rule #36633wordingwordingFF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers.
T2 Errors #36214other -75 lbsunclearT2 Corvette C6 LS2 restrictor increases to 63mm; Camaro 1LE weight drops to 3500 lbs, restrictor tightens to 58mm FRP.
T2 Subaru Appeal #36258wordingwordingT2 Subaru Impreza WRX STi (03-07) and (08-11) expiration notes removed.
T2 S550 Brakes #36571otherfasterT2 Ford Mustang 5.0L gets 100 lb weight reduction with 4-piston Brembo brakes and 355mm rotors; EcoBoost brake note removed.
GT2 GT4 cars may run in GT2-ST #36235cars addedcars addedGT4 cars now permitted in GT2-ST with factory restrictor, must comply with 2012 STO rules, slicks allowed with 100-pound penalty.
T2 Mustang T2/T3 #35877wordingunclearFord Mustang GT 5.0L and V6 now permit Track/Performance Package parts in T2 and T3.
T2 S550 Brakes #35926weightslowerT2 Ford Mustang S550 5.0 Gen2/Gen3 gains 100 lbs with stock or Brembo 355mm brakes.
T2 T2-T4 Driveshaft Mistake...? #36050weightfasterT2-T4 Ford Mustangs: remove 25 lbs penalty for non-OEM driveshaft, clarify alternate driveshaft allowances.
T2 request for allowance of 6 piston calipers for T2 C5 corvettes #36126suspension & brakesfasterT2 Corvette C5, Camaro SS, Firebird, Solstice GXP, C6 allow four or six piston front calipers.
T2 B8/8.5 Audi S4 T3 and T2 #36195cars addedcars addedAudi S4 (2000-2002) moves to T3 with 3400 lbs minimum weight, 38mm turbo inlet restrictor required.
GT2 Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.
GT2 Request to Eliminate the FPR from the Corvette (-2013) with LS2 #35878inductionfasterGT2-ST Corvette 14-19 LS2 restrictor increases from 78mm to 80mm flat plate.
T2 Allow T4 and T3 RX8 to Disable/Remove Factory Oil Inj. #35761engineunclearT3 and T4 Mazda RX-8 may remove or disable factory oil injection system.
T2 Competition Adjustment Request/Wheel Size of E46 #35895tyres & wheelsfasterT2 BMW M3 01-06 max wheel size increases from 18 x 9 to 18 x 10 inch.
T2 Driveshafts #35916weightslowerT2, T3, T4 driveshafts may use alternative materials or one-piece units; non-OEM adds 25 lbs.
T2 Brake Request for 2009 Porsche Cayman #35723suspension & brakesslowerT2 Porsche Cayman S 06-09 allows StopTech ST60/ST40 brake kit with 50 lb penalty.
GT2 Classify Corvette C8 (2020- ) into GT2/ST #33759cars addedcars addedChevrolet Corvette C8 (2020–) classified into GT2-ST with 6162cc displacement, 3300 lbs minimum weight, 71mm restrictor.
GT2 Requesting classification for a 2015 Mitjet ST in GT2 #35408cars addedcars added2015 Mitjet ST added to GT2, must run per VTS specifications with complete FIA form CdM008.
T2 370Z Brake Rotor Size Correction #35487suspension & brakessuspension & brakesT2 and T3 Nissan 370Z brake rotors enlarged: front 320x28 to 355x32mm, rear 320x16 to 350x20mm vented.
T2 Letter #35154 2018+ Mustang GT Expansion #35488suspension & brakessuspension & brakesT2 Mustang GT 5.0L 2018+ now permits BMR rear upper control arm camber links part #UTCA064.
GT2 Rear Blade Spoiler Clarification #35261aerofasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.
GT2 GT Direct Injection allowance and rules #35437enginefasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.
GT2 REDUCE C6 CORVETTE WEIGHT WITH OEM 7 LITER ENGINE REDUCE BY 150LB #35385weight -150 lbsfasterGT2 Chevrolet Corvette 7011 OEM 7 liter weight reduced 150 lbs, to 3125 lbs.
GT2 GT2/3 remove Direction Injection not allowed in Spec line notes #35439inductionfasterGT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E.
T2 2015+ Mustang Sway Bar and A-Arm Request #35154suspension & brakessuspension & brakesT2 Mustang GT 5.0L 15-17 now permits BMR rear upper control arm camber links part #UTCA064.
T2 Brake Kits #35245otherotherT2 Chevrolet Camaro SS, 1LE, Corvette C5/C6, Z06, and Pontiac Firebird, Solstice GXP now allow four or six piston front calipers.
T2 Runoffs wording on Caddy in T2 #35377wordingwordingT2 Cadillac CT4-V Blackwing Runoffs qualification requirement removed.
T2 More Car Lightening Stuff #35319weightfasterT2, T3, T4 battery replacement wording simplified; OEM weight tolerance requirement removed.
T2 Inclusion of B-C spec cars in T4 #35374cars addedcars addedT4 now permits C-Spec cars to compete alongside B-Spec cars.
T2 T2-T4 Set expiration dates on spec lines #35378wordingwordingT2-T4 spec lines for 46 cars expire 12/31/24; appeal required to continue.
T2 Reply to letter #35161 and #31661 #35384weight +75 lbsslowerT2 Chevrolet Camaro 1LE minimum weight increases to 3575 lbs, restrictor plate widens to 60mm.
FF Honda Fit Oversize Piston Rings #35305wordingwordingFF Honda Fit gains Fast Forward FF800-100 oversize piston ring pack option.
GT2 Dodge Viper Gen 3 hybrid Kit Update Request #35200inductionslowerGT2-ST Dodge Viper hybrid kit restrictor reduced from 50mm to 45mm flat plates.
T2 Rebalance Blackwing Cadillac T2 #35079tyres & wheelsfasterT2 Cadillac CT4-V Blackwing rear wheels widen from 18 x 10 to 18 x 11.
T2 M2 CS RACING #35130weight -50 lbsfasterT2 BMW M2 CS Cup drops 50 lbs to 3550; M235iR drops 50 lbs to 3300.
T2 Spec Corvette in T2 #35139weight -175 lbsfasterT2 Spec Corvette minimum weight drops 175 lbs to 3200, tire rules tighten to Nankang NS-2R only.
T2 T2 Viper BoP #35155tyres & wheelsslowerT2 Dodge Viper SRT-10 rear tyre narrowed from 345/30 to 335/30.
T2 BOP Adjustment for 5.0L Mustangs #35156weight +75 lbsslowerT2 Ford Mustang GT 5.0L three generations gain 50-75 lbs minimum weight; restrictors increase to 58-60mm.
T2 Take at Look at T-2 BOP #35161weight -50 lbsfasterT2 Chevrolet Camaro 1LE minimum weight drops 50 lbs to 3500, restrictor opens to 58mm flat plate.
T2 C5 Corvette Spec Line Oversight #35169inductionfasterT2 C5 Z06 removes restrictor note from weight; C5/C6 Corvettes increase restrictors to 59mm, 63mm LS2, 53mm LS3.
T2 Requested Update of Model Years of 370Z #35231wordingwordingT3 Nissan 370Z model years expanded to include NISMO Edition through 2022.
GT2 Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingwordingGTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL.
T2 M2 CS RACING #35122aeroaeroT2 BMW M2 CS Cup 2020- permitted to add hood vents conforming to 9.1.9.2.D.8.a.7.
GT2 Late E & O #34966weightfasterGT2-ST Dodge Viper including Comp Coupe, ACR/ACR-X with VRL front fascia loses 100 lbs.
GT2 GT2 Mazda 20B 3 rotor ENO #34765weight -220 lbsfasterGT2 Mazda 20B 3 rotor loses 220 lbs, to 2280, consolidating two spec lines.
T2 Corvette LS2 Restrictor Plate Adjustment #34456inductionfasterT2 Chevrolet Corvette C6 LS2 restrictor plate increases from 58mm to 60mm flat plate.
T2 Blacking Cadillac Fuel Capacity #34624wordingwordingT2 Cadillac CT4-V Blackwing permitted to use Radium fuel surge tank behind fireproof bulkhead.
T2 Rules Clarification for Mazda RX8 Spec Line #34395wordingwordingT3 Mazda RX-8 removes transmission/final drive pairing requirement; T4 removes same requirement, adds Mazdaspeed radiator and coil spring kit.
T2 rule book corrections #34437otherfasterT3 BMW 320i (14-15) gains aftermarket intercooler permission; T4 loses it.
T2 Ride Height Correction for the T3 Solstice. #34615wordingwordingT3 Pontiac Solstice GXP minimum ride height set to 3 inches.
GT2 appendix letter #33635 #34206wordingwordingGT2 BMW engines: 3.4L 6-cyl at 2575 lbs, 4.0L V8 at 2900 lbs, 4.5L V8 at 2950 lbs, 5.0L V8 at 3000 lbs; S54 with 97mm stroke permitted at 2800 lbs.
GT2 Remove Weight and Restrictor Penalty for Corvette C7 Body #34342inductionfasterGT2 Corvette C7 restrictor increases from 73mm to 77mm flat plate, removing weight penalty.
T2 370Z Obsolete Parts & NISMO Alternatives to SPL Parts #34297wordingwordingT2 Nissan 370Z allows NISMO suspension alternatives to SPL parts; rear toe arms removed from permitted list.
FA Simplify Pro Formula Mazda wheel allowance #34190tyres & wheelsunclearFA Pro Formula Mazda front wheels widen to 10 in. max; rear wheels narrow to 14 in. min.
T2 2009 Porsche Cayman Classing Request #34147wordingwordingT2 Porsche Cayman S model year range extended from 06-08 to 06-09.
FA E&O - Correct Pro Formula Mazda spec line dimensional equivalent #34085aerofasterFA Pro Formula Mazda maximum bodywork width behind front wheels increases to 51.97 inches.
FA Add new spec line for MSR Formula Mazda FMzR to Table 2 #34139cars addedcars addedFA MSR Formula Mazda FMzR added to Table 2 classification.
GT2 Request to class 2011 Porsche Cayman S #33771cars addedcars added2009-2012 Porsche Cayman S classified in GT2, 3.4L, RWD, no PDK transmission allowed.
GT2 Please classify Fields Cardinal V8 #33784cars addedcars addedFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
T2 C5 Z06 Straight Line Speed #33575inductionslowerT2 Chevrolet Corvette C5 Z06 restrictor increases from 53mm to 56mm; 58mm option removed.
GT2 Adding Ginetta G56 GTA Factory ProTune for GT2 Class #33825wordingunclearGT2 Ginetta G56 GTA may now use Factory installed ProMap ECU Map.
T2 Allowance of any nonmetallic bushing material in T2 #33833suspension & brakessuspension & brakesT2 upper and lower control arm bushings can now use polyurethane, delrin, or alternate synthetic materials.
