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BoP Lab / Buttonwillow Raceway Park

FA + STU at Buttonwillow Raceway Park

No mapCal Club 2024, Cal Club 2023

Track map: sectors and speed trap

Track map with timing sectors and speed trap
Shown for: Cal Club 2026 (practice, qualifying, race) · Cal Club 2025 (practice, qualifying, race)
Class · click a class to switch, + to compare alongside
Track configuration
Events

This track has been raced on 4 configurations (The Circuit, 2.57 mi; 19, 2.92 mi; 1.83 mi; 3.02 mi). Laps on different configurations are not comparable, so only events on the 2.57 mile layout are shown; switch above to see the others.

7 laps are left out as timing errors (far too short to be a lap of this track). The rest of those sessions, sectors included, is used.

PosCarDriverClass#LapTheoreticalQualRace5-lap stintConsistencyTrapS1S2S3
1Elan Pro Formula MazdaGreg Labadie 2+ carsFA351:14.588 D-Q21:14.588 D-Q2
2Swift 016Greg Labadie 2+ cars >115%FA351:35.792 A-Q11:35.3511:35.792 A-Q11:37.275 A-R11:37.692 A-R1+3.958 A-R1163.8 A-R126.713 A-Q226.816 A-Q141.822 A-Q1
3Mazda RX-3Tony RiveraSTU091:50.913 A-Q21:50.8701:50.913 A-Q21:52.737 A-R21:54.126 A-R2+2.638 A-R2135.2 A-Q230.415 A-Q232.456 A-Q247.999 A-Q2
4Mazda MiataWhitfield GreggSTU171:51.602 B-P1:51.6022:02.264 B-Q22:01.538 B-R12:02.222 B-R1+1.271 B-R1116.3 A-Q130.652 B-P32.263 B-P48.687 B-P
5BMW M3Wilson PowellSTU771:52.380 B-P1:52.1641:55.401 B-Q11:53.843 B-R11:54.699 B-R1+1.965 B-R1102.6 B-R130.577 B-P32.372 B-P49.215 B-P
6Honda S2000Rylan HazeltonSTU491:53.640 B-R11:53.1401:55.834 B-Q11:53.640 B-R11:54.534 A-R2+0.714 A-R2134.8 A-R230.582 B-R132.779 B-R149.779 A-R2
7BMW 330Sean LovettSTU371:56.492 A-Q21:56.4261:56.492 A-Q21:57.049 A-R21:57.605 A-R2+1.649 A-R2133.7 A-R231.816 A-Q233.669 A-Q150.941 A-Q2
8Nissan 300ZXJames SlechtaSTU751:59.183 A-Q21:59.1831:59.183 A-Q22:00.458 A-R22:01.009 A-R2+0.921 A-R2132.0 A-Q132.882 A-Q234.528 A-Q251.773 A-Q2
9Mazda MX-5Oscar JacksonSTU1611:59.707 B-R21:58.8881:59.707 B-R21:59.952 B-R2+1.112 B-R2103.9 B-R232.339 B-R234.219 B-R252.330 B-R2
10Mazda RX-7Michael LewisSTU322:00.248 A-R12:00.1792:00.248 A-R12:02.190 A-R2+1.431 A-R2130.4 A-R132.729 A-R134.570 A-R152.880 A-R1
11Mazda MX-5Dale ShoemakerSTU522:01.642 B-R22:01.1762:04.115 B-Q12:01.642 B-R22:02.793 B-R2+2.442 B-R2125.9 A-Q232.956 B-R234.983 B-R253.237 B-R2

One row per driver and car (a driver who changed cars has a row for each). Each cell is that driver's best in that car across the selected events, with the session it was set in. Best 5-lap stint is the mean of the driver's quickest five consecutive race laps, and consistency is how far their median race lap sat behind their best in that race (small is a driver who does it every lap); both come from the race with the best stint. The fastest in each column is purple, and a car whose best lap is more than 115% of the fastest in its class is greyed (marked ">115%" beside the driver) and left out of the colour scale. Click a column to sort, a row to highlight it. Theoretical lap is the sum of the best sectors, whichever laps they came from, and never slower than the best lap (where a car's fastest laps were recorded without sector times, its best lap is used). The 115% mark is about the car's best lap only: a car whose best lap is within 115% of the fastest in its class is never marked. Greyed sectors with no theoretical lap mean the sector times on file do not add up to a believable lap. Letters refer to the events above; Q is qualifying, R a race.

