EP + STU + GTX 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)

Summary

As printed in 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"

2023-04-01 EP Investigate Parity of Z3

#33343 from Tim Schreyer · Rule change · TB 23-01 (2023-01 Fastrack)

Summary

As printed in Fastrack

Effective 4/1/2023 In EP Spec Line BMW Z3 2.5L, change Notes as follows:
"58 56mm Flat Plate Intake Restrictor is required with both stock or alternate throttle body."

2023-04-01 STU Alternate OEM Miata Intake Manifold

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

Summary

As printed in 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 GTX 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 EP 914-6 Valve Size Correction

#34185 from Kip VanSteenburg · Rule change · TB 23-06 (2023-05 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Porsche 914 - 6 2.0L, change Valves IN & EX mm/(in.) as follows:
"(I) 41.9 2.0/(1.65)
(E) 38.1 0/(1.50)"

2023-07-01 GTX Request Ligier LMP3 Classification

#34043 from Alex Kirby · Rule change · TB 23-06 (2023-07 Fastrack)

Summary

As printed in Fastrack

In GTX Spec Lines, classify Ligier LMP3 as follows:
GTX - MISC
Make Model Engine Restrictor
(mm) Weight (lbs) Notes
Ligier LMP3 3.7L NA 2203

2023-07-01 GTX Ligier JSP4 Request

#34173 from Bob Monette · Rule change · TB 23-06 (2023-07 Fastrack)

Summary

As printed in Fastrack

In GTX Spec Lines, classify Ligier JSP4 as follows:
GTX - MISC
Make Model Engine Restrictor
(mm) Weight (lbs) Notes

2023-07-01 EP Correct Intake Valve Size on 1500cc Midget/Spitfire

#34419 from Production Committee · Rule change · TB 23-06 (2023-05 Fastrack)

Summary

As printed in Fastrack

In FP Spec Lines, Austin-Healey Sprite Mk. I, II,III, IV MG Midget Mk I,II, III, IV & 1500, change Intake Valve Size as follows:
"(I) 36.65.3/(1.44)"
In FP Spec Lines, Triumph Spitfire Mk. IV & 1500, change Intake Valve Size as follows:
"(I) 36.65.5/(1.440)"
In HP Spec Lines, Triumph Spitfire 1500, change Intake Valve Size as follows:
"(I) 36.65.5/(1.440)"
In HP Spec Lines, Triumph Spitfire Mk. III & IV 1500, change Intake Valve Size as follows:
"(I) 36.65.5/(1.440)"

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

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

Summary

As printed in 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 EP Hub Note Clean Up In EP TR8 Spec Line

#34649 from Jeff young · Rule change · TB 23-09 (2023-09 Fastrack)

Summary

As printed in Fastrack

In the EP Spec Lines, Triumph TR8 (78-81), remove the following wording from Notes:
"Alternate front hubs are allowed provided they are of the same external dimensions as stock and weigh no less than the stock
hubs."

2023-09-01 EP Triumph GT6 Adjustments

#34662 from ANTHONY PARKER · Rule change · TB 23-09 (2023-09 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Triumph GT6, change Carburetor. No. & Type as follows:
"(2) 1.5” SU or Stromberg Auto-type carburetor(s)"

2023-09-01 EP Triumph GT6 Adjustments: Brakes

#34663 from ANTHONY PARKER · Rule change · TB 23-09 (2023-09 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Triumph GT6, add the following to Brakes Alt.: mm/(in.):
"(F) Calipers & discs from TR-6 (std. or alt)"

2023-12-01 GTX 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

2023-12-01 EP Porsche 944/924S Rule Change Request

#35002 from Adam Achepohl · Rule change · TB 23-12 (2023-12 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, delete the Porsche 944/924S 2.5L (2V) (83-88) spec line entirely, and create a new spec line for Porsche
944/924S 2.5L(2V) 2.7L(2V) (83-89) as follows:

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

2023-12-01 EP Triumph GT6 Adjustments

#35054 from ANTHONY PARKER · Rule change · TB 23-12 (2023-12 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Triumph GT6, change weight as follows:
"1830 1800"

