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BoP Lab / Buttonwillow Raceway Park

GT2 + FF at Buttonwillow Raceway Park

No mapCal Club 2024

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 2 configurations (The Circuit, 2.57 mi; 2.92 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.

PosCarDriverClass#LapTheoreticalQualRace5-lap stintConsistencyTrapS1S2S3
1Chevrolet CamaroTim CarrollGT2461:42.698 A-Q11:42.6981:42.698 A-Q11:44.128 A-R11:44.791 A-R1+2.721 A-R1149.0 A-P28.597 A-Q129.839 A-Q144.262 A-Q1
2Chevrolet CamaroJean MeynetGT2281:44.227 A-Q11:44.2271:44.227 A-Q11:46.043 A-R11:46.393 A-R1+1.382 A-R1149.2 A-Q128.543 A-Q130.683 A-Q145.001 A-Q1
3Ford MustangBrad McAllisterGT2291:45.818 B-Q21:45.4091:45.818 B-Q21:46.926 B-R11:47.740 B-R1+1.198 B-R1115.9 B-Q228.729 B-Q230.833 B-R145.847 B-Q2
4Dodge ChallengerBen ValentineGT2124, 241:46.922 A-Q11:46.6081:46.922 A-Q11:47.171 B-R11:47.975 B-R1+0.946 B-R1132.9 A-P29.689 B-Q130.929 A-Q145.990 B-Q2
5Chevrolet CamaroSean BerardiGT291:47.904 A-R21:47.2661:50.095 A-Q21:47.904 A-R21:48.562 A-R2+1.288 A-R2133.2 A-R229.806 A-R231.073 A-R246.387 A-R2
6Porsche GT3Rocky CrockerGT2611:47.914 A-Q11:47.3121:47.914 A-Q11:48.433 A-R11:50.149 A-R1+3.225 A-R1155.7 A-Q129.826 A-Q131.456 A-Q146.030 A-Q1
7SWIFT DB-6 HondaEdward Erlandson 2+ carsFF81:49.259 A-P47.766 A-P
8Chevrolet CorvetteIgor LyustinGT2711:49.904 A-R21:49.6891:50.345 A-Q11:49.904 A-R21:50.694 A-R2+3.172 A-R2145.8 A-Q130.271 A-R231.850 A-R247.568 A-R2
9Mazda RX-7Guy LaidigGT2521:51.013 A-Q21:50.2661:51.013 A-Q21:52.486 A-R21:53.354 A-R2+1.740 A-R2138.7 A-Q130.134 A-P32.225 A-P47.907 A-Q1
10Piper DL7-HondaEric PoulsenFF481:51.118 B-R11:50.7441:52.044 B-Q11:51.118 B-R11:51.583 B-R1+3.025 B-R1114.7 B-R130.276 B-R131.650 B-R148.818 B-R1
11SWIFT DB-Edward Erlandson 2+ carsFF541:53.098 A-Q11:53.0411:53.098 A-Q11:54.741 A-R21:56.774 A-R2+1.819 A-R2133.7 A-Q130.951 A-Q132.299 A-Q149.791 A-Q1
12Swift Db6Johnnie CreanFF351:54.993 A-R21:54.4901:55.247 A-Q21:54.993 A-R21:56.752 A-R2+1.519 A-R2124.5 A-R231.358 A-Q132.841 A-R250.291 A-R2
13Mazda RX-7Scott GrahamGT2911:56.607 B-R21:55.0142:00.008 B-Q11:56.607 B-R21:57.173 B-R2+2.205 B-R2100.8 B-R230.931 B-R233.562 B-R250.521 B-R2
14Porsche GT3 CupRobert Kelley 2+ carsGT2981:57.745 A-Q21:57.4401:57.745 A-Q21:58.760 A-R11:59.706 A-R1+1.876 A-R1125.1 A-R132.864 A-R133.998 A-Q250.578 A-Q2
15Dodge VIPERRobert Kelley 2+ carsGT2881:57.753 B-P1:57.5012:00.453 B-Q21:59.538 B-R22:02.474 B-R2+3.373 B-R292.9 B-Q131.983 B-P33.965 B-P51.553 B-P
16Mazda RX-7Wayne Graham >115%GT2962:00.512 B-R11:59.5332:01.239 B-Q12:00.512 B-R12:01.174 B-R1+1.175 B-R1100.1 B-R132.073 B-R134.881 B-R152.579 B-R1