Sectors

Sectors are numbered in lap order from start/finish, whatever each event's timing called them; the loop names are SCCA timing's.

By car

CarClassDriversLapQualRaceTrapS1S2S3
Pro Formula MazdaFA11:14.588Greg Labadie1:14.588Greg Labadie
Swift 016FA11:35.792Greg Labadie1:35.792Greg Labadie1:37.275Greg Labadie163.8Greg Labadie26.713Greg Labadie26.816Greg Labadie41.822Greg Labadie
Mazda RX-3STU11:50.913Tony Rivera1:50.913Tony Rivera1:52.737Tony Rivera135.2Tony Rivera30.415Tony Rivera32.456Tony Rivera47.999Tony Rivera
Mazda MiataSTU11:51.602Whitfield Gregg2:02.264Whitfield Gregg2:01.538Whitfield Gregg116.3Whitfield Gregg30.652Whitfield Gregg32.263Whitfield Gregg48.687Whitfield Gregg
BMW M3STU11:52.380Wilson Powell1:55.401Wilson Powell1:53.843Wilson Powell102.6Wilson Powell30.577Wilson Powell32.372Wilson Powell49.215Wilson Powell
Honda S2000STU11:53.640Rylan Hazelton1:55.834Rylan Hazelton1:53.640Rylan Hazelton134.8Rylan Hazelton30.582Rylan Hazelton32.779Rylan Hazelton49.779Rylan Hazelton
BMW 330STU11:56.492Sean Lovett1:56.492Sean Lovett1:57.049Sean Lovett133.7Sean Lovett31.816Sean Lovett33.669Sean Lovett50.941Sean Lovett
Nissan 300ZXSTU11:59.183James Slechta1:59.183James Slechta2:00.458James Slechta132.0James Slechta32.882James Slechta34.528James Slechta51.773James Slechta
Mazda MX-5STU21:59.707Oscar Jackson2:04.115Dale Shoemaker1:59.707Oscar Jackson125.9Dale Shoemaker32.339Oscar Jackson34.219Oscar Jackson52.330Oscar Jackson
Mazda RX-7STU12:00.248Michael Lewis2:00.248Michael Lewis130.4Michael Lewis32.729Michael Lewis34.570Michael Lewis52.880Michael Lewis

The best any driver of each car managed across the selected events, with who set it. Spellings and model years of the same car are grouped; click a row marked ▸ to see each version. Grouping is worked out from the names, so tell us if two cars are wrongly merged or split.

Rule changes between these events

Cal Club 2023 → Cal Club 2024 2023-02-24 to 2024-02-23

STU E&O STU NA Weight Chart.

#33737 from Eric Heinrich · Rule change · TB 23-03 (2023-03 Fastrack)

Summary

fasterSTU minimum weight chart updated: 2450cc to 2595lbs, 2600cc to 2710lbs.

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"

STU Alternate OEM Miata Intake Manifold

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

Summary

wordingSTU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01.

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.

FA E&O - Correct Pro Formula Mazda spec line dimensional equivalent

#34085 from Club Racing Board · Rule change · TB 23-05 (2023-05 Fastrack)

Summary

fasterFA Pro Formula Mazda maximum bodywork width behind front wheels increases to 51.97 inches.

As printed in Fastrack

In FA Table 2, Pro Formula Mazda spec line, change as follows:
"The overall maximum width of the bodywork behind the front wheels shall not exceed 132cm (51.17 51.97 inches)."

FA Add new spec line for MSR Formula Mazda FMzR to Table 2

#34139 from Club Racing Board · Rule change · TB 23-05 (2023-05 Fastrack)

Summary

cars addedFA MSR Formula Mazda FMzR added to Table 2 classification.

As printed in Fastrack

RM 23-06 – MSR - FMzR Formula Atlantic Classification dated 4/21/2023
In FA Table 2, add a spec line as follows:

FA Simplify Pro Formula Mazda wheel allowance

#34190 from Club Racing Board · Rule change · TB 23-06 (2023-06 Fastrack)

Summary

unclearFA Pro Formula Mazda front wheels widen to 10 in. max; rear wheels narrow to 14 in. min.

As printed in Fastrack

In FA, Pro Formula Mazda spec line, change wheel width as follows:
"Pro Mazda series wheels

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

STU 2022 Toyota GR Cup for STU

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

Summary

cars addedToyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine.

