GT1 at Road America

2021-08-01 GT1 Request to Update GTA Obsolete Part Numbers

#30615 from Butch Kummer · Rule change · TB 21-08 (2021-08 Fastrack)

In GCR, Section 9.1.2.G.16., change as follows:
"0-80541-1 0-80541-2"
In GCR, Section 9.1.2.G., Appendix Z 5.a. change as follows:
"0-80541-1 0-80541-2"
In GCR, TA2 Appendix B.3.4, change as follows:
"#6010 6014X"

2021-10-01 GT1 Request car classification

#31032 from Bryan Scheible · Rule change · TB 21-10 (2021-10 Fastrack)

In GT3 Engines - VOLKSWAGEN, classify Fun Cup Beetle EVO3 as follows:
GT3 Engines - VOLKSWAGON

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

2022-02-01 GT1 Wheel Widths

#31844 from Richard Grant · Rule change · TB 22-02 (2022-02 Fastrack)

In GCR, Section 9.1.2.D.7.a., change as follows:
"2. Wheels may be thirteen (13), fourteen (14), fifteen (15), or sixteen (16), seventeen (17) or eighteen (18) inches in diameter,
but all four (4) wheels shall be the same diameter. Use of eighteen (18) inches wheels must add 50 lb. weight penalty.
3. Wheels shall have a maximum width of twelve (12) inches in the front and thirteen (13) inches in the rear. 18" tires shall have
thirteen (13) in the front and fourteen (14) inches in the rear ."
SP - Tony A to consolidate response.

2022-03-01 GT1 Mercedes Benz AMG GT3 in GT1

#31883 from THOMAS HERB · Rule change · TB 22-03 (2022-03 Fastrack)

In GT1 Cars - Mercedes Benz, classify Mercedes Benz AMG GT3 as follows:
GT1 Cars – MERCEDES BENZ
Model Years Body Style Drive-

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

2022-03-01 GT1 Wheel Widths

#32205 from Club Racing Board · Rule change · TB 22-03 (2022-03 Fastrack)

In GT1, GCR section 9.1.2.D.7.a., change as follows and renumber:
"1. Wheels shall be made of steel, aluminum, magnesium, or a combination thereof. Multi-piece wheels shall utilize mechanical
fasteners (bolts, rivets, etc.) for assembly.
2. Wheels may be thirteen (13), fourteen (14), fifteen (15), sixteen (16), seventeen (17), or eighteen (18) inches in diameter, but
all four (4) wheels shall be of the same diameter. Use of eighteen (18) inches wheels must add 50 lb. weight penalty.
3. 1.Wheels shall have a maximum width of twelve (12) inches in the front and thirteen (13) inches in the rear. 18” tires shall
have thirteen (13) MAX inches in the front and fourteen (14) MAX inches in the rear."

2022-08-01 GT1 GT-1/TransAm rules simplification/modernizing

#32763 from Tony Ave · Rule change · TB 22-08 (2022-08 Fastrack)

In GT1 Category Specifications, GCR Section 9.1.2.D.8.a. add the following:
"7. Current Trans Am bodywork is allowed with a 100lb. weight penalty."

2022-09-01 GT1 Tail lights on all GT category race cars.

#32799 from John Mills · Rule change · TB 22-09 (2022-09 Fastrack)

In GT, GCR Section 9.1.2.F.7.a.6:
"Glass and/or plastic headlights, front parking lights, front signal lights, lenses, and bulbs shall be removed. Headlight openings
shall be covered with a wire mesh screen or panel having the same contour as the original lens, mounted so that the headlight
bezel/rim remains in place, maintaining the standard appearance of the Production automobile. Side marker light assemblies
shall be removed and the resulting openings covered with a plate whose dimensions do not exceed those of the original parts;
side marker lights that are an integral part of the taillight assembly cannot be removed. Other lighting parts and operating
mechanisms may be removed. In the case of pop-up headlights, the entire assembly may be removed and the opening covered
with a screen or plate (as above, without the headlight bezel/rim requirement) which provides a stock appearance. It is not

2022-12-01 GT1 GT2 (TA2)/GTA Part Number Update

#33315 from Butch Kummer · Rule change · TB 22-12 (2022-12 Fastrack)

In GCR Appendix L-TA2 rules, Addendum A, change A.2. as follows:
"The throttle body must be either a GM 90mm, electronic, part #1257 → 0790, or Edelbrock 90mm, mechanical, part 33869 or
#3870."
In GTA, GCR Section 9.1.2.G.3., change as follows:
"The throttle body must be either a GM 90mm, electronic, part #1257 → 0790, or Edelbrock 90mm, mechanical, part 33869 or
#3870."

