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BoP Lab / Buttonwillow Raceway Park

F6 + F500 + SRF + P at Buttonwillow Raceway Park

Track maps: sectors and speed trap

Track map with timing sectors and speed trap
Shown for: Super Tour Feb 2026 (practice, qualifying, race) · Super Tour Feb 2025 (practice, qualifying, race)

No map published for Super Tour Feb 2024.

Class · click a class to switch, + to compare alongside
Track configuration
Events

This track has been raced on 2 configurations (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.

F6 has no laps in the events chosen. It ran at Super Tour Feb 2024: add that event.

F500 has no laps in the events chosen. It ran at Super Tour Feb 2022: add that event.

SRF has no laps in the events chosen. It ran at Super Tour Apr 2017, Majors Apr 2016: add those events.

PosCarDriverClass#LapTheoreticalQualRace5-lap stintConsistencyTrapS1S2S3
1Elan DP02/MazdaJim DevenportP23, 281:32.576 A-P1:32.2841:32.872 B-Q21:33.972 B-R21:35.195 B-R1+1.742 B-R1171.9 A-P25.461 B-Q226.606 A-P40.217 A-P
2Dauntless StohrJohnnie CreanP3, 1351:36.516 B-Q11:36.5161:36.516 B-Q11:39.209 B-R11:40.027 B-R1+1.943 B-R1157.4 B-P25.956 B-Q128.143 B-Q142.417 B-Q1
3Dauntless-Stohr P07dJohn ManfroyP081:37.287 A-R21:36.3391:41.818 A-Q11:37.287 A-R21:39.027 A-R2+2.902 A-R2160.4 A-R226.696 A-R227.257 A-R242.386 A-R2
4Stohr WF1Kevin MitzP131:38.716 A-Q21:38.6671:38.716 A-Q21:39.638 A-R21:40.087 A-R2+0.641 A-R2155.4 A-Q126.934 A-Q228.397 A-Q243.336 A-Q2
5Penton Norma M20FCJoseph MoranP71:39.296 A-Q21:38.8681:39.296 A-Q21:40.832 A-R11:42.328 A-R1+3.544 A-R1149.0 A-Q227.106 B-Q128.111 A-Q143.651 A-Q1
About this data
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.

By car

CarClassDriversLapQualRaceTrapS1S2S3
Elan DP02/MazdaP11:32.576Jim Devenport1:32.872Jim Devenport1:33.972Jim Devenport171.9Jim Devenport25.461Jim Devenport26.606Jim Devenport40.217Jim Devenport
Dauntless StohrP21:36.516Johnnie Crean1:36.516Johnnie Crean1:37.287John Manfroy160.4John Manfroy25.956Johnnie Crean27.257John Manfroy42.386John Manfroy
Stohr WF1P11:38.716Kevin Mitz1:38.716Kevin Mitz1:39.638Kevin Mitz155.4Kevin Mitz26.934Kevin Mitz28.397Kevin Mitz43.336Kevin Mitz
Penton Norma M20FCP11:39.296Joseph Moran1:39.296Joseph Moran1:40.832Joseph Moran149.0Joseph Moran27.106Joseph Moran28.111Joseph Moran43.651Joseph Moran
About this data
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

Super Tour Feb 2022 → Super Tour Feb 2024 2022-02-17 to 2024-02-23

SRF SRF Tire Rule Update

#32614 from Robey Clark · Rule change · TB 22-06 (2022-06 Fastrack)

wordingSRF tire rule wording clarified: tires must be run as delivered.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.X.f, change as follows:
"Tires: must be run as delivered."

SRF Brake, seal, and air filter clarifications

#32670 from Club Racing Board · Rule change · TB 22-06 (2022-06 Fastrack)

fasterSRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.X.g, change as follows:
"Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 shall be used as delivered with no
machining of any kind. Minimum thickness 13.25 12.20mm (0.522 0.481"). The 1985 Renault Alliance solid front rotor (Reference:
Bendix PRT1318 or Centrix 121.11004) may be used on front, rear, or both axles, but each axle must be paired to the same type
rotor. Rubber caliper bushings may be replaced with bronze bushings P/N 1196185 or P/N 1196185."
In SRF, GCR section 9.1.8.D.2.H, change as follows:
"No performance M modifications of any kind.
SCCA Enterprises’ seals shall be intact.
(2) on cam cover, (2) on the oil pan, (1) on the each cam shaft. Automatic Drivetrain Violation if removed."
In SRF, GCR section 9.1.8.D.2.H.23, change as follows:
"Air Filter: P/N WM301020 or K&N RC-9160"

