STU + GT2 + P + FF at Buttonwillow Raceway Park

2023-03-01 STU E&O STU NA Weight Chart.

#33737 from Eric Heinrich · Rule change · TB 23-03 (2023-03 Fastrack)

In STU, GCR Section 9.1.4.1.H.1. chart, Factory Engine Displacement (cc) Minimum Weight (lbs), change as follows:
"2450 2596 2595"
"2600 2860 2710"

2023-03-01 FF Add Fast Forward Part Numbers for Honda Fit Engine

#33752 from Formula/Sports Racing Committee · Rule change · TB 23-03 (2023-03 Fastrack)

In FC/FF, GCR section 9.1.1.B.14.a.6, change as follows:
"For all Honda part numbers in these specifications, superc seding part numbers are considered equivalent.
In FC/FF, GCR section 9.1.1.B.14.f.5, change as follows:
"Cylinder head breather restrictor must be used as supplied by HPD or Fast Forward, unmodified.: HPD PN: 15262-F21S-A200; Fast
Forward PN: FF200-503."
In FC/FF, GCR section 9.1.1.B.14.k.2, change as follows:
"The upper manifold, air box and throttle body assembly must be used as delivered from Honda, HPD, or Fast Forward as noted
below."

2023-04-01 GT2 Adding Ginetta G56 GTA Factory ProTune for GT2 Class

#33825 from Robert Mueller · Rule change · TB 23-04 (2023-04 Fastrack)

In GT Cars - Ginetta, Ginetta G56 GTA, add to Notes as follows:
"May use Factory installed ProMap ECU Map."

2023-04-01 STU Alternate OEM Miata Intake Manifold

#33827 from Brandon Steinhauer · Rule change · TB 23-04 (2023-04 Fastrack)

In STU Spec lines, classify Mazda BP5A as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Mazda BP5A 1839 Chart May use engine in its entirety or specific
components from the engine.

2023-05-01 GT2 Request to class 2011 Porsche Cayman S

#33771 from Coyote Black · Rule change · TB 23-05 (2023-05 Fastrack)

In GT Cars - Porsche, classify Porsche Cayman ‘S’ as follows:
GT Cars - Porsche
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
Porsche Cayman ‘S’ 09-12 2 dr. Coupe RWD 95.08 3.4L No PDK Transmission

2023-05-01 GT2 Please classify Fields Cardinal V8

#33784 from James Rogersn · Rule change · TB 23-05 (2023-05 Fastrack)

In GT Spec Lines, GT1 Cars - Fields Cardinal, classify Fields Cardinal V8 as follows:
GT1 Cars – Fields Cardinal
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
Fields Cardinal V8 2023 2 Dr. RWD 92.0 Roll Cage MUST be modified to comply with

A specification table follows in the original; it is not shown here.

2023-07-01 GT2 appendix letter #33635

#34206 from Ian Barberi · Rule change · TB 23-06 (2023-07 Fastrack)

In GT2-ST Spec Lines, BMW E46 M3 & E36 / BMW Z3 / BMW 5000cc V8, change notes as follows:
"The 3.4 liter 6 cyl. (87.0 bore x 93.0 stroke) is permitted at 2575lbs. 4.0L V8 permitted at 2900lbs. 4.5L V8 permitted at 2950lbs.
5.0L V8 permitted at 3000lbs. Flossman body kit permitted as found at http://www.racingpartsbmw.de/start/eng/start.htm.
Trans Am SGT spec: Regular shifter 3000 lbs., paddle shifter plus 150 lbs. 95mm S54 crankshaft @ +150lbs. Lang Racing part#
S54-95mm-StrokerCrk.
S54 engine is permitted a 97mm stroke crankshaft (part #VAC-SC-S54) @2800lbs."

2023-07-01 GT2 Remove Weight and Restrictor Penalty for Corvette C7 Body

#34342 from Jorge A Nazario · Rule change · TB 23-06 (2023-07 Fastrack)

In GT2/ST, Chevrolet Corvette (2014-2019) change as follows:
Restrictor: "73 7mm flat plate"

2023-07-01 STU 2022 Toyota GR Cup for STU

#34449 from Club Racing Board · Rule change · TB 23-06 (2023-05 Fastrack)

In STU Spec Lines, Toyota GR Cup (2022-), classify as follows:

A specification table follows in the original; it is not shown here.

2023-09-01 GT2 GT2 Mazda 20B 3 rotor ENO

#34765 from Grand Touring Committee · Rule change · TB 23-09 (2023-09 Fastrack)

In GT2 Spec Lines, Engines - MAZDA, combine both 20B to one spec lines and keep the following:
Weight: "2500 2280"
Notes: "Must run +100 lbs. for Grand Am transaxle and independent rear suspension. Must comply with all other GT2 rules."