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.

STU ST Electric-Assisted Steering Systems

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

Summary

wordingSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.

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"

Cal Club 2024 → Cal Club 2025 2024-02-23 to 2025-02-22

STU Letter #35397 addendum

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

Summary

wordingSTU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted.

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."

STU S54 Drysump

#35464 from Macey Urso · Rule change · TB 24-03 (2024-03 Fastrack)

Summary

wordingSTU BMW S54 B32 OEM now permits dry sump oiling system.

As printed in Fastrack

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

STU RWD Turbo Disadvantage

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

Summary

fasterSTU RWD turbo cars no longer required to reduce restrictor by 1 mm from table.

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"

STU R53 15% Pulley Request

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

Summary

slowerSTU Mini Cooper S SC 1900 restricts to 2.565 diameter pulley; 2100 allows 2.285 diameter pulley.

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."

STU Request to Remove Miata Hubs from General category

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

Summary

wordingSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.

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."

STU BMW N54/N55 Engine Allowance

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

Summary

slowerSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; turbo swapping prohibited.

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.

STU Audi 1.8t Wagon STU Table B

#36685 from Mike McLaughlin · Rule change · TB 25-01 (2025-01 Fastrack)

Summary

fasterSTU Audi 1.8T wagon deleted; Porsche 944 1800 weight to Chart, turbo inlet restrictor removed.

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."

STU Merger GT3 to STU

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

Summary

wordingSTU-GT3 reclassified as STU-GT3U effective January 1, 2026.

As printed in Fastrack

In STU, Table C, change STU-GT3 charge as follows:
"(Effective January 1, 2026) TABLE C: STU-GT3U"

STU GT3 TCR Tire allowance

#37494 from Club Racing Board · Rule change · TB 25-01 (2025-01 Fastrack)

Summary

slowerSTU GT3 TCR gains 275-width tire option with 100 lb weight penalty, but not in A compound.

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."

FA Classify FR European Championship car as spec line car in Table 2

#37658 from Club Racing Board · Rule change · TB 25-02 (2025-02 Fastrack)

Summary

cars addedFA adds Tatuus F.3 T-318 or FR-19 as spec line car in Table 2 for Formula Regional European Championship.

As printed in Fastrack

In FA Table 2, add the following:
Table 2 (Spec Line Cars)
Car Engine
Wheel
Width (in)
± .060
Aero Transmission Weight Notes

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

Cal Club 2025 → Cal Club 2026 2025-02-22 to 2026-02-21

STU BMW N54/N55 Engine Allowance Follow Up

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

Summary

engineSTU BMW N54/N55 3.0L classified at Chart +3% minimum weight; N54 twin turbo not allowed.

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

STU STU Mini Cooper pulley size clarification re: letter #36980

#37717 from Aaron Fitzsimmons · Rule change · TB 25-03 (2025-03 Fastrack)

Summary

fasterSTU Mini Cooper S SC supercharger pulley diameter reduced from 2.285 to 2.185.

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."

STU Question About a Weight Modifier

#37782 from Peter St Pierre · Rule change · TB 25-03 (2025-03 Fastrack)

Summary

fasterSTU Honda K20C1 Turbo I4 exempted from 3% DI weight adder in Spec Lines Table A.

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."

FA Update Formula Renault 2.0 spec line notes

#37853 from Club Racing Board · Rule change · TB 25-03 (2025-03 Fastrack)

Summary

wordingFA Formula Renault 2.0 (10-17) spec notes clarified: engine sealed, manual compliance required, tire choice unrestricted, no alterations except repairs.

As printed in Fastrack

In FA Table 2, Formula Renault 2.0 (10-17) spec line, change the notes as follows:
"Engine must remain sealed. Car must comply with year-specific Formula Renault 2.0 manual, technical regulations, and all
applicable bulletins found here:. Competitors must have copies of these materials in their possession and present them upon
request.
https://sites.google.com/a/renault-sport.com/formule-renault-2-0-en/bulletins-techniques/2017,
https://sites.google.com/a/renault-sport.com/formule-renault-2-0-en/manuel-d-utilisateur/2017.
The following exceptions apply: Tire choice is unrestricted. No part of the car may be altered from original Formula Renault 2.0
components, except for necessary repairs that do not affect performance."