2024-01-01 GTX KTM X Bow GTX

#34956 from Demetrio Bilbatua · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In GTX Spec Lines, classify KTM as follows:
GTX – KTM
Make Homologation Model Restrictor
(mm) Weight (lbs) Notes

2024-01-01 EP Request to Review Z3 2.5 Spec Line

#35073 from Tim Schreyer · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In EP spec line, BMW Z3 2.5L, change weight as follows:
"2450 2500
*2511 2563
**2573 2625"

2024-01-01 EP Miata Alternate Head

#35253 from Don Tucker · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Mazda MX-5 /Miata 1.8L (90-97), change weight as follows:
"2200 2150"
Mazda MX-5 /Miata (94-97)
"2035 2000
*2086 2050
**2137 2100"

Applies to Mazda Miata on this page: Joe Carr

Applies to Mazda MX-5 on this page: Glen McCready, Whitfield Gregg

2024-01-01 EP Triumph GT6 Adjustments

#35255 from Anthony Parker · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In EP spec line, Triumph GT6, make the following change in the Notes section:
"Two (2) 1.75” auto-type carburetors @ 1970 40 lbs. Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990
lbs. Laycock overdrive, May use 5 speed gearbox w/o overdrive. Three (3) Weber 40mm DCOE w/28mm venturi on individual
runner manifold @ 2020 lb."

2024-01-01 EP Honda S2000 throttle body

#35272 from Aaron Johnson · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In EP spec line, Honda S2000, make the following changes to its spec line:
Fuel Injected Equipped Throttle Body Inside Diameter: "62 64"
Notes: "Comp. Ratio limited to 12.0:1. Valve lift limited to .500”. An adaptor plate can be used to mount the 62mm throttle body
from '00-05 to the '06-09 intake manifold. The adaptor plate can be no more than 1.25" thick, and its bore must not exceed the
"Fuel Injected Equipped Throttle Body Inside Diameter" maximum spec of 64mm."

2024-01-01 EP Correction within Triumph TR8 Spec Line

#35315 from Production Committee · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In EP spec line, Triumph TR8 (78-81), move the "Dry sump allowed" wording to the appropriate location as follows:
Carburetor. No. & Type: “Zenith Stromberg carbs or fuel injection. Dry sump is allowed.”
Notes: “Comp. Ratio limited to 12.0:1, Valve lift limited to .500”. Dry sump is allowed.”

2024-01-01 EP Correction to EP 924S/944 Spec Line

#35317 from Production Committee · Rule change · TB 24-01 (2024-01 Fastrack)

Summary

As printed in Fastrack

In EP spec line, Porsche 944/924S 2.5L (2V) / 2.7L (2V) (83-89), change Weight as follows:

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

2024-02-01 STU 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 GTX 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 EP Update 1988-1991 Civic to Match 1988-1991 CRX

#35399 from Enrik Benazic · Rule change · TB 24-02 (2024-01 Fastrack)

Summary

As printed in Fastrack

In HP, make the following weight change:
Honda Civic 1.5 (88-91)
“2245 2175
*2301 2229
**2357 2284”

2024-02-01 GTX 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 GTX 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.”

2024-03-01 STU Letter #35397 addendum

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

Summary

As printed in 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)

Summary

As printed in Fastrack

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

2024-03-01 EP GCR Correction - Redundant HP Spec Lines

#35623 from Production Committee · Rule change · TB 24-03 (2024-03 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, delete the following redundant spec lines in their entirety:
Spec line #10 - VW Rabbit Cabriolet 1780
Spec line #3 - VW Scirocco 1588
Spec line #4 - VW Scirocco 1780 (8-valve) (83-88)
Spec line #5 - VW Scirocco 1588

2024-05-01 GTX 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"

2024-06-01 EP NIssan 300ZX Z31 to EP

#35830 from Murphy Nichols · Rule change · TB 24-06 (2024-06 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, classify Nissan 300ZX (84-89), as follows:

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

2024-06-01 EP RX7 1993 and Up Request In EP Spec Lines, classify

#36031 from Edward Zabinski · Rule change · TB 24-06 (2024-06 Fastrack)