2023-10-01 GT2 Late E & O

#34966 from Scotty B White · Rule change · TB 23-10 (2023-10 Fastrack)

RM 23-10 GT2-ST Dodge Viper, incl Comp Coupe, ACR/ACR-X VRL Front Fascia
As an Errors and omissions fix to what was originally intended for these cars, the Club Racing Board and Board of Directors have
approved the following:
In GT2-ST, Dodge Viper, incl Comp Coupe, ACR/ACR-X add VRL front fascia -100lbs to all Spec Lines.

2023-12-01 GT2 Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules

#34453 from David Gomberg · Rule change · TB 23-12 (2023-12 Fastrack)

from the current (or before) Table of Contents (TOC), to what is shown in the after TOC.
GTL spec lines will now be contiguous with GT2 and 3 spec lines.
GTA category and spec lines will be moved and renumbered behind GTL. GTA Section will not change but page numbers will, (as
shown in Red italics).
9.1.2.F. GT-2, 3, LITE Category Specifications 314
GT2 Cars 327
GT2/ST 341
GT3 Cars 348

2024-01-01 GT2 Dodge Viper Gen 3 hybrid Kit Update Request

#35200 from Sean McCann · Rule change · TB 24-01 (2024-01 Fastrack)

In GT2-ST Spec Lines, Dodge Viper, incl Comp Coupe, ACR/ ACR-X change NOTES as follows:
8300 OEM: "Stock OEM engine. Engine long block, valve train, and intake system must meet stock, shop manual specifications.
Hybrid update including Mopar Performance Part #P5156137. May use Mopar part #5038554AF (Gen 5 Intake Manifold
manifold allowed with (2) 55mm flat plates) and 8.4L mechanical throttle body allowed. VRL Front Fascia -100lbs."
8300: "Hybrid update including Mopar Performance Part # P5156137, Mopar part #5038554AF manifold and 8.4L mechanical
throttle body allowed using (2) 50 45mm flat plate restrictors. VRL Front Fascia –100lbs."
8400: "Intake and Throttle Body from Mopar Performance Part # P5156137allowed using (2) 50 45mm flat plate
restrictors. , Mopar part #5038554AF manifold (Gen 5 Intake Manifold allowed with (2) 50mm flat plates) VRL Front Fascia -

2024-01-01 FF Honda Fit Oversize Piston Rings

#35305 from Doug Learned · Rule change · TB 24-01 (2024-01 Fastrack)

In FF, GCR section 9.1.1.B.14.e.3.a, add the following:
"The standard ring pack, PN 13011-RB1-004 (Riken) or 13011-RB1-006 (Nippon), or the oversize ring pack, PN 13021-RB7-Z01
(Riken), or 13021-RB7-Z02 (Nippon), or FF800-100 (Fast Forward), may be used."

2024-02-01 STU ST Electric-Assisted Steering Systems

#35066 from Jose Osiris Pena · Rule change · TB 24-02 (2024-01 Fastrack)

In GCR, Section 9.1.4.M.16., change as follows:
"Power steering may be modified in any of the following ways:
a. disconnected , pump, belt, pulley, and hoses may be removed. Hoses may also be looped. Steering rack or box may be
modified internally to work without pump.
b. an OEM manual steering rack for that model may be fitted
c. an electric power steering pump may be fitted
d. an OEM electric-assisted steering system may be used or any column mounted electric steering assist may be used
e. an OEM hydraulic-assisted steering system may be used"

2024-02-01 GT2 Rear Blade Spoiler Clarification

#35261 from Butch Kummer · Rule change · TB 24-02 (2024-01 Fastrack)

In GCR Section 9.1.2.G (GTA Category Specifications), change as follows:
“9.1.2.G.III.I
The single-plane rear spoiler must be mounted at an angel angle from 50 to 75 degrees (perpendicular to the ground
being 90 degrees) and may not extend beyond the rear bumper when viewed from directly above the rear
bumper. Spoilers must be a minimum of .063 aluminum or Lexan and may vary in overall height to match the contours
of the bodywork. The rear spoiler dimensions shall not exceed 59.0 inches wide by 5.0 inches in height, (measured on
the material surface) , or 295.0 square inches total surface area. Braces to prevent spoiler deflection are allowed, but
may serve no other purpose.”

2024-02-01 GT2 REDUCE C6 CORVETTE WEIGHT WITH OEM 7 LITER ENGINE REDUCE BY 150LB

#35385 from Mike McGinley · Rule change · TB 24-02 (2024-02 Fastrack)

In GT2/ST Chevrolet Corvette 7011 OEM change weight as follows:
“3275 3125“

2024-02-01 GT2 GT Direct Injection allowance and rules

#35437 from Grand Touring Committee · Rule change · TB 24-02 (2024-01 Fastrack)

In GCR, Section 9.1.2.F.7.5.E. change as follows:
“Direct Injection is not permitted only if it came OE and must be installed using only OE high pressure pump(s), hard and
soft hoses and injectors.”

