GT2 + GT1 at Buttonwillow Raceway Park

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

2024-05-01 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 GT1 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 GT1 Camaro 1993- and 2010-

#35652 from John Bodnar · Rule change · TB 24-05 (2024-05 Fastrack)

In GCR, Section 9.1.2.E.1.b.3., change as follows:
"Camaro (1993-2002)"

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."

2024-11-01 GT1 Request to Classify Mazda 26B Engine

#36230 from Wayne Graham · Rule change · TB 24-09 (2024-09 Fastrack)

In GT1 Spec Lines, GT1 Approved Automobile List, Mazda, add the following:
"(Effective 11/1/2024) 26B engine = 2850 lbs."

2024-12-01 GT1 Lamborghini Huracan GT3 Evo Restrictor Help

#36254 from Michael McAleenan · Rule change · TB 24-12 (2024-12 Fastrack)

In GT1-ST Spec Lines, Lamborghini Huracan GT3 EVO(1) (2018-), change Restrictor as follows:
"2 X 39mmUnrestricted"
In GT1-ST Spec Lines, Lamborghini Huracan GT3 (2019-), change Restrictor as follows:
"52mm Unrestricted"

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 GT1 Addition of a limited prep LS Chevy engine for GT1

#37045 from Robert Logsdon · Rule change · TB 25-01 (2025-01 Fastrack)

In GCR, Section 9.1.2. GT1 Spec Lines, GT1 Approved Automobile List, LS1 V8 engine allowed with stock intake, add the
following:
"LS1 Limited Prep GT1 motor
2600 # with driver
Blocks : GM castings or aftermarket, no lightening, Max volume 383 cubic inches
Cylinder Heads: GM LS castings or aftermarket, stock valve angle, intake and exhaust ports must be in stock location, porting
and polishing allowed
Valves: No titanium valves, must be stock size for head part number

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 GT1 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 GT1 GT1-ST Adjustments

#37481 from Grand Touring Committee · Rule change · TB 25-01 (2025-01 Fastrack)

In GT1-ST SPEC LINES, change as follows:
Aston Martin Vantage GT3 (2012) :
Restrictor: "2 x 41.5mm"
Audi R8 LMS Ultra GT3 (10-14) :
Restrictor: "2 x 49mm"
BMW Z4 GT3 (10-13):
Restrictor: "70mm"
Chevrolet Corvette C8 (20-):

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."

2025-03-01 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 GT1 Request to Classify Acura NSX GT3 Evo 22

#37367 from Taz Harvey · Rule change · TB 25-03 (2025-03 Fastrack)

In GT1 Spec Lines, GT 1 Cars - ACURA, classify Acura NSX GT3 EVO 22 as follows:
GT 1 Cars - ACURA
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
Acura NSX GT3 EVO 22 N/A 2dr RWD 103.5 Ground Clearance 50mm

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

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."

2025-08-01 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."

2025-09-01 GT1 Correction to Limited prep LS Chevy engine for GT1

#38902 from Robert Logsdon · Rule change · TB 25-09 (2025-09 Fastrack)

In GCR, Section 9.1.2. GT1 Spec Lines, GT1 Approved Automobile List, LS1 engine allowed with stock intake, make the following
change:
"LS1 Limited Prep GT1 Motor Chevy LS Limited Prep Engine including LS1, LS2, LS3 and LS6."
"Pistons: Factory or aftermarket flat top pistons only, valve reliefs allowed, coatings allowed. Maximum compression ratio
11:1."

2025-10-01 GT1 RM 25-06 GT1 reclassify the Acura NSX GT3 EVO 22 to GT1-ST

#39101 from Club Racing Board · Rule change · TB 25-10 (2025-10 Fastrack)

IN GT1 reclassify the Acura NSX GT3 EVO 22 to GT1-ST as follows:
GT1 Approved Automobile List
Make/Model Wheelbase
ACURA
NSX GT3 EVO 22 103.5”
DOHC 4v per cylinder EFI Twin Turbo Crossflow V-6 Displacement 3500cc Bore and Stroke 91x90
MAX RPM 7500 MAX BOOST 2.1 bar Weight 3100 lbs
GT1-ST Maximum

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 GT1 NSX Parity With Other GT3s Let Alone a GT1 Car

#39311 from Taz Harvey · Rule change · TB 26-01 (2026-01 Fastrack)

In GT1-ST, Acura NSX GT3 EVO 22, change Weight as follows:
"3100 3000"

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 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 GT1 Request for Addition of Porsche 992.1 GT3 Cup into GT1

#39322 from Erik Madsen · Rule change · TB 26-02 (2026-02 Fastrack)

In 9.1.2. GT1 Spec Lines, add the following:
"992.1 GT3 Cup (2022-2025)
OEM ABS and Traction Control allowed. Porsche OEM RSR bumper and canards allowed. Any exhaust system may be utilized."

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.