removedSTL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge and Global Cup (16-18), updates notes.
As printed in Fastrack
In STL Spec Lines, removed Mazda MX-5 Cup in its entirety. In STL Spec Lines, Mazda Spec MX5 Challenge, change as follows: Model: "Mazda Spec MX5 Challenge" Notes: "Must conform completely to GCR 9.1.7.1, except alternative tires (only) per STL regs allowed. May run 8" spec wheel. Tires per STL rules." In STL Spec Lines, Mazda MX-5 Global Cup (16-18), change as follows: Model: Mazda MX-5 Global Cup (16-18) Notes: "Must meet all MX-5 Global Cup rules."
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In STL Spec Lines, remove Mazda MX-5 Global Cup (2019) in its entirety.
wordingSTL and STU weight calculation wording clarified; percentage adjustments combined before applying fixed weight adjustments.
As printed in Fastrack
In GCR, Section 9.1.4.1.H.6., change as follows: "The minimum weight is determined by the installed engine displacement, TIR or table spec line. It is to be used as the base weight for any chassis weight related adjustments. Chassis related All positive adjustments that are percentage based are performed by adding the total of all specified percentages first and subtracting the total of all negative specified percentages second if necessar y. Final step is addition or subtraction of specified weight in pounds." In GCR, Section 9.1.4.2.H.4., change as follows: "The minimum weight is determined by the installed engine displacement or table spec line. It is to be used as the base weight for any chassis weight related adjustments. Chassis related All positive adjustments that are percentage based are performed by
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adding the total of all specified percentages first and subtracting the total of all negative specified percentages second if necessary. Final step is addition or subtraction of specified weight in pounds."
In STL, Table A: Alternate Vehicle and Engine Requirements, add the following: Model: "Mazda BP 1.6" Maximum Displacement: "1600cc" Minimum Weight: "2160"
unclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1 instead of 2500 lbs; spec components removed, only alternative tires allowed.
As printed in Fastrack
In STL Spec Lines, Table B, Mazda Spec MX5 Challenge, change as follows: Minimum Weight: "2500 See 9.1.7.1." Notes: "Mazda MX5 Challenge car must utilize the following components: Roush CNC cylinder head 0000-01-5300,Mahle standard or +0.005 0000-01-5310, OEM camshaft, 11:1 compression ratio, header 0000-06-5407-NC, exhaust 0000-06-5427-NC, cold air intake 0000- 06-5150-KT, ECU flash 0000-01-5379, Pagid front brake pads 0000-03-5104-SP or endurance pads 0000-03- 5104-EN, Pagid rear brake pads 0000-03-5114-SP or endurance pads 0000-03-5114-EN, Penske front shock 0000-04-5291-SA, Penske rear shock 0000-04-5292-SA, Penske rear mount kit 0000-04-5358, Front mount kit 0000-04-5359, Front offset bushing 0000-04-5407-NC, Eibach front springs 0000-04-9700-08, Eibach rear springs 0000-04-9400-07, Eibach helper springs 0000-04-
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9926, Eibach front sway bar 0000-04-5306-FT, Eibach rear sway bar 0000-04-5306-RR, Interior finish panels 0000-07-5822, C&R radiator/oil cooler assembly 0000-01-5504-CR, Oil cooler adapter and lines 0000-01-5511-KT, ACT clutch 0000-02-5004-G6, wheels 17x8 #0000-04-5706-GM, # 0000- 04-5706-SL, and Toyo RR 235-40-17 dry, Toyo RA1 235-40-17 wet. Alternative tires on 17x7 wheels per STL rules. No other Super Touring modifications or allowances permitted except as noted in this spec line. Must conform completely to GCR 9.1.7.1, except alternative tires (only) per STL regs allowed."
Request to Remove Miata Hubs from General category
wordingSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.
As printed in Fastrack
In GCR, Section 9.1.4.M.18., change as follows: "18. Allow alternate front wheel front hubs, Mazda Motorsports Development Part #0000-04-5HUB-S1, for the 90-05 Mazda Miata: Mazda Motorsports Development Part #0000-04-5HUB-S1."
wordingSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.