2024-02-01 GT2 GT2/3 remove Direction Injection not allowed in Spec line notes

#35439 from Grand Touring Committee · Rule change · TB 24-02 (2024-02 Fastrack)

In GT2/3 modify Spec Line notes as follows:
GT2:
Nissan: “Direct Injection not permitted, may be used per 9.1.2.F.7.5.E.”
GT3:
Mazda: “Direct Injection not permitted, may be used per 9.1.2.F.7.5.E.”
Mitsubishi 4G93: “Direct Injection not permitted, may be used per 9.1.2.F.7.5.E. ”
Nissan QR25DE/DD 1988cc: “Direct Injection not permitted, may be used per 9.1.2.F.7.5.E.”
Nissan QE25DE/DD 2489cc: “Direct Injection not permitted, may be used per 9.1.2.F.7.5.E.”

2024-03-01 GT2 Classify Corvette C8 (2020- ) into GT2/ST

#33759 from Andrew Aquilante · Rule change · TB 24-03 (2024-03 Fastrack)

In GT2 Spec Lines, classify Chevrolet Corvette C8 (20-) as follows:
GT2-ST Maximum Displacement Minimum Weight Restrictor Notes
Chevrolet Corvette C8
(20-)
6162 3300 71mm -
Flat Plate
LT2 engine.

Applies to Chevrolet Corvette on this page: Igor Lyustin

2024-03-01 GT2 Requesting classification for a 2015 Mitjet ST in GT2

#35408 from Jim Froula · Rule change · TB 24-03 (2024-03 Fastrack)

In GT2 Spec Lines, GT Cars - MITJET ST, classify MITJET ST as follows:
GT Cars – MITJET ST
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
MITJET ST 2015 RWD 94.5 Must run per VTS specifications. Must have

2024-03-01 STU Letter #35397 addendum

#35453 from Aaron Fitzsimmons · Rule change · TB 24-03 (2024-03 Fastrack)

In STU Spec Lines, Mini Cooper S SC with Minimum Weight 1900 and 2100, add to Notes:
"Alternate LEAP OMICRON hood scoop part # LEP-OMICRON3 is permitted."

2024-03-01 STU S54 Drysump

#35464 from Macey Urso · Rule change · TB 24-03 (2024-03 Fastrack)

In STU Spec Lines, BMW S54 B32 OEM, add to Notes as follows:
"Dry Sump oiling system permitted."

2024-05-01 GT2 Request for Spec Line 1010 Reconsideration

#35009 from Kristofer Olson · Rule change · TB 24-05 (2024-05 Fastrack)

In GT2-ST Spec Lines, Acura NSX, change as follows:
Minimum Weight: "2700 3000"
Restrictor: "43 45mm TIR"

2024-05-01 GT2 Request to Eliminate the FPR from the Corvette (-2013) with LS2

#35878 from Michael Quattlebaum · Rule change · TB 24-05 (2024-05 Fastrack)

In GT2-ST Spec Lines, Chevrolet Corvette (14-19), change Restrictor as follows:
"78 80mm flat plate"

2024-07-01 GT2 GT2-ST Rule Clarification

#36093 from Dominic Starkweather · Rule change · TB 24-07 (2024-07 Fastrack)

In GCR Section, Appendix K. 2012.M2, add the following:
"After market replacement differential housings are permitted as long as they are an exact equivalent."

2024-07-01 GT2 GT4 cars may run in GT2-ST

#36235 from Grand Touring Committee · Rule change · TB 24-07 (2024-07 Fastrack)

In 9.1.2. GT2 Spec Lines, GT3 Cars, change Note as follows:
"Note: All GT4 cars are permitted to compete in GT2-ST provided they use a factory supplied power stick or Pro Series
required restrictor. Must have GT4 rules in possession at all race events. Cars must comply with 2012 STO rules as
stated in Appendix K of the GCR. Engine Displacements in this table are nominal. Each competitor shall have available
definitive documentation (e.g., factory manual) of the original displacement for the engine used. Slicks allowed on all
GT2/ST cars with a 100-pound weight penalty."