T2 Allow Adjustable stabilizer bar links #33861suspension & brakessuspension & brakesT2 Cadillac CT4-V Blackwing now permits adjustable sway bar end links.
FF Add Fast Forward Part Numbers for Honda Fit Engine #33752wordingwordingFF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components.
T2 Honda Civic Type R Tire Size Increase #33672tyres & wheelsfasterT2 Honda Civic Type-R tire size increases from 275 to 295.
Cal Club 2023 CALCL232023-02-24
1:14.588Greg Labadie · only car
264 earlier rule changes on record, in force before Cal Club 2023 (from 2019)52 cars added · 43 weight · 21 induction · 17 suspension & brakes · 12 engine · 8 aero · 5 tyres & wheels · 1 removed · 100 wording · 5 other · GT2 Mazda 13B Street Port turbo changes from EFR 76/70 to BW7670 or Garrett G30-660 with 46mm TIR at 2280 lbs. · T2 C5 Corvette permitted GM Motorsports T1 suspension package and SpecCorvette SCT-1 swaybars. · T2/T3 Mustang GT 5.0L and V6 (11-14) may remove upper grille fog lights, replace with mesh or screen. · FA BDA engine displacement specification line added to Table 1, effective 2023-01-01. · GT2 Porsche SOHC 2478/2681/2992 turbo sizes increase from 42mm to 44mm SIR to TIR. · GT2-ST Chevrolet Corvette 14-19 L76 5967 restrictor increases from 70 to 73 mm. · GT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines newly classified in spec line. · GT2 Mazda 13B Street/Bridge Port turbocharger changes from EFR 70/76 to 76/70, compressor from 42mm to 46mm. · GT2-ST BMW E36/46 spec line adds MA Shaw carbon/composite door offerings to Notes. · GT3 normally aspirated cars may use intake chokes instead of SIRs, fitted to each carburetor barrel, same size as required SIR. · GT3 2.0L 4-valve non-turbo engines may run unrestricted at 2060 lbs instead of with a choke restriction. · GT2 Porsche 991.1 TBR 70–72mm, 991.2 weight 3100–3000lbs TBR 65–67mm, ABS penalties removed; GT2-ST Corvette LS engines flat plate 75–78mm, LS7 65–68mm; Viper weights 3275–3125lbs. · T2 BMW M235iR weight reduced 50 lbs to 3350, aftermarket shocks now allowed. · T5 class added as regional-only; T5 tyres maximum width 225, minimum aspect ratio 45. · T2-T5 Touring front and rear suspension maximum negative camber changed to 3.5 degrees. · Formula Renault 2.0 (10-17) reclassified from FX to FA; weight reduced to 1280 lbs, restrictor removed. · FA Swift 016 2.3L restrictor increases from 31mm to 32mm SIR; minimum weight drops 30 lbs to 1420. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · GT2 Ginetta G56 GTA gains optional 18" x 9" and 18" x 10" wheels. · T2 Dodge Viper SRT-10 wheel size 18x11 rear, weight to 3675 lbs, throttle restrictor hole 44mm convertible or 42mm hardtop. · GT2/ST BMW E36/E46 now allows MAShaw body kit parts: wide body, bumpers, fenders, rockers, flairs. · Pro Formula Mazda allows street or bridge port, unrestricted apex seals, 70mm throttle body, 99cm wing height max, 132cm bodywork width max. · GT2 Chevrolet Corvette L76 5967 restrictor increases from 73mm to 74mm. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · Ginetta GTA G56 added to GT2 as spec car: 2600 lbs, 3.7L Ford V6 sealed, 6-speed Quaife sequential. · GT2 BMW E36/E46 carbon roof and door suppliers added to notes: Lang Racing, 2M Automotive, Flossmann, MA Shaw. · GT2-ST BMW E46 M3, E36, Z3, 5000cc V8 can use 95mm S54 crankshaft at +150 lbs. · Audi R8 GT4 classified to GT2 with 5.2L displacement, 3000 lbs minimum weight, per factory specs restrictor. · T2 BMW M235iR/M240iR: 240iR/Evo package now permitted without 50 lb penalty; Evo package clarified to 75 lbs. · T2 BMW E92 M3 (08-14) permitted to use Fall Line Suspension arms from G8X/F8x/E9x M3, E9x M3/E82 1M. · FA Ligier JS F3 must comply with Formula Regional Americas rules instead of FIA Formula 3 Regional Technical Regulations. · FA sealed engines must undergo full inspection; competitor pays reassembly and resealing costs. · FA Formula Lites FL15 and FR Americas Ligier JS F3 engine sealing requirements clarified to reference respective series technical regulations. · GT2 shock absorber attachment points clarified as moveable; wording correction only. · GT2 Porsche 104.0 x 88.0 engine weight increases from 1950 to 2090 lbs; 2V variants may use Borg Warner EFR 76/70 42mm turbo. · T2-T4 Touring cars with alternative springs may use performance top hats with spherical bearings on shocks and struts. · T2 BMW E92 M3 (08-14) note reference changed from 77 to 78. · Cadillac CT4-V Blackwing (2022+) classified in T2 at 3800 lbs with 94 x 85.6mm engine. · FA transmission rule clarified: transverse shafts prohibited except final drive and motorcycle gearbox in Formula 1000. · FA Swift 016 2.5 liter aero spec now references 2.3 liter notes instead of N notes. · T2-T4 cars model year 2018+ may use non-OEM ECU with 75 lb weight penalty via spec line adjustment. · BMW M2 CS Cup 2020- now permits specific exhaust part #18302459928 and hot country package cooling parts. · 2022+ Cadillac CT4-V Blackwing classified in T2 at 3564cc, 3800 lbs, 18×10/11 wheels, 295 MT tires. · FA Pro Formula Mazda now allows street port or bridge port, previously porting was prohibited. · Ginetta G40 classified in GT2 with Mazda MZR/L5-VE engine, 2488cc or 2399cc, 1950 lbs base weight. · Toyota Supra GT4 added to GT2-ST: 3000cc, 3000 lbs minimum, factory restrictor. · GT2 Porsche 944/924 may use ERC 76/70 Turbo instead of Jayco super 50. · T2-T4 grill openings may remove non-metallic webbed false sections; 16 square inch limit removed. · T2 Chevrolet Corvette C6 LS2 restrictor increases from 56mm to 58mm. · FA adds Honda K20Z3 2.0L engine spec at 1350 lbs minimum and Mazda MZR 2.0L spec at 1300 lbs minimum to Table 1. · GT2 Porsche Cayman 05-15 turbo restrictor increases from 70mm to 75mm. · T2 BMW Z4M 06-08 weight reduced from 3150 to 3100 lbs. · GT2 Porsche Cayman 05-15 uses Throttle Body Restrictor instead of Flat Plate Restrictor at 2700 lbs. · T2 Dodge Viper SRT-10 loses 50 lbs to 3550; throttle restrictor hole shrinks from 43mm to 41mm. · T2-T4 clarified: grill opening area may increase max 16 sq in for radiator cooling only, retaining factory mesh shape. · T2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted. · T2, T3, T4 clarify that spec lines listing permitted or allowed parts are alternatives to category rules, not replacements. · T2 Spec Mustang model designation changed to Ford Spec Mustang. · T2 BMW M2 CS Cup 2020 rear brake rotor reduced from 390 mm to 380 mm. · T4 Volkswagen Passat, Jetta 1.8T adds 2014 model year to eligible years. · BMW M2 (2017+) added to T2 with 2979cc engine, 10.5x18 wheels, 295 tires, 3650 lbs weight. · Porsche 911 997.2 GTS (09-12) classified in T2 at 3400 lbs with 60mm flat plate restrictor required. · GT2 Mazda 13B street port adds EFR 70/76 turbo with 42mm restrictor at 2280 lbs. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · FA Mazda MZR 2.0 spec line removes redundant '2.0' designation; Honda Civic K20Z3 spec line unchanged. · GT2 Dodge Viper Comp Coupe ACR/ACR-X loses 100 lbs minimum weight to 3275. · T2 BMW M2 CS Cup 2020- must run Purple power stick, part #8324089 instead of #TBD. · FA Toyota 1800 moves from Table 1 to Table 2 (Spec Line Cars). · FA Swift 016 Mazda MZR/Ford Duratec wheel width specification clarified: front 10, rear 14 minimum and 15 maximum. · 04-06 World Challenge Pontiac GTO added to GT2-ST: 6062 cc, 3000 lbs minimum, unrestricted. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · Grullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted. · T2 Porsche 911/997.1 (06-08) now allows alternate Cargraphics CARP97DFIFKR exhaust manifold. · FA rule wording clarified: Table 1 for purpose-built and ex-pro cars, Table 2 for spec line cars with exceptions noted. · FA Mazda MZR/Ford Duratec 2296cc and 2500cc moved from Table 1 to Table 2. · FA Mazda MZR 2.0 and Honda Civic K20Z3 remove sequential designation from 5-speed transmission spec. · GT2-ST Porsche Cayman restrictor increases from 65mm to 75mm flat plate at 2700 lbs. · GT2 Dodge Viper including Comp Coupe, ACR/ACR-X minimum weight reduced 100 lbs to 3275 in VRL Spec. · TA2 minimum weight set to 2930 lbs with free tire make and size. · T2 BMW M2 CS Cup 2020- weight increases from 3625 to 3600 lbs; mandatory Purple power stick added. · FA Mazda MZR 2.0 limited to Ralt RT40, RT41, Swift 008, 014 chassis; Honda Civic K20Z3 removes Swift 016 chassis. · T3 Honda Civic Type-R 2020+ allows brake rotor 45251-TGH-A01 with 25 lb penalty. · T2 Ford Mustang GT 5.0L 15-17 restrictor grows 55mm to 58mm; 2018- grows 53mm to 55mm. · T2 BMW Z4M 06-08 weight increases from 3100 to 3150 lbs. · T2 BMW E92M3 08-14 weight drops 50 lbs to 3425, intake restrictor reduces 3mm to 77mm. · FA Swift 016 2.3 liter engine name corrected to Mazda MZR/Ford Duratec. · FA Swift 016 2.5 liter engine name corrected to Mazda MZR/Ford Duratec. · FA removes four spec lines and replaces Ford Duratec/Mazda MZR with Honda B16 at 1615cc, 1175 lbs minimum. · T2 C5 and C6 Corvettes permit specific dry sump kits and minor air dam trimming up to 3.9 cm depth. · T2 Chevrolet Camaro 1LE auto trans gets new gear ratios and 2.77 final drive ratio. · T2 BMW M3 01-06 minimum competition weight drops 100 lbs to 3000. · T2 Chevrolet Camaro SS/1LE model years expanded from 2010–2014 to 2010–2015. · FA Spec Line C loses 25 lbs to 1175; Line I loses 75 lbs to 1175; Line K gains 15 lbs to 1175. · FA purpose built and ex-Pro Atlantic cars lose 25 lb sequential transmission penalty wording. · FA Ligier JS F3 car name corrected in FR Americas spec line. · FA