As printed in Fastrack
In GCR, Section 9.1.4.M.16., change as follows: "Power steering may be modified in any of the following ways: a. disconnected , pump, belt, pulley, and hoses may be removed. Hoses may also be looped. Steering rack or box may be modified internally to work without pump. b. an OEM manual steering rack for that model may be fitted c. an electric power steering pump may be fitted d. an OEM electric-assisted steering system may be used or any column mounted electric steering assist may be used e. an OEM hydraulic-assisted steering system may be used"
fasterSTL Acura/Honda B-series and Mazda MZR restrictors reduced 2mm; minimum weights down 25–75 lbs for 1900–2000cc engines.
As printed in Fastrack
In GCR, 9.1.4.H.1., change as follows: "Minimum weights for cars with normally aspirated piston engines will be determined by 1.35 lbs/cc displacement for the installed engine (see the following table). Displacement is the factory displacement for the installed engine. For the purpose of weight assignment, engine displacement will be rounded to the nearest 50cc (e.g., 2176cc = 2200cc and 2175cc = 2150cc)." In GCR, 9.1.4.H.1., change Minimum Weight on Chart as follows: Factory Engine Displacement 1900: "Effective 3-1-24: 2565 2540" Factory Engine Displacement 1950: "Effective 3-1-24: 2633 2583"
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Factory Engine Displacement 2000: "Effective 3-1-24: 2700 2625" In GCR, 9.1.4.H.3., change as follows: "Front wheel drive cars with a strut type front suspension may reduce their minimum weight by 2.5 percent. Effective 3- 1-24: Front wheel drive cars with 95" or less wheelbase must add 1.25% to their minimum weight." In STL Spec Lines, change Notes as follows: Acura/Honda B16: "Effective 3-1-24: 53 51mm" Acura/Honda B17: "Effective 3-1-24: 53 51mm" Acura/Honda B18C1: "Effective 3-1-24: 53 51mm" Acura/Honda B18C (JDM Type R), B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R): "Effective 3-1-24:52 50mm" Mazda MZR: "Effective 3-1-24: 52 50mm"
unclearSTL Mazda RX-7 12A (79-85) now allows auto-type 2 bbl with 42mm choke(s) on dual-y manifold as alternate to stock Nikki 4 bbl.
As printed in Fastrack
In STL Table B: Alternate Vehicle and Engine Allowances, Mazda RX-7 12A (79-85), change Notes as follows: "Street Porting of the engine only. Bridge porting, peripheral porting, and eyelash porting are prohibited. Contact SCCA National Office for details of Street porting. Stock Nikki 4 bbl carburetor on a stock manifold only. or auto-type 2 bbl w/42mm choke(s) on a “dual-y” manifold. Allow the standard removal of emissions related components, and allow air and fuel jets to be corrected. Modification of the water jacket in the area of the spark plug for cooling purposes is permitted."
wordingSTL ITA/ITS RX7 and 1985+ ITA/ITS/ITB/ITC vehicles clarified to conform to section 9.1.4.2 tire specifications.
As printed in Fastrack
In STL Spec Lines, Table B: Alternate Vehicle and Engine Allowances, change Notes as follows: ITA-spec and ITS-spec RX7: "Must completely conform to ITCS specifications. Tires must conform to 9.1.4, Tires & Wheels. Tires must also conform to 9.1.4.2.Tires." ITS, ITA, ITB, or ITC vehicles (1985- ): "Must completely conform to ITCS specifications. Tires must conform to 9.1.4, Tires & Wheels. Tires must also conform to 9.1.4.2.Tires."
wordingSTL Spec MX5 clutch, wheels, and tyres specified: ACT 0000-02-5004-G6, 17x8 wheels, Toyo RR and RA1 235-40-17.
As printed in Fastrack
In STL, Table B: Alternate Vehicle and Engine Allowances, Mazda Spec MX5 Challenge, change notes as follows: "ACT clutch 0000-02-5004-G6, wheels 17x8 #0000-04-5706-GM, # 0000-04- 5706-SL, and Toyo RR 235-40-17 dry, Toyo RA1 235- 40-17 wet. Alternative tires on 17x7 wheels per STL rules. No other Super Touring modifications or allowances permitted except as noted in this spec line."
fasterSTU normally aspirated engines: minimum weights reduced up to 310 lbs; single throttle body weight reduction removed.