Summary

As printed in Fastrack

Mazda RX-7 (92-97) as follows:

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

2024-06-01 EP Clean-up Multiple EP RX-8 Spec Lines In EP

#36156 from Production Committee · Rule change · TB 24-06 (2024-06 Fastrack)

Summary

As printed in Fastrack

Spec Lines, make the following changes to the two Mazda RX-8 spec lines.
Remove spec line entirely:
Mazda RX-8 (04-11)
Remove the wording "alternate":
Mazda RX-8 (04-11)(alternate)
Spec Mazda (SM/SMX) None.

2024-08-01 EP Errant entry in HP production line item

#36231 from Angus Crome · Rule change · TB 24-08 (2024-08 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, change Track (F/R)mm/(in.) as follows:
Volkswagen Golf (GTI, GT, GL) (85-92): "2 1537/1529 (60.5/60.2)"
Volkswagen Jetta (GLI, GL) (85-92): "2 1537/1529 (60.5/60.2)"

2024-08-01 STU RWD Turbo Disadvantage

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

Summary

As printed in 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"

2024-11-01 EP 1275 HP Spridget Level 2 Only

#36518 from Darryl Saylor · Rule change · TB 24-09 (2024-09 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, Austin-Healey Sprite MkI, II, III, IV MG Midget (ALL) - Level 2 - 1275cc, change Notes as follows:
"(Effective 11/1/2024) Compression ratio limited to 11 12.0:1"
In HP Spec Lines, Austin-Healey Sprite MkI, II, III, IV MG Midget (ALL) - Level 2 - 1098cc, change Notes as follows:
"(Effective 11/1/2024) Compression ratio limited to 11 12.0:1"

2024-11-01 EP NA Miata Track Width Correction

#36902 from Production Committee · Rule change · TB 24-11 (2024-11 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Track (F/R) mm/(in.), change as follows:
Mazda MX-5 /Miata 1.6L (-1993) - "1478/1491 (58.2/58.7) 1516/1534 (59.7/60.4)"
Mazda MX-5 /Miata 1.8L (90-97) - "1483/1509 (58.4/59.4) 1516/1534 (59.7/60.4)"
Mazda MX-5 /Miata (94-97) - "1483/1509 (58.4/59.4) 1516/1534 (59.7/60.4)"

2024-11-01 STU R53 15% Pulley Request

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

Summary

As printed in 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."

2024-12-01 EP Triumph GT6 Adjustments

#37112 from Anthony Parker · Rule change · TB 24-12 (2024-12 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, make the following changes in the "Triumph GT6" spec line:
Carburetor No. & Type: (2): "1.5” 1.75" Auto-type carburetor(s)"
Notes: "Two (2) 1.75” auto-type carburetors @ 1940 lbs. Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990
lbs. Laycock overdrive, May use 5 speed gearbox w/o overdrive."

2024-12-01 STU 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."

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

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

Summary

As printed in 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)

Summary

As printed in 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 EP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line

#37119 from Tim Schreyer · Rule change · TB 25-01 (2025-01 Fastrack)

Summary

As printed in Fastrack

In EP SPEC LINES, BMW 325i/is (E30) (84-91), change Weight as follows:
"2200 2150
*2255 2204
**2310 2258"

2025-01-01 GTX 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 STU Merger GT3 to STU

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

Summary

As printed in 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)

Summary

As printed in 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."

2025-02-21 EP Effective date for Jan 2025 GCR updates

#37654 from Doug Piner · Rule change · TB 25-02 (2025-02 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, add to Notes as follows:
BMW Z3 2.5LL "(Effective 2/21/2025) 52mm Flat Plate Intake Restrictor is required."
BMW Z3 2.8L (97-00): "(Effective 2/21/2025) 55mm Flat Plate Intake Restrictor is required."
BMW 328i/is E36 (96-99): "(Effective 2/21/2025) 58mm Flat Plate Intake Restrictor is required."
BMW 328i/ci E46 (01-06): "(Effective 2/21/2025) 58mm Flat Plate Intake Restrictor is required."
BMW 325i/is E46 (01-06): "(Effective 2/21/2025) 56mm Flat Plate Intake Restrictor is required."
BMW 325i/is E-36 (92-95): "(Effective 2/21/2025) 56mm Flat Plate Intake Restrictor is required."
BMW 325is M-Technic (1994): "(Effective 2/21/2025) 56mm Flat Plate Intake Restrictor is required."