2024-08-01 STU RWD Turbo Disadvantage

#36255 from David Fiorelli · Rule change · TB 24-08 (2024-08 Fastrack)

In GCR, Section 9.1.4.1.H.3 - Inlet Restrictor (mm) Minimum Weight (lbs) table, change as follows:
"RWD cars must reduce restrictor 1 mm from this table"

2024-10-01 FF Update to FF EGR Blanking Plate Rule

#36633 from Matt Boian · Rule change · TB 24-10 (2024-10 Fastrack)

In FF, GCR section 9.1.1.B.14.r.1, change as follows:
"All emission control devices must be removed and blocked off by the blanking plate provided by HPD or Fast Forward as noted
below, except for the VTEC activation valve. The VTEC activation valve must be retained; and it must be functioning. No
modifications are permitted.
a. EGR Plate: Fast Forward PN: FF200-301.
b. EGR Port Cover: Fast Forward PN: FF200-302."

2024-11-01 FF Change FF/FC Weight with Sequential Gearbox

#36651 from Robert Wright · Rule change · TB 24-11 (2024-11 Fastrack)

In FF, GCR section 9.1.1.B.20.A.3, change as follows:
"Cars running with a sequentially shifted gear box shall must add 25 10 lbs. to minimum weight."
In FC, GCR section 9.1.1.B.20.B.4, change as follows:
"Cars running with a sequentially shifted gear box shall must add 25 10 lbs. to minimum weight."

2024-11-01 STU R53 15% Pulley Request

#36980 from Aaron Fitzsimmons · Rule change · TB 24-11 (2024-11 Fastrack)

In STU Spec Lines, Mini Cooper S SC, add to notes:
1900: "Stock supercharger pulley. 2.565 diameter."
2100: "JCW Pulley permitted. May run a 2.285 diameter pulley."

2024-11-01 FF Alternative Oversize Honda Fit Pistons

#37064 from Formula/Sports Racing Committee · Rule change · TB 24-11 (2024-11 Fastrack)

In FF, GCR section 9.1.1.B.14.e.1, change as follows:
"Honda Fit OEM standard size pistons, PN: 13010-RB1-000, or Honda Fit OEM 0.25mm oversize pistons, PN: 13020-RB7-Z00, or
Fast Forward 0.25mm oversize pistons, PN: FF800-110, may be used."
In GCR section 9.1.1.B.14.e.2, change as follows:
"a. Maximum standard piston diameter, measured at a point 16mm from the bottom of the skirt: 73.240mm
(2.8834 2.8835 inches).
b. Centerline of wrist pin to crown maximum: 26.21mm (1.032 inches).
c. Maximum overall height from skirt to crown edge: 47.80mm (1.882 inches).

2024-12-01 STU Request to Remove Miata Hubs from General category

#37138 from Christopher Childs · Rule change · TB 24-12 (2024-12 Fastrack)

In GCR, Section 9.1.4.M.18., change as follows:
"18. Allow alternate front wheel front hubs, Mazda Motorsports Development Part #0000-04-5HUB-S1, for the 90-05 Mazda
Miata: Mazda Motorsports Development Part #0000-04-5HUB-S1."

2024-12-01 STU BMW N54/N55 Engine Allowance

#37146 from Martin Sarukhanyan · Rule change · TB 24-12 (2024-12 Fastrack)

"Turbo inlet restrictors designed per GCR Appendix F Technical Glossary definition of “Turbo Inlet Restrictor” may be required;
see table 9.1.4.1.H.h.2 3. Swapping of turbochargers between engine makes and models is prohibited. Supercharged cars may be
approved on a case-by-case basis; twin turbo engines are allowed on a case-by-case basis only. Contact the Road Racing
Technical Office for details. Twin turbo engines may be converted to single turbo using one of the allowed alternate turbos (see
9.1.4.1.H.3 2). Aftermarket turbocharger and supercharger kits will be allowed on a case-by-case basis.

2025-01-01 STU Audi 1.8t Wagon STU Table B

#36685 from Mike McLaughlin · Rule change · TB 25-01 (2025-01 Fastrack)

In STU Spec Lines, Table B: Alternate Vehicle and Engine Requirements, delete Audi/VW 1.8 Turbo in its entirety.
In STU Spec Lines, Table B: Alternate Vehicle and Engine Requirements, Porsche 944 w/Max Displacement 1800, change as
follows:
Weight: "3050 Chart"
Notes: "VW/Audi 1.8L 35mm turbo engine permittedinlet restrictor required."

2025-01-01 GT2 Panoz Esperante GTS BOP

#36686 from Brian Goldburg · Rule change · TB 25-01 (2025-01 Fastrack)

In GT2 SPEC LINES, GT Engines - PANOZ, classify 2013-2016 Ford EcoBoost Twin Turbo as follows:
GT Engines – PANOZ
Engine
Family
Engine Type Bore x
Stroke
(in.)
Disp.

A specification table follows in the original; it is not shown here.

2025-01-01 GT2 Correct language regarding OEM Areo Devices

#37137 from Christopher Childs · Rule change · TB 25-01 (2025-01 Fastrack)

In GCR, Section APPENDIX L. 2013 TA2 TECHNICAL REGULATIONS, B.2.c., change as follows:
"B. Aerodynamic Devices
2. Rear wing
c. The entire rear wing assembly, including the end plates and any Gurney flap, shall be mounted level
with, or below, the peak of the roof. OEM aerodynamic devices do not need to adhere to the height rule."

