wordingP1 now encourages unspecified engines including Diesel, hybrid, or electric via case-by-case request to Club Racing Board.
As printed in Fastrack
In P1, GCR section 9.1.8.B.J.7, change as follows: "Engines not specified in the table below are not permitted in P1. SCCA does encourages members who wishing to race other engines designs or propulsion systems not listed above, including Diesel internal combustion engines, hybrid or electric drive solutions, below to request consideration on a case–by–case basis via letter to the Club Racing Board at crbscca.com."
Remove redundant effective date language in GCR 9.1.8.B.J.4
wordingP1 removes redundant effective date language from engine stalling prohibition during SIR testing.
As printed in Fastrack
In P1, GCR section 9.1.8.B.J.4, change as follows: "(Effective 9/1/2023) The use of an ECU map, a computer program, or any other artificial means to stall an engine at any time during the SIR testing procedure in Appendix F. Technical Glossary (Restrictor, Intake) is prohibited."
engineF600 Rotax 494, 493, 593 engines now require single expansion chamber and pull starter; electric starter optional.
As printed in Fastrack
In Cars and Equipment, GCR section 9.3.33.B.2, add the following: "(Effective 1/1/2024) A red taillight meeting FIA Standard 8874-2019, Technical List No. 76, is required on all Formula (open wheel) and Sports Racing cars." In Appendix F. Technical Glossary, Minimum Weight, change as follows: "Minimum Weight: – Weight specified with driver, exactly as they come off the race circuit, at the conclusion of any race or qualifying session." In FA Table 1, Spec Line E notes, add the following: "Any BD series iron or alloy cylinder block and alternate crankshaft permitted."
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In FC, GCR section 9.1.1.B.11.c, change as follows: "The Mazda MZR LF-DE 2 liter for use only in USF2000 cars, as described in the Spec Line Cars Table below."" In F600, GCR section 9.1.1.D.14, add the following: "Rotax Model 494, Model 493, and Model 593 must use a single expansion chamber and must be equipped with a pull starter; an electric starter may be added." In P1, GCR section 9.1.8.B.J.2, add the following: "Where a flat plate intake restrictor, restricted venturi, or Single Inlet Restrictor (SIR) is required, all intake air for each cylinder or the entire fuel-air mixture, if prepared before this point, must pass through the restrictor."
Adjust restrictors and weights for Engine Table lines H and I
unclearP1 Group CN Honda K20A-FD2 removes engine modification restrictions; CRB may add intake restrictor.
As printed in Fastrack
In P1 Engine Table, Spec Line G, change as follows: P1 Engine Table Spec Line Engine Series Max. Displ. (cc) Max Valves / Cyl.
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Req’d Restrictor Min. Weight (lbs) Notes G Group CN-spec Honda K20A-FD2 2000 4 Stock Honda intake manifold with unmodified 64mm single throttle body 1400 No engine modifications except dry sump oil system, ECU map, and exhaust. Must use stock Honda OEM parts as listed in CN Honda K20A- FD2 Parts List found here: https:/www.scca.com/pages/technical-forms-and- downloads. No machining allowed. The CRB reserves the right to add an appropriately sized flat plate intake restrictor at any time if warranted by the data.
wordingP1 SIR testing procedure modified: vehicle deemed compliant if stalls within 3 seconds.
As printed in Fastrack
In P1, GCR section 9.1.8.B.J, add a new section and re-letter the following sections accordingly: "3. The SIR testing procedure in Appendix F. Technical Glossary (Restrictor, Intake) is modified as follows: If the vehicle stalls within 3 seconds, the vehicle is deemed compliant with the stall test."
wordingP1 Single Inlet Restrictor wording clarified; all intake air or fuel-air mixture must pass through it.
As printed in Fastrack
In P1, GCR section 9.1.8.B.J.2, change as follows: "Where a carburetor or fuel injection restriction is specified, a flat plate intake restrictor, restricted venturi, or Single Inlet Restrictor (SIR) is required through which, all intake air for each cylinder or the entire fuel-air mixture, if prepared before this point, shall must pass through the restrictor."
wordingP1 ducted air rule clarified: cockpit opening, fender louvers, and engine bay heat escape devices exempt from heat exchanger requirement.
As printed in Fastrack
In P1, GCR section 9.1.8.B.D.2, change as follows: "All ducted air that exits through the top of the bodywork behind the rear of the front tires must pass through a heat exchanger., excluding This requirement does not apply to the cockpit opening, fender louvers, or slots, louvers, grills, and similar devices for allowing intended to allow heat to escape the engine bay, shall pass through a heat exchanger."
wordingP1 cockpit length dimension corrected from 23.662 to 23.622 inches; height and extension limits clarified with metric-imperial equivalents.
As printed in Fastrack
In P1, GCR section 9.1.8.B.C.3, change as follows: "Height: No part of the vehicle having special or significant aerodynamic function shall exceed a height of 115cm (45.275 inches) above the ground with car in normal racing trim, driver aboard." In P1, GCR section 9.1.8.B.C.4, change as follows: "However, no portion shall extend more than 10cm (3.937 inches) beyond a plane tangent to the outer face of the front and rear wheels with tires." In P1, GCR section 9.1.8.B.C.6.b, change as follows: "Cockpit length: 60cm (23.662 622 inches). Cockpit width for each seat: 45cm (17.717 inches) maintained over 30cm (11.811
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inches)."
November 2022 Rules Clarification for Suspension Covers
slowerP1 suspension covers must have symmetrical upper and lower surfaces, no airfoil shaping, cannot angle for downforce.
As printed in Fastrack
In P1, GCR section 9.1.8.B.D.1, effective 3/1/23, change as follows: "Body panels intended to cover suspension components as viewed from the side and above must not be shaped as an airfoil cross-section or create a pressure differential from the action of air flowing over the upper and lower surfaces of the panel. Upper and lower panel surfaces must be symmetrical (mirror images) across a straight line connecting the center of the leading edge with the center of the trailing edge. Leading and trailing edges may be rounded. Panel angle front to rear and side to side is unrestricted, but it is not permitted to angle the body panels for the purpose of providing aerodynamic downforce on the car."
