suspension & brakesPrototype carbon-carbon and carbon-ceramic brake rotors now permitted instead of prohibited.
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."
unclearP class 13B rotary engine 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"
Add Radical Cup series Radical SR3 spec line to Table 1
wordingPrototype P2 cars may now run P2 spec or modified Prototype spec in Prototype class; clarified language and added Radical Cup series table.
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.
wordingClass P adds clarification notes on restrictor requirements, throttle bodies, Mazda 12A engine spec, and P2 auto-based engine rules.
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:
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"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."
wordingPrototype Staudacher and unrestricted engine notes corrected for minimum weight wording.
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."
wordingPrototype class renamed from P1 to P, affecting designation throughout rules with no performance changes.
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:
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"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:"
In GCR, Section 9.1.8.C., change heading as follows: "C. PROTOTYPE 2 (P2) CLASSIFICATION (Regional Class Only)" In P2 Spec Lines, P2 Engine Table, change Header as follows: "P2 Engine Table (Regional Class Only)" In P2 Spec Lines, Table 1 (Spec Line Cars), change Header as follows: "Table 1 (Spec Line Cars) (Regional Class Only)"
Thank you for your letter. The Club Racing Board does not recommend these changes. The CRB had sufficient AiM data for a wide variety of P1 and P2 platforms as of 2024 and did not need to collect additional data in 2024 because the specifications of the platforms had not changed since the previous data was collected. Further, a majority of the P2 platforms fit readily into spec lines in the existing P1 engine table, and adjustments were made for P2 platforms that did not. For example, in P2 the tube- frame Group CN car was limited to a stock Honda K20A engine using a stock single throttle body with a 50mm flat plate intake restrictor at 1,500 lbs. minimum weight, and in the Prototype class that car is now permitted to use an internally modified K20A with unrestricted individual throttle bodies at the same minimum weight. The CRB intends to obtain AiM data from various platforms in the Prototype class during the season but has no plans to make BoP changes in the class prior to the June Sprints.