A specification table follows in the original; it is not shown here.

2025-01-01 GT2 GT2 Sunbeam Tiger Alternate Carburetor

#37198 from Tom Patton · Rule change · TB 25-01 (2025-01 Fastrack)

In GT2 Spec Lines, GT Engines - SUNBEAM, add to Fuel Induction as follows:
"Carburetors(s) Holly 650 cfm PN #80541-1 and PN #80541-2"

2025-01-01 STU Merger GT3 to STU

#37486 from Club Racing Board · Rule change · TB 25-01 (2025-01 Fastrack)

In STU, Table C, change STU-GT3 charge as follows:
"(Effective January 1, 2026) TABLE C: STU-GT3U"

2025-01-01 STU GT3 TCR Tire allowance

#37494 from Club Racing Board · Rule change · TB 25-01 (2025-01 Fastrack)

In STU, Table C, GT3 TCR, add to Notes the following:
"May run DOT approved tire with maximum section width of 275 with 100 pound weight adder. May not run A compound with
275."

2025-02-01 GT2 GT2/ST - Remove Aftermarket/Racing ABS penalty

#36538 from Jorge A Nazario · Rule change · TB 25-02 (2025-02 Fastrack)

In GCR, Appendix K. 2012 STO Rules, O.9., change as follows:
"May run OEM ABS or convert to an aftermarket ABS controller with 100 50 lb. weight penalty."

2025-02-01 P Correct text in engine table notes

#37606 from Club Racing Board · Rule change · TB 25-02 (2025-02 Fastrack)

In Prototype Engine Table, Spec Line B, change the notes as follows:
"Staudacher cars may run 950 lb min. wt. minimum weight with 38.5mm flat plate intake restrictor."
In Prototype Engine Table, Spec Line D, change the notes as follows:
"No restrictor required at 1150 lb min. wt. minimum weight."

2025-02-01 P Update Prototype class designation

#37653 from Club Racing Board · Rule change · TB 25-02 (2025-02 Fastrack)

In Categories and Classes, GCR section 9.1, change as follows:
"9.1.8. SPORTS RACING CATEGORY CLASSES
A Sports Racing (ASR) Regional Class
Prototype 1 (P1)"
In Homologation Requirements, GCR section 9.2.2, change as follows:
"All Formula, Sports Racing, and P1, and P2 cars must be constructed in strict accordance with the rules and regulations
contained in the current GCR unless specifically excepted."
In Non-Metallic Wheel/Chassis Construction, GCR section 9.3.37, change as follows:

2025-03-01 GT2 Hood Bulge allowed

#37000 from Gordon Leslie · Rule change · TB 25-03 (2025-03 Fastrack)

In GT2 Spec Lines, GT2 Cars - PONTIAC, Fiero, change as follows:
Drive-line: "FWD RWD"
Add to Notes: "Hood bulge permitted as requested for front engine relocation only."

2025-03-01 STU BMW N54/N55 Engine Allowance Follow Up

#37447 from Martin Sarukhanyan · Rule change · TB 25-03 (2025-03 Fastrack)

In STU Spec Lines, Table A, classify BMW N54/N55 as follows:
STU Maximum Displacement
(cc's) Minimum Weight Notes
BMW N54/N55 3.0 Chart +3% (DI) Short blocks, heads, and intakes may be
freely swapped within these engine
designations. N54 twin turbo not allowed

2025-03-01 GT2 OEM Wing Adjustment

#37590 from Christopher Childs · Rule change · TB 25-03 (2025-03 Fastrack)

In GCR, Section APPENDIX L. 2013 TA2 TECHNICAL REGULATIONS, B.2.c., change as follows:
"The entire rear wing assembly, including the end plates and any Gurney flap, shall be mounted level with, or below, the peak of
the roof. OEM aerodynamic devices do not need to adhere to the height rule."
In GCR, Section APPENDIX K. 2012 STO GENERAL TECHNICAL REGULATIONS, D.4.b., add the following:
"Factory wings, and spoilers, and roof vortex generators are permitted, but must be removed if an approved aftermarket wing is
installed. OEM aerodynamic devices do not need to adhere to the height rule."

2025-03-01 STU STU Mini Cooper pulley size clarification re: letter #36980

#37717 from Aaron Fitzsimmons · Rule change · TB 25-03 (2025-03 Fastrack)

In STU Spec Lines, Mini Cooper S SC, add to notes:
2100: "May run a 2.285 2.185 diameter pulley."