STU Increase Minimum Weight

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

Summary

slowerSTU GT3U minimum weight increases 150 to 250 pounds.

As printed in Fastrack

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

STU Wheel Size Inconsistency

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

Summary

wordingSTU wheel width rules clarified: cars ≤2,850 lbs max 8 inches, cars >2,850 lbs max 9 inches.

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."

STU Table C: STU-GT3U Clarification

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

Summary

fasterSTU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments.

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

Show 1 more lines

including the 225 lbs."

STU 2.8-3.2L N/A Engine Allowances

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

Summary

unclearSTU 2.8-3.2L N/A engines now allow 245 max tire width; over 3150 lbs may run 275 with 2% weight penalty.

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."

STU 2006-2015 Mazda Miata Intake Manifold

#38422 from German Candelario Candelario · Rule change · TB 25-07 (2025-07 Fastrack)

Summary

wordingSTU Mazda MZR may use Goodwin 61-2510 or Gato Performance 31972 intake manifold.

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 . "

FA Ligier JS F3 Tire Choice

#38434 from Rocco Magni · Rule change · TB 25-07 (2025-07 Fastrack)

Summary

tyres & wheelsFA Ligier JS F3 front tires may be Hoosier 43363 240/580R13 MS, rear 43368 300/590R13 MS.

As printed in Fastrack

In FA Table 2, FR Americas Ligier JS F3 spec line, change the notes as follows:
"Engine must be sealed in compliance with FR Americas or prior F3 Americas requirements. Car must comply with FR Americas
rules, with the following exception: front tires may be Hoosier P/N 43363, size 240/580R13 in MS compound, and rear tires may
be Hoosier P/N 43368, size 300/590R13 in MS compound. Competitors must have current copies of Formula Regional Americas
Championship Sporting Regulations, Onroak Automotive Ligier JS F3 Information Manual, and HPD engine-related specifications
and instructions in their possession and present them upon request."

STU Requesting Approval of the JDM Honda h23a

#38489 from Eric Fiest · Rule change · TB 25-07 (2025-07 Fastrack)

Summary

cars addedSTU Honda JDM H23a added, 2259cc displacement, minimum weight per Chart, must meet ST engine regulations.

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.

STU STU-TCR Adjustments

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

Summary

slowerSTU-TCR tire width increases to 275 with weight adder raised from 100 to 150 pounds.

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."

STU Lotus Weight Reduction

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

Summary

fasterSTL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs.

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"

STU Lotus Weight Reduction E&O

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

Summary

fasterSTU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs.

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"

STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ

#38746 from William Rori · Rule change · TB 25-09 (2025-09 Fastrack)

Summary

slowerSTU Honda K24 engine swap weight increases by 2% effective November 1, 2025.

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%"

FA Re-Consider USF Pro 2000 Car for Formula Atlantic Class

#38783 from Augie Pabst · Rule change · TB 25-09 (2025-09 Fastrack)

Summary

cars addedFA class adds USF Pro 2000 car eligibility for Formula Atlantic racing.

As printed in Fastrack

Effective 11/1/25 in FA Table 2, add the following:

STU Turbo Inlet Restrictor Table

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

Summary

slowerSTU 36mm restrictor allows 2830 lbs (up 10 lbs from 2820); 37mm allows 2980 lbs (down 5 lbs from 2985).

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.

STU 275 Tire Rule

#38983 from Peter Federlin · Rule change · TB 25-12 (2025-12 Fastrack)

Summary

slowerSTU cars over 3150 lbs lose 275-tire option with 2% weight adder.

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."

STU STU Honda Engine weight penalty

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

Summary

fasterSTU Honda K20 and K24 engines lose 2% minimum weight penalty.

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%"

FA Alternate Intake Manifold for MZR

#38223 from Ove Olsson · Rule change · TB 26-01 (2026-01 Fastrack)

Summary

unclearFA MZR gains alternate Noor P/N 0088-8-00 intake manifold with AT Power runners as option to Elan or Mazda Speed Elite.

As printed in Fastrack

In FA, GCR section 9.1.1.2.d, modify as follows:
"9. Intake manifold must be unmodified Elan DP02-60-003 or Mazda Speed equivalent Elite USF2015AT, 1.882” maximum bore
diameter at throttle plates. Elan or Mazda Speed equivalent Elite intake manifold may be replaced with unmodified intake Noor
P/N 0088-8-00 with intake runners AT Power P/N 13624."
"10. Elan DP02-60-003 or Mazda Speed equivalent Elite USF2015AT intake manifold must use an A aluminum spacer must be
used between the intake manifold and cylinder head castings; minimum spacer length is 2.200”."