As printed in Fastrack
Effective 5.1.2022 In STU, GCR Section 9.1.4.H.1., change as follows: "1. Minimum weights for cars with normally aspirated piston engines will be determined by 1.1 lbs/cc displacement for the installed engine (see following table) the following table. Displacement is the stock displacement for the installed engine. For the purpose of weight assignment, engine displacement will be rounded to the nearest 50cc (e.g., 2176cc = 2200cc and 2175cc = 2150cc)." Factory Engine Displacement (cc) Minimum Weight (lbs)
A specification table follows in the original; it is not shown here.
tyres & wheelsSTL and STU Improved Touring vehicles must conform to 9.1.4 Tires & Wheels requirements.
As printed in Fastrack
In STU Table B, Improved Touring Vehicles (1985-), change Notes as follows: "Must completely conform to ITCS requirements. Tires must conform to 9.1.4, Tires & Wheels" In STL Table B, ITA-spec and ITS-spec RX7, change Notes as follows: "Must completely conform to ITCS requirements. Tires must conform to 9.1.4, Tires & Wheels" In STL Table B, ITS, ITA, ITB, or ITC vehicles (1985- ), change Notes as follows: "Must completely conform to ITCS requirements. Tires must conform to 9.1.4, Tires & Wheels"
wordingSTL and STU piston engines clarified: intake manifold and cylinder head porting remains free.
As printed in Fastrack
In GCR, Section 9.1.4.1.B.4., change as follows: "The intake and exhaust porting on piston engines is free. Porting of intake manifolds and cylinder heads is free on piston engines."
wordingSTL Mazda RX-7 12A 79-85 clarifies carburetor, emissions, and water jacket modification rules.
As printed in Fastrack
In STL, Mazda RX-7 12A (79-85), change notes as follows: "Stock Nikki 4 bbl carburetor on a stock manifold only. Allow the standard removal of emissions related components, and allow air and fuel jets to be corrected. Modification of the water jacket in the area of the spark plug for cooling purposes is permitted."
slowerSTL Volkswagen 2.0L TFSI 1984cc classified with turbocharger removal required, meeting all other STL specs.
As printed in Fastrack
In STL Spec Lines, classify Volkswagen 2.0L TFSI, as follows: STL Maximum Displacement (cc's) Minimum Weight Notes Volkswagen 2.0 TFSI 1984 Chart Engine Permitted with turbocharger removed. Must meet all other STL specifications.
cars addedSTL Mazda B5 DOHC added to classification with standard STL regulations.
As printed in Fastrack
In STL Table A, classify Mazda B5 DOHC as follows: STL Maximum Displacement (cc's) Minimum Weight Notes Mazda B5 DOHC Chart Must meet ALL STL regulations.
wordingST oil coolers and filters now explicitly allowed to be added or substituted; wording clarifies existing permissions.
As printed in Fastrack
In ST, section 9.1.4.G.14, change as follows: "Vents, breathers, and oil filters and oil coolers may be added, or substituted. All emission control devices may be removed and the resulting holes plugged."
wordingSTL GM Ecotec engines now permit any combination within the family, must use 55mm flat plate restrictor.
As printed in Fastrack
In STL, Table B, change GM Ecotech LNF, as follows: "GM Ecotech LNF" In STL, Table B, GM Ecotech LNF, add to Notes as follows: "Any combination of GM Ecotech engine family permitted. Must use 55mm flat plate restrictor. Must meet all other STL specifications."
wordingSTL/STU 90-05 Mazda Miata gains approval for Mazda Motorsports Development alternate front wheel hubs.
As printed in Fastrack
In ST, GCR section 9.1.4.M, add alternate front wheel hubs as follows: "18. Allow alternate front wheel front hubs for the 90-05 Mazda Miata: Mazda Motorsports Development Part #0000-04-5HUB-S1"
aeroSTL rear wing trailing edge, including end plates and gurney flap, maximum rearward mounting clarified to center of rearmost bodywork.
As printed in Fastrack
In GCR, Section 9.1.4.D.g, change as follows: "The trailing edge of the rear wing, including end plates and gurney flap, may be mounted no further rearward than the center of the rearmost part approved bodywork."
wordingSTL allows OEM gear sets from same manufacturer transmissions with input shaft modifications for fitment.