SRF Update SRF Brake Rule

#33469 from Robey Clark · Rule change · TB 23-01 (2023-01 Fastrack)

faster · engineSRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.X.g, change as follows:
"Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 shall be used as delivered with no
machining of any kind. Minimum thickness 12.20mm (0.481"). The 1985 Renault Alliance solid front rotor (Reference: Bendix
PRT1318 or Centrix 121.11004) may be used on front, rear, or both axles, but each axle must be paired to the same type
rotor. The Renault Alliance solid front rotors may not be used. Rubber caliper bushings may be replaced with bronze bushings P/N
1196185 or P/N 1196185. Original caliper pistons may be replaced with vented caliper piston P/N 1196184; no other
modification allowed. Wilwood caliper with bracket universal fit P/N 800038 may be used as delivered with no modification of
any kind. Wilwood knock back spring (2.63 lbs.) P/N 800045 may be used as delivered with no modification of any kind;
maximum of one spring per caliper."
P2 Engine Table
Spec
Line Engine Series

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

SRF Update SRF Front W2 Rain Tire Part Number

#34118 from Robey Clark · Rule change · TB 23-05 (2023-05 Fastrack)

tyres & wheelsSRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.X.f, change as follows:
"Front – Hoosier P/N 46100 1 P185/65R13 W2"

SRF Hoosier SRF Wet Front Tire Rule Update

#34189 from Robey Clark · Rule change · TB 23-06 (2023-06 Fastrack)

tyres & wheelsSRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.X.f, change as follows:
"Wet:
Front – Hoosier P/N 46100 P185/60R13 H20 or W2
Rear – Hoosier P/N 46105 P205/60R13 H20 or W2
Ground clearance is 2.5" with driver as raced when P185/60R13 (H20 or W2) tires are used."

SRF SRF Radiator Rule Update

#34805 from Robey Clark · Rule change · TB 23-10 (2023-10 Fastrack)

addedSRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.V.j, change as follows:
"Radiator - Enterprises new style P/N 480465 (requires baffle P/N 480464) or P/N 480466 can be used. P/N 480466, may can be
replaced with Automotive P/N 1R698, CU698 or equivalent OEM manufacturer justified by one cross-reference chart equivalent,
as long as the size, shape, and material are the same as the original P/N. The capacity, core thickness, etc., cannot be changed
even if allowed under the above. The competitor is responsible for providing this documentation of the cross-reference P/N."

SRF Update SRF Rain / Brake Rule

#34706 from Robey Clark · Rule change · TB 23-09 (2023-09 Fastrack)

otherSRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.W.l, change as follows:
"A Super Bright LEDs Inc. rain / brake light comprised of a single standard trailer oval lamp, 2-1/4 inches x 6-1/2 inches, with
incandescent or LED illumination, P/N PT-STRB-R24, is required in the original roll hoop mounting location. This rule supersedes
GCR section 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. No changes may be made to the original 3-pin connector on the
wiring harness. The secondary filament of the brake light assembly shall must be connected to a switch enabling its use as a rain
light."

SRF Update SRF Brake Light Rule v1

#34853 from Robey Clark · Rule change · TB 23-10 (2023-10 Fastrack)

otherSRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.W.l, change as follows:
"A Super Bright LEDs Inc. P/N PT-STRB-R24 (SCCA Enterprises P/N 180427A) rain / brake light, P/N PT-STRB-R24, is required in the
original roll hoop mounting location. This rule supersedes GCR section 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. No
changes may be made to the original 3-pin connector on the wiring harness. An SCCA Enterprises P/N 1190503 Strobing Brake
Light Pigtail is required. The secondary filament of the brake light assembly must be connected to a switch enabling its use as
a strobing rain light. A Strobing Brake Light Kit P/N 1168003 is available, which includes the brake light and pigtail."