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
Chevrolet CamaroGT231:42.698Tim Carroll1:42.698Tim Carroll1:44.128Tim Carroll149.2Jean Meynet28.543Jean Meynet29.839Tim Carroll44.262Tim Carroll
Ford MustangGT211:45.818Brad McAllister1:45.818Brad McAllister1:46.926Brad McAllister115.9Brad McAllister28.729Brad McAllister30.833Brad McAllister45.847Brad McAllister
Dodge ChallengerGT211:46.922Ben Valentine1:46.922Ben Valentine1:47.171Ben Valentine132.9Ben Valentine29.689Ben Valentine30.929Ben Valentine45.990Ben Valentine
Porsche GT3GT221:47.914Rocky Crocker1:47.914Rocky Crocker1:48.433Rocky Crocker155.7Rocky Crocker29.826Rocky Crocker31.456Rocky Crocker46.030Rocky Crocker
Swift Db6FF21:49.259Edward Erlandson1:55.247Johnnie Crean1:54.993Johnnie Crean124.5Johnnie Crean31.358Johnnie Crean32.841Johnnie Crean47.766Edward Erlandson
Chevrolet CorvetteGT211:49.904Igor Lyustin1:50.345Igor Lyustin1:49.904Igor Lyustin145.8Igor Lyustin30.271Igor Lyustin31.850Igor Lyustin47.568Igor Lyustin
Mazda RX-7GT231:51.013Guy Laidig1:51.013Guy Laidig1:52.486Guy Laidig138.7Guy Laidig30.134Guy Laidig32.225Guy Laidig47.907Guy Laidig
Piper DL7-HondaFF11:51.118Eric Poulsen1:52.044Eric Poulsen1:51.118Eric Poulsen114.7Eric Poulsen30.276Eric Poulsen31.650Eric Poulsen48.818Eric Poulsen
SWIFT DB-FF11:53.098Edward Erlandson1:53.098Edward Erlandson1:54.741Edward Erlandson133.7Edward Erlandson30.951Edward Erlandson32.299Edward Erlandson49.791Edward Erlandson
Dodge VIPERGT211:57.753Robert Kelley2:00.453Robert Kelley1:59.538Robert Kelley92.9Robert Kelley31.983Robert Kelley33.965Robert Kelley51.553Robert Kelley

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

GT2 Classify Corvette C8 (2020- ) into GT2/ST

#33759 from Andrew Aquilante · Rule change · TB 24-03 (2024-03 Fastrack)

neutralChevrolet Corvette C8 (2020–) classified into GT2-ST with 6162cc displacement, 3300 lbs minimum weight, 71mm restrictor.

In GT2 Spec Lines, classify Chevrolet Corvette C8 (20-) as follows:
GT2-ST Maximum Displacement Minimum Weight Restrictor Notes
Chevrolet Corvette C8
(20-)
6162 3300 71mm -
Flat Plate
LT2 engine.

Applies to Chevrolet Corvette on this page: Igor Lyustin

GT2 Requesting classification for a 2015 Mitjet ST in GT2

#35408 from Jim Froula · Rule change · TB 24-03 (2024-03 Fastrack)

neutral2015 Mitjet ST added to GT2, must run per VTS specifications with complete FIA form CdM008.

In GT2 Spec Lines, GT Cars - MITJET ST, classify MITJET ST as follows:
GT Cars – MITJET ST
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
MITJET ST 2015 RWD 94.5 Must run per VTS specifications. Must have

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complete car Specifications (FIA form
CdM008) at every entered race event.

GT2 Request for Spec Line 1010 Reconsideration

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

slowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.

In GT2-ST Spec Lines, Acura NSX, change as follows:
Minimum Weight: "2700 3000"
Restrictor: "43 45mm TIR"

GT2 Request to Eliminate the FPR from the Corvette (-2013) with LS2

#35878 from Michael Quattlebaum · Rule change · TB 24-05 (2024-05 Fastrack)

fasterGT2-ST Corvette 14-19 LS2 restrictor increases from 78mm to 80mm flat plate.

In GT2-ST Spec Lines, Chevrolet Corvette (14-19), change Restrictor as follows:
"78 80mm flat plate"

GT2 GT2-ST Rule Clarification

#36093 from Dominic Starkweather · Rule change · TB 24-07 (2024-07 Fastrack)

neutralGT2-ST allows aftermarket replacement differential housings if exact equivalents.

In GCR Section, Appendix K. 2012.M2, add the following:
"After market replacement differential housings are permitted as long as they are an exact equivalent."