Ford Duratec/Mazda MZR 2500 spec line D wording cleanup: 4-valve becomes 4 valves per cylinder. · FA Honda Civic K20Z3 intake manifold and throttle body assembly now allows AT Power Direct-To-Head 45mm individual throttle bodies as alternative to HPD parts. · FF block relief permitted only as needed to fit allowed crankshaft. · GT2 Sunbeam SBF 302 engine firing order option now explicitly allows Boss 302 variant. · T2-T4 clutch disc and pressure plate must be at least 95% of factory OEM weight. · Spec Corvette newly classified in T2 at 3375 lbs with 53mm restrictor and 3.75" minimum ride height required. · T2 BMW E92 M3 front and rear springs increased to 1000 lbs/in from 800. · T2 Toyota Supra 2020- spring rates limited to 800# front and 1000# rear maximum. · FA Ford Duratec/Mazda MZR intake restrictor reduced from 32mm to 30mm SIR; Swift 016 2.5 Mazda restrictor reduced from 35mm to 33mm SIR. · FA Toyota 4A-GE engines cleaned up, spec lines A and B engine designations corrected. · FA Ford BD Series max displacement increases from 1600 to 1615 cc, minimum weight stays 1200 lbs. · FA Ford Duratec/Mazda MZR and Honda B16 both now 1615cc max displacement; Honda B16 removes NA requirement. · FA Pro Formula Mazda engine specs moved from Table 1 to Table 2 notes; Renesis Rotary details consolidated. · FA F3 Americas spec line updated effective 2021-03-01; specific changes not legible in provided text. · GT2-ST Corvette (-2019) LS2 and L76 5967cc gain 100 lbs minimum weight to 3100; 6162cc variants gain 50–100 lbs; 7011 gains 100–50 lbs; L76 restrictor opens 70 to 73 mm. · GT2 rear engine opening location requirement removed. · GT2 Ford Mustang/Thunderbird Boss 302 firing order now optional from later SBF 302 versions. · T2 BMW M2 CS Cup 2020- permitted to remove door glass and mechanism. · GT2 ABS braking systems now allowed if shown on individual Spec Line. · GT2 Corvette C6 and C7 spec lines clarified and split; C7 LS2/L76/LS3/LT1/LS7 weights increased 100–150 lbs effective 3/1/2021. · T2 BMW M235iR allows 240iR/Evo package with 50 lb penalty, must run DOT tires. · Toyota Supra 2020- newly classified in T2 at 3450 lbs minimum weight with 295 tire and 19-inch wheels. · T2 Honda Civic Type-R gains allowance for PRL cold air intake #PRL PRL-HCR-INT-HVI. · T2 Porsche Carrera S 997.2 (06-08) weight reduced 50 lbs to 3225. · T2 Ford Mustang GT 5.0L (15-17) gear ratios corrected to 3.66, 2.43, 1.69, 1.32, 1.00, 0.65 or 4.17, 2.34, 1.52, 1.14, 0.87, 0.69. · T2 BMW Z4M 06-08 maximum wheel size increases from 18x9 to 18x10 inches. · T2 BMW M2 CS Cup 2020- and M235iR clarify homologation notes for DOT tires and BMW Motorsports components. · Formula Lites Crawford FL15 newly classified in FA. · GT2 Ford Mustang/Thunderbird Boss 302 firing order becomes unrestricted. · GT2 BMW E46 M3 weight reduced from 2600 to 2500 lbs. · BMW M2 CS Cup 2020+ classified in T2 at 3625 lbs with 2979cc engine, 10.5x18 wheels, 295 tires. · T2 and T3 Nissan 350Z and 370Z permit 44011-RC350 rear caliper kit and SZ350 rotors. · T4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.55 final drive, adds 25 lb penalty. · T3 and T4 FR-S, 86, and BRZ year ranges capped: T3 at 2021, T4 at 2017-2021. · FF class cylinder head may now have optional coolant bleed line fitting to top of head for air release. · FF Honda LC1 ECU by HPD permitted effective 12/1/2020, must use HPD lambda sensor. · GT2 Chrysler/Dodge/Plymouth 2429cc DOHC engine classified at 1950 lbs, unrestricted fuel induction. · T2 BMW E92 M3 (08-14) weight reduced 50 lbs to 3475, with detailed brake, spring, sway bar, and restrictor specs. · T2 Corvette C5 Z06 restrictor sizes increase to 53mm and 58mm; C6 LS2 to 56mm, LS3 to 50mm; Camaro SS/1LE weight drops 75 lbs to 3625; 2016+ Camaro restrictor to 56mm; Mustang GT 11-14 to 58mm, 15-17 to 55mm, 2018+ to 53mm; Viper SRT-10 th… · T3 Alfa Romeo 4C Launch Edition now allowed in Spec Lines. · GT2 stock car bodies removal rescinded; 1997-current year commercially available stock car bodies remain allowed. · GT2 Appendix L renumbering eliminates sections .17 through .19 after 4.8.4.2.10.3.6. · GT2 TA2 wing width maximum set to 65 -5/16 inches, previously undefined. · T2 Ford Mustang GT 5.0L and Ecoboost 2.3 sway bar part numbers added to notes. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · GT2 Chevrolet Corvette -2019 LS1/LS6 allows DORMAN part # 615-900 alternate intake manifold. · GT2 Porsche 997.2 GT3 Cup minimum weight drops to 2900 lbs. · T2 brake rotors expand from ferrous metal only to 2-piece ferrous disks with aluminum hats, within 5% OE diameter. · T2 Corvette C-5 Z06 loses 50 lbs to 3425; Camaro SS/1LE loses 50 lbs to 3650; Mustang GT and Boss 302 gain 275 to 295 tyres. · T2 Porsche Cayman S, Spyder (10-12) allows 800#/in front and 1000#/in rear springs, cooler ducting, rotor ducting, and specific Porsche and StopTech brake items. · FF Honda LC1 ECU implementation date changed from 3/1/2020 to pending availability of support materials. · GT2 BMW E46 M3, E36, Z3, and 5000cc V8 gain Trans Am SGT spec allowance: regular shifter 3000 lbs., paddle shifter plus 150 lbs. · GT2 allows up to four hood/fender louvered panels, max 600 sq inches total, min five slots each, mounted in front of windscreen. · T2 Ford Mustang EcoBoost and GT 5.0L gain three optional gear ratio sets for competition use. · FA stock engines not given weight adjustment; modified engines now allowed in class. · TA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration. · STO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules. · GT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged. · Cannot read: letter references external document #27663 not provided. · T2 Porsche Cayman S, Spyder (10-12) gains brake, suspension, and drivetrain upgrades: StopTech calipers, 800#/in front and 1000#/in rear springs, Porsche control arms, PDK allowed. · FA engine modifications wording clarified: bore/crankshaft/stroke/flywheel unrestricted if displacement limit met, distributor/transistor ignition allowed without engine modification, compression ratio increasable by machining/gasket chang… · FA transmission rules clarified: no more than five forward speeds and operational reverse gear unless Table 2 notes otherwise. · FA Swift 016 Mazda Duratec Gurney flap wording clarified; terminology and mounting rules unchanged. · GT2 Dodge Viper 8400 OEM minimum weight drops 50 lbs to 3275. · GT2 Chevrolet Corvette -2019 OEM minimum weight cut 50 lbs to 3275. · 2004 Mercedes Benz CLK 320 Coupe classified in T4 at 3200 lbs with 3299cc engine and Eibach PN# 2563.140 springs allowed. · T1 and T2 Corvettes may convert leaf spring suspension to coilover with 800 lb max spring rate allowed. · FA Volkswagen 1835cc SOHC removed from Table 1. · FA engine rules clarified: blocks and heads must be OEM unless Tables note exceptions. · GT2 Corvette LS6 may reduce weight by 50 lbs. · T2 BMW E92 M3 08-14 gains approved AP Racing brake kit part numbers 13.01.10038 front, 13.01.10053 rear. · T2 Chevrolet Corvette C5 Z06 loses 50 lbs with 45mm restrictor, to 3175; 50 lbs with 55mm restrictor, to 3350. · T3 BMW Z3 M & Coupe 1998-1999 weight reduced from 3350 to 3150 lbs. · FA Formula 1000 motorcycle-based engine compression ratio raised to 14.5:1 from 13.5:1. · FA removes Ex-FSV front wheel width 6–8 inches and rear 8–10 inches provisions; all cars use front 10 inches, rear 14–15 inches. · FA Formula 3 engines now allowed through 2017, previously 2008, with 30mm restrictor required. · FF alternator changes from not required to optional. · GT2 Panoz GT-S now allowed to use TA2 Choice Engine with any 5-speed H-pattern transmission. · GT2-ST Corvette LS2 restrictor increases from 70mm to 75mm flat plate. · GT2-ST Corvette L76 added: 5967cc, 3000 lbs minimum, 70mm flat plate restrictor. · T2 Porsche 911 997.2 allows GT3 Cup front fascia with 75 lb penalty; OEM rear deck lid and GT3 Cup splitter now required or prohibited. · T2 Ford Mustang GT 5.0L 15-17 transmission gear ratios corrected to two allowed options. · FA engine note clarification removes Table E reference, Pro Formula Mazda directed to Table 1. · FF allows Honda HPD LC1 low-cost ECU with lambda sensor; E1 ECU no longer supported but existing units permitted if sealed. · FF rain tyres now allow Hoosier W3 Radial in addition to existing Hoosier Wet option. · GT2 Porsche 991.2 GT3 Cup Car engine displacement increases from 3.8L to 4.0L. · T2 Porsche 911/997 (06-08, 09-12, Carrera S 06-08) aero rules relaxed; 997.2 adds 60mm restrictor and PDK +100lbs option. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · GT2 Chevrolet SS replaces Dodge Charger; all stock car bodies removed from GT2 in 2021. · Pontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18 x 9.5 inches, Sky weight drops to 3200 lbs. · T2 cars now allowed to use ferrous metal 2-piece brake rotors within 5% of OE diameter. · Mazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01. · T2 Nissan 370Z gains alternative Stoptech brake kit option with 50 lb weight penalty. · T2 Ford Mustang Ecoboost 2.3 loses 100 lbs to 3400, wheels widen to 19 x 11, intercooler TIR increases to 50mm. · T2 Mustang GT5.0L gets 19x11 wheels instead of 18x11, Brembro BBK weight penalty removed. · Formula 1000 motorcycle-based engine classified into FA, throttle bodies and ECUs unrestricted. · F1000 reclassified into FA with specification changes effective 2020-01-01. · FA Swift 016 2.3L Mazda Duratec restrictor reduced from 33mm to 31mm SIR, making it slower. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · 991.2 GT3 Cup Car classified in GT2 at 3100 lbs with 63mm throttle body restrictor. · GT2 Acura NSX minimum weight reduced from 3000 to 2700 lbs. · GT2 Porsche 991.1 GT3 Cup restrictor size increases from 67 mm to 70 mm. · GT2 Porsche 996/997.1 GT3 Cup minimum weight reduced 100 lbs, to 2800. · GT2/ST Corvette -2019 5967cc restrictor reduced from 75 mm to 70 mm. · T2 requires onboard fire system; T3 and T4 may have one per GCR 9.3. · T3 Ford Mustang EcoBoost 2015- gains three transmission gear ratio options. · T2 Chevrolet Camaro SS/1LE (10-14) adds Dailey Engineering dry sump P/N 20-02-0666-ASSY and other approved parts. · T2 Camaro SS 1LE gains approval for half shafts Drive Shaft Shop RA-5424 and RA-5425. · T2 Ford Mustang Boss 302 restrictor 54mm to 56mm; GT 5.0L 11-14 restrictor 52mm to 54mm; GT 5.0L 15-17 restrictor 50mm to 52mm; C5 Z06 weight 3525 to 3475 lbs; C6 weight 3450 to 3400 lbs; Porsche 911 997.2 restrictor 60mm to 57mm. · T2 Chevrolet Camaro 1LE 2016- weight reduced from 3600 to 3550 lbs. · T2 Honda Civic Type-R (2017-) weight reduced from 3050 to 3000 lbs; tire TIR requirement increased from 50mm to 51mm. · Mazda RX-8 Base/R3 (04-12) reclassified in T3 and T4 to include Sport and GT variants. · Toyota 86 GT (2017-) added to T3 and T4 Spec Line. · FA wheel dimension rules moved from Bodywork subsection to General section; no specification changes. · FA Mazda MZR 2.0 now limited to Ralt RT40, Ralt RT41, and Swift 014 chassis only. · FA Honda Civic K20Z3 engines consolidated: three separate base/uprated specs removed, replaced with single unified 1350 lb minimum weight spec for Swift 014/016. · FA Swift 014 Mazda MZR 2.0 piston minimum weight reduced from 320g to 280g. · T2-T4 spare tire/wheel rules clarified: removable covers can be removed with hardware and bracketry. · GT2 TA2 cars must weigh minimum 2930 lbs per current Trans Am rules or prior Appendix L. · T2 Cadillac CTS-V classification expanded from 06-07 to include 04-05 model years. · T2 Cadillac CTS-V 06-07 allowed to use Hotchkiss sway bars up to 36mm front, 25mm rear. · T2 Cadillac CTS-V 06-07 requires 57mm flat plate restrictor. · T2 Ford Mustang GT 5.0L tire size reduced from 315 to 295. · FA Line N minimum weight increases to 1375 lbs. · GT2 Toyota Supra 3SGTE newly classified at 2900 lbs minimum weight, 43mm restrictor. · Acura NSX All Years classified to GT2-ST: 3.5L turbo, 3000 lbs minimum, 43mm restrictor. · GT2 TA2 minimum weight increases from 2830 to 2930 pounds. · T2 2018+ Audi TT RS gains suspension and intercooler allowances: 30mm front sway bar, 28mm rear, 1200lb/in springs, aftermarket intercooler. · T2 Honda Civic Type-R 2017- weight rises 2900 to 3050 lbs, TIR increases 38mm to 50mm. · FA cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. · GT2 BMW E36/E46 4.5L V8 classified at 2950 lbs minimum weight. · GTX tube frame cars gain fuel injection with 90mm maximum throttle body size. · Ligier JS2 R classified in GTX, no performance parameters specified in filing. · GT2 Ford Mustang 5.2L classified at 3300 lbs minimum with 82mm single throttle body restrictor. · GT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b. · T2 Mustang GT anti-roll bars may now be removed or disconnected, previously required as manufactured. · FA Formula 3 car sequential gearbox weight penalty of 25 lbs removed; minimum weight now 1215 lbs. · GT2 Porsche Cayman model years change from 05-11 to 05-15. · GT2 Porsche Cayman adds 4.0L engine with 65mm flat plate restrictor at 2700 lbs minimum weight. · T1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor. · T2 Audi TT RS (2018-) newly classified at 3400 lbs minimum weight with 19-inch wheels and 275 tire size. · T2 2017 Civic Type R allows any sway bar front/rear up to 30mm, front springs to 800lb, rear to 2000lb. · T4 Mazda MX-5 Club (06-15) and (2016-), T3 MX-5 Cup and Miata (2016-) hardtop rules clarified; wording changes to permitted parts and specifications. · T2, T3, T4 now allow any thermostat serving only OE intent, previously restricted. · T2 Ford Mustang Boss 302 (12-13) weight drops 50 lbs to 3500. · T2 Corvette C6 Coupe/Grand Sport removes 3.0 degrees MAX front camber restriction. · T2 Pontiac Firebird and Chevrolet Camaro SS (98-02) permitted spring relocation to shock. · T3 and T4 Mazda MX-5 Miata eligibility capped at 2018 model year, effective 2019-03-01. · Ford Mustang GT 5.0L 2018+ classified in T2 at 3600 lbs with 50mm restrictor, 19x11 wheels, 315 tyres. · FA Swift 014-Mazda MZR 2.0 engine now requires OE block casting #LF95 and specific OE components instead of sealed Elite Engines sourcing. · FA Swift 016 Mazda Duratec 2.3L and 2.5L minimum weight increases from 1420 to 1450 lbs. · FF Honda Fit permitted to use 0.25mm oversize pistons, cylinder honing increased to 73.315mm maximum. · FF heat shield rule clarified: thermal wrap allowed on manifold exterior if easily removable for inspection. · FF catch tank minimum capacity rules clarified: coolant catch tank now one U.S. pint minimum, oil catch tank one U.S. quart minimum. · GT2 BMW E46 M3, E36, Z3, and 5000cc V8 now permit Flossman body kit. · GT2 TA2 cars: wheels cost cap drops to $175 each, carbon fiber allowed on rear wing, engine setback maximum 21.75 inches (A-F) or 24 inches (G), various nomenclature and clarification updates. · BMW 1 Series E82 classified into GT2 with N52B30 engine, 2996 cc, 2140 lbs minimum weight. · GT2 Porsche Cayman 05-11 base weight drops 75 lbs to 2800; adds STO/X51 motor notes. · GT2 Ford Mustang 05- with 5.2L Aluminator engine classified: 3400 lbs minimum weight, 2×41mm flat plate restrictor. · GT2 Porsche 996/997.1 GT3 Cup adds 3.6L displacement and 2900 lbs minimum weight; removes aftermarket exhaust header allowance for 996. · GT2 Ford Mustang FP350S minimum weight reduced 100 lbs, to 3400. · GT2 Ford Mustang 05- EcoBoost classified: 3500cc, 3200 lbs minimum, 41mm restrictor. · GT2 Mazda RX7 Downing GTS body kit allowed without 75 lbs. weight penalty. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified. · T4 Ford Fiesta ST years corrected to 14-; T4 Fiat 124/Abarth Edition years added 16-18; battery rule clarified. · T2 Porsche Cayman S/GTS model years expanded from 13-14 to 13-15, now includes GTS variant. · T2 Honda Civic Type-R 2017- allows Cuztom Tuning FG-CIV16-V3-TR-BK alternate grill. · T1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes. · T2-T4 subframe bushings may now be replaced with non-spherical bushings of any material.showhide
GT2 GT2 Mazda 13B Turbo #33729engineunclearGT2 Mazda 13B Street Port turbo changes from EFR 76/70 to BW7670 or Garrett G30-660 with 46mm TIR at 2280 lbs.
T2 Mustang OEM Grill Request #33333aeroaeroT2/T3 Mustang GT 5.0L and V6 (11-14) may remove upper grille fog lights, replace with mesh or screen.
FA BDA Displacement #33431wordingwordingFA BDA engine displacement specification line added to Table 1, effective 2023-01-01.
GT2 Request Permission to Use a Substitute Turbo #33337inductionfasterGT2 Porsche SOHC 2478/2681/2992 turbo sizes increase from 42mm to 44mm SIR to TIR.
GT2 Request to Reduce Restriction on C7 GT2 Corvette #33342inductionfasterGT2-ST Chevrolet Corvette 14-19 L76 5967 restrictor increases from 70 to 73 mm.
GT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V Engine Request #33415cars addedcars addedGT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines newly classified in spec line.
GT2 GT2 Mazda 13b turbocharger part # update #33437enginefasterGT2 Mazda 13B Street/Bridge Port turbocharger changes from EFR 70/76 to 76/70, compressor from 42mm to 46mm.
GT2 GT2-ST BMW E36/46 spec line remove #33610wordingwordingGT2-ST BMW E36/46 spec line adds MA Shaw carbon/composite door offerings to Notes.
GT2 GT3 Choke option effective 1-01-2023 #33669inductioninductionGT3 normally aspirated cars may use intake chokes instead of SIRs, fitted to each carburetor barrel, same size as required SIR.
GT2 GT3 2.0L choke/weight option #33670inductionfasterGT3 2.0L 4-valve non-turbo engines may run unrestricted at 2060 lbs instead of with a choke restriction.
T2 BMW M235iR/M240iR Aftermarket 2WNR Shocks Allowed - Touring 2 #33464weight -50 lbsfasterT2 BMW M235iR weight reduced 50 lbs to 3350, aftermarket shocks now allowed.
T2 Touring (T2-T5) Category #33617cars addedcars addedT5 class added as regional-only; T5 tyres maximum width 225, minimum aspect ratio 45.
T2 ENO 9.1.9.2.D.1.e.1.a. #33651suspension & brakessuspension & brakesT2-T5 Touring front and rear suspension maximum negative camber changed to 3.5 degrees.
FA Reclassify 2010-2017 Formula Renault 2.0 as a spec line car in FA #33395cars addedfasterFormula Renault 2.0 (10-17) reclassified from FX to FA; weight reduced to 1280 lbs, restrictor removed.
FA Change Swift 016 2.3L restrictor size and minimum weight #33472induction -30 lbsfasterFA Swift 016 2.3L restrictor increases from 31mm to 32mm SIR; minimum weight drops 30 lbs to 1420.
GT2 GT2 (TA2)/GTA Part Number Update #33315wordingwordingGT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870.
GT2 Ginetta G56 GTA - Optional Wheels #33357tyres & wheelstyres & wheelsGT2 Ginetta G56 GTA gains optional 18" x 9" and 18" x 10" wheels.
T2 Heavy Cars #33345weight +125 lbsslowerT2 Dodge Viper SRT-10 wheel size 18x11 rear, weight to 3675 lbs, throttle restrictor hole 44mm convertible or 42mm hardtop.
GT2 Allow the MAShaw Body Kit on the GT2/ST Spec Line for BMW E36/E46 #32447aerofasterGT2/ST BMW E36/E46 now allows MAShaw body kit parts: wide body, bumpers, fenders, rockers, flairs.