As printed in Fastrack
In STL, Section 9.4.1.2.C.2, change as follows: "Either the original transmission or an alternate transmission must be used; the alternate transmission must be from the same manufacturer as the vehicle (i.e., an Acura transmission may be installed in a Honda car). Alternate transmissions must be used in their entirety; any OEM gear sets (drive and driven gear pairs) that fit w/o any modifications to gears, shafts, and/or case are permitted. Modifications to input shafts for fitment are allowed."
fasterSTL RWD strut suspension weight penalty cut to 0.5%, other RWD cut to 2.5%.
As printed in Fastrack
In STL, GCR Section 9.1.4.2.H.2, change as follows: "Rear wheel drive cars with strut front suspension must add 3 0.5 percent to their baseline STL weight. All other rear wheel drive cars must add 5.5 2.5 percent to their standard baseline STL weight."
slowerSTL Honda B16/B17/B18C1 restrictor tightened to 53mm; B18C variants and Mazda MZR to 52mm.
As printed in Fastrack
In STL, Table A, Acura/Honda B16, change Notes as follows: "54 53mm flat plate restrictor required." In STL, Table A, Acura/Honda B17, change Notes as follows: "54 53mm flat plate restrictor required." In STL, Table A, Acura/Honda B18C1, change Notes as follows: "54 53mm flat plate restrictor required." In STL, Table A, Acura/Honda B18C (JDM Type R), B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R), change Notes as follows:
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"53 52mm flat plate restrictor required." In STL, Table A, Mazda MZR, change Notes as follows: "53 52mm flat plate restrictor required."
aeroST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch.
As printed in Fastrack
IN ST, GCR Section 9.1.4.D.4.e, add the following: "Unless otherwise specified in the applicable rules the measurement of aero dynamic devices and reference areas shall include end plates but not include fasteners as long as the fasteners serve no other purpose. Fasteners may protrude no more than 1/2” from the mounting surface."
wordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis adjustments.
As printed in Fastrack
In STU, GCR section 9.1.4.10., add the following: "All weight adjustments for engines shall be applied first, then that total is to be used as the baseline for any chassis-related weight adjustments. Chassis related adjustment that are percentage based are performed by adding specified percent first and subtracting specified percentage second if necessary. Final step is addition or subtraction of specified weight in pounds." In STL, GCR Section 9.1.4.4., add the following: "All weight adjustments for engines shall be applied first, then that total is to be used as the baseline for any chassis-related weight adjustments. Chassis related adjustment that are percentage based are
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performed by adding specified percent first and subtracting specified percentage second if necessary. Final step is addition or subtraction of specified weight in pounds."
wordingSTL and STU rear wing rules clarify that wicker is a Gurney flap; no performance change.
As printed in Fastrack
In GCR section 9.1.4.D.4, clarify wording as follows: "d. Wings shall be a single element with a maximum chord length of 8.50 inches, including any wicker Gurney flap." "f. The entire rear wing assembly, including the end plates and any wicker Gurney flap, shall be mounted a minimum of 6.0 inches below the peak of the roof or roll cage main hoop whichever is higher, measured at the highest point. Cars with a wagonback/notchback/hatchback style body may have the rear wing assembly, including the end plates and any wicker Gurney flap, mounted a maximum of 4.0inches above the highest point of the roof."
cars addedSTL adds 2016-2019 Mazda MX-5 Global Cup at 2000cc, 2450-2550 lbs minimum weight.
As printed in Fastrack
In STL, classify the Mazda MX-5 Global Cup (16-18) as follows: STL Maximum Displacement (cc's) Minimum Weight Notes Mazda MX-5 Global Cup (16-18) 2000 2450 Must meet all MX-5 Global Cup rules. Any OEM or aftermarket
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hardtop is permitted that retains the OEM silhouette. If a hardtop is used, latches shall be replaced with positive fasteners. OBD2 requirement does not apply. Ballast box may be removed. Tires per STL rules. In STL, classify the Mazda MX-5 Global Cup (2019) as follows: STL Maximum Displacement (cc's) Minimum Weight Notes Mazda MX-5 Global Cup (2019) 2000 2550 Must meet all MX-5 Global Cup rules. Any OEM or aftermarket hardtop is permitted that retains the OEM silhouette. If a hardtop is used, latches shall be replaced with positive fasteners. OBD2 requirement does not apply. Ballast box may be removed. Tires per STL rules.
unclearSTL Honda/Acura B18 non-C gets 54mm restrictor; B18C variants drop B18C1, get 53mm restrictor.