2025-03-01 EP Request Competition Adjustment to BMW Z3 2.5L

#37120 from Tim Schreyer · Rule change · TB 25-01 (2025-01 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, change Notes as follows:
BMW Z3 2.5LL "(Effective 3/1/2025) 56mm 52mm Flat Plate Intake Restrictor is required."
BMW Z3 2.8L (97-00): "(Effective 3/1/2025) 59mm 55mm Flat Plate Intake Restrictor is required."
BMW 328i/is E36 (96-99): "(Effective 3/1/2025) 62mm 58mm Flat Plate Intake Restrictor is required."
BMW 328i/ci E46 (01-06): "(Effective 3/1/2025) 62mm 58mm Flat Plate Intake Restrictor is required."
BMW 325i/is E46 (01-06): "(Effective 3/1/2025) 60mm 56mm Flat Plate Intake Restrictor is required."
BMW 325i/is E-36 (92-95): "(Effective 3/1/2025) 60mm 56mm Flat Plate Intake Restrictor is required."
BMW 325is M-Technic (1994): "(Effective 3/1/2025) 60mm 56mm Flat Plate Intake Restrictor is required."

2025-03-01 EP Interpretation of Production Rules on Mirrors

#37235 from Lawrence Slivinski · Rule change · TB 25-03 (2025-03 Fastrack)

Summary

As printed in Fastrack

In GCR, add new rule as Section 9.1.5.E.10.f:
"Any interior or exterior mirror(s) that meets rule 9.3.36 may be used."

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

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

Summary

As printed in 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 EP Weight Reduction for Honda S2000

#37466 from Michael Unger · Rule change · TB 25-03 (2025-03 Fastrack)

Summary

As printed in Fastrack

In EP, Spec Lines make the following weight changes:

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

2025-03-01 EP Mazda 1999 Miata 1.8L

#37488 from Joe Carr · Rule change · TB 25-03 (2025-03 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, make the following weight change:
Mazda MX-5 /Miata (99-05):
"2150 2100
*2204 2153
**2258 2205"

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)

Summary

As printed in 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)

Summary

As printed in 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 STU Increase Minimum Weight

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

Summary

As printed in Fastrack

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

2025-04-01 EP Request for Classification of Chevrolet Spark

#37755 from Kristian Smith · Rule change · TB 25-04 (2025-04 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, classify the Chevrolet Spark (16-22):

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

2025-04-01 EP Request to Lower Ford Festiva Minimum Weight to 1600 LBS

#37939 from Doug DeRonne · Rule change · TB 25-04 (2025-04 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines "Ford Festiva (88-93)" change as follows:
Weight:
"1700 1600
*1743 1640
**1785 1680"
Notes:
"Compression ratio limited to 10.5 11.0:1. Valve lift limited to .450”."

2025-05-01 GTX Request to Classify Porsche GT2 RS Clubsport

#37972 from Paul Fairchild · Rule change · TB 25-05 (2025-05 Fastrack)

Summary

As printed in Fastrack

In GTX, Classify Porsche GT2 RS Clubsport, as follows:
GTX
Make Homologation Model Restrictor
(mm)
Weight
(lbs) Notes
Porsche GT2 RS Clubsport Must have factory specifications available at all race events

2025-05-01 STU Wheel Size Inconsistency

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

Summary

As printed in 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 STU Table C: STU-GT3U Clarification

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

Summary

As printed in 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

2025-06-01 GTX Ligier P3 LS Swap

#38164 from Bart Wolf · Rule change · TB 25-06 (2025-06 Fastrack)

Summary

As printed in Fastrack

In GTX Spec Lines, GTX-MISC., Ligier, LMP3, 3.0L, Add to Notes the following:
"Allow any normally aspirated LS Chevrolet engine may be used."