FA Pro Formula Mazda Dimension E&O #33160wordingwordingPro Formula Mazda allows street or bridge port, unrestricted apex seals, 70mm throttle body, 99cm wing height max, 132cm bodywork width max.
GT2 Request for C5/C6 Corvette Restrictor Size Review #32982inductionfasterGT2 Chevrolet Corvette L76 5967 restrictor increases from 73mm to 74mm.
GT2 Tail lights on all GT category race cars. #32799wordingwordingGT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only.
GT2 Addendum to letter #32514 Ginetta GTA G56 #33076cars addedcars addedGinetta GTA G56 added to GT2 as spec car: 2600 lbs, 3.7L Ford V6 sealed, 6-speed Quaife sequential.
GT2 Information requested for carbon roofs on BMW E36/E46 cars in GT2 #32682wordingwordingGT2 BMW E36/E46 carbon roof and door suppliers added to notes: Lang Racing, 2M Automotive, Flossmann, MA Shaw.
GT2 Request to Allow the 95mm S54 BMW Crankshaft in GT2-ST #32698weightslowerGT2-ST BMW E46 M3, E36, Z3, 5000cc V8 can use 95mm S54 crankshaft at +150 lbs.
GT2 Request to classify Audi R8 FIA GT4 to GT2 #32805cars addedcars addedAudi R8 GT4 classified to GT2 with 5.2L displacement, 3000 lbs minimum weight, per factory specs restrictor.
T2 BMW M235iR/M240iR Min Weight Clarification #32430wordingfasterT2 BMW M235iR/M240iR: 240iR/Evo package now permitted without 50 lb penalty; Evo package clarified to 75 lbs.
T2 Follow up to Letter 30888 #32477suspension & brakesfasterT2 BMW E92 M3 (08-14) permitted to use Fall Line Suspension arms from G8X/F8x/E9x M3, E9x M3/E82 1M.
FA Update FR Americas rulebook requirement #32491wordingwordingFA Ligier JS F3 must comply with Formula Regional Americas rules instead of FIA Formula 3 Regional Technical Regulations.
FA Clarify verification of sealed engine compliance #32522wordingwordingFA sealed engines must undergo full inspection; competitor pays reassembly and resealing costs.
FA Clarify Formula Lites and FR Americas sealed engine requirement #32523wordingwordingFA Formula Lites FL15 and FR Americas Ligier JS F3 engine sealing requirements clarified to reference respective series technical regulations.
GT2 Typo in rules for shocks #32308wordingwordingGT2 shock absorber attachment points clarified as moveable; wording correction only.
GT2 additional response to letters #31898 & 32083 #32424weight +140 lbsslowerGT2 Porsche 104.0 x 88.0 engine weight increases from 1950 to 2090 lbs; 2V variants may use Borg Warner EFR 76/70 42mm turbo.
T2 Request Alternate Front & Rear Strut/Shock Top Hats #32452suspension & brakessuspension & brakesT2-T4 Touring cars with alternative springs may use performance top hats with spherical bearings on shocks and struts.
T2 Request BoP E92 torque #32456wordingwordingT2 BMW E92 M3 (08-14) note reference changed from 77 to 78.
T2 Classify Cadillac Blackwing #32535cars addedcars addedCadillac CT4-V Blackwing (2022+) classified in T2 at 3800 lbs with 94 x 85.6mm engine.
FA E&O FA Transmission section #32251wordingwordingFA transmission rule clarified: transverse shafts prohibited except final drive and motorcycle gearbox in Formula 1000.
FA E&O Swift 016 2.5 liter Aero column #32363wordingunclearFA Swift 016 2.5 liter aero spec now references 2.3 liter notes instead of N notes.
T2 Request to Allow the Use of Aftermarket ECU's in Touring #31067weightslowerT2-T4 cars model year 2018+ may use non-OEM ECU with 75 lb weight penalty via spec line adjustment.
T2 BMW M2 CS Cup 2020- Exhaust #32243wordingunclearBMW M2 CS Cup 2020- now permits specific exhaust part #18302459928 and hot country package cooling parts.
FA Closing the Gap #31934inductionfasterFA Pro Formula Mazda now allows street port or bridge port, previously porting was prohibited.
GT2 Request to Classify Ginetta G40 in GT2 #31597cars addedcars addedGinetta G40 classified in GT2 with Mazda MZR/L5-VE engine, 2488cc or 2399cc, 1950 lbs base weight.
GT2 2021 Supra GR GT4 #31737cars addedcars addedToyota Supra GT4 added to GT2-ST: 3000cc, 3000 lbs minimum, factory restrictor.
GT2 Proposed Technical Bulletin #31900wordingunclearGT2 Porsche 944/924 may use ERC 76/70 Turbo instead of Jayco super 50.
T2 Reply to letter #31486/29879 T2-T4 Grill openings #31935aerofasterT2-T4 grill openings may remove non-metallic webbed false sections; 16 square inch limit removed.
T2 C6 Restrictor Help #31995inductionfasterT2 Chevrolet Corvette C6 LS2 restrictor increases from 56mm to 58mm.
FA Reorganize Tables 1 and 2 #31985cars addedcars addedFA adds Honda K20Z3 2.0L engine spec at 1350 lbs minimum and Mazda MZR 2.0L spec at 1300 lbs minimum to Table 1.
GT2 GT2/ST Porsche Cayman #31451 correct TBR size error #31991enginefasterGT2 Porsche Cayman 05-15 turbo restrictor increases from 70mm to 75mm.
T2 BMW Z4M Adjustment #31885weight -50 lbsfasterT2 BMW Z4M 06-08 weight reduced from 3150 to 3100 lbs.
GT2 Restrictor Clarification for 2015 Cayman #31451wordingunclearGT2 Porsche Cayman 05-15 uses Throttle Body Restrictor instead of Flat Plate Restrictor at 2700 lbs.
T2 Touring 2 BOP adjustments for 2022 #31480weight -50 lbsfasterT2 Dodge Viper SRT-10 loses 50 lbs to 3550; throttle restrictor hole shrinks from 43mm to 41mm.
T2 Reply to letter 29879 T2-T4 Grill Openings #31486aerofasterT2-T4 clarified: grill opening area may increase max 16 sq in for radiator cooling only, retaining factory mesh shape.
T2 Request to clarify radiator hoses #31682wordingwordingT2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted.
T2 Clarify Permitted/Allowed #31743wordingwordingT2, T3, T4 clarify that spec lines listing permitted or allowed parts are alternatives to category rules, not replacements.
T2 SMG #31837wordingwordingT2 Spec Mustang model designation changed to Ford Spec Mustang.
T2 Typo for BMW M2 CS Cup 2020 #31173suspension & brakesslowerT2 BMW M2 CS Cup 2020 rear brake rotor reduced from 390 mm to 380 mm.
T2 Request to Classify 2014 VW Jetta 1.8t TSI #30436cars addedcars addedT4 Volkswagen Passat, Jetta 1.8T adds 2014 model year to eligible years.
T2 Request new car 2017 BMW M2 #30486cars addedcars addedBMW M2 (2017+) added to T2 with 2979cc engine, 10.5x18 wheels, 295 tires, 3650 lbs weight.
T2 Request to Classify Porsche 997.2 GTS in T2 (body not = to C2S) #30686cars addedcars addedPorsche 911 997.2 GTS (09-12) classified in T2 at 3400 lbs with 60mm flat plate restrictor required.
GT2 Turbo Request for 13B Engine #30656engineunclearGT2 Mazda 13B street port adds EFR 70/76 turbo with 42mm restrictor at 2280 lbs.
GT2 Request car classification #31032cars addedcars addedGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
FA E&O Table 2 engine names #31085wordingwordingFA Mazda MZR 2.0 spec line removes redundant '2.0' designation; Honda Civic K20Z3 spec line unchanged.
GT2 Correct letter 30565 GT2/ST #31088weightfasterGT2 Dodge Viper Comp Coupe ACR/ACR-X loses 100 lbs minimum weight to 3275.
T2 BMW M2 CS Power Stick Part Number #31087wordingwordingT2 BMW M2 CS Cup 2020- must run Purple power stick, part #8324089 instead of #TBD.
FA Move Toyota 1800 to Table 2 #30822cars addedcars addedFA Toyota 1800 moves from Table 1 to Table 2 (Spec Line Cars).
FA E&O Swift 016 wheel width reference #30939wordingwordingFA Swift 016 Mazda MZR/Ford Duratec wheel width specification clarified: front 10, rear 14 minimum and 15 maximum.
GT2 Request the 04-06 Pontiac GTO WC Car Be Added to the GT2/ST Chart #30339cars addedcars added04-06 World Challenge Pontiac GTO added to GT2-ST: 6062 cc, 3000 lbs minimum, unrestricted.
GT2 Request to Update GTA Obsolete Part Numbers #30615wordingwordingGTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix.
GT2 GTX class correction to GT2/ST #30973cars addedcars addedGrullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted.
T2 997.1 EO #30933wordingwordingT2 Porsche 911/997.1 (06-08) now allows alternate Cargraphics CARP97DFIFKR exhaust manifold.
FA Update FA rules package #30717wordingwordingFA rule wording clarified: Table 1 for purpose-built and ex-pro cars, Table 2 for spec line cars with exceptions noted.
FA Move Mazda MZR/Ford Duratec 2296cc and 2500cc to Table 2 #30718wordingwordingFA Mazda MZR/Ford Duratec 2296cc and 2500cc moved from Table 1 to Table 2.
FA Clean up Table 2 Mazda MZR 2.0L and Honda Civic K20Z3 spec lines #30719wordingwordingFA Mazda MZR 2.0 and Honda Civic K20Z3 remove sequential designation from 5-speed transmission spec.
GT2 Porsche Cayman Engine Modification and Engine Request #30472inductionfasterGT2-ST Porsche Cayman restrictor increases from 65mm to 75mm flat plate at 2700 lbs.
GT2 Request weight clarification Viper CC #30565weightfasterGT2 Dodge Viper including Comp Coupe, ACR/ACR-X minimum weight reduced 100 lbs to 3275 in VRL Spec.
GT2 Variance, 2021 TA2 Rules vs GCR Appendix L #30641wordingwordingTA2 minimum weight set to 2930 lbs with free tire make and size.
T2 Request #30406weightfasterT2 BMW M2 CS Cup 2020- weight increases from 3625 to 3600 lbs; mandatory Purple power stick added.
FA E&O Mazda MZR 2.0 and Honda Civic K20Z3 chassis eligibility #30632wordingwordingFA Mazda MZR 2.0 limited to Ralt RT40, RT41, Swift 008, 014 chassis; Honda Civic K20Z3 removes Swift 016 chassis.
T2 Civic Type R Brake Rotors #29817weightslowerT3 Honda Civic Type-R 2020+ allows brake rotor 45251-TGH-A01 with 25 lb penalty.