FA Engine Compression Rule Change Request

#39302 from Reilly Harris · Rule change · TB 26-01 (2026-01 Fastrack)

Summary

fasterFA Formula 1000 motorcycle-based engine loses maximum compression ratio 14.5:1 limit.

As printed in Fastrack

In FA Table 2, Formula 1000 spec line, change the Engine as follows:
"Motorcycle-based 4-cycle up to 1000cc, maximum compression ratio 14.5:1;. o Otherwise, current FA engine rules apply."

STU Request for Permission on Aftermarket Turbo Kit and Intake

#39529 from John Grim · Rule change · TB 26-01 (2026-01 Fastrack)

Summary

fasterSTU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved.

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

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Varies Chart Short blocks, heads, and intakes may be freely
swapped within these engine designations. May
use Jack Spania Racing 70 mm sheet-metal
aluminum Intake manifold. Must use stock
throttle body or Acura part number 16400-PND-
A17. Fab9 Tuning bottom-mount turbo kit
approved with one of the STU approved Turbos.

FA Change Formula 1000 allowances

#39608 from Club Racing Board · Rule change · TB 26-01 (2026-01 Fastrack)

Summary

fasterFA Formula 1000 allows carbon fiber external panels, forward-facing gaps, raises floor to 125mm, adds eight 75×125mm rub blocks, expands diffuser to 110cm with 75mm radius transitions.

As printed in Fastrack

In FA Table 2, Formula 1000 spec line, change the Notes as follows:
"Car must comply with December 2019 GCR Formula 1000 (FB) Preparation Rules, https://www.scca.com/downloads/48184-
gcr-december-2019/download, except as modified by this spec line. The prohibition of using carbon fiber in any external panels
or any panels licked by the airstream in Part 3.C of the December 2019 GCR F1000 (FB) Preparation Rules is removed, with the
exception that the car's floor pan/undertray must comply with the requirements of Part 2.D of the December 2019 GCR F1000
(FB) Preparation Rules. The prohibition of forward-facing gaps or openings in the bodywork in Part 3.I of the December 2019 GCR
F1000 (FB) Preparation Rules is removed. Part 3.D of the December 2019 GCR F1000 (FB) Preparation Rules is modified as
follows: "Between the rear of the front tire and the front of the rear tire, no point on the lower surface of the car (the surface

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licked by the air stream) shall be more than 125mm above the plane determined by the reference area designated by the entrant
and on a line perpendicular to that reference plane." Part 3.D of the December 2019 GCR F1000 (FB) Preparation Rules is also
modified as follows: "A maximum of eight (8) rub blocks of maximum dimension 75mm by 125mm are allowed anywhere on the
lower surface of the chassis and may extend below the reference plane." Part 3.E of the December 2019 GCR F1000 (FB)
Preparation Rules is modified as follows: "The radius of transitions between the diffuser sides and adjacent horizontal structures
may be up to 75mm. The width of the diffuser, as measured between its sides and above any radiused transitions, may not
exceed 110cm in any lateral section." The CRB may require the use of Flat Plate Intake Restrictors at any time."

FA Pro Mazda Classification and Performance Enhancement Proposal

#39411 from Stephen Lamana · Rule change · TB 26-02 (2026-02 Fastrack)

Summary

fasterFA Pro Mazda: lower intake manifold now unrestricted, throttle body raised to 80mm, wing height must not exceed 99cm, bodywork width must not exceed 132cm.

As printed in Fastrack

In FA Table 2, Pro Formula Mazda spec line, change the notes as follows:
"All current FA rules apply to areas not covered by this spec line. Apex seals unrestricted. Street port or bridge port
allowed. Unmodified OEM l Lower intake manifold required unrestricted, upper intake manifold unrestricted. Balance tube not
permitted. Fuel injection only. Maximum 70 80mm T throttle B body. The maximum height of the wing and/or
endplates shall must not exceed 99cm (38.98 inches). The overall maximum width of the bodywork behind the front
wheels shall must not exceed 132cm (51.97 inches)."

What the rules allowed changed as listed; this does not say what any particular car ran.