As printed in Fastrack
In STL, Table A, Acura/Honda B18 (except C engine) change as follows: "Acura/Honda B18 (except C1 engine)" In STL, Table A, Acura/Honda B18 (except C engine) change Notes as follows: "53 54mm" In STL, Table A, Acura/Honda B18C (JDM Type R), B18C1, B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R) change as follows: "Acura/Honda B18C (JDM Type R), B18C1, B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R)"
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In STL, Table A, Acura/Honda B18C (JDM Type R), B18C1, B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R)) change Notes as follows: "54 53mm"
fasterSTL Honda B18 restrictor reduced from 54mm to 53mm flat plate; B18C1 added with 54mm restrictor.
As printed in Fastrack
In STL Spec Lines, Honda B18, change as follows: "53mm flat plate restrictor required." In STL Spec Lines, change as follows: "Acura/Honda B18C (JDM Type R), B18C1, B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R)" In STL Spec Lines, Acura/Honda B18C (JDM Type R), B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R), change notes as follows: "Any porting and or polishing of intake and or exhaust ports outside of the 1” port matching allowance,
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factory or otherwise, is prohibited. Must meet all other STL specifications. 54 53mm flat plate restrictor required." In STL, Acura/Honda B18C1, add Spec Line as follows: STL Maximum Displacement (cc's) Minimum Weight Notes Acura/Honda B18C1 Chart 54mm flat plate restrictor required.
Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0
slowerSTU GM Ecotech LNF now allowed with turbo removed or with LE5 head and intake manifold, meeting STL specs.
As printed in Fastrack
In STU, GM Ecotech LNF Spec Lines, add to Notes as follows: “LNF Engine Permitted with turbocharger removed. LNF Engine short block with LE5 cylinder head and intake manifold permitted. Must meet all other STL specifications.”
Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat
fasterSTU alternate intake manifolds now allowed case-by-case instead of prohibited.
As printed in Fastrack
In STU, GCR section 9.1.4.1.B.3, make changes as follows: "All cars shall use the installed engine’s or vehicle's stock air throttling device (e.g., throttle body, carburetor) and intake manifold, unless noted otherwise. Alternate intake manifolds will be permitted on a case-by-case basis."
wordingSTL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld.
As printed in Fastrack
In GCR Appendix K.F.5, add as follows: “Ride height will be measured without driver at the lowest point of the rocker panel, not including the pinch weld.” In GCR section 9.1.4.F.5, add as follows: “Ride height will be measured without driver at the lowest point of the rocker panel, not including the pinch weld.”
In STL, classify the VW 20V 1.8 in Table B as follows: STL Maximum Displacement (cc’s) Minimum Weight Notes VW 1.8L R4 20VT 1781 Chart Engine Permitted with turbocharger removed. Must meet all other STL specifications
Request to reduce weight of RX8 with Renesis rotary
cars addedSTL adds Acura/Honda B18C1 GSR with 54mm flat plate restrictor and port matching limited to 1 inch.
As printed in Fastrack
In STL, add Acura/Honda B18C1 to Table A as follows: STL Maximum Displacement (cc’s) Minimum Weight Notes Acura/Honda B18C1 Acura/Honda
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B18C (JDM Type R), B18C5 (USDM Type R), B18C6 (UK and Euro Type R), B18C7 (Australia Type R) Chart Any porting and or polishing of intake and or exhaust ports outside of the 1” port matching allowance, factory or otherwise, is prohibited. Must meet all other STL specifications. 54mm flat plate restrictor required.
fasterSTL Mazda 12 and 13B now permit port matching; previous ban removed.
As printed in Fastrack
In STL, Mazda 12, table A, strike the wording in the notes as follows: “No porting or port matching is permitted.” In STL, Mazda 13B, table A, strike the wording in the notes as follows: “No porting or port matching is permitted.”
Request to equalize FPR Reduction on all B-Series Vtec Engines
slowerSTL B18C Type R variants get 54mm flat plate restrictor; B17 also gets 54mm restrictor.