Clarify body panel coverage of suspension components
slowerP1 aerodynamic devices limited to 1cm below lower surfaces rear of front axle; body panels covering suspension cannot be airfoil-shaped.
As printed in Fastrack
In P1, GCR section 9.1.8.B.D.1, add the following: "No aerodynamic devices (e.g. "skirts," body sides) may extend more than 1cm (0.394 inches) below a lower surface anywhere on the car to the rear of the front axle. Seat bucket or other protrusions shall not circumvent this rule. Aerodynamic devices shall be securely mounted on the entirely sprung part of the car and not be movable when the car is in motion. It is not permitted to duct air through any part of the bodywork for the purpose of providing aerodynamic downforce on the car. This prohibition includes openings above the front spoiler or splitter that allow air to pass through the front bodywork for the purpose of providing aerodynamic downforce. Body panels intended to cover suspension components as viewed from the side and above must not be shaped as an airfoil cross-section or create a pressure differential from the action of air flowing over the upper and
wordingP1 motorcycle-based engines with individual throttle bodies must install flat plate restrictors within 4 inches of primary butterfly.
As printed in Fastrack
In P1, GCR section 9.1.8.B.J.7, add the following: "On 4-cycle motorcycle-based engines equipped with individual throttle bodies, individual flat plate intake restrictors must be installed within 4 inches of the primary butterfly throttle shaft or centerline on the intake side of the individual throttle body's primary butterfly."
wordingP1 bodywork rules clarified: cycle fenders prohibited, side body minimum height at front axle centerline required, air ducting for downforce banned.
As printed in Fastrack
In P1, GCR section 9.1.8.B.C.2, add the following: "Cycle-type fenders (which that cover only the tire and are not continuous with the rest of the body) and may thereby permit a view of the ground from above are prohibited." In P1, GCR section 9.1.8.B.C.3, add the following: "As viewed from the side, T the outermost surface of body between the front and rear wheel openings and above the floor must have a minimum height equal to the height of the front axle centerline." In P1, GCR section 9.1.8.B.D.1, add the following: "It is not permitted to duct air through any part of the bodywork for the purpose of providing aerodynamic downforce on the
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car. This prohibition includes openings above the front spoiler or splitter that allow air to pass through the front bodywork for the purpose of providing aerodynamic downforce."
Displacement & Weight Change Request for 2-Cycle 6 Cylinder
fasterP1 Staudacher cars with 38.5mm flat plate intake restrictor reduced to 950 lbs minimum weight.
As printed in Fastrack
In P1 Engine Table, Spec Line B, change the notes as follows: "Staudacher cars may run 950 lbs. min. wt. with 38.5mm flat plate intake restrictor at 950 lbs. min. wt."
wordingP1 tonneau cover wording clarified: equipment must be securely attached; covers allowed for minimum dimensions.
As printed in Fastrack
In P1, GCR section 9.1.8.C.C.6.c, make changes as follows: "Allowed equipment would include batteries, ballast, fire bottles, data recording devices, and cool suit equipment, providing provided such equipment is securely attached to the car. Tonneau covers are allowed in order to meet minimum dimensions."
wordingP1 Staudacher with 1005cc homologated before 1-1-2014 may run 38.5mm flat plate intake restrictor at 950 lbs minimum weight.
As printed in Fastrack
In P1 Engine Table, Spec Line B, change the notes as follows: "Staudacher cars homologated before 1-1-2014 using 1005cc may run 38.5mm flat plate intake restrictor at 950 lbs. min. weight wt."
wordingP1 Spec Lines C and G: intake restrictor rules clarified with specific displacement and weight thresholds; wording standardized.
As printed in Fastrack
In P1 Engine Table, Spec Line C, change the notes as follows: "May run without intake restrictor FPIR not required at 1150 lbs. min. weight wt. Up to 1355cc max. may run without intake restrictor FPIR at 1075 lbs. min. weight wt." In P1 Engine table, Spec Line G, change the notes as follows: "Up to 2000cc max. may run with intake restrictor 30mm SIR at 1400 lbs. min. weight wt. Up to 2300cc max. may run with intake restrictor 30mm SIR at 1445 lbs. min. weight wt."
unclearP1 Spec Lines B, C, D maximum valves per cylinder set to 4, was NA.
As printed in Fastrack
In P1 Engine Table, Spec Line B, change the maximum valves per cylinder section as follows: "NA 4" In P1 Engine Table, Spec Line C, change the maximum valves per cylinder section as follows: "NA 4" In P1 Engine Table, Spec Line D, change the maximum valves per cylinder section as follows: "NA 4"
wordingP1 Spec Line A clarifies carburetor induction only, one per cylinder, balance tubes not allowed.
As printed in Fastrack
In P1 Engine Table, Spec Line A, change the notes as follows: "Balance tubes not allowed. One Carb per cylinder. Carburetor induction only. One carburetor per cylinder. Restricted venturi size. Balance tubes not allowed."
wordingP1 engine table updates terminology from inlet to intake restrictor across multiple spec lines.
As printed in Fastrack
In P1 Engine Table, Spec Line C, change the notes as follows: "May run without inlet intake restrictor at 1150 lbs. min. weight. Up to 1355cc may run without inlet intake restrictor at 1075 lbs. min. weight." In P1 Engine Table, Spec Line G, change the notes as follows: "Up to 2000cc may run with inlet intake restrictor at 1400 lbs. min. weight. Up to 2300cc may run with inlet intake restrictor at 1445 lbs. min. weight."
fasterP1 intake manifolds unrestricted on engines without flat plate restrictor; plenums and balance pipes prohibited on individual runner manifolds with restrictor.
As printed in Fastrack
In P1, delete GCR section 9.1.8.C.J.1 as follows: "Applicable minmum weights are specified in the P1 Engine Table." In P1, GCR section 9.1.8.C.J.3, make changes as follows: "Intake manifolds: individual runner, no plenum or balance pipes permitted are unrestricted on engines that do not require a flat plate intake restrictor unless using an SIR or otherwise noted on the in an engine spec line. Cars using an SIR may use any manifold type. Plenums and/or balance pipes are not permitted on engines that use an individual runner-type manifold and require a flat plate intake restrictor."