T2 Mustang S550 Parity in T2 #29925inductionfasterT2 Ford Mustang GT 5.0L 15-17 restrictor grows 55mm to 58mm; 2018- grows 53mm to 55mm.
T2 Request BOP on BMW Z4 T2 car #30597weight +50 lbsslowerT2 BMW Z4M 06-08 weight increases from 3100 to 3150 lbs.
T2 E92 #30639weight -50 lbsfasterT2 BMW E92M3 08-14 weight drops 50 lbs to 3425, intake restrictor reduces 3mm to 77mm.
FA Correct engine name in Swift 016 2.3 liter spec line #30447wordingwordingFA Swift 016 2.3 liter engine name corrected to Mazda MZR/Ford Duratec.
FA Correct engine name in Swift 016 2.5 liter spec line #30448wordingwordingFA Swift 016 2.5 liter engine name corrected to Mazda MZR/Ford Duratec.
FA Revise Table 1 Spec Lines and clarify application of Engine Notes #30456cars addedunclearFA removes four spec lines and replaces Ford Duratec/Mazda MZR with Honda B16 at 1615cc, 1175 lbs minimum.
T2 C5/6 Corvette in T1, T1-LP and T2 Dry Sump Standardization #29046wordingwordingT2 C5 and C6 Corvettes permit specific dry sump kits and minor air dam trimming up to 3.9 cm depth.
T2 Request for Chevrolet Camaro 1LE (2016-) Auto Trans #29067wordingunclearT2 Chevrolet Camaro 1LE auto trans gets new gear ratios and 2.77 final drive ratio.
T2 Request to add 2015 to Chevrolet Camaro SS/1LE 2010-2014 #29736cars addedcars addedT2 Chevrolet Camaro SS/1LE model years expanded from 2010–2014 to 2010–2015.
FA Update Table 1 Weights for Spec Lines C, I, and K #30355weight -25 lbsfasterFA Spec Line C loses 25 lbs to 1175; Line I loses 75 lbs to 1175; Line K gains 15 lbs to 1175.
FA Remove redundant reference in Table 2 spec line #30366wordingfasterFA purpose built and ex-Pro Atlantic cars lose 25 lb sequential transmission penalty wording.
FA Correct the name of the FR Americas car #30369wordingwordingFA Ligier JS F3 car name corrected in FR Americas spec line.
FA Clean up Spec Line D in Table 1 #30372wordingwordingFA Ford Duratec/Mazda MZR 2500 spec line D wording cleanup: 4-valve becomes 4 valves per cylinder.
FA Table 2 Honda K20Z3 request #30386inductionfasterFA Honda Civic K20Z3 intake manifold and throttle body assembly now allows AT Power Direct-To-Head 45mm individual throttle bodies as alternative to HPD parts.
FF Kent crankshaft clarification #30426wordingwordingFF block relief permitted only as needed to fit allowed crankshaft.
GT2 GT2 tiger firing order #30421wordingwordingGT2 Sunbeam SBF 302 engine firing order option now explicitly allows Boss 302 variant.
T2 Request consistency review in GCR #30263wordingslowerT2-T4 clutch disc and pressure plate must be at least 95% of factory OEM weight.
T2 Class Spec Corvette in T2? #30297cars addedcars addedSpec Corvette newly classified in T2 at 3375 lbs with 53mm restrictor and 3.75" minimum ride height required.
T2 E92 BMW Spring Rate Request #30391suspension & brakesfasterT2 BMW E92 M3 front and rear springs increased to 1000 lbs/in from 800.
T2 Please correct recent T2 Spec Line #30401suspension & brakessuspension & brakesT2 Toyota Supra 2020- spring rates limited to 800# front and 1000# rear maximum.
FA E&O FA Intake Restrictors #30273inductionslowerFA Ford Duratec/Mazda MZR intake restrictor reduced from 32mm to 30mm SIR; Swift 016 2.5 Mazda restrictor reduced from 35mm to 33mm SIR.
FA Clean up Spec Lines A and B in Table 1 #30274wordingwordingFA Toyota 4A-GE engines cleaned up, spec lines A and B engine designations corrected.
FA Clean up Spec Line C in Table 1 #30275enginefasterFA Ford BD Series max displacement increases from 1600 to 1615 cc, minimum weight stays 1200 lbs.
FA Clean up Spec Lines J and L in Table 1 #30276wordingwordingFA Ford Duratec/Mazda MZR and Honda B16 both now 1615cc max displacement; Honda B16 removes NA requirement.
FA Move engine specifications to Pro Formula Mazda spec line notes #30278wordingwordingFA Pro Formula Mazda engine specs moved from Table 1 to Table 2 notes; Renesis Rotary details consolidated.
FA Update F3 Americas spec line #30280wordingunclearFA F3 Americas spec line updated effective 2021-03-01; specific changes not legible in provided text.
GT2 GT2-ST CORVETTE CHANGES #30029weight +100 lbsslowerGT2-ST Corvette (-2019) LS2 and L76 5967cc gain 100 lbs minimum weight to 3100; 6162cc variants gain 50–100 lbs; 7011 gains 100–50 lbs; L76 restrictor opens 70 to 73 mm.
GT2 29742 Change new wording to read as: #30329wordingwordingGT2 Ford Mustang/Thunderbird Boss 302 firing order now optional from later SBF 302 versions.
T2 Request BMW M2CS door glass removal #30254aerofasterT2 BMW M2 CS Cup 2020- permitted to remove door glass and mechanism.
GT2 ABS Restrictions #30064wordingwordingGT2 ABS braking systems now allowed if shown on individual Spec Line.
T2 Request Addition of BMW M240iR #29503cars addedslowerT2 BMW M235iR allows 240iR/Evo package with 50 lb penalty, must run DOT tires.
T2 2021 Toyota Supra #29567cars addedcars addedToyota Supra 2020- newly classified in T2 at 3450 lbs minimum weight with 295 tire and 19-inch wheels.
T2 Request Cold Air Intake for Honda Civic Type R #29942wordingwordingT2 Honda Civic Type-R gains allowance for PRL cold air intake #PRL PRL-HCR-INT-HVI.
T2 Adjust T2 spec line that was missed in T2 BOP #30055weight -50 lbsfasterT2 Porsche Carrera S 997.2 (06-08) weight reduced 50 lbs to 3225.
T2 Fix T2 Mustang spec line #30106wordingwordingT2 Ford Mustang GT 5.0L (15-17) gear ratios corrected to 3.66, 2.43, 1.69, 1.32, 1.00, 0.65 or 4.17, 2.34, 1.52, 1.14, 0.87, 0.69.
T2 Z4 Wheel Size #30113tyres & wheelsfasterT2 BMW Z4M 06-08 maximum wheel size increases from 18x9 to 18x10 inches.
T2 Clarify T2 Spec lines #30194wordingwordingT2 BMW M2 CS Cup 2020- and M235iR clarify homologation notes for DOT tires and BMW Motorsports components.
FA Request to classify Formula Lites Crawford FL15 #29702cars addedcars addedFormula Lites Crawford FL15 newly classified in FA.
GT2 Request change to engine firing order rule #29742engineunclearGT2 Ford Mustang/Thunderbird Boss 302 firing order becomes unrestricted.
GT2 Request E-46 BMW M3 balance of performance #29833weight -100 lbsfasterGT2 BMW E46 M3 weight reduced from 2600 to 2500 lbs.
T2 Request to Classify BMW M2 CS #29523cars addedcars addedBMW M2 CS Cup 2020+ classified in T2 at 3625 lbs with 2979cc engine, 10.5x18 wheels, 295 tires.
T2 350Z Rear Caliper Replacement #29710wordingwordingT2 and T3 Nissan 350Z and 370Z permit 44011-RC350 rear caliper kit and SZ350 rotors.
T2 Request Mustang 8.8†rear axle replacement #29860weightslowerT4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.55 final drive, adds 25 lb penalty.
T2 Cap year range on all 86s #29908wordingwordingT3 and T4 FR-S, 86, and BRZ year ranges capped: T3 at 2021, T4 at 2017-2021.
FF Allow Optional Coolant Bleed Line to Correct a Known Problem #29673wordingwordingFF class cylinder head may now have optional coolant bleed line fitting to top of head for air release.
FF Clarification regarding Honda LC1 ECU implementation date #29684wordingwordingFF Honda LC1 ECU by HPD permitted effective 12/1/2020, must use HPD lambda sensor.
GT2 Request for Bigger Engine in Plymouth Breeze #29380cars addedcars addedGT2 Chrysler/Dodge/Plymouth 2429cc DOHC engine classified at 1950 lbs, unrestricted fuel induction.
T2 Request to Reevaluate T2 Spec Line for E92 M3 #28266weight -50 lbsfasterT2 BMW E92 M3 (08-14) weight reduced 50 lbs to 3475, with detailed brake, spring, sway bar, and restrictor specs.
T2 Request for Parity Among Vehicles Including S550 Mustang #29486induction -75 lbsfasterT2 Corvette C5 Z06 restrictor sizes increase to 53mm and 58mm; C6 LS2 to 56mm, LS3 to 50mm; Camaro SS/1LE weight drops 75 lbs to 3625; 2016+ Camaro restrictor to 56mm; Mustang GT 11-14 to 58mm, 15-17 to 55mm, 2018+ to 53mm; Viper SRT-10 th…
T2 Alfa Romeo 4C Launch Edition #29531wordingwordingT3 Alfa Romeo 4C Launch Edition now allowed in Spec Lines.
GT2 rescind GT2 stock car bodies removal #29219cars addedfasterGT2 stock car bodies removal rescinded; 1997-current year commercially available stock car bodies remain allowed.
GT2 E&O Typos in Appendix L #29447wordingwordingGT2 Appendix L renumbering eliminates sections .17 through .19 after 4.8.4.2.10.3.6.
GT2 GT2 wing width wording correction #29469wordingwordingGT2 TA2 wing width maximum set to 65 -5/16 inches, previously undefined.
T2 Request 2018+ mustang swaybar update #28659wordingwordingT2 Ford Mustang GT 5.0L and Ecoboost 2.3 sway bar part numbers added to notes.
GT2 GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
GT2 Corvette GT2-ST intake manifold #29221wordingwordingGT2 Chevrolet Corvette -2019 LS1/LS6 allows DORMAN part # 615-900 alternate intake manifold.
GT2 997.2 E&O link to 27915 #29373weightfasterGT2 Porsche 997.2 GT3 Cup minimum weight drops to 2900 lbs.
T2 Request to Clarify New 2-piece Brake Rotor Rule #29106wordingwordingT2 brake rotors expand from ferrous metal only to 2-piece ferrous disks with aluminum hats, within 5% OE diameter.