2025-03-01 STU Question About a Weight Modifier

#37782 from Peter St Pierre · Rule change · TB 25-03 (2025-03 Fastrack)

In STU Spec Lines, Table A, Honda K20C1 Turbo I4, add to Notes the following:
"The 3% DI weight adder does not need to be applied."

2025-03-01 FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change

#37802 from Anthony Stefanelli · Rule change · TB 25-03 (2025-03 Fastrack)

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Formula F shall be limited to the following tires (front tires may not be used as rears):
Dries:
Front - Hoosier R60A Radial 43322 or F1600 Radial 43321 185/60R13
Rear - Hoosier R60A Radial 43327 or F1600 Radial 43326 205/60R13
Wets:
Front - Hoosier Wet or W3 Radial 44421 185/60R13
Rear - Hoosier Wet or W3 Radial 44426 205/60R13

2025-03-01 STU Increase Minimum Weight

#37919 from Club Racing Board · Rule change · TB 25-03 (2025-03 Fastrack)

In STU Spec Lines, Table C: STU-GT3U, change Minimum Weight as follows:
"150 250 pounds"

2025-05-01 STU Wheel Size Inconsistency

#38018 from David Fiorelli · Rule change · TB 25-05 (2025-05 Fastrack)

In GCR, Section 9.1.4.1.F.1., change as follows:
"Wheels may not exceed 18 inches in diameter. or 8.0 inches in width for vehicles 2950 lbs. and under minimum allowed race
weight. Vehicles over 2850 minimum allowed race weight may use a 9 inch wide wheel. Cars equal to or less than 2,850 lbs.
minimum allowed race weight may not use wheels wider than 8 inches. Cars greater than 2,850 lbs. minimum allowed race
weight may not use wheels wider than 9 inches."

2025-05-01 P Add missing punctuation marks

#38150 from Club Racing Board · Rule change · TB 25-05 (2025-05 Fastrack)

In P Engine Table, Spec Line D notes, add the following:
"No restrictor required at 1150 lbs. minimum weight."
In P Engine Table, Spec Line G notes, add the following:
"Group CN non-composite chassis with Honda K20A-FD2 may use unrestricted individual throttle bodies at 1500 lbs. minimum
weight."
In P Table 1, Beasley B2 spec line notes, add the following:
"Engine must be Mazda 12A rotary with 40.5mm venturi. Car must comply with all other Prototype requirements."
In P Table 1, P2 cars built to 2000cc auto-based specification spec line notes, add the following:

2025-05-01 FF Page 228, FF tire rule 9.1.1.10.e

#38251 from Anthony Stefanelli · Rule change · TB 25-05 (2025-05 Fastrack)

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Formula F shall be limited to the following tires (front tires may not be used as rears):
Dries:
Front - Hoosier R60A Radial 43322 or F1600 Radial 43321 185/60R13
Rear - Hoosier R60A Radial 43327 or F1600 Radial 43326 205/60R13
Wets:
Front - Hoosier Wet or W3 Radial 44421 185/60R13
Rear - Hoosier Wet or W3 Radial 44426 205/60R13

2025-05-01 STU Table C: STU-GT3U Clarification

#38268 from Club Racing Board · Rule change · TB 25-05 (2025-05 Fastrack)

In STU Spec Line, Table C: STU-GT3U, change as follows:
Minimum Weight: “Current GT3 race weight plus 250 225 pounds”
Notes: "DOT approved tire with maximum section width of 245. GT3 cars base wheel is a maximum of 15”x9”. 18”x9” wheels
allowd with a 3% weight addition. GT3 cars utilizing 15”x7” wheels are limited to a maximum section width of 225 with a 25
pound weight reduction"
"All GT3U (Majors and Runoffs) cars using up to 15"x7" wheels limited to 225 section width tires shall run at current GT3 race
weight plus 225lbs. All Gt3U cars shall run a DOT approved tire with a maximum section width of 245. GT3U cars are allowed
optional 15"x9" wheels with a 1.5% weight addition or up to 18"x9" wheels with a 3.0% weight addition to the total weight

2025-07-01 STU 2.8-3.2L N/A Engine Allowances

#38007 from Ben Slechta · Rule change · TB 25-07 (2025-07 Fastrack)

In GCR, Section 9.1.4.G.1, add the following:
"A maximum section width of 245 is permitted. Cars over 3150 lbs. may run a 275 tire with a 2% weight adder."

2025-07-01 STU 2006-2015 Mazda Miata Intake Manifold

#38422 from German Candelario Candelario · Rule change · TB 25-07 (2025-07 Fastrack)

In STU, Table A, Mazda MZR (LF, L3, L5), change Notes as follows:
"May use Goodwin Part # 61-2510 or Gato Performance Part #31972 Intake manifold . "

2025-07-01 STU Requesting Approval of the JDM Honda h23a

#38489 from Eric Fiest · Rule change · TB 25-07 (2025-07 Fastrack)

In STU, Table B, classify Honda JDM H23a as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Honda JDM H23a 2259 Chart Must meet all ST engine regulations.