As printed in Fastrack
In STL, Table A, Acura/Honda B17, add to the notes as follows: “54mm flat Plate restrictor required.” In STL, Table A, Acura/HondaB18C(JDM Type R),B18C5(USDM Type R),B18C6(UK and Euro Type R),B18C7(Australia Type R), make changes to weight and notes as follows: “Chart + 2% Chart” “Effective 03/01/2018, 53 54mm flat plate restrictor required.”
Due to time restraints, it would not be practical to include every letter writer to the monthly zoom calls and manage bringing them in and removing them for just the discussion of their letter.
In GCR, Section 9.1.4.E.6., change as follows: "Stock d Dash/instrument panel cover (dash pad) must be used which fully encloses instrument wiring and mechanical components. Original instruments/gauges may be replaced, or supplemented, with additional engine monitoring gauges. Accessories, lights and switches may be added or removed. Box-type extensions from the dash pad may be used to mount switches and controls, in the areas where the OEM insert panels were mounted, so that they more easily accessible to the driver. Audio and video systems may be removed. In GCR, Section 9.1.4.E.8., change as follows: "8. Dash pad modification – It is permitted to modify the dash pad in order to run the roll cage tubes through the dash area as
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long as the dash pad is modified only enough for roll cage fitment. If necessary, the dash pad may be parted to ease installation around roll cage. Any such parting shall be done in such a way as to minimize the appearance that they have been separated once pieces of dash pad are installed."
We appreciate your perspective and feedback. Extended Ball Joints are not allowed in STL, however, SM cars which may run Extended Ball Joints may run in STL, must adhere to SM rules.
In GCR, Section 9.1.4.N., add the following: "(Effective 6/1/2025) 12. Any OE ABS System from the same manufacturer may be used."
Body Parts Interchangeability
#37474 from Super Touring Committee · Recommended to the Board · Minutes (2025-04 Fastrack)
In GCR, Section 9.1.4.C.1., change as follows: "(Effective 6/1/2025) Unless otherwise allowed, standard body appearance must be strictly maintained. Different models of the same generation chassis may interchange body panels, trim and lights."
In GCR, Section 9.1.4.G.8, change as follows: "(Effective 4/1/2025) Cars produced with an electronic throttle body may use the OEM electronic throttle body. The OEM electronic throttle body may be converted to manual actuation and the actuation cam on a manual throttle body may be changed to alter the opening/closing rate of the butterfly. Alternately actuated throttle bodies may be considered on a case by case basis. Vehicle/engine combinations with manual OEM throttle bodies may be converted to an OEM electronic throttle body of the same inner diameter as the original OEM throttle body. An 1" thick adapter plate may be used to facilitate mounting."
In GCR, Section 9.1.4.C., add the following: "(Effective 4/1/2025) 15. Hoods may have a maximum of 2 vents installed for cooling purposes. Cars with mid or rear engines may have a maximum of 2 vents located in the hood or fenders for cooling purposes. The maximum combined total area of the vents shall not exceed 200 square inches. The 200 Square inches includes any area that deviates from the factory hood profile or fender(s). Louvers within the 200 sq. inch are allowed. Louver vents that are OEM do not count in the number of vents allowed or 200 square inch allowance." In GCR, Section 9.1.4.1.A.2. delete in its entirety and renumber. "(Effective 4/1/2025) 2. Hoods may have a maximum of 2 vents installed for cooling purposes. Cars with mid or rear engines may
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have a maximum of 2 vents located in the hood or fenders for cooling purposes. The maximum combined total area of the vents shall not exceed 200 square inches. The 200 Square inches includes any area that deviates from the factory hood profile or fender(s). Louvers within the 200 sq. inch are allowed. Louver vents that are OEM do not count in the number of vents allowed or 200 square inch allowance."
Thank you for your letter. The car's Motorsport ABS and sequential transmission are outside of the STL class philosophy. The car is eligible in EP, STU or T3.
remove wording from 9.1.4.2 D3
#37452 from Super Touring Committee · Recommended to the Board · Minutes (2025-01 Fastrack)
In GCR Section, 9.1.4.2.D.3. change as follows: "Unless otherwise allowed in these regulations, no other relocation or reinforcement of any suspension component or mounting point is permitted."