2022-12-01 GT1 Request to Reduce Trans Am Bodywork Weight Penalty

#33331 from David Pintaric · Rule change · TB 22-12 (2022-12 Fastrack)

In Grand Touring 1 (GT1) Specifications, GCR Section 9.1.2.D.8.a.7., change as follows:
"Current Trans Am bodywork is allowed with a 100 75lb. weight penalty."

2022-12-01 GT1 Request for Reduction in FR9 Weight Penalty

#33332 from David Pintaric · Rule change · TB 22-12 (2022-12 Fastrack)

In GT1 (GT1) Specifications, GCR Section 9.1.2.E.1.b.1., change as follows:
"Chevrolet/GM - RO7 + 50 25 lbs.
Ford - FR9 + 50 25 lbs.
Dodge - R7 + 50 25lbs."

2023-02-01 GT1 Sequential Transmission Weight Penalty

#33503 from Richard Grant · Rule change · TB 23-02 (2023-02 Fastrack)

In GCR 9.1.2 Grand Touring 1 (GT1) Specifications, Section 9.1.2.D.4.b.2, change as follows:
"Sequential shifting transmissions are permitted with a 50 25lb. weight penalty."

2023-02-01 GT1 GT1 Porsche 992

#33730 from Grand Touring Committee · Rule change · TB 23-02 (2023-02 Fastrack)

In GT1-ST Spec Lines, Cars - Porsche, classify Porsche 992 GT3 Cup Car as follows:
GT1-ST Maximum
Displacement
Minimum
Weight Restrictor Notes
Porsche 992 GT3 Cup 3997 2950 Car must be prepared in accordance with
the appropriate model/year Porsche 992
factory service manual. Factory (OEM

2023-04-01 GT1 Mercedes AMG GT3 Notes

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

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.

2023-12-01 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)

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)

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)

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."

2024-02-01 GT1 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 GT1 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 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)

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)

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)"

2024-11-01 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 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 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 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-):

2025-03-01 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.

2025-09-01 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 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"

2026-02-01 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."

2026-03-01 GT1 Reduce Weight for GM 275ci Carbureted V6s

#39713 from Cameron Wagner · Rule change · TB 26-03 (2026-03 Fastrack)

In GCR, Section 9.1.2.D.E.b., V-6 - up to 275 (4.5), change as follows:
"2345 2295"

2026-03-01 GT1 Remove GT3U from GCR as it is now in STU

#39862 from SCCA Staff · Rule change · TB 26-03 (2026-03 Fastrack)

In GCR, change as follows:
9.1.2 Page 68: "GT-3U (GT3U)"
9.1.2.F page 320: "9.1.2.F. GT-2, 3, 3U LI TE CATEGORY SPECIFICATIONS"
9.1.3.9 Page 320: "9. 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 including the 225 lbs. TCR cars are ineligible for GT3/GT3U.
Table B: Alternate Vehicle and Engine Allowances Page 461:

2026-06-01 GT1 Request for Huracan GT3 Evo Weight Reduction to 2950lbs

#40147 from Mike McAleenan · Rule change · TB 26-06 (2026-06 Fastrack)

In GT1-ST Spec Lines, Lamborghini Huracan GT3 (2019-), change weight as follows:
"3000 2950"

2026-07-01 GT1 Request TA Cup Cars Into GT1

#40250 from Scotty B White · Rule change · TB 26-07 (2026-07 Fastrack)

In GT1 Spec Lines, GT1 Cars – T/A Cup, classify T/A Porsche Cup as follows:
GT1 Cars – T/A Cup
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
T/A Porsche Cup Max flat plate size 1-11/16 inch, must run

2026-07-01 GT1 Lamborghini Huracan Super Trofeo in GT1

#40288 from Tony Ave · Rule change · TB 26-07 (2026-07 Fastrack)

In GT1 Spec Lines, GT1 Cars - Lamborghini, classify Huracan Trofeo, Evo 2, Evo 3 as follows:
GT1 Cars - Lamborghini
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
Huracan Trofeo, Evo 2,

2026-08-01 GT1 Request TA Cup Cars Into GT1

#40250 from Scotty B White · Rule change · TB 26-08 (2026-08 Fastrack)

In GT1 Spec Lines, GT1 Cars – Porsche T/A Cup, change as follows:
Model: "T/A Porsche Cup"
Notes: "Max flat plate size 1-11/16 inch, must run T/A Porsche Cup rule set, Must have T/A Porsche Cup rule set in possession at
all race events."