Extend date for removing sealed DP02-spec 2.0L option
slowerP1 sealed DP02-spec 2.0 MZR engine removed effective 1/1/2020; competitors may use Spec Line G.
As printed in Fastrack
line effective 1/1/2020 In the P1 Engine Table, 2.0L Elan DP02-spec Mazda MZR line, change the notes as follows: "Must have four (4) numbered seals in place on cam cover, oil pan, front cover, and crank angle sensor as installed by Elan Power Products or Elite Engines. No engine modifications permitted. Sealed engine option will be removed effective 1/1/2020." Note from the Club Racing Board: The Elan DP02 and its sealed Mazda 2.0 MZR engine became ineligible for the IMSA Prototype Challenge series after the 2018 season. Due to
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the absence of engine build, mapping, and performance criteria for the IMSA 2.0 MZR engine, the CRB is unable to ensure that the specifications that have allowed it to run without a restrictor in P1 remain unchanged. Consistent with the removal of the sealed 2.3 liter option after the 2017 season, the sealed 2.0 liter option will be removed from Spec Line F at the end of the 2019 season. As with the 2.3 liter engine, competitors may continue to run the 2.0 MZR engine in the P1 class subject to the requirements of Spec Line G.
wordingP1 allows mechanical and solenoid shifters, prohibits electronic controls and pre-selected changes.
As printed in Fastrack
In P1, GCR section 9.1.8.C.H, add the following: "All gear changes shall be initiated by the driver. Mechanical gear shifters, direct-acting electric solenoid shifters, air-shifters and similar devices are permitted. Electronically controlled differentials and devices that allow pre-selected gear changes are prohibited. Power shall not be applied to more than two (2) wheels."
wordingP1 bodywork minimum height provision moved to aerodynamic section; 115cm height limit for aero parts added.
As printed in Fastrack
bodywork height section In P1, GCR section 9.1.8.C.C.11, delete in its entirety as follows: "The outermost surface of body between the front and rear wheel openings must have a minimum height equal to the height of the front axle centerline." In P1, GCR section 9.1.8.C.C.3, add new wording as follows: "Height: No part of the vehicle having special or significant aerodynamic function shall exceed a height of 115cm (45.25 in) above the ground with car in normal racing trim, driver aboard. The outermost surface of body between the front and rear wheel openings
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must have a minimum height equal to the height of the front axle centerline."
wordingP1 clarifies fender louver and brake duct rules, consolidating duplicative provisions in GCR 9.1.8.C.
As printed in Fastrack
In P1 GCR section 9.1.8.C.C.9, make changes as follows: "Louvers or exit ducts for extraction of the air from the top of the fenders are allowed. Brake ducts are allowed. and D ducts allowing air into the engine compartment are allowed permitted." In P1, GCR section 9.1.8.C.C.2, make changes as follows: "The bodywork as viewed from the side and above shall cover all mechanical components including suspension except that the intake, exhaust, tow hooks, jack points, and radiators may be exposed. As viewed from the side, the bodywork shall extend over the full width
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of the tires for at least one-third (1/3) of their circumference. Ventilation slots Louvers for the extraction of air from the tops of the fenders are permitted. The tires shall not be seen as viewed from above except through ventilation slots ( louvers), provided that the fore/aft opening through which the tire may be seen does not exceed 3/16 inches when viewed from above; rear tires may be exposed as viewed from the rear. Cycle-type fenders (which cover only the tire and are not continuous with the rest of the body) are prohibited. Fenders shall be firmly attached to the bodywork."
wordingP1 bodywork wording corrected: 'a passenger' becomes 'passenger' in three GCR sections.
As printed in Fastrack
E&O correction to GCR In GCR section 9.1.8.C.C.1, change as follows: "Bodywork shall provide comfort and safety for a driver and a passenger or for a driver only." In GCR section 9.1.8.B.7.b, change as follows: "Bodywork shall provide comfort and safety for a driver and a passenger or for a driver only." In GCR section 9.1.8.D.7, change as follows: "Bodywork shall provide comfort and safety for a driver and a passenger or for a driver only."
wordingP1 Engine Table reference cleaned up; no performance change.
As printed in Fastrack
In GCR section 9.1.8.C.J, change as follows: “The table ( P1 Engine Table) that follows provides general specification of engine types, displacement limits, intake restrictions, and automobile weights allowed.”
wordingP1 Staudacher and Honda K20A-FD2 engine table language cleaned up; no performance changes.
As printed in Fastrack
In P1 Engine Table, Spec Line B, change as follows: “Staudacher cars homologated before 1-1-2014 utilizing using 1005cc may run 38.5mm flat plate intake restrictor at 950 lbs. min. weight.” In P1 Engine Table, Spec Line F, Honda K20A-FD2, change as follows: “No engine modifications except for dry sump oil system, ECU mapping, and exhaust system.”
wordingP1 closed cockpit single-seat cars moved from subsection J.5 to subsection B.4; prohibition unchanged.
As printed in Fastrack
Chassis section In P1, delete GCR section 9.1.8.C.J.5 in its entirety as follows: “5. Closed cockpit single seat cars are prohibited.” In GCR section 9.1.8.C.B, add a new wording as follows: “4. Closed cockpit single seat cars are prohibited.”
wordingP1 engine table reference corrected from 'above' to 'below'; ECU throttle wording clarified for dual sensors and fail-safes.
As printed in Fastrack
In P1, GCR section 9.1.8.C.J, make corrections as follows: “6. Engines not specified in the tables above below are not permitted in P1.” “7. Any ECU utilizing ETC/FBW/DBW ETC throttles, must use dual output pedal position sensors[add space](or other ECU required fail-safes) and be capable of detecting a fault and limiting throttle activation.”
wordingP1 removes redundant TIR inlet restrictor provisions; SIR and flat plate restrictors remain required.
