STL + STU + FV 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 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.

2023-06-01 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."

2023-07-01 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.

2023-12-01 FV FV Wheel Bearing Clarification

#35150 from Formula/Sports Racing Committee · Rule change · TB 23-12 (2023-12 Fastrack)

Summary

As printed in Fastrack

In FV, GCR section 9.1.1.C.10.G, change as follows:
"Front W wheel bearings"

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 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 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 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."

2024-03-01 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."

2024-08-01 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"

2024-10-01 FV Disc Brakes

#36822 from Guy Bellingham · Rule change · TB 24-10 (2024-10 Fastrack)

Summary

As printed in Fastrack

In FV, GCR section 9.1.1.C.4.D, change as follows:
"Any ferrous alloy, unvented rotor may be used, but must have a maximum diameter of 11.75 in. and a minimum thickness of
0.20 in. The otherwise smooth rotor may not be cross-drilled and may have a maximum of three pad cleaning grooves per side."

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 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."

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 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."

2025-03-01 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 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"

2025-05-01 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

2025-05-01 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

2025-07-01 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.

2025-08-01 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 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"

2025-08-01 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"

2025-11-01 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%"

2025-12-01 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 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 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

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.