SRF SRF / SRF3 Rule Updates

#35268 from Robey Clark · Rule change · TB 24-01 (2024-01 Fastrack)

suspension & brakesSRF adds mandatory front brake ducts 12–36 inches, throttle pedal heel-toe extension, braided stainless flex lines, camber limit 5.0 degrees, radiator opening height 3½ ± ½ inches, rear shift cable clamp P/N WM302007A.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.H, add the following:
"NO MODIFICATIONS ALLOWED. Front brake ducts are required, attached to the openings in the lower radiator baffles, any
flexible 4" duct material allowed, installed length minimum 12" maximum 36" in length. Must be securely fastened, Bracket Part
# P/N 800368 can be used. Shall Must serve no other purpose. An extension may be welded to the side of the throttle pedal to
improve heel-and-toe braking. Master cylinder casting / location must be used as delivered on P/N 180110 Pedal Mounting
support. Aeroquip style -3 braided stainless flex lines only, must attach to all brake components without modification. Brake pad
"anti-rattle" clips must be removed."
In SRF, GCR section 9.1.8.D.1.V, add the following:
"ii. Rear SADEV shift cable aluminum two-piece style clamp may be used. The P/N WM302007A clamp must serve no other
purpose."
In SRF, GCR section 9.1.8.D.1.X.k, add the following:
"Negative camber shall must not exceed 5.0 degrees absolute maximum front and rear."
In SRF, GCR section 9.1.8.D.1.AA.b, add the following:
"2. Height of the radiator opening vertical surface 3 1/2“ +/- 1/2"."
P2 Engine Table B.1
2008 and older Stock
Suzuki, Yamaha,
Honda, BMW
38.5mm
P2 Engine Table B.2 Not required
P2 Engine Table B.3 38.5mm
Modified
Engine
950 lbs.
1005cc max
P2 Engine Table B.1
2008 and older 37mm
P2 Engine Table B.2 Not required
P2 Engine Table B.3 39mm
Stock Engine
1050 lbs.

Super Tour Feb 2024 → Super Tour Feb 2025 2024-02-23 to 2025-02-22

SRF Update Rain Tire Rule and Hoosier Decal Placement

#36436 from Robey Clark · Rule change · TB 24-08 (2024-08 Fastrack)

tyres & wheelsSRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.X.f, change as follows:
"Wet:
Front – Hoosier P/N 46100 P185/60R13 H20 or W2
Rear – Hoosier P/N 46105 P205/60R13 H20 or W2
Ground clearance is 2.5” with driver as raced when P185/60R13 (H20 or W2) tires are used.
OR
Front – Hoosier P/N 46101 P185/65R13 W2
Rear – Hoosier P/N 46105 P205/60R13 W2
1. It is forbidden to regroove tires.
2. The use of tire warmers or cooling methods other than natural air convection or conduction is prohibited. The penalty for
violation will be the loss of qualifying times and/or the disqualification of race results.
3. Hoosier SRF/SRF3 Decal Placement:
Four (4) "Hoosier" decals are required in the following locations: Two (2) 11" X 3" decals on the vertical plane of the front nose to
the outside of the cooling opening on each side and two (2) 18" X 5" decals, one on each side of the engine cover or above the
rear wheel openings on the vertical plane. Hoosier decals are available, free of charge, from all Hoosier tire distributors including
SCCA Enterprises."

SRF Protest Fee Clarification

#36540 from SCCA Staff · Rule change · TB 24-09 (2024-09 Fastrack)

wordingFE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure.
As printed in Fastrack

In FE, GCR section 9.1.1.I.2.U.b.3, change as follows:
"Protest Fee: Regional -$25.00, National -$50.00. See GCR section 8.3.1.D for fees and payment procedure."
In SRF, GCR section 9.1.8.D.1.U.b.3, change as follows:
"Protest Fee: Regional -$25.00, National -$50.00. See GCR section 8.3.1.D for fees and payment procedure. Item 1 will be done by
the CSR or other shop that is equipped for this type of work and will be paid directly."

SRF Update to Letter 36619 with new Hoosier Contingency Decal Info

#36624 from Robey Clark · Rule change · TB 24-09 (2024-09 Fastrack)

wordingSRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.X.f.3, change as follows:
"Four (4) "Hoosier" decals are required in the following locations: Two (2) 11" X 3" decals on the vertical plane of the front nose
to the outside of the cooling opening on each side and two (2) 18" X 5" decals, one on each side of the engine cover or above the
rear wheel openings on the vertical plane. Hoosier decals are available, free of charge, from all Hoosier tire distributors including
SCCA Enterprises Per Hoosier's contingency program, three (3) decals are required to qualify for contingency awards. One (1)
decal must be located on each side of the car and one (1) decal must be visible on the front."

SRF Update SRF3 Air Filter Rule

#36681 from Robey Clark · Rule change · TB 24-10 (2024-10 Fastrack)

removedSRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.2.H.23, change as follows:
"Air Filter: P/N WM301020 or K&N RC-9160"

SRF Update SRF Brake Rotor Thickness

#36687 from Robey Clark · Rule change · TB 24-10 (2024-10 Fastrack)

suspension & brakesSRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.X.g, change as follows:
"Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 shall must be used as delivered with
no machining of any kind. Minimum thickness 12.20mm (0.481”) 13.25mm (0.522”)."