As printed in Fastrack
In GCR section 9.1.8.C.J.2, make changes as follows: “Where a carburetor or fuel injection restriction is specified, a flat plate restrictor, venturi, or SIR or TIR is required through which all intake air for each cylinder or the entire fuel- air mixture, if prepared before this point, shall pass. SIR and TIR installations are per the Technical Glossary requirements. Where intake restrictors (excluding SIR and TIR) are specified, the restrictors shall be round orifices (unless otherwise specified) and located within four (4) inches of the throttle butterfly.” Delete GCR section 9.1.8.C.J.10 in its entirety and re-number as appropriate:
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“On turbocharged and supercharged engines, only one turbocharger or supercharger unit shall be used, and all air shall pass through a single inlet restrictor.”
wordingP1 Honda K20A-FD2 CN-spec clarifies allowed parts to OEM list only, no machining.
As printed in Fastrack
In P1 Engine Table, Group CN-spec Honda K20A-FD2 line, change the notes as follows: “No engine modifications except for dry sump oil system, ECU mapping, and exhaust system. Must use stock Honda OEM parts as listed in CN Honda K20A-FD2 Parts List found here: https://www.scca.com/pages/technical-forms-and-downloads. with n No machining allowed.”
wordingP1 engine table wording corrected; head designs removed from listed specifications.
As printed in Fastrack
In GCR section 9.1.8.C.J, make corrections as follows: “Generally applicable information for P1 engines and automobile weights are is given in the following paragraphs. The table (P1 Engine Table) that follows provides general specification of engine types, displacement limits, head designs, intake restrictions, and automobile weights allowed.”
Thank you for your letter. The Club Racing Board does not recommend this change. The P1 class will be discontinued effective 1/1/25 and no rule changes are planned in P1 before the end of the year, but the P1 rule set will be incorporated with minor changes in the rule set for the new Prototype class and the spec line for the Group CN Honda K20A-FD2 engine will be carried forward. Please note that since 1/1/24, the P1 Group CN spec line has allowed competitors to make unlimited internal modifications to the Honda K20A-FD2 engine while continuing to require the stock intake manifold with the stock 64mm single throttle body, and this specification will be continued in the new Prototype class. The requirement of using the stock intake system as the "restrictor" for the internally modified K20A-FD2 engine is based on information provided to the CRB which indicates that the Single Inlet Restrictor (SIR) typically used on P1 cars with automotive-based engines is incompatible with the
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K20A-FD2's intake layout on Group CN cars. On-track data obtained from a Group CN car using the Honda K20A-FD2 engine in unrestricted form (with unlimited internal modifications and aftermarket individual throttle bodies) established that the car was an overdog compared to other P1 platforms, and accordingly restrictions were imposed on the K20A-FD2 engine. The CRB obtained dynamometer data for an internally modified K20A-FD2 engine using various types of intake restrictions, including the restriction provided by using the stock Honda intake manifold with the stock 64mm single throttle body. The dynamometer data indicates that an internally modified K20A-FD2 engine using the stock 64mm single throttle body intake system produces horsepower comparable to a 2500cc engine with a 30mm SIR. While various factors limited opportunities to set a representative qualifying time during the official Runoffs qualifying sessions, the CRB has access to lap times recorded during the unofficial test days, and these records show that the qualifying lap time attributed to the Group CN car as evidence of the need for a competition adjustment is not indicative of the car's true potential. In addition, a Group CN car using the Honda K20A-FD2 engine in the form permitted by the P1 spec line (with unlimited internal modifications and the stock 64mm single throttle body intake system) has demonstrated lap-time performance similar to that of an Elan DP02 using a 2500cc engine with the same driver in West Coast SCCA events. Also, weight data obtained from that car shows that it is reasonably close to the Honda K20A- FD2 spec line's minimum weight. The CRB will monitor performance in the new Prototype class and will make adjustments as necessary based upon AiM data collected during on-track sessions.
Thank you for your letter. The Club Racing Board does not recommend this change. The Radical SR8 has a turbocharged engine, which is not permitted in P1 and will not be permitted in the new Prototype (P) class. In addition, the SR8 is 300 pounds heavier than the heaviest car in P1 and nearly 800 pounds heavier than the lightest car in the class. This is undesirable from a safety standpoint. Also, the referenced height differences between cars in the GTX class's run group are not uncommon in other race groups in the SCCA, and drivers are accustomed to adjusting to this by being more observant when running together.
Thank you for your letter. Rain lights in Technical List No. 19 meet the previous 2008 FIA specification, while rain lights in Technical List No. 76 meet the current 2019 FIA specification. A significant difference exists between the two specifications. Rain lights that meet the 2019 FIA specification are more than three times brighter than rain lights that meet the 2008 FIA specification. When researching the subject, the FSRAC and the CRB reviewed video footage of formula and sports racing cars in SCCA rain races, and the visibility of the cars ahead was clearly a function of the level of brightness from individual rain lights. Please see the response to letter #34859 in the November 2023 Fastrack. The FSRAC and the CRB concluded that the current 2019 FIA standard's three-times-brighter specification would have made a significant difference in the visibility of the cars ahead in these rain races, providing a measurable improvement in the safety of the competitors. The CRB's decision to
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follow the current 2019 FIA specification for F/SR rain lights was based on choosing the standard that afforded the level of safety believed to be appropriate for these cars.
Thank you for your letter. The Club Racing Board does not recommend this change. P1 is a development class in which a majority of respondents to a 2023 survey favored retaining non-ferrous/carbon-carbon brake systems, and penalizing development within the rules would be contrary to the class philosophy. Although Balance of Performance (BoP) adjustments are used to permit different platforms to race together in the same class, the criterion for a BoP adjustment is limited to the analysis of a car's acceleration rate in a speed range before aerodynamic drag has a significant effect — typically between 60 and 100 mph. BoP adjustments are not used to equalize lap-time performance or ensure overall competitiveness, and the CRB does not adjust power or minimum weight based on the use of different brake systems, aerodynamic configurations, or chassis setups. BoP adjustments based on the type of brake system used would be particularly infeasable, given that driver technique during braking
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is highly variable, unlike driver technique under full-throttle acceleration.
