GT1 + STL at Buttonwillow Raceway Park

2023-04-01 GT1 Mercedes AMG GT3 Notes

#33804 from Gary D'Abate · Rule change · TB 23-04 (2023-04 Fastrack)

Summary

As printed in Fastrack

In GT1-ST Spec Lines, Mercedes Benz AMG GT3 (16-19), change Notes as follows:
"Car must be prepared to per its FIA GT3 homologation. except as specified differently within the GT1 class rules."

2023-05-01 GT1 Please classify Fields Cardinal V8

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

Summary

As printed in 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.

2023-06-01 STL Clarify STL table B - IT spec notes on Tires

#34187 from Austin Hilliard · Rule change · TB 23-06 (2023-05 Fastrack)

Summary

As printed in Fastrack

In STL Spec Lines, Table B: Alternate Vehicle and Engine Allowances, change Notes as follows:
ITA-spec and ITS-spec RX7: "Must completely conform to ITCS specifications. Tires must conform to 9.1.4, Tires & Wheels. Tires
must also conform to 9.1.4.2.Tires."
ITS, ITA, ITB, or ITC vehicles (1985- ): "Must completely conform to ITCS specifications. Tires must conform to 9.1.4, Tires &
Wheels. Tires must also conform to 9.1.4.2.Tires."

2023-12-01 GT1 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)

Summary

As printed in 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 GT1 Request for Acceptance of Lamborghini Huracan GT3 in GT1-ST

#34929 from Michael McAleenan · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In GT1-ST Spec Lines, classify Lamborghini Huracan GT3 EVO(1) (2018-) as follows:
GT1-ST Maximum Displacement Minimum Weight Restrictor Notes
Lamborghini Huracan
GT3 EVO(1)
(2018-)
5204 3000 2 X39mm Per FIA Homologation
GT3-040
In GT1-ST Spec Lines, classify Lamborghini Huracan GT3 (2019-) as follows:

2024-01-01 GT1 Cylinder heads

#35040 from Pater Mumford · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In GCR, Section 9.1.2.D.1.e.3., add at the end of section add the follows:
"Trick Flow Specialties Ultra 18 Degree GM Cylinder Head assembly Part #TFS-3181T001-CO1 is allowed."

2024-01-01 STL Alternate Carburetor Request for 79-85 RX7 12a

#35181 from Dan Sheppard · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In STL Table B: Alternate Vehicle and Engine Allowances, Mazda RX-7 12A (79-85), change Notes as follows:
"Street Porting of the engine only. Bridge porting, peripheral porting, and eyelash porting are prohibited. Contact SCCA National
Office for details of Street porting. Stock Nikki 4 bbl carburetor on a stock manifold only. or auto-type 2 bbl w/42mm choke(s) on
a “dual-y” manifold. Allow the standard removal of emissions related components, and allow air and fuel jets to be corrected.
Modification of the water jacket in the area of the spark plug for cooling purposes is permitted."

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

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

Summary

As printed in 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 STL BOP Adjustments

#35112 from Super Touring Committee · Rule change · TB 24-02 (2024-01 Fastrack)

Summary

As printed in Fastrack

In GCR, 9.1.4.H.1., change as follows:
"Minimum weights for cars with normally aspirated piston engines will be determined by 1.35 lbs/cc displacement for
the installed engine (see the following table). Displacement is the factory displacement for the installed engine. For the
purpose of weight assignment, engine displacement will be rounded to the nearest 50cc (e.g., 2176cc = 2200cc and
2175cc = 2150cc)."
In GCR, 9.1.4.H.1., change Minimum Weight on Chart as follows:
Factory Engine Displacement 1900: "Effective 3-1-24: 2565 2540"
Factory Engine Displacement 1950: "Effective 3-1-24: 2633 2583"

2024-02-01 GT1 Rear Blade Spoiler Clarification

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

Summary

As printed in 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 STL Mazda 12A

#35320 from Super Touring Committee · Rule change · TB 24-02 (2024-02 Fastrack)

Summary

As printed in Fastrack

In STL Spec Lines, Table A, Mazda 12A, change Notes as follows:
"The 5th and 6th intake port actuators and valves may be removed or disabled."

2024-02-01 GT1 GT Direct Injection allowance and rules

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

Summary

As printed in 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 GT1 GT2/3 remove Direction Injection not allowed in Spec line notes

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

Summary

As printed in 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.”

2024-05-01 GT1 Request for Spec Line 1010 Reconsideration

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

Summary

As printed in 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)

Summary

As printed in Fastrack

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

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

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

Summary

As printed in 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)

Summary

As printed in 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"

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

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

Summary

As printed in 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."

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)

Summary

As printed in 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 GT1 Correct language regarding OEM Areo Devices

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

Summary

As printed in 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 GT1-ST Adjustments

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

Summary

As printed in 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-):

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

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

Summary

As printed in 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.

2025-05-01 STL E&O: SMX Allowance in STL

#37945 from Greg Amy · Rule change · TB 25-05 (2025-05 Fastrack)

Summary

As printed in Fastrack

In STL Spec Lines, Table B, Mazda Spec MX5 Challenge, change as follows:
Minimum Weight: "2500 See 9.1.7.1."
Notes: "Mazda MX5 Challenge car must utilize the following components: Roush CNC cylinder head 0000-01-5300,Mahle
standard or +0.005 0000-01-5310, OEM camshaft, 11:1 compression ratio, header 0000-06-5407-NC, exhaust 0000-06-5427-NC,
cold air intake 0000- 06-5150-KT, ECU flash 0000-01-5379, Pagid front brake pads 0000-03-5104-SP or endurance pads 0000-03-
5104-EN, Pagid rear brake pads 0000-03-5114-SP or endurance pads 0000-03-5114-EN, Penske front shock 0000-04-5291-SA,
Penske rear shock 0000-04-5292-SA, Penske rear mount kit 0000-04-5358, Front mount kit 0000-04-5359, Front offset bushing
0000-04-5407-NC, Eibach front springs 0000-04-9700-08, Eibach rear springs 0000-04-9400-07, Eibach helper springs 0000-04-

Applies to Mazda Miata on this page: Jared Korth, Ricardo Arruda, Gavin Wardle, Ryan Gutile, Bryce Johnson, Andy Chittum, Adrian Comstock

2025-08-01 STL Lotus Weight Reduction

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

Summary

As printed in 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"

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

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

Summary

As printed in 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)

Summary

As printed in 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 GT1 NSX Parity With Other GT3s Let Alone a GT1 Car

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

Summary

As printed in Fastrack

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

2026-01-01 STL Weight adjustment for STL

#39579 from Super Touring Committee · Rule change · TB 26-01 (2026-01 Fastrack)

Summary

As printed in Fastrack

In GCR, Section 9.1.4.2.H.1. change Minimum Weight on chart as follows:

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

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)

Summary

As printed in 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."