GT2 GT4 cars may run in GT2-ST

#36235 from Grand Touring Committee · Rule change · TB 24-07 (2024-07 Fastrack)

neutralGT4 cars now permitted in GT2-ST with factory restrictor, must comply with 2012 STO rules, slicks allowed with 100-pound penalty.

In 9.1.2. GT2 Spec Lines, GT3 Cars, change Note as follows:
"Note: All GT4 cars are permitted to compete in GT2-ST provided they use a factory supplied power stick or Pro Series
required restrictor. Must have GT4 rules in possession at all race events. Cars must comply with 2012 STO rules as
stated in Appendix K of the GCR. Engine Displacements in this table are nominal. Each competitor shall have available
definitive documentation (e.g., factory manual) of the original displacement for the engine used. Slicks allowed on all
GT2/ST cars with a 100-pound weight penalty."

FF Update to FF EGR Blanking Plate Rule

#36633 from Matt Boian · Rule change · TB 24-10 (2024-10 Fastrack)

neutralFF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers.

In FF, GCR section 9.1.1.B.14.r.1, change as follows:
"All emission control devices must be removed and blocked off by the blanking plate provided by HPD or Fast Forward as noted
below, except for the VTEC activation valve. The VTEC activation valve must be retained; and it must be functioning. No
modifications are permitted.
a. EGR Plate: Fast Forward PN: FF200-301.
b. EGR Port Cover: Fast Forward PN: FF200-302."

FF Change FF/FC Weight with Sequential Gearbox

#36651 from Robert Wright · Rule change · TB 24-11 (2024-11 Fastrack)

fasterFF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs.

In FF, GCR section 9.1.1.B.20.A.3, change as follows:
"Cars running with a sequentially shifted gear box shall must add 25 10 lbs. to minimum weight."
In FC, GCR section 9.1.1.B.20.B.4, change as follows:
"Cars running with a sequentially shifted gear box shall must add 25 10 lbs. to minimum weight."

FF Alternative Oversize Honda Fit Pistons

#37064 from Formula/Sports Racing Committee · Rule change · TB 24-11 (2024-11 Fastrack)

neutralFF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches.

In FF, GCR section 9.1.1.B.14.e.1, change as follows:
"Honda Fit OEM standard size pistons, PN: 13010-RB1-000, or Honda Fit OEM 0.25mm oversize pistons, PN: 13020-RB7-Z00, or
Fast Forward 0.25mm oversize pistons, PN: FF800-110, may be used."
In GCR section 9.1.1.B.14.e.2, change as follows:
"a. Maximum standard piston diameter, measured at a point 16mm from the bottom of the skirt: 73.240mm
(2.8834 2.8835 inches).
b. Centerline of wrist pin to crown maximum: 26.21mm (1.032 inches).
c. Maximum overall height from skirt to crown edge: 47.80mm (1.882 inches).

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d. Minimum weight: 198.0 grams (6.984 ounces).
e. Minimum weight of piston pin: 66 grams (2.25 ounces).
f. Combined minimum weight of piston, piston pin and connecting rod: 543.5 grams (18.85 ounces).
g. Combined minimum weight of piston, wrist pin, and circlips: 267 grams (9.418 ounces).
h. Centerline of wrist pin to crown edge: 26.289mm (1.035 inches).
i. Ring groove widths:
Top ring groove: 1.003mm (0.0395 inches).
Middle ring groove: 1.016mm (0.0400 inches).
Oil ring groove: 1.981mm (0.0780 inches).
j. Ring groove distance from wrist pin center to bottom of groove:
Top ring groove: 19.63mm (0.7730 inches).
Middle ring groove: 15.29mm (0.6020 inches).
Oil ring groove: 10.91mm (0.4295 inches)."

GT2 Panoz Esperante GTS BOP

#36686 from Brian Goldburg · Rule change · TB 25-01 (2025-01 Fastrack)

neutralGT2 Panoz Esperante GTS adds 2013-2016 Ford EcoBoost Twin Turbo V-6 3496cc engine, 2600 lbs.

In GT2 SPEC LINES, GT Engines - PANOZ, classify 2013-2016 Ford EcoBoost Twin Turbo as follows:
GT Engines – PANOZ
Engine
Family
Engine Type Bore x
Stroke
(in.)
Disp.

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(CC)
Head Type Valves /

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

GT2 Correct language regarding OEM Areo Devices

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

neutralTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement.

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.