T2 please consider BoP for the following cars in T2 #29266weight -50 lbsfasterT2 Corvette C-5 Z06 loses 50 lbs to 3425; Camaro SS/1LE loses 50 lbs to 3650; Mustang GT and Boss 302 gain 275 to 295 tyres.
T2 Request clarification on most recent approval by the Board #29284wordingwordingT2 Porsche Cayman S, Spyder (10-12) allows 800#/in front and 1000#/in rear springs, cooler ducting, rotor ducting, and specific Porsche and StopTech brake items.
FF Clarification regarding Honda LC1 ECU implementation #29135wordingwordingFF Honda LC1 ECU implementation date changed from 3/1/2020 to pending availability of support materials.
GT2 Request for allowance Trans Am SGT #28951wordingwordingGT2 BMW E46 M3, E36, Z3, and 5000cc V8 gain Trans Am SGT spec allowance: regular shifter 3000 lbs., paddle shifter plus 150 lbs.
GT2 Omitted GT2 fender/hood openings #29171aeroaeroGT2 allows up to four hood/fender louvered panels, max 600 sq inches total, min five slots each, mounted in front of windscreen.
T2 Request to correct GCR for 2018+ FORD Mustang GT & Ecoboost #28803wordingwordingT2 Ford Mustang EcoBoost and GT 5.0L gain three optional gear ratio sets for competition use.
FA Request to Adjust FB Weight for Stock Engines #29005wordingwordingFA stock engines not given weight adjustment; modified engines now allowed in class.
GT2 TA2 Gurney flap wicker clarification #28874wordingwordingTA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration.
GT2 STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
T2 Request to Add a Vehicle to the Roster (contd.) #27698cars addedunclearCannot read: letter references external document #27663 not provided.
T2 Request brake upgrade and electric power steering pump #28946suspension & brakesfasterT2 Porsche Cayman S, Spyder (10-12) gains brake, suspension, and drivetrain upgrades: StopTech calipers, 800#/in front and 1000#/in rear springs, Porsche control arms, PDK allowed.
FA E&O permitted engine modifications #28831wordingwordingFA engine modifications wording clarified: bore/crankshaft/stroke/flywheel unrestricted if displacement limit met, distributor/transistor ignition allowed without engine modification, compression ratio increasable by machining/gasket chang…
FA E&O Transmissions #28832wordingwordingFA transmission rules clarified: no more than five forward speeds and operational reverse gear unless Table 2 notes otherwise.
FA Swift 016 Gurney flap wicker clarification #28884wordingwordingFA Swift 016 Mazda Duratec Gurney flap wording clarified; terminology and mounting rules unchanged.
GT2 Request to Adjust Weight of OEM 8.4 Viper #28739weight -50 lbsfasterGT2 Dodge Viper 8400 OEM minimum weight drops 50 lbs to 3275.
GT2 Request to Adjust Weight of OEM Chevrolet Corvette #28896weight -50 lbsfasterGT2 Chevrolet Corvette -2019 OEM minimum weight cut 50 lbs to 3275.
T2 Request to Classify 2004 Mercedes Benz 320 CLK #27663cars addedcars added2004 Mercedes Benz CLK 320 Coupe classified in T4 at 3200 lbs with 3299cc engine and Eibach PN# 2563.140 springs allowed.
T2 Consider coil spring conversion Corvette in T2 #28824suspension & brakessuspension & brakesT1 and T2 Corvettes may convert leaf spring suspension to coilover with 800 lb max spring rate allowed.
FA Remove redundant spec line in Table 1 #28720removedremovedFA Volkswagen 1835cc SOHC removed from Table 1.
FA E&O general engine rules #28772wordingwordingFA engine rules clarified: blocks and heads must be OEM unless Tables note exceptions.
GT2 Request Corvette engine parity #28576weightfasterGT2 Corvette LS6 may reduce weight by 50 lbs.
T2 Please Add the Following BBK to Allowed List for E92 M3 #28421suspension & brakessuspension & brakesT2 BMW E92 M3 08-14 gains approved AP Racing brake kit part numbers 13.01.10038 front, 13.01.10053 rear.
T2 C5 Weight Adjustment #28433weight -50 lbsfasterT2 Chevrolet Corvette C5 Z06 loses 50 lbs with 45mm restrictor, to 3175; 50 lbs with 55mm restrictor, to 3350.
T2 Z3M Roadster Weight #28437weightfasterT3 BMW Z3 M & Coupe 1998-1999 weight reduced from 3350 to 3150 lbs.
FA Request higher compression ratio and prior weights for F1000 cars #28162enginefasterFA Formula 1000 motorcycle-based engine compression ratio raised to 14.5:1 from 13.5:1.
FA Remove redundant wheel dimension provisions #28554wordingwordingFA removes Ex-FSV front wheel width 6–8 inches and rear 8–10 inches provisions; all cars use front 10 inches, rear 14–15 inches.
FA E&O Formula 3 spec line #28596enginefasterFA Formula 3 engines now allowed through 2017, previously 2008, with 30mm restrictor required.
FF E&O FF Kent Engine alternator language #28204wordingwordingFF alternator changes from not required to optional.
GT2 Request to revisit Panoz GT-S BoP #28280wordingunclearGT2 Panoz GT-S now allowed to use TA2 Choice Engine with any 5-speed H-pattern transmission.
GT2 GT2-ST Corvette LS2 & L76 #28583inductionfasterGT2-ST Corvette LS2 restrictor increases from 70mm to 75mm flat plate.
T2 Limit Changes to the 997.2 Porsche #28242aeroslowerT2 Porsche 911 997.2 allows GT3 Cup front fascia with 75 lb penalty; OEM rear deck lid and GT3 Cup splitter now required or prohibited.
T2 Correct T2 Mustang Transmission #28732wordingunclearT2 Ford Mustang GT 5.0L 15-17 transmission gear ratios corrected to two allowed options.
FA FA weight correction/clarification #28430wordingwordingFA engine note clarification removes Table E reference, Pro Formula Mazda directed to Table 1.
FF Honda Racing HPD low cost ECU proposal #27563engineengineFF allows Honda HPD LC1 low-cost ECU with lambda sensor; E1 ECU no longer supported but existing units permitted if sealed.
FF Update rain tire designation #28443tyres & wheelstyres & wheelsFF rain tyres now allow Hoosier W3 Radial in addition to existing Hoosier Wet option.
GT2 Request 991.2 Porsche engine displacement verify typo #28194enginefasterGT2 Porsche 991.2 GT3 Cup Car engine displacement increases from 3.8L to 4.0L.
T2 Request to Readjust the T2 Porsches #27746aeroslowerT2 Porsche 911/997 (06-08, 09-12, Carrera S 06-08) aero rules relaxed; 997.2 adds 60mm restrictor and PDK +100lbs option.
GT2 Windshield Clips #27323wordingwordingGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
GT2 Request to Add Chevrolet SS Body to Appendix L #27898cars addedcars addedGT2 Chevrolet SS replaces Dodge Charger; all stock car bodies removed from GT2 in 2021.
T2 Please Switch the Solstice GXP as Specified in T2, to T3 #27413cars added -50 lbsfasterPontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18 x 9.5 inches, Sky weight drops to 3200 lbs.
T2 Request for Two Piece Stop Tech Brake Rotors #27582otherotherT2 cars now allowed to use ferrous metal 2-piece brake rotors within 5% of OE diameter.
T2 Request to Classify all Mazda RX8 Models in T3/T4 #27606cars addedcars addedMazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01.
T2 Request for Alternative Brake Kit on Nissan 370Z #27912suspension & brakesslowerT2 Nissan 370Z gains alternative Stoptech brake kit option with 50 lb weight penalty.
T2 2015- Current Ecoboost Mustang #27971weight -100 lbsfasterT2 Ford Mustang Ecoboost 2.3 loses 100 lbs to 3400, wheels widen to 19 x 11, intercooler TIR increases to 50mm.
FA Request to merge FB into FA #25611cars addedfasterFormula 1000 motorcycle-based engine classified into FA, throttle bodies and ECUs unrestricted.
FA Suggestions for FB/F1000 into FA #27319cars addedunclearF1000 reclassified into FA with specification changes effective 2020-01-01.
FA Change Swift 016 - 2.3 liter Mazda Duratec restrictor size #27880inductionslowerFA Swift 016 2.3L Mazda Duratec restrictor reduced from 33mm to 31mm SIR, making it slower.
GT2 Request Factory Five Daytona coupe classification #26308cars addedcars addedFactory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs.
GT2 Porsche 991.2 GT3 Cup GT2 Classification #27701cars addedcars added991.2 GT3 Cup Car classified in GT2 at 3100 lbs with 63mm throttle body restrictor.
GT2 Request for Acura NSX Spec Line Changes #27755weightfasterGT2 Acura NSX minimum weight reduced from 3000 to 2700 lbs.
GT2 GT2 991.1 restrictor size change #27914inductionfasterGT2 Porsche 991.1 GT3 Cup restrictor size increases from 67 mm to 70 mm.
GT2 GT2 996/997.1 weight change #27915weight -100 lbsfasterGT2 Porsche 996/997.1 GT3 Cup minimum weight reduced 100 lbs, to 2800.
GT2 GT2/ST Corvette comp adjustment #27920inductionslowerGT2/ST Corvette -2019 5967cc restrictor reduced from 75 mm to 70 mm.
T2 Clarification of On-Board Fire System for T2 #27183wordingwordingT2 requires onboard fire system; T3 and T4 may have one per GCR 9.3.
T2 Mustang Ecoboost and GT Transmission #27439otherunclearT3 Ford Mustang EcoBoost 2015- gains three transmission gear ratio options.
T2 Request for Dailey Engineering Dry Sump on 2010 Camaro SS #27514otherotherT2 Chevrolet Camaro SS/1LE (10-14) adds Dailey Engineering dry sump P/N 20-02-0666-ASSY and other approved parts.
T2 Request for Half Shafts - 2014 Camaro SS 1LE #27584otherotherT2 Camaro SS 1LE gains approval for half shafts Drive Shaft Shop RA-5424 and RA-5425.
T2 Request for Parity Among Vehicles #27665induction -50 lbsfasterT2 Ford Mustang Boss 302 restrictor 54mm to 56mm; GT 5.0L 11-14 restrictor 52mm to 54mm; GT 5.0L 15-17 restrictor 50mm to 52mm; C5 Z06 weight 3525 to 3475 lbs; C6 weight 3450 to 3400 lbs; Porsche 911 997.2 restrictor 60mm to 57mm.
T2 Request for 2016-2020 Camaro SS Help #27776weight -50 lbsfasterT2 Chevrolet Camaro 1LE 2016- weight reduced from 3600 to 3550 lbs.
T2 Request for Competitive Adjustments to Honda Civic Type R #27839weight -50 lbsfasterT2 Honda Civic Type-R (2017-) weight reduced from 3050 to 3000 lbs; tire TIR requirement increased from 50mm to 51mm.