2025-06-01 EP Base Weight Adjustment for H-Production X1/9 Spec Lines

#38255 from Matthew Brannon · Rule change · TB 25-06 (2025-06 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, change Weight as follows:
Fiat X-1/9 & Bertone1500: “1790 1740 *1835 1784 **1880 1827”
Fiat X-1/9 1300: “1650 1600 *1691 1640 **1733 1680”
Fiat X-1/9 1300: “2060 2010”
Fiat X-1/9 1500: “1950 1900”

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

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

Summary

As printed in 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)

Summary

As printed in 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)

Summary

As printed in 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.

2025-07-01 EP BMW Z4 update

#38490 from Bryce McGuire · Rule change · TB 25-07 (2025-07 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, BMW Z4 (03-05), add to Notes the following:
“52mm Flat Plate Intake Restrictor.”

2025-07-01 EP EP Fiat 124 Spider Competition Adjustment Request

#38498 from John Baucom · Rule change · TB 25-07 (2025-07 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Fiat 124 Sport Spider 1600 & 124 Spider 2000, change as follows:
Weight: "2050 2000"
Carburetor No. & Type: "(2) Weber 40 IDF-40IFI, (2) Solex C40P116, 34 36mm choke(s) req’d, (2) Weber 45DCOE w/ 34 36 mm
choke(s) on I.R. manifold or fuel injection."

2025-08-01 STU STU-TCR Adjustments

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

Summary

As printed in 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)

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 STU Lotus Weight Reduction E&O

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

Summary

As printed in Fastrack

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

2025-10-01 EP HP Plymouth Arrow spec omission

#38995 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, Plymouth Arrow (76-80), add the following wording to Trans. Speeds(max):
"4 or 5"

2025-10-01 EP Add Wheel Diameter to Appendix G

#39008 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

Summary

As printed in Fastrack

In Appendix G.2.3, change as follows:
"Rim width and diameter are is absolute maximums."

2025-10-01 EP Add TB ID tolerance to general Prod rules

#39009 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

Summary

As printed in Fastrack

In GCR, Section 9.1.5.E., change as follows:
9.1.5.E.1.b.4: "The inside dimensions of the throttle body casting/housing (as measured at the throttle butterfly) must remain
stock (tolerance of +/-.25mm), but the throttle body can otherwise be ported and polished."
9.1.5.E.2.b.4: "The inside dimensions of the throttle body casting/housing and all dimensions of the throttle butterfly must
remain stock (tolerance of +/-.25mm)."

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)

Summary

As printed in Fastrack

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

2025-11-01 EP Please Lower Weight of 280Z

#38871 from Matthew Miller · Rule change · TB 25-09 (2025-09 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Nissan 280Z, change Weight (lbs) as follows:
"(Effective 11/1/2025) 2560 2400
*2624 2460
**2688 2520"

2025-11-01 EP Miata Weight Adjustment Follow Up

#38949 from Don Tucker · Rule change · TB 25-10 (2025-10 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Mazda MX-5 / Miata 1.8L (90-97), Effective 11/1/2025 make the following weight change:
"2150 2125"

2025-11-01 EP Weight Break for 1098 Midget / Sprite

#38970 from Kendall Jones · Rule change · TB 25-10 (2025-10 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, Austin-Healey Sprite/Midget 1098cc, Effective 11/1/2025make the following weight change:
"1630 1550"

2025-11-01 EP HP Volvo 142 spec omission

#38994 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, Volvo 142/142E P-1800 Engine, Effective 11/1/2025 add the following wording to Notes:
"Comp. Ratio limited to 12.0:1. Valve lift limited to .425”."

2025-11-01 EP HP Mini DOHC 1.6

#38996 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

Summary

As printed in Fastrack

In HP Spec Lines, Mini Cooper (07-13) (includes 09-15 convertible and 12-15 Coupe), Effective 11/1/2025 make the following
changes to the Notes:
"Compression ratio limited to 11.0:1, Valve lift limited to .450”.390"."