GT2 GT2 Sunbeam Tiger Alternate Carburetor

#37198 from Tom Patton · Rule change · TB 25-01 (2025-01 Fastrack)

neutralGT2 Sunbeam Tiger gains Holly 650 cfm carburetor alternate options PN #80541-1 and #80541-2.

In GT2 Spec Lines, GT Engines - SUNBEAM, add to Fuel Induction as follows:
"Carburetors(s) Holly 650 cfm PN #80541-1 and PN #80541-2"

GT2 GT2/ST - Remove Aftermarket/Racing ABS penalty

#36538 from Jorge A Nazario · Rule change · TB 25-02 (2025-02 Fastrack)

fasterGT2 STO aftermarket ABS weight penalty reduced from 100 lbs to 50 lbs.

In GCR, Appendix K. 2012 STO Rules, O.9., change as follows:
"May run OEM ABS or convert to an aftermarket ABS controller with 100 50 lb. weight penalty."

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

GT2 Hood Bulge allowed

#37000 from Gordon Leslie · Rule change · TB 25-03 (2025-03 Fastrack)

unclearGT2 Pontiac Fiero changes from FWD to RWD; hood bulge permitted for front engine relocation.

In GT2 Spec Lines, GT2 Cars - PONTIAC, Fiero, change as follows:
Drive-line: "FWD RWD"
Add to Notes: "Hood bulge permitted as requested for front engine relocation only."

GT2 OEM Wing Adjustment

#37590 from Christopher Childs · Rule change · TB 25-03 (2025-03 Fastrack)

slowerTA2 and STO OEM wings no longer exempt from rear wing height rule at roof peak.

In GCR, Section APPENDIX L. 2013 TA2 TECHNICAL REGULATIONS, B.2.c., change as follows:
"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."
In GCR, Section APPENDIX K. 2012 STO GENERAL TECHNICAL REGULATIONS, D.4.b., add the following:
"Factory wings, and spoilers, and roof vortex generators are permitted, but must be removed if an approved aftermarket wing is
installed. OEM aerodynamic devices do not need to adhere to the height rule."

FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change

#37802 from Anthony Stefanelli · Rule change · TB 25-03 (2025-03 Fastrack)

fasterFF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials.

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Formula F shall be limited to the following tires (front tires may not be used as rears):
Dries:
Front - Hoosier R60A Radial 43322 or F1600 Radial 43321 185/60R13
Rear - Hoosier R60A Radial 43327 or F1600 Radial 43326 205/60R13
Wets:
Front - Hoosier Wet or W3 Radial 44421 185/60R13
Rear - Hoosier Wet or W3 Radial 44426 205/60R13

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Alternatively, Formula F cars with rocker arm suspension (e.g., Swift DB1, 1987-90 Reynard) and/or outboard suspension on at
least one chassis end may use the following tires:
Dries:
Front - Hoosier H43130 R60A 20.0 x 6.0-13 or H43164 R60A 20.5 x 7.0-13 bias ply slick
Rear – Hoosier H43307 R60A 22.5 x 7.2-13 bias ply slick
Wets:
Radial wets listed above
or
Front - Hoosier 44165 135/545-13 VFF
Rear - Hoosier 44170 165/580-13 VFF
Front tires may not be used as rears, and tires may not be mixed, i.e., radial tires may not be mixed with bias ply slick tires, bias
ply slick tires may not be mixed with VFF tires, and radial tires may not be mixed with VFF tires."

FF Page 228, FF tire rule 9.1.1.10.e

#38251 from Anthony Stefanelli · Rule change · TB 25-05 (2025-05 Fastrack)

neutralFF adds rocker arm and outboard suspension cars optional bias ply and VFF tires; removes front-as-rear rule, adds mixing restrictions.

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Formula F shall be limited to the following tires (front tires may not be used as rears):
Dries:
Front - Hoosier R60A Radial 43322 or F1600 Radial 43321 185/60R13
Rear - Hoosier R60A Radial 43327 or F1600 Radial 43326 205/60R13
Wets:
Front - Hoosier Wet or W3 Radial 44421 185/60R13
Rear - Hoosier Wet or W3 Radial 44426 205/60R13

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Alternatively, Formula F cars with rocker arm suspension (e.g., Swift DB1, 1987-90 Reynard) and/or outboard suspension on at
least one chassis end may use the following tires:
Dries:
Front - Hoosier H43130 R60A 20.0 x 6.0-13 or H43164 R60A 20.5 x 7.0-13 bias ply slick
or
Hoosier 44165 135/545-13 VFF
Rear – Hoosier H43307 R60A 22.5 x 7.2-13 bias ply slick
or
Hoosier 44170 165/580-13 VFF
Wets:
Radial wets or VFF tires listed above
or
Front - Hoosier 44165 135/545-13 VFF
Rear - Hoosier 44170 165/580-13 VFF
Front tires may not be used as rears, and tires may not be mixed, i.e., radial tires may not be mixed with bias ply slick tires, bias
ply slick tires may not be mixed with VFF tires, and radial tires may not be mixed with VFF tires."