T2 T4 RX8 Classification Error #27902wordingwordingMazda RX-8 Base/R3 (04-12) reclassified in T3 and T4 to include Sport and GT variants.
T2 Request to add Toyota 86 GT to Spec Line #27910cars addedcars addedToyota 86 GT (2017-) added to T3 and T4 Spec Line.
FA Move wheel dimensions from Bodywork subsection to #27493wordingwordingFA wheel dimension rules moved from Bodywork subsection to General section; no specification changes.
FA Table 2 Mazda MZR 2.0 E&O #27640wordingwordingFA Mazda MZR 2.0 now limited to Ralt RT40, Ralt RT41, and Swift 014 chassis only.
FA Follow up to Letter #27344 on Honda Powered FA Rules #27363wordingwordingFA Honda Civic K20Z3 engines consolidated: three separate base/uprated specs removed, replaced with single unified 1350 lb minimum weight spec for Swift 014/016.
FA Swift 014 Mazda MZR 2.0 E&O #27305enginefasterFA Swift 014 Mazda MZR 2.0 piston minimum weight reduced from 320g to 280g.
T2 Request spare tire/wheel clarification #27012wordingwordingT2-T4 spare tire/wheel rules clarified: removable covers can be removed with hardware and bracketry.
GT2 TA2 Weight Clarification #27077weightslowerGT2 TA2 cars must weigh minimum 2930 lbs per current Trans Am rules or prior Appendix L.
T2 Request to change Cadillac CTS-V years from 06-07 to 04-07 #26842cars addedcars addedT2 Cadillac CTS-V classification expanded from 06-07 to include 04-05 model years.
T2 Request to allow Hotchkiss front / rear sway bars on T2 CTS-V #26845suspension & brakesfasterT2 Cadillac CTS-V 06-07 allowed to use Hotchkiss sway bars up to 36mm front, 25mm rear.
T2 Correct T2 Mustang tire size #27024tyres & wheelsslowerT2 Ford Mustang GT 5.0L tire size reduced from 315 to 295.
FA Adjust Line N restrictor size and minimum weight #26691weight +30 lbsslowerFA Line N minimum weight increases to 1375 lbs.
GT2 Request to classify Toyota Supra with 3SGTE engine #25185cars addedcars addedGT2 Toyota Supra 3SGTE newly classified at 2900 lbs minimum weight, 43mm restrictor.
GT2 Request to Classify Acura NSX from T1 to GT2? #26121cars addedcars addedAcura NSX All Years classified to GT2-ST: 3.5L turbo, 3000 lbs minimum, 43mm restrictor.
GT2 Request for TA2 BOP in GT2 #26509weightslowerGT2 TA2 minimum weight increases from 2830 to 2930 pounds.
T2 2018+ Audi TT RS Suspension Allowances #26631suspension & brakesfasterT2 2018+ Audi TT RS gains suspension and intercooler allowances: 30mm front sway bar, 28mm rear, 1200lb/in springs, aftermarket intercooler.
T2 Request BOP adjustment for 2018 Honda Civic Type R-TIR removal #26882weight +150 lbsslowerT2 Honda Civic Type-R 2017- weight rises 2900 to 3050 lbs, TIR increases 38mm to 50mm.
FA Add data plate requirement #26707wordingwordingFA cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs.
GT2 Request for e36/e46 bmw 4500 cc v8 at 2950lbs in GT2/ST #26106cars addedcars addedGT2 BMW E36/E46 4.5L V8 classified at 2950 lbs minimum weight.
GT2 Request GTX Fuel injection for previous GT-1 tube frame cars #26141inductionfasterGTX tube frame cars gain fuel injection with 90mm maximum throttle body size.
GT2 Request to Classify Ligier JS2 R #26535cars addedcars addedLigier JS2 R classified in GTX, no performance parameters specified in filing.
GT2 Request Ford Perfomance 5.2L crate engine FPR clarification #26159cars addedcars addedGT2 Ford Mustang 5.2L classified at 3300 lbs minimum with 82mm single throttle body restrictor.
GT2 Request Ride Height Clarification #26600wordingwordingGT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b.
T2 Request for Removal of Rear Anti-roll Bar in T2 Mustang GT #26533suspension & brakesfasterT2 Mustang GT anti-roll bars may now be removed or disconnected, previously required as manufactured.
FA Request to add FA engine spec lines #26183weightfasterFA Formula 3 car sequential gearbox weight penalty of 25 lbs removed; minimum weight now 1215 lbs.
GT2 Request Porsche Cayman year classification #26241wordingwordingGT2 Porsche Cayman model years change from 05-11 to 05-15.
T2 Request Mustang GT Limited Prep 2018 Classification #24431cars addedcars addedT1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor.
T2 Request to Classify 2018 Audi TT RS #25961cars addedcars addedT2 Audi TT RS (2018-) newly classified at 3400 lbs minimum weight with 19-inch wheels and 275 tire size.
T2 Request for Adjustments on 2017+ Civic Type R #25969suspension & brakessuspension & brakesT2 2017 Civic Type R allows any sway bar front/rear up to 30mm, front springs to 800lb, rear to 2000lb.
T2 Correct Mazda MX-5 Hard Top Notes #26137wordingwordingT4 Mazda MX-5 Club (06-15) and (2016-), T3 MX-5 Cup and Miata (2016-) hardtop rules clarified; wording changes to permitted parts and specifications.
T2 Consider opening class rules to allow any thermostat #26187wordingwordingT2, T3, T4 now allow any thermostat serving only OE intent, previously restricted.
T2 Ford Mustang Boss 302 (12-13) - correct weight #26287weight -50 lbsfasterT2 Ford Mustang Boss 302 (12-13) weight drops 50 lbs to 3500.
T2 Request camber correction 005-2013 corvette C6 #26288suspension & brakesfasterT2 Corvette C6 Coupe/Grand Sport removes 3.0 degrees MAX front camber restriction.
T2 Request 98-02 Firebird 98-02 Camaro reloacte rear spring #26291suspension & brakessuspension & brakesT2 Pontiac Firebird and Chevrolet Camaro SS (98-02) permitted spring relocation to shock.
T2 Cap 2016 Mazda Miata year at 2018 #26388wordingwordingT3 and T4 Mazda MX-5 Miata eligibility capped at 2018 model year, effective 2019-03-01.
T2 Class Ford Mustang GT 2018+ (reference letter 24431) #26400cars addedcars addedFord Mustang GT 5.0L 2018+ classified in T2 at 3600 lbs with 50mm restrictor, 19x11 wheels, 315 tyres.
FA FA MZR 2.0 Engine Specification #25814wordingwordingFA Swift 014-Mazda MZR 2.0 engine now requires OE block casting #LF95 and specific OE components instead of sealed Elite Engines sourcing.
FA FA 016 weight increase #26063weightslowerFA Swift 016 Mazda Duratec 2.3L and 2.5L minimum weight increases from 1420 to 1450 lbs.
FF Request for Oversize Honda Fit Pistons #25810enginefasterFF Honda Fit permitted to use 0.25mm oversize pistons, cylinder honing increased to 73.315mm maximum.
FF Heat Shield - Fit Intake #26102wordingwordingFF heat shield rule clarified: thermal wrap allowed on manifold exterior if easily removable for inspection.
FF Request catch cans/tanks clarification #26158wordingwordingFF catch tank minimum capacity rules clarified: coolant catch tank now one U.S. pint minimum, oil catch tank one U.S. quart minimum.
GT2 ST/GT2 BMW Flossman Kit Clarification #22138wordingunclearGT2 BMW E46 M3, E36, Z3, and 5000cc V8 now permit Flossman body kit.
GT2 Request Clarification/Revision of Appendix L (2013 TA2 Rules) #25110otherfasterGT2 TA2 cars: wheels cost cap drops to $175 each, carbon fiber allowed on rear wing, engine setback maximum 21.75 inches (A-F) or 24 inches (G), various nomenclature and clarification updates.
GT2 Request to classify BMW E82 (1 series) into GT2 #25539cars addedcars addedBMW 1 Series E82 classified into GT2 with N52B30 engine, 2996 cc, 2140 lbs minimum weight.
GT2 2010 Cayman Street Tuner Into an STO Car,Addendum #25545weightfasterGT2 Porsche Cayman 05-11 base weight drops 75 lbs to 2800; adds STO/X51 motor notes.
GT2 Request - Classify Ford Performance 5.2l #25716cars addedcars addedGT2 Ford Mustang 05- with 5.2L Aluminator engine classified: 3400 lbs minimum weight, 2×41mm flat plate restrictor.
GT2 Add missing displacement, minimum weight. Remove #25765wordingwordingGT2 Porsche 996/997.1 GT3 Cup adds 3.6L displacement and 2900 lbs minimum weight; removes aftermarket exhaust header allowance for 996.
GT2 Request for Ford FP 350s Weight Reduction #25806weightfasterGT2 Ford Mustang FP350S minimum weight reduced 100 lbs, to 3400.
GT2 Request to Classify EcoBoost Mustang #25842cars addedcars addedGT2 Ford Mustang 05- EcoBoost classified: 3500cc, 3200 lbs minimum, 41mm restrictor.
GT2 Request to Remove Mazda RX 7 Body Work Penalty #26024weightfasterGT2 Mazda RX7 Downing GTS body kit allowed without 75 lbs. weight penalty.
GT2 GTX Homologation table update #26034cars addedcars addedGTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.
T2 Errors, Omissions, and Updates (Various) #22414wordingwordingT4 Ford Fiesta ST years corrected to 14-; T4 Fiat 124/Abarth Edition years added 16-18; battery rule clarified.
T2 Request to classify 2015 Cayman GTS 3.4L in T2 #25335cars addedcars addedT2 Porsche Cayman S/GTS model years expanded from 13-14 to 13-15, now includes GTS variant.
T2 Request for 2017-2018 Honda Civic Type R - 4 BOP Grill #25513wordingwordingT2 Honda Civic Type-R 2017- allows Cuztom Tuning FG-CIV16-V3-TR-BK alternate grill.
T2 Add Clarification to Spec Car Classifications Vehicle Spec #25774wordingwordingT1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes.
T2 Clarify Subframe Bushings Permitted for T2-T4 #25800wordingwordingT2-T4 subframe bushings may now be replaced with non-spherical bushings of any material.
Best is the class's fastest lap in that event's qualifying or race sessions, with the driver who set it, how many cars set a time that session and how close the top five were; a best from fewer than three cars is greyed. With two or more classes, "vs" is the gap of each class's best to the first class's at the same event. "% of FF" is the class's best as a share of FF's best at the same event (100% is level, less is quicker): weather and track condition move every class together, so this compares across years where the raw times do not. It still breaks when FF's own field changes or one session was wet and another dry. Newest event first. The coloured figure under each value is the change from the previous event that has one (green is quicker, red slower). Whole laps only, so events with different sector layouts still compare. Weather and track condition are not accounted for.