2025-11-01 EP Add to Rabbit description

#39019 from Production Committee · Rule change · TB 25-11 (2025-11 Fastrack)

Summary

As printed in Fastrack

In FP Spec Lines, make the following spec line correction:
"Volkswagen Rabbit (Includes Convertible Cabriolet)"
In HP Spec Lines, make the following spec line correction:
"Volkswagen Rabbit 1588 (Includes Cabriolet)"
"Volkswagen Rabbit 1715 (Includes Cabriolet)"
"Volkswagen Rabbit 1780 (Includes Cabriolet)"

2025-11-01 EP Clean-up 9.1.5.E.7e

#39025 from Production Committee · Rule change · TB 25-11 (2025-11 Fastrack)

Summary

As printed in Fastrack

In GCR, Section 9.1.5.E.7., change as follows:
"e. Cars fitted with rear drum brakes, can convert to rear disc brakes without penalty. Note that the “Brakes Std.” and “Brakes
Alt.” listings on a vehicle’s spec line do not prohibit a car that was fitted with rear drum brakes stock, from converting to rear
disc brakes under this rule. When converting from rear drum brakes to rear disc brakes:
1. Rear brake rotors must be solid and can be no larger in diameter than the largest permitted front brake rotor, as defined on
the vehicle’s spec line.
2. Rear calipers and mounting brackets are unrestricted but must be made of a ferrous or aluminum material. The standard and
alternate brake listings on a vehicle’s specification line, does not prohibit a car that was fitted with rear drum brakes as stock

2025-11-01 EP Add TB size to Ford Mustang (94-98) Spec Line

#39130 from Production Committee · Rule change · TB 25-11 (2025-11 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Ford Mustang (94-98) add the following to the Fuel Injected Equipped Throttle Body Inside Diameter column:
"60"

2025-12-01 STU Turbo Inlet Restrictor Table

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

Summary

As printed in 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)

Summary

As printed in 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 EP TR2 Notes E&O

#39180 from Anthony Parker · Rule change · TB 25-12 (2025-12 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, Triumph TR2, 3, 3A, 4, 4A, TR4, TR4A, IRS, make the following change to the Notes:
"Front apron assembly may be made of alternate material. Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990
lbs. Laycock overdrive, may use 5 speed gearbox without overdrive."

2025-12-01 EP Balance of Power

#39187 from Jim Simaras · Rule change · TB 25-12 (2025-12 Fastrack)

Summary

As printed in Fastrack

In EP Spec Lines, make the following changes to Restrictors:
BMW Z3 2.5L: "52mm 50mm Flat Plate Intake Restrictor"
BMW Z3 2.8L (97-00): "55mm 53mm Flat Plate Intake Restrictor"
BMW 328i/is E36 (96-99): "58mm 55mm Flat Plate Intake Restrictor"
BMW 328i/ci E46 (01-06): "58mm 55mm Flat Plate Intake Restrictor"
BMW 325i/is (E46) (01-06): "56mm 53mm Flat Plate Intake Restrictor"
BMW 325is M-Technic (1994): "56mm 53mm Flat Plate Intake Restrictor"
BMW 325i/is E-36 (92-95): "56mm 53mm Flat Plate Intake Restrictor"

2025-12-01 STU STU Honda Engine weight penalty

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

Summary

As printed in 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 EP Request to Update E30 BMW Throttle Body Diameter Verbiage

#39363 from Tim Schreyer · Rule change · TB 26-01 (2026-01 Fastrack)

Summary

As printed in Fastrack

In EP Spec Line BMW 325i/is E30 (84-91), change Drivetrain Notes as follows:
"Fuel Injection, TB: 60mm"

2026-01-01 GTX Please Consider Adding a Spec Line to GTX Table 4 for the RCR T70

#39470 from Peter Jankovskis · Rule change · TB 26-01 (2026-01 Fastrack)

Summary

As printed in Fastrack

In GTX-Misc. Table 4, classify RCR70 Coupe:
GTX – MISC. TABLE 4
Make Homologation Model Restrictor

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

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)

Summary

As printed in 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