GT2 Rear Deck Lid for Older Air-Cooled Porsche

#38506 from Justin Erion · Rule change · TB 25-08 (2025-08 Fastrack)

neutralGT2 Porsche 911 Coupe & Targa may use 993 3.8 RSR rear deck lid or approved aftermarket reproductions.

In GT2 Spec Lines, GT2 Cars-Porsche, 911 Coupe & Targa., add to Notes the following:
"Porsche 911-based race cars (911,963,994), the use of the 993 3.8 RSR rear deck lid/spoiler is permitted. Aftermarket
reproductions of the original Porsche Motorsports deck lid provided they faithfully replicate OEM dimensions and functionality,
are acceptable for use."

GT2 Additional Body Options to Replace Older Stock Car Bodies

#39086 from Samuel Daniels · Rule change · TB 26-01 (2026-01 Fastrack)

neutralGT2 adds Cadillac CTS, Chevrolet Impala/Malibu/Monte Carlo/SS, Dodge Intrepid, Ford Fusion/Taurus, Lincoln MKS, Pontiac G8/GTO/Grand Prix, Toyota Camry, and Gen late Model Stock Car bodies.

In GCR, Section 4.8.4.2.1., add the following:
"Cars in the class must use 1997, through current year, commercially available stock car bodywork. The following make/model
bodies are allowed:
1. Cadillac CTS
2. Chevrolet Impala
3. Chevrolet Malibu
4. Chevrolet Monte Carlo
5. Chevrolet SS

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6. Dodge Intrepid
7. Ford Fusion
8. Ford Taurus
9. Lincoln MKS
10. Pontiac G8
11. Pontiac GTO
12. Pontiac Grand Prix
13. Toyota Camry
Gen late Model Stock Car Bodies are allows:
1. Chevrolet Camaro
2. Ford Mustang
3. Toyota Camry"

FF Formula F Alternative Tire Rule Proposed Clarifications

#39281 from Jay Messenger · Rule change · TB 26-01 (2026-01 Fastrack)

neutralFF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners.

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Alternatively, Formula F cars with rocker arm suspension (e.g., 1987-90 Reynard, Swift DB1,) and/or outboard suspension on at
least one chassis end homologated in 1989 or earlier with any combination of rocker arm or outboard suspension on all four
corners (e.g., 1987 – 1990 Reynard, Swift DB1) may use the following alternative tires. Note: This rule is intended to allow older
cars with the described suspension design to use the alternative tires. It is not to be exploited by modifying cars with push-rods or
pull-rods to meet the above requirements or by modifying either end of older cars to push- or pull-rod suspension to be eligible to
run the alternative tires. Cars that were homologated in 1989 or earlier with push- or pull-rod suspension on no more than two
corners may seek approval to run the alternative tire by utilizing the compliance process outlined in GCR section 8.1.4."

GT2 GT3 Turbo to GT2?

#39365 from Chris Edens · Rule change · TB 26-01 (2026-01 Fastrack)

neutralGT2 Mazda BP engine 1839cc classified with 46mm turbo inlet restrictor, 2250 lbs minimum weight.

In GT2 Spec Lines, Engines - MAZDA, classify Engine Family BP as follows:
GT2 Engines - MAZDA
Engine
Family
Engine Type Bore x Stroke
(mm)
Disp.
(CC)

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Head Type Valves /

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

GT2 Tech Bulletins for GT2 and GT2-ST

#39537 from Grand Touring Committee · Rule change · TB 26-01 (2026-01 Fastrack)

slower991.2 GT3 Cup throttle body restrictor increases from 65mm to 70mm; 997.2 loses 100 lbs to 2800; Corvette LS engines get larger restrictors across multiple displacements and model years; LS3 and LT1 weight reduced 100 lbs each to 3150.