SRF Hoosier Tire Decal Placement

#36739 from Robey Clark · Rule change · TB 24-10 (2024-10 Fastrack)

wordingSRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.2.B, change as follows:
"Mandatory identification: "SRF3" near the side car numbers. "Hoosier" logo (4) on both sides front lower outer corners of the
nose and each side of the tail. Three (3) "Hoosier" logos, one (1) on each side of the car and one (1) on the center front of the car."

P Correct text in engine table notes

#37606 from Club Racing Board · Rule change · TB 25-02 (2025-02 Fastrack)

wordingPrototype Spec Lines B and D: wording corrections to engine table notes; no performance change.
As printed in Fastrack

In Prototype Engine Table, Spec Line B, change the notes as follows:
"Staudacher cars may run 950 lb min. wt. minimum weight with 38.5mm flat plate intake restrictor."
In Prototype Engine Table, Spec Line D, change the notes as follows:
"No restrictor required at 1150 lb min. wt. minimum weight."

P Update Prototype class designation

#37653 from Club Racing Board · Rule change · TB 25-02 (2025-02 Fastrack)

wordingPrototype class renamed from P1 to P, with P1 and P2 designations removed throughout GCR sections 9.1, 9.2.2, 9.3.37, and appendices.
As printed in Fastrack

In Categories and Classes, GCR section 9.1, change as follows:
"9.1.8. SPORTS RACING CATEGORY CLASSES
A Sports Racing (ASR) Regional Class
Prototype 1 (P1)"
In Homologation Requirements, GCR section 9.2.2, change as follows:
"All Formula, Sports Racing, and P1, and P2 cars must be constructed in strict accordance with the rules and regulations
contained in the current GCR unless specifically excepted."
In Non-Metallic Wheel/Chassis Construction, GCR section 9.3.37, change as follows:
"Non-metallic wheel construction is prohibited. Non-metallic chassis construction is prohibited, except in ASR, P1, FS and FA."
In Appendix B, GCR section 1.4.2.G, change as follows:
"It is preferable not to combine GT1, AS, T1, T2, T3, and STU with P1, P2, SRF, FP, HP, or GTL."
In Appendix C, GCR section 2.6.G, change as follows:
"A 14 or 15 year-old must complete his first SCCA driver school in a car not classed in GT1, GT2, FA, FB, F S, ITR, ASR, P1, P2, or
T1."
In Appendix E, section 1, change as follows:
"Depending on the length and banking of the oval course being used, it is recommended that Regions consider restricting the
faster classes (GT1, FA, and P 1) from competition at oval track events."
In Sports Racing Category, GCR section 9.1.8.1, change as follows:
"The SCCA Sports Racing Category shall be for automobiles which are designed and constructed for road racing competition,
offering provisions for a driver and passenger, or a driver alone (single-seater). They shall conform to the following
requirements. Sports Racers Cars except SRF & SRF3 homologated prior to 1-1-2014 are eligible to compete as P1 or P2 as long
as they meet applicable class rules,; no re-homologation is required."
"Single seat Formula car chassis (Ex.: FA, FC, FF, FV) fitted with enclosed bodies (as specified in these rules) may run in a Sports
Racing/Prototype Class (ASR, P 1, P2) provided they comply with the requirements of the Classification Specification and GCR
Section 9."
In Sports Racing Category, GCR section 9.1.8.2, change as follows:
"In an effort to control shock/damper technology and cost to a level reasonable for Road Racing, in ASR, P1, and P2, any fluid
dampers are allowed with the following restrictions:"

Super Tour Feb 2025 → Super Tour Feb 2026 2025-02-22 to 2026-02-21

SRF Driver Safety & Comfort

#37966 from Robey Clark · Rule change · TB 25-04 (2025-04 Fastrack)

addedSRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.D, add the following:
"f. Driver Safety and Comfort modifications to seat and controls for drivers with disabilities may be made only by approval. These
modifications must be reported to SCCA Enterprises and noted in the car logbook. The modifications are approved only for the
noted driver with disabilities. If the car is used by or sold to another driver, it must be returned to the previous standard
configuration."