2025-08-01 GT2 Rear Deck Lid for Older Air-Cooled Porsche

#38506 from Justin Erion · Rule change · TB 25-08 (2025-08 Fastrack)

In GT2 Spec Lines, GT2 Cars-Porsche, 911 Coupe & Targa., add to Notes the following:
"Porsche 911-based race cars (911,963,994), the use of the 993 3.8 RSR rear deck lid/spoiler is permitted. Aftermarket
reproductions of the original Porsche Motorsports deck lid provided they faithfully replicate OEM dimensions and functionality,
are acceptable for use."

2025-08-01 STU STU-TCR Adjustments

#38723 from Club Racing Board · Rule change · TB 25-08 (2025-08 Fastrack)

In STU Spec Lines, Table C: STU-GT3U, GT3-TCR, change as follows: Remove the current TCR spec line and add the TCR spec lines
from GT3 that are being removed, adding the below to the notes.
"DOT approved tire with maximum section width of 245. May run DOT approved tire with maximum section width of 275 with
100 150 pound weight adder. May not run A-compound with 275. STU-TCR spitters and side valance must comply with
9.1.4.D.3.f. STU-TCR chassis ride height must comply with 9.1.4.1.A.1."

2025-08-01 STU Lotus Weight Reduction

#38772 from Club Racing Board · Rule change · TB 25-08 (2025-08 Fastrack)

In 9.1.2. GT2/ST Spec Lines, Lotus Evora GT4, change Weight as follows:
"2750 2700"
In STU Table B: Alternate Vehicle and Engine Allowances, change Weight as follows:
Lotus Elise Cup R: "2300 2250"
Lotus Elise SC/ Lotus Exige SC: "2300 2550
2500 2450"

2025-08-01 P RM 25-05 - Prototype Engine Table A, 2 Cycle Restrictor Change

#38929 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

Effective 8/1/25 in Prototype Engine Table, Spec Line A, change the restrictor as follows:
"40mm 38mm Restricted Venturi Size"

2025-09-01 P 13B Rotary Engine Rules Change Request

#38856 from Jason Vinkemulder · Rule change · TB 25-09 (2025-09 Fastrack)

Effective 9/1/25 in Prototype Engine Table, Spec Line K, change the restrictor as follows:
"40mm SIR with fuel injection or 41.5mm venturi with carburetor"

2025-09-01 P Add Radical Cup series Radical SR3 spec line to Table 1

#38916 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

Effective 9/1/25 in Prototype Table 1 (Spec Line Cars), add the following:

2025-09-01 STU Lotus Weight Reduction E&O

#38919 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

In STU Table B: Alternate Vehicle and Engine Allowances, change Weight as follows:
Lotus Elise SC/ Lotus Exige SC: "2450 2250"

2025-09-01 P Clarify spec line cars language

#38943 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

Effective 9/1/25, in Prototype, GCR section 9.1.8.B.K, change as follows:
"P2 cars may compete in either the Prototype class or the P2 class but must participate in the Prototype class to the extent
necessary to qualify for an invitation to the Runoffs in Prototype. P2 cars may be modified to comply with the general Prototype
rules and Prototype Engine Table or may continue to run in P2 specification in the Prototype class as permitted in Table 1 below."
Table 1 (Spec Line Cars)

A specification table follows in the original; it is not shown here.

2025-11-01 STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ

#38746 from William Rori · Rule change · TB 25-09 (2025-09 Fastrack)

In STU Spec Lines, Table B: Alternate Vehicle and Engine Allowances, Honda K24, change Weight as follows:
"(Effective 11/1/2025) Chart + 2%"

2025-12-01 STU Turbo Inlet Restrictor Table

#38961 from John Weisberg · Rule change · TB 25-12 (2025-12 Fastrack)

In GCR, Section 9.1.4.H.3, change chart as follows:

A specification table follows in the original; it is not shown here.

2025-12-01 STU 275 Tire Rule

#38983 from Peter Federlin · Rule change · TB 25-12 (2025-12 Fastrack)

In GCR, Section 9.1.4.G.1., change as follows:
"A maximum section width of 245 is permitted. Cars over 3150 lbs. may run a 275 tire with a 2% weight adder."