In GT2 Spec Lines, GT2 Cars – Porsche, classify 992.1 GT3 Cup as follows:
GT2 Cars – Porsche
Model Year Body
Style Driveline Wheel Base Notes
992.1
GT3 Cup
(22-25) 2 Dr RWD 4.0L flat six. 3250lbs. w/60mm Throttle Body Restrictor (TBR).
Cars must be prepared in accordance with the appropriate

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model/year Porsche factory 911 GT3 Cup parts
catalog/service manual. Cars may not be altered in any way
except as authorized below. Drivers must have the correct
year manuals as they apply to their specific car in their
possession. Safety, drivers comfort, driver control and
instrumentation items may be modified per the GCR. Original
factory installed Matter/ IMV roll cages are allowed. The
stock unmodified fuel tank is allowed. Windshield clips must
be installed per GCR 9.3 Windshield Clips/Rear Window
Straps. All other SCCA safety standards apply. Tires per GCR
9.3 Tires. Lubricants, consumable fluids (brake fluid, coolant
etc.) and oil filters are open free. Factory (OEM manufacturer)
Lexan front windows allowed as delivered. ABS is allowed.
In GT2 Spec Lines, GT2 Cars – Porsche, change Notes as follows:
991.1 GT3 Cup: "3.8L flat six. 3000lbs. w/72mm Throttle Body Restrictor (TBR). Aftermarket header allowed."
991.2 GT3 Cup: "4.0L flat six. 3000lbs. w/65mm 70mm Throttle Body Restrictor (TBR)."
997.2 GT3 Cup: "3.8L flat six. 2900 2800 lbs. Aftermarket header allowed."
In GT2 Spec Lines, GT2 – ST, Chevy Corvette (-2013), change as follows:
5665:
Restrictor: "81 85mm flat plate"
Notes: "GM LS1, LS6. LS1/LS6 C6 Corvettes using the OEM C6 intake manifold and 90 mm throttle body must use a 78mm flat
plate restrictor. OEM 75mm throttle body and manifold do not require a restrictor. LS6 may reduce weight by 50 lbs. L S1/LS6
alternate intake manifold, DORMAN part # 615-900."
LS2 5967 Restrictor: "83 85mm "
L76 5967 Restrictor: "80 83mm flat plate"
LS3 6162 Restrictor: "80 83mm flat plate"
6162 GM LS3:
Weight: "3250 3150"
Restrictor: "74 80mm flat plate"
6162 GM LT1:
Weight: "3250 3150"
Restrictor: "74 77mm flat plate"
In GT2 Spec Lines, GT2 – ST, Chevy Corvette (14-19), change as follows:
5665:
Restrictor: "83 85mm flat plate"
Notes: "GM LS1, LS6. LS1/LS6 C6 Corvettes using the OEM C6 intake manifold and 90 mm throttle body must use a 78mm flat
plate restrictor. OEM 75mm throttle body and manifold do not require a restrictor. LS6 may reduce weight by 50 lbs. L S1/LS6
alternate intake manifold, DORMAN part # 615-900."
LS2 5967:
Weight: "3100 3000"
Restrictor: "83 85mm flat plate"
L76 5967 Restrictor: "80 83mm flat plate"
6162 Restrictor: "80 83mm flat plate"
6162 LS3:
Weight: "3200 3100"
Restrictor: "77 80mm flat plate"
6162 LT1:
Weight: "3200 3100"
Restrictor: "74 80mm flat plate"

GT2 Allow Larger Air Cooled Engines in Porsche 911 GT2

#39249 from Justin Erion · Rule change · TB 26-02 (2026-02 Fastrack)

fasterGT2 Porsche 911 SC gains option of 4.0L 4V engine at 2350 lbs or 4.0L 2V at 2275 lbs.

In GT Spec Lines, create GT Cars - PORSCHE and classify SC as follows:
GT Cars - PORSCHE
Model Years Body Style Drive- line Wheel- base
(in)
Notes
SC 1978 2 Dr. Rear engine/RWD 89.45 May use alternate engine bore.
4.0L 2V @2275 lbs. 4.0L 4V @ 2350 lbs.

GT2 Classify T1 BMW in GT2

#39408 from Jared Lendrum · Rule change · TB 26-02 (2026-02 Fastrack)

neutralM3 E92 classified in GT2 with 3999cc V8, 35mm restrictor, 3300 lbs minimum weight.

In GT Spec Lines, classify M3 E92 in GT Cars - BMW as follows:
GT Cars - BMW
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
M3 E92 (08-13) 2 Dr. RWD 108.7 Cannot be built to any other rule set.

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In GT Spec Lines, classify M3 E92 in GT Engines - BMW - BMW as follows:
GT Engines - BMW
Engine
Family
Engine Type Bore x Stroke

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

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