Thank you for your letter. The Club Racing Board does not recommend these changes. A P1 car using the 1615 cc Toyota 4A-GE engine with 40 mm chokes was on pole position, set the fastest race lap, and won the National Championship race at the 2020 Runoffs, and the AiM data collected at the 2022 June Sprints shows the acceleration rate of the 1615 cc 4A-GE platform is in line with the acceleration rates of the other P1 engine options, so no basis is seen for increasing the 4A-GE's displacement to the requested 1654 cc. With respect to the Toyota 4A-GE's classification in the P2 class, the CRB needs to have on-track data to be able to make accurate comparisons. If a competitor believes the acceleration rate of the Toyota WSR car using the 1615 cc engine with a 41.5 mm restrictor is out of line with the P2 class BoP standard, it is incumbent upon the competitor to contact the CRB in advance of entering and competing in a U.S. Majors Tour or Hoosier Super Tour event to allow the CRB an opportunity to
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gather the relevant data and make appropriate adjustments if warranted.
Thank you for your letter. The Club Racing Board does not recommend these changes as requested, but please see the response to letter #35337 in this Fastrack's Technical Bulletin.
Thank you for your letter. The Club Racing Board does not recommend this change. LMP cars were originally classified in the Prototype X (PX) class, which was intended to provide a place for members to race unmodified prototype cars that had previously run with GT-type cars in professional racing series such as IMSA, Grand-Am, etc. It was understood from the beginning that PX cars such as LMPs would be grouped with big-bore GT, Sedan, and Touring cars (GT1/GT2/AS/T1), because the cars had too much mass and too much straight-line speed to be safely grouped with F/SR classes such as P1, P2, FA, FC, FE2, and FX. Ultimately, because both PX and GTX were non-points, non-championship classes in which a Balance of Performance (BoP) formula was not used, there was no need for two non-points, non-championship, non-BoP classes in the same run group. Reclassification of the PX cars into the GTX class did not change the LMP cars' original run group. In addition, GTX cars such as
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the LMP do not fit within the class philosophy and specifications of the P1 class, which runs under a BoP formula to promote closely-matched performance between cars, unlike the GTX class. The P1 rules accordingly prohibit V-8 and V-6 engines like those used by LMP cars, which would be well outside the BoP standard for P1. Further, LMP cars such as the Ligier are 800-1200 pounds heavier than P1 cars and other F/SR cars with which they would be grouped on track, meaning that some cars would be less than half the Ligier's weight. This is undesirable from a safety standpoint. The referenced height differences of 5.0 to 7.5 inches between cars in the GTX class's run group are not uncommon in other race groupings in the SCCA, and drivers are accustomed to adjusting to this by being more observant when running together.
Prohibit artificial means of stalling engine during SIR test
In P1, GCR section 9.1.8.B.J, add a new section and renumber the following sections accordingly: "(Effective 9/1/2023) 4. The use of an ECU map, a computer program, or any other artificial means to stall an engine at any time during the SIR testing procedure in Appendix F. Technical Glossary (Restrictor, Intake) is prohibited."
Thank you for your letter. The Club Racing Board does not recommend this change. The Mazda 13B has not regularly competed in recent U.S. Majors Tour events, and the Club Racing Board does not have current on-track data for the platform. The on-track data collected at the VIR Super Tour event in 2019 showed a Mazda 13B using the current restrictor size to be fully in line with its competitors for the factors that enter into a Balance of Performance powertrain assessment. Please see the response to letter #27736 in the December 2019 Fastrack Minutes. If a member who is interested in racing the 13B enters and competes in a U.S. Majors Tour event in 2023, the Club Racing Board will arrange to obtain on-track data to assess the platform’s current performance potential relative to other cars in the class and will make data-based adjustments if warranted.
Thank you for your letter. The P1 rules state that "Engines not specified in the table below are not permitted in P1." No spec line in the referenced engine table permits a turbocharged engine by engine series or requires a Turbo Inlet Restrictor (TIR). Please see GCR section 9.1.8.B.J.4 and the P1 Engine Table. Forced induction engines are outside the class philosophy. Please see the responses to letter #28809 in the June 2020 and September 2020 Fastrack Minutes and the response to letter #33123 in this Fastrack's Technical Bulletin.
Thank you for your letter. The Club Racing Board does not recommend the use of two different methods of intake restriction for the same spec line. SIRs have been successfully implemented on other P1 cars with similar auto-based engines. Please see the response to letter #23792 in the March 2018 Fastrack Minutes.
Thank you for your letter. The Club Racing Board does not recommend this change. The proposed RDRF car's actual weight with a Halo device is presently unknown and when completed could conceivably meet the current minimum weight under whichever spec line the car is intended to run without the requested 30 lb. increase. Also, a need for an across-the-board 30 lb. increase has not been demonstrated because no existing P1 car uses a Halo device and no P1 competitor has expressed a desire to retrofit an existing car with a Halo device, so the requested increase would penalize all other cars in the class with no factual basis for doing so. In addition, the fact that adding a Halo device would result in a higher center of gravity provides no basis for a Balance of Performance adjustment under the P1 class philosophy. BoP adjustments are not used in P1 to compensate for chassis design choices, including ones that might result in a higher center of gravity. Weight is added or subtracted (or restrictor
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size reduced or increased) based solely upon a car's longitudinal acceleration rate in a speed range of approximately 60 to 100 mph, which would not likely be affected by a higher center of gravity.
MA – 22-01 The Club Racing Board has become aware that P1 competitors are attempting to defeat the SIR stall test by programming the ECU to shut down the engine when it senses a drop in RPM to avoid the detection of controlled leaks in the air box. The rules clearly state that the introduction of air behind the SIR by any means is prohibited. The CRB is developing innovative methods for detection and requests that the Stewards of the Meeting (SOM) employ zero tolerance in connection with any SIR infractions or attempts to defeat the SIR stall test.” For additional details, contact the tech department at SCCA.