2025-12-01 STU STU Honda Engine weight penalty

#39375 from Super Touring Committee · Rule change · TB 25-12 (2025-12 Fastrack)

In STU Spec Lines, Table B: Alternate Vehicle and Engine Allowances, change Minimum Weight as follows:
Honda K20: "Chart + 2%"
Honda K24: "Chart + 2%"

2026-01-01 GT2 Additional Body Options to Replace Older Stock Car Bodies

#39086 from Samuel Daniels · Rule change · TB 26-01 (2026-01 Fastrack)

In GCR, Section 4.8.4.2.1., add the following:
"Cars in the class must use 1997, through current year, commercially available stock car bodywork. The following make/model
bodies are allowed:
1. Cadillac CTS
2. Chevrolet Impala
3. Chevrolet Malibu
4. Chevrolet Monte Carlo
5. Chevrolet SS

2026-01-01 FF Formula F Alternative Tire Rule Proposed Clarifications

#39281 from Jay Messenger · Rule change · TB 26-01 (2026-01 Fastrack)

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Alternatively, Formula F cars with rocker arm suspension (e.g., 1987-90 Reynard, Swift DB1,) and/or outboard suspension on at
least one chassis end homologated in 1989 or earlier with any combination of rocker arm or outboard suspension on all four
corners (e.g., 1987 – 1990 Reynard, Swift DB1) may use the following alternative tires. Note: This rule is intended to allow older
cars with the described suspension design to use the alternative tires. It is not to be exploited by modifying cars with push-rods or
pull-rods to meet the above requirements or by modifying either end of older cars to push- or pull-rod suspension to be eligible to
run the alternative tires. Cars that were homologated in 1989 or earlier with push- or pull-rod suspension on no more than two
corners may seek approval to run the alternative tire by utilizing the compliance process outlined in GCR section 8.1.4."

2026-01-01 GT2 GT3 Turbo to GT2?

#39365 from Chris Edens · Rule change · TB 26-01 (2026-01 Fastrack)

In GT2 Spec Lines, Engines - MAZDA, classify Engine Family BP as follows:
GT2 Engines - MAZDA
Engine
Family
Engine Type Bore x Stroke
(mm)
Disp.
(CC)

A specification table follows in the original; it is not shown here.

2026-01-01 P Request to Continue to Allow Carbon Brakes

#39476 from Jeffrey Lederman · Rule change · TB 26-01 (2026-01 Fastrack)

In Prototype, GCR section 9.1.8.B.F.2, change as follows:
"Brake calipers may be ferrous or aluminum alloy. Effective 1/1/2026, carbon-carbon and carbon-ceramic brake rotors are
prohibited and rotors must be ferrous. Brake rotor material is unrestricted."

2026-01-01 STU Request for Permission on Aftermarket Turbo Kit and Intake

#39529 from John Grim · Rule change · TB 26-01 (2026-01 Fastrack)

In STU Spec Lines, Table A: Alternate Vehicle and Engine Allowances, Mazda MZR (LF, L3, L5), change Notes as follows:
"Short blocks, heads, and intakes may be freely swapped within these engine designations. May use Goodwin Part # 61-
2510 or, Gato Performance Part #31972 or Jack Spania Racing 70 mm sheet-metal aluminum Intake manifold. Must use stock
throttle body or Acura part number 16400-PND-A17."
In STU Spec Lines, Table A: Alternate Vehicle and Engine Allowances, classify Mazda MZR (LF, L3, L5) Turbo as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Mazda MZR (LF, L3,
L5) Turbo

2026-01-01 GT2 Tech Bulletins for GT2 and GT2-ST

#39537 from Grand Touring Committee · Rule change · TB 26-01 (2026-01 Fastrack)

In GT2 Spec Lines, GT2 Cars – Porsche, classify 992.1 GT3 Cup as follows:
GT2 Cars – Porsche
Model Year Body
Style Driveline Wheel Base Notes
992.1
GT3 Cup
(22-25) 2 Dr RWD 4.0L flat six. 3250lbs. w/60mm Throttle Body Restrictor (TBR).
Cars must be prepared in accordance with the appropriate

2026-02-01 GT2 Allow Larger Air Cooled Engines in Porsche 911 GT2

#39249 from Justin Erion · Rule change · TB 26-02 (2026-02 Fastrack)

In GT Spec Lines, create GT Cars - PORSCHE and classify SC as follows:
GT Cars - PORSCHE
Model Years Body Style Drive- line Wheel- base
(in)
Notes
SC 1978 2 Dr. Rear engine/RWD 89.45 May use alternate engine bore.
4.0L 2V @2275 lbs. 4.0L 4V @ 2350 lbs.

2026-02-01 GT2 Classify T1 BMW in GT2

#39408 from Jared Lendrum · Rule change · TB 26-02 (2026-02 Fastrack)

In GT Spec Lines, classify M3 E92 in GT Cars - BMW as follows:
GT Cars - BMW
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
M3 E92 (08-13) 2 Dr. RWD 108.7 Cannot be built to any other rule set.

A specification table follows in the original; it is not shown here.