SRF Update SADEV transmission specs

#37992 from Club Racing Board · Rule change · TB 25-04 (2025-04 Fastrack)

wordingSRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.2.K, change as follows:
"OR
SADEV-SRF3 6-Speed Sequential (beginning from Oct. 4, 2021 onward):
1st 12-36 3.0000 : 1
2nd 15-31 2.0667 : 1
3rd 18-28 1.5556 : 1
4th 22-28 1.2727 : 1
5th 24-26 1.0833 : 1
6th 25-23 0.9200 : 1
Final Drive Ratio: 15-48 3.20"

P Add missing punctuation marks

#38150 from Club Racing Board · Rule change · TB 25-05 (2025-05 Fastrack)

addedClass P adds engine and car notes: Line D no restrictor at 1150 lbs; Line G CN Honda K20A-FD2 unrestricted ITBs at 1500 lbs; Beasley B2 Mazda 12A 40.5mm venturi; P2 2000cc auto rules clarified.
As printed in Fastrack

In P Engine Table, Spec Line D notes, add the following:
"No restrictor required at 1150 lbs. minimum weight."
In P Engine Table, Spec Line G notes, add the following:
"Group CN non-composite chassis with Honda K20A-FD2 may use unrestricted individual throttle bodies at 1500 lbs. minimum
weight."
In P Table 1, Beasley B2 spec line notes, add the following:
"Engine must be Mazda 12A rotary with 40.5mm venturi. Car must comply with all other Prototype requirements."
In P Table 1, P2 cars built to 2000cc auto-based specification spec line notes, add the following:
"Car must comply with all other P2 rules applicable to cars using stock production-based four-cylinder automotive engines.
Note: Competitors are also free to modify their cars to comply with the general Prototype rules and Engine Table Spec Line H
instead."

P RM 25-05 - Prototype Engine Table A, 2 Cycle Restrictor Change

#38929 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

slower · enginePrototype Engine Table A 2-cycle restrictor reduced from 40mm to 38mm venturi size.
As printed in Fastrack

Effective 8/1/25 in Prototype Engine Table, Spec Line A, change the restrictor as follows:
"40mm 38mm Restricted Venturi Size"

P 13B Rotary Engine Rules Change Request

#38856 from Jason Vinkemulder · Rule change · TB 25-09 (2025-09 Fastrack)

unclearPrototype 13B rotary restrictor changes to 40mm SIR fuel injection or 41.5mm venturi carburetor.
As printed in Fastrack

Effective 9/1/25 in Prototype Engine Table, Spec Line K, change the restrictor as follows:
"40mm SIR with fuel injection or 41.5mm venturi with carburetor"

P Add Radical Cup series Radical SR3 spec line to Table 1

#38916 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

addedPrototype class adds Radical SR3 to Table 1 Spec Line Cars.
As printed in Fastrack

Effective 9/1/25 in Prototype Table 1 (Spec Line Cars), add the following:

P Clarify spec line cars language

#38943 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

addedPrototype P2 cars may now run P2 specification or modify to Prototype rules in Prototype class; Radical Cup series added as spec line car.
As printed in Fastrack

Effective 9/1/25, in Prototype, GCR section 9.1.8.B.K, change as follows:
"P2 cars may compete in either the Prototype class or the P2 class but must participate in the Prototype class to the extent
necessary to qualify for an invitation to the Runoffs in Prototype. P2 cars may be modified to comply with the general Prototype
rules and Prototype Engine Table or may continue to run in P2 specification in the Prototype class as permitted in Table 1 below."
Table 1 (Spec Line Cars)

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

SRF Add HD Oil Cooler

#38979 from Robey Clark · Rule change · TB 25-10 (2025-10 Fastrack)

added · engineSRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted.
As printed in Fastrack

In SRF, GCR section 9.1.8.D.1.V.ff, change as follows:
"SRF3 Oil Cooler, P/N G480503 or HD Oil Cooler P/N G1148500 may be used as mounted per the GEN3 Assembly Manual. No fan
permitted for SRF. HD Oil Cooler kit P/N G1148500 may be used as mounted per the GEN3 Conversion Manual."

P Request to Continue to Allow Carbon Brakes

#39476 from Jeffrey Lederman · Rule change · TB 26-01 (2026-01 Fastrack)

addedPrototype carbon-carbon and carbon-ceramic brake rotors permitted; rotor material now unrestricted.
As printed in Fastrack

In Prototype, GCR section 9.1.8.B.F.2, change as follows:
"Brake calipers may be ferrous or aluminum alloy. Effective 1/1/2026, carbon-carbon and carbon-ceramic brake rotors are
prohibited and rotors must be ferrous. Brake rotor material is unrestricted."

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

Sectors

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