Thank you for your letter. The Club Racing Board does not recommend these changes. Nothing in the P1 rules prohibits the use of individual throttle bodies (ITBs) on a Honda FD2 engine. Honda FD2 owners have two options: they can use OEM parts with the 64mm single throttle body and no SIR at 1,400 lbs. minimum under Line G, or they can add higher performance pistons, rods, and cams and use ITBs with a 30mm SIR at the same weight under Line H. In addition, nothing in the rules prohibits enlarging a Honda FD2 to 2.3L and using higher performance parts and ITBs with a 30mm SIR at 1,445 lbs. minimum under Line I. A CN Honda FD2 engine is permitted to run without an SIR under Line G because the OEM parts (including the 64mm single throttle body) limit the power such that an SIR is not necessary. Competitors who wish to modify a Honda FD2 in the same way that competitors modify the Mazda MZR are free to do so under a spec line appropriate for the displacement. What the rules do
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not allow is adding ITBs and/or higher performance pistons, rods, and cams to a Honda FD2 without using an SIR. This would be unfair to other competitors whose modified engines are required to use an SIR. Data obtained at the 2019 Runoffs from a Norma M20FC using the stock Honda FD2 under the CN spec line showed that the car’s acceleration rate was fully in line with and at no disadvantage to the Elan DP02-Mazda 2.5L cars from which data was also obtained. Please see the response to letter #27639 in the December 2019 Fastrack. P1 is the most technologically advanced and open class in SCCA's Road Racing program. Competitors may choose the chassis, engine, and tires they wish to race, and the rules allow for improvement of aerodynamics, suspension, brakes, and other systems to make a platform more competitive, so it should not be assumed that manufactured cars like CN cars will be able to run at the front without modification. This additional development results in increased performance in cornering, braking, and top speed, which are not subject to the BoP process and are factors entirely within a competitor's control.
Thank you for your letter. The Club Racing Board does not recommend this change. The P1 class is intended to be the premier sports racing category promoting advanced technology in design and innovation, and the class philosophy is not to classify cars that could not be competitive in P1. The Mazda 12A is outside the P1 performance envelope, but the engine is approved for use in the P2 class, and the Beasley B2 is also in line with P2 performance expectations. Please see the response to letter #32147 in this Fastrack’s Technical Bulletin.
Thank you for your letter. Data obtained at the 2021 June Sprints shows that the three Stohr chassis that were equipped with AiM data boxes—the referenced 1615cc car, a 1455cc car, and the 1355cc car that won the 2021 P1 National Championship— had acceleration rates that were very closely matched and were at no disadvantage to the two 2500cc Elan DP02s and the converted FA 1615cc Swift 014a that were fitted with the data boxes. The national championship race at Indianapolis refutes the notion that a Stohr cannot compete with a "high downforce" DP02. An individual car's deficits in braking power, cornering performance, and right/left transitional handling capabilities are not subject to the SCCA's BoP process and are not remedied by increasing the car's restrictor size. If concerns remain about the referenced 1615cc car's weight and restrictor size despite the acceleration rate data, then the engine table provides an alternative: a car using the 1455cc engine has the option to run
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without a restrictor at a minimum weight of 1150 lbs.
Thank you for your letter. The Club Racing Board does not recommend this change. Please see the response to letter #31168 in the November 2021 Fastrack Minutes.
Thank you for your letter. The Club Racing Board does not recommend this change. The sealed engines are no longer viable because they have not been used by IMSA for several years and SCCA cannot ensure that power would remain at the level that previously allowed them to run without an inlet restrictor in P1. While new seals conceivably could be applied after engine rebuilds, the Club Racing Board and Tech officials would have no means of verifying that the proprietary parts that originally allowed the engines to run without an inlet restrictor were used during each rebuild. Moreover, even if it were possible to confirm that the proper parts were used, this would not eliminate the sealed engines' inherent problem. DP02s with sealed engines are outside the P1 performance envelope – when they were legal in P1, the data showed that their trap speeds were 12- 15 mph slower than the trap speeds of other cars in the class. As a result, DP02s with sealed engines were rarely entered when
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they were legal in P1. For all these reasons, the best option for the class is to do what other DP02 owners have done since 2017: upgrade the engine components and install the required 30mm SIR, which balances power with much greater precision than could be achieved by attempting to prescribe allowable parts and modifications for individual engine applications.
Request restrictor change for the Wombat for more power
Thank you for your letter. Please see the responses to letter #30787 in the August 2021 Fastrack, letter #30484 in the May 2021 Fastrack, letter #29621 in the December 2020 Fastrack, and letter #29232 in the October 2020 Fastrack.
Eliminate carbon rotors & pads or add weight to cars using them
Thank you for your letter. The Club Racing Board does not recommend this change. P1 is intended to be the premier sports racing class, promoting advanced technology in car design and innovation while utilizing established cost-effective engine technology. Consistent with this class philosophy, competitors may improve brakes, aerodynamics, suspension design, and other systems to make a platform more competitive. The Club Racing Board uses an SCCA-developed Power Factor formula (PF = Weight/Peak HP + Peak Torque/2) to set weight and power parameters and periodically collects on-track data to confirm that cars have similar acceleration rates from roughly 60 to 100 mph, but, consistent with the class philosophy, braking performance is the competitor's responsibility and is not subject to the Balance of Power (BoP) process.
Request Disp. Change for 2-Cycle 6 Cyl. eng or min. weight change
Thank you for your letter. The Club Racing Board does not recommend this change. A review of on-track data obtained during the 2020 National Championship Runoffs, including a request for additional views, does not support a 255cc increase in displacement or a 100-lb. decrease in minimum weight. Please see the response to letter #29901 in the January 2021 Fastrack Minutes.