Thank you for your letter. The STAC is confident that recent changes to the Mazda MZR and Honda vehicles are directionally correct. The STAC will continue to collect data, evaluate BOP, and make changes as needed in STL.
Thank you for your letter. This engine doesn't require a spec line. It falls under 2.0 L and is normally aspirated. It is 11.5:1 compression so it has to have the compression lowered when prepared or take the weight penalty of 1.5% as outlined in 9.1.4.2.B.4a. The lift on the intake cam is also greater than .425 so it could be modified to meet our spec or take the weight penalty as outlined in 9.1.4.2.B.5.a.
Thank you for your letter. Your request is not consistent with class rules, however, the committee believes there are other changes that could be made to make the car more competitive that are within class rules.
Thank you for your letter. Please see 9.1.4.G.2. which provides a very specific list of information (VTS, shop manual etc) which must be provided to request a non USDM engine for consideration.
Thank you for your letter. Please see 9.1.4.G.2. which provides a very specific list of information (VTS, shop manual etc) which must be provided to request a non USDM engine for consideration.
In GCR section 9.1.11, remove Spec MX-5 Regional only rules from the GCR as follows: Remove Spec MX-5 ruleset and place on SCCA website in technical forms and Downloads. Former SM5 cars are classified in T4 and STL. In STL, Mazda MX-5 Cup, add link to the SM5 ruleset in the Notes as follows: "SM5 rules can be found here - https://www.scca.com/pages/technical-forms-and-downloads."
Thank you for your letter. Request is not recommended due to being outside of class philosophy. Alternate material hubs are not an approved modification.
Thank you for your letter. ABS systems may be added to cars not originally equipped. The ABS system must be of the same manufacturer as the car it is being added to and be a street car production system. Non ABS weight break does not apply.".
Adjust the Size of the Restrictor for the Honda B16, B17, and B18
Thank you for your letter. We are interested in seeing the car race and collecting data for future BoP. Please request SCCA to collect data on the performance of the car in events that you will be participating in.
Thank you for your letter. We are interested in seeing the car race and collecting data for future BoP. Please request SCCA to collect data on the performance of the car in events that you will be participating in.
Remove 55mm Restrictor Plate from RX8 Renesis Motor in STL
Thank you for your letter. We are interested in seeing the car race and collecting data for future BoP. Please request SCCA to collect data on the performance of the car in events that you will be participating in.
The Club Racing Board requests class stakeholder input on considered throttle body changes in the ST class. Please reply via the CRB letter log system. 1. Should ST standardize a throttle body size per displacement? Or per class? 2. Should individual throttle bodies be allowed in all STU engines with a weight penalty?
Thank you for your letter. We will continue to collect data and monitor the class. The limited racing in 2020 has not given us the amount of data to make an educated decision.
Thank you for your letter. The JDM and Euro K20s are STL legal with the use of the USDM intake manifold, 11.0:1 compression and 0.425 valve lift or the USDM OEM cam shaft. Aftermarket pistons are allowed in STL to achieve the 11.0:1 compression ratio.
Strut Car Weight Reduction (Existing Rule) Question
Thank you for your letter. With the allowable STU suspension pick up point modifications, the CRB believes a front strut weight reduction is necessary. The CRB will continue to monitor performance.
Thank you for your letter. Competitor may race JDM Integra as long as it meets this part of the ST Regulations; "Vehicles used in this category must be identifiable with the vehicles offered for sale to the public and available through the manufacturer’s distribution channels in the US."
Thank you for your letter. 9.1.4.G.1.e Is a general category rule and applies to both STL and STU. 9.1.4.1.B.3 is a STU specific rule applying only to STU and over riding 9.1.4.g.1.e.
Thank you for your letter. Please see below BRZ calculation: 2.0L = 2700# X 1.5% for 12.5:1 compression ratio = 2740.5 pounds 2740.5 # X 5.5% rear wheel drive adder = 2891.
Thank you for your letter. Per Racing Memo 18-02, It was intended that you use a restrictor plate since 1/1/2018. The Club Racing Board will continue to monitor class performance.
Thank you for your letter. In STL the wing in its entirety must be no higher than 6 inches below the highest point of the body or the main hoop of the roll cage. Whichever is higher.