Please Allow 1180 Pound Stohr More Air to Equalize Acceleration
Thank you for your letter. The Club Racing Board does not recommend this change. On-track data obtained at the 2021 June Sprints Super Tour event confirms that the referenced Stohr has no deficit in low-speed, medium-speed, or high-speed acceleration rate as compared to the 2.5 liter Elan DP02 platform. Any deficits in the Stohr's lateral acceleration and braking performance, whether the result of chassis setup or driver input, would not be eliminated by increasing the size of the car's intake restrictor. Adjustments or changes to reduce or eliminate cornering and braking deficits are the responsibility of the competitor and are not subject to the SCCA's Balance of Power (BoP) process.
Thank you for your letter. Equalizing lap times is contrary to the P1 class philosophy. P1 cars are not built to a formula, and the variety of chassis and engine combinations does not lend itself to the balance of performance adjustments seen in some professional prototype series. P1 cars are therefore subject to balance of power adjustments. The Club Racing Board uses an SCCA-developed Power Factor formula (PF = Weight/Peak HP + Peak Torque/2) to set weight and power parameters and periodically collects on-track data to confirm that cars have similar acceleration rates from roughly 60 to 100 mph, before aerodynamic forces become significant. Competitors may choose the chassis, engine, and tires they wish to race, and the rules allow for the improvement of aerodynamics, suspension design, brakes, and other systems to make the platform more competitive, so it should be not assumed that a manufactured car will be capable of running at the front without modification.
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Adding performance parts and components may make it more difficult to meet the applicable minimum weight. The burden is on the competitor to weigh the pros and cons and decide whether the benefits of adding such parts and components exceed the penalty of additional weight. Smaller/lighter cars such as the Stohr do not need to develop the same level of downforce or have the same amount of tire on the road as larger/heavier cars such as the DP02 and converted FA cars to be able to compete with those cars.
Thank you for your letter. The Club Racing Board does not recommend this change. The sealed DP02-spec 2.0L engine is outside the P1 performance envelope. Please see the responses to letters #26753 in the July 2019 Fastrack Technical Bulletin, #27867 in the January 2020 Fastrack Minutes, #29756 in the December 2020 Fastrack Minutes, #30038 in the January 2021 Fastrack Technical Bulletin, and #30032 in this Fastrack. A restrictor is not being added to modified DP02 engines for 2021. Modified engines have been required to use a single inlet restrictor since the class was inaugurated in 2014.
Thank you for your letter. The Club Racing Board does not recommend this change. Please see the response to letter #30038 in the January 2021 Fastrack Technical Bulletin. Switching to a 2.5L engine is not the only option. Line G's notes include a lower minimum weight for cars using a modified 2.0L engine that allows for the difference in torque compared to larger displacement engines. The 30mm single inlet restrictor (SIR) required on Line G engines balances power with greater precision than could be achieved by prescribing allowable parts and modifications for each engine application. A sealed SIR airbox for the DP02 is commercially available to competitors who do not wish to build their own.
Thank you for your letter. The Club Racing Board does not recommend this change. The engine platform is not within the P1 performance envelope, but its capabilities are in line with performance expectations in the P2 class. Please see the response to letter #30272 in this Fastrack’s Technical Bulletin.
Thank you for your letter. The Club Racing Board does not recommend this change. The requirements for 2.3L engines have not been changed for 2021. The rules have required all 2.3L engines to use a single inlet restrictor (SIR) since the sealed 2.3L engine was eliminated at the end of 2017. Please see the responses to letter #22614 in the October 2017 Fastrack Technical Bulletin, letter #23875 in the March 2018 Fastrack Technical Bulletin, and letter #28018 in the February 2019 Fastrack Minutes. Members may continue to run 2.3L engines in compliance with Spec Line G of the engine table.
Request displacement change for 2-Cycle 6 cylinder engines
Thank you for your letter. The Club Racing Board does not recommend this change. A review of the data obtained during the 2020 National Championship Runoffs, including a request for additional views, has not shown that an adjustment to the two- cycle engine's displacement is warranted.
Thank you for your letter. The Club Racing Board does not recommend this change. The sealed IMSA-spec 2.0L engine is not within the P1 performance envelope. In the U.S. Majors Tour event at Sebring, an Elan DP02 using the sealed engine qualified more than 11 seconds off the pole position time of a DP02 equipped with a modified engine, and at the 2020 Runoffs a DP02 using the sealed engine failed to qualify within 115% of the fastest P1 qualifying time and did not improve on its grid time after receiving a waiver for the race.
Thank you for your letter. The Club Racing Board does not recommend this change. On-track data obtained during the 2020 National Championship Runoffs confirms that the 1.0 liter platform's rate of acceleration is fully in line with and at no disadvantage to the acceleration rates of other P1 engine platforms, so a 50lb. weight reduction is not warranted.
Request to reduce horsepower of DP02 and FA conversions
Thank you for your letter. The Club Racing Board does not recommend these changes. The competitiveness of the Elan DP02 and FA conversions is not the result of a better power-to-weight ratio than other P1 platforms. On-track data obtained during the 2020 U.S. Majors Tour season and the 2020 National Championship Runoffs confirms that the acceleration rates of the 2.5 liter Elan DP02 and 1.6 liter FA conversions are fully in line with and have no advantage over the acceleration rates of other P1 engine platforms, so a reduction in power is not warranted.
Thank you for your letter. The Club Racing Board does not recommend this change. Balance of Performance (BoP) adjustments are used to bring an engine platform in line with other platforms' rate of acceleration in a speed range before aerodynamic drag has a significant effect. BoP adjustments are not used to equalize lap time performance or ensure overall competitiveness, and the Club Racing Board does not adjust power or minimum weight to balance differing chassis configurations. Data obtained during the 2019 U.S. Majors season shows that the Mazda 13B’s performance is fully in line with and at no disadvantage to other engine platforms' rate of acceleration, so removal of the 13B's inlet restrictor is not warranted. Please see the responses to letter #25759 in the January 2019 Fastrack Minutes and letter #27736 in the December 2019 Fastrack Minutes.
Thank you for your letter. This change is not recommended. The P1 Engine Table includes multiple engine types and displacements for which minimum weights and restrictor sizes have been established through the collection of on-track rate-of- acceleration data. The Club Racing Board does not have the resources to tailor alternative weight and restrictor combinations to the specific needs of individual competitors while ensuring a balance of performance with existing platforms.
Thank you for your letter. Please see the responses to letters #28809 and #28810 in this Fastrack.
Closed-cockpit, single-seat cars
#28810 from Formula/Sports Racing Committee · Not recommended · Minutes (2020-09 Fastrack)
Thank you for your letter. After reviewing the response to the WDYT published in the June 2020 Fastrack Minutes, the Club Racing Board does not recommend this change.
Turbocharged engines
#28809 from Formula/Sports Racing Committee · Not recommended · Minutes (2020-09 Fastrack)
Thank you for your letter. After reviewing the response to the WDYT published in the June 2020 Fastrack Minutes, the Club Racing Board does not recommend this change.
Closed-cockpit, single-seat cars
#28810 from Formula/Sports Racing Committee · Member feedback requested · Minutes (2020-06 Fastrack)
The Club Racing Board requests class stakeholder input on whether closed-cockpit, single-seat cars should be allowed in the P1 class. Please reply via the CRB letter log system.
Turbocharged engines
#28809 from Formula/Sports Racing Committee · Member feedback requested · Minutes (2020-06 Fastrack)
The Club Racing Board requests class stakeholder input on whether turbocharged engines should be allowed in the P1 class. Please reply via the CRB letter log system.
Thank you for your letter. The Club Racing Board does not recommend this change. Removal of the required restrictor is not supported by the data: the P1 rules permit cars using a 2.0L engine to weigh 75 lbs. less than those using a 2.5L engine. The Club Racing Board will continue to monitor class performance and will make appropriate, data-based adjustments as necessary.
Thank you for your letter. Competitors have always had the ability to choose between running a DP02- spec sealed 2.0L engine without an inlet restrictor under Line F or an unsealed 2.0L engine with a 30mm SIR under Line G. Delaying the previously announced sunset date for the DP02-spec sealed engine option until 1/1/2021 does not affect a competitor's ability to run an unsealed 2.0L engine during the 2020 season.
Thank you for your letter. The CRB appreciates the concern for collecting sufficient data for decision making. There are many factors that influence data collected at any given event; track configuration, CLUB RACING BOARD weather conditions, and most important entry list. For Major’s events the entry list is reviewed and must represent a reasonable mix of engine platforms for data to be collected. The CRB will continue to monitor the entry lists and collect data where there is a reasonable expectation of good data being available.
Thank you for your letter. The Club Racing Board does not recommend this change. On-track performance shows that the sealed DP02-spec 2.0L MZR engine is not within the performance envelope of the P1 class, but suitable modifications to the 2.0L engine will allow it to be competitive using the required Single Inlet Restrictor.
Thank you for your letter. The Club Racing Board does not recommend this change. Although Balance of Performance (BoP) adjustments are used to allow different platforms to race together in the same class, the criterion for a BoP adjustment is limited to a car's rate of acceleration in a speed range before aerodynamic drag has a significant effect -- typically between 60 and 100 mph. BoP adjustments are not used to equalize lap time performance, ensure overall competitiveness, or boost class entries. Data obtained during the 2019 U.S. Majors Tour event at Virginia International Raceway showed that the Mazda rotary-powered car's rate of acceleration was fully in line with and not at any disadvantage to the other platforms' performance, so the removal of the car's inlet restrictor is not warranted.
Request for Weight Reduction Consideration for P1 - 1000cc Engine
Thank you for your letter. The Club Racing Board does not recommend these changes. Although Balance of Performance (BoP) adjustments are used to allow different platforms to race together in the same class, the criterion for a BoP adjustment is limited to a car's rate of acceleration in a speed range before aerodynamic drag has a significant effect -- typically between 60 and 100 mph. BoP adjustments are not used to equalize lap time performance or ensure overall competitiveness, and the Club Racing Board does not adjust minimum weight or power to allow for differing aerodynamic configurations, brake systems, or chassis setups. Data obtained during the National Championship Runoffs shows that the CN car's rate of acceleration was fully in line with and not at any disadvantage to the other platforms'
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performance, so adjustments to the car's minimum weight and power are not warranted.
Thank you for your letter. The Club Racing Board does not recommend this change. Although Balance of Performance (BoP) adjustments are used to allow different platforms to race together in the same class, the criterion for a BoP adjustment is limited to a car's rate of acceleration in a speed range before aerodynamic drag has a significant effect -- typically between 60 and 100 mph. BoP adjustments are not used to equalize lap time performance or ensure overall competitiveness, and the Club Racing Board does not adjust minimum weight or power to allow for differing aerodynamic configurations, brake systems, or chassis setups. Data obtained during the National Championship Runoffs shows that the 1000cc car's rate of acceleration was fully in line with and not at any disadvantage to the other
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platforms' performance, so an adjustment to the car's minimum weight is not warranted.
Thank you for your letter. The Club Racing Board does not recommend this change at this time. No competition adjustments will be made during the remainder of this season. The Club Racing Board will review the data obtained this season, including during the Runoffs, and will make appropriate adjustments as necessary for the 2020 season.
Thank you for your letter. The Club Racing Board does not recommend this change. The minimum weight is correct for the current power level and is supported by both acceleration rate data and lap time performance.
Request Correction to P1 Spec Line E Minimum Weight
Thank you for your letter. The Club Racing Board does not recommend this change. The minimum weight is correct for the current power level and is supported by both acceleration rate data and lap time performance.
Request to release weight and intake for Staudacher race cars
Thank you for your letter. The Club Racing Board does not recommend this change. The P1 rules permit the Staudacher chassis to run at a lighter weight than all other 1000cc cars, and the required intake restrictor properly compensates for the Staudacher’s weight allowance.
Thank you for your letter. The Club Racing Board does not recommend classification because the Praga R1 Turbo and Praga R1 Turbo Evo are outside the P1 class philosophy. Please see the response to letter #21457, June 2017 Fastrack Minutes. Competitors may race in the Regional only ASR class.
Request for Competition Adjustment to Help P1/P2 Participation