Classing your car appropriately can be a daunting task when you don’t even know where to start. This guide is intended to give you a good idea of where you should be, but may not be fully up to date with the current rulebook. For the current rules, check https://www.scca.com/pages/solo-cars-and-rules.
Whether you are going to your 1st event or your 100th event, you will need to know what class your car falls into. Regions are allowed to run non-standard classing to better serve the local membership, so it’s always a good idea to know where you’d fall within national classing to make things easier when visiting other regions.
The SCCA offers several classes in different groups in an effort to give most popular cars a place to compete, regardless of modification levels. The number of classes can be confusing at times though, so let’s break it down a little. There are groups based on allowed modifications (NOTE: The rulebook is a list of allowances, so if it doesn’t explicitly say you *can* do something, then you cannot). Those groups are:
- Street Touring
- Xtreme Street
- Classic American Muscle
- Street Prepared
- Street Modified
- Solo Spec Coupe
Each of those groups is broken down into classes that include specific cars, with the hopes that the cars in a class are roughly competitive with each other. Let’s talk about what’s Each of those groups is broken down into classes that include specific cars, with the hopes that the cars in a class are roughly competitive with each other. Let’s talk about what’s allowed for each group.
Street is the most limited class. You are allowed to change 1 sway bar, and you can change your wheel size by 1″ in diameter either way, but you must maintain the OEM width. You can run any shock that is of OEM type, and any brake pad material. Tires must be 200TW minimum and can be changed from the OEM size.
Street is broken down into SS, AS, BS, CS, DS, ES, FS, GS, and HS. Classes generally flow from the “fastest” to the “slowest”. Below are some of the more common examples in each class (This is not a definitive list and may be out of date)
SS: C8 Corvette, Dodge Viper, Porsche’s that have GT3 and GT4 in them.
AS: Corvette Z06, Newer Porsche Cayman and Boxster S
BS: New Supra, BMW M2, non-Z06 C5 Corvettes
CS: Most NC and ND Miata’s, S2000
DS: Civic Type-R, WRX and STI, FR-S/Toyota-86/BRZ, Focus RS (except 2018’s)
ES: NB Miata Toyota MR2-Spyder
FS: Most Mustangs up to the GT350 and Camaros up to the SS 1LE, E92 BMW M3
GS: Civic Si, GTI, Focus ST
HS: Fiesta ST, Civic Sport, Fiat 500 Abarth
The allowed modifications list in the rulebook starts getting pretty long and involved, so from this point forward, I’m just going to list major things. Please consult the rulebook for more information.
Street Touring opens up modifications for suspension, tuning, wheels, brakes. So, you can do any shock/spring/coilover that bolts in the OEM location, any sway bars, any exhaust (must have a cat), wheels are limited by width (for example, STS is limited to 7.5″ wide wheel), any brake setup is allowed. ECU tuning is allowed, with some restrictions (stand-alone systems for pre OBD2 only). 200TW tires minimum. For turbo cars, intercoolers and associated hardware can also be change as well as blow-off and diverter valves.
The biggest things that will disqualify you from Street Touring are: aftermarket lightweight flywheels, turbo upgrades, and any internal engine-work (Cams, TGV-deletes, engine porting) See the Xtreme-Street category is you want to stay on 200tw tires.
Street Touring is broken down into STS, STX, STU, STR, STH and SST. Below are common examples in each class:
STS: NA-Miatas. Older Honda CRX’s
STX: First Gen Scion FR-S, Toyota-86, and Subaru BRZ, RX-8, 8th gen civic si, Supercharged Mini Cooper.
STH: WRX, GTI, Focus ST, Audi TT, 1st Gen 4-cyl Genesis Coupe
STU: 350/370Z, E46 and E92 M3, STI, Lancer Evo, Civic Type-R
STR: NB NC and ND Miatas, 2nd gen Toyota 86 and Subaru BRZ
SST: New Supra, M2, S2000, C5 Z06 Corvette
Xtreme Street is a recent addition. It’s basically an unlimited street-tire, street-car class, so long as you have a full interior, have 200TW tires and meet the minimum weight. Full rules can be found here: https://www.scca.com/downloads/48556-xtreme-street-xs-rules-2020/download
Xtreme Street is broken down like this:
XS-A: Min weights are AWD-3000lbs, RWD-2750, FWD-2500
XS-B: Min weights are RWD-2150lbs, FWD-2000lbs
Classic American Muscle
Unlimited street tire class for RWD American cars. Must have a full interior and 200+ treadwear tires. Full rules here: https://www.scca.com/downloads/48152-2020-cam-handout-v3-2019-11-26/download
Classic America Muscle is broken down like this with examples:
CAM-S (Min weight 2500-2900lbs depending on car) Corvettes and Vipers
CAM-C (Min weight: 3300lbs) 2001 and newer cars that don’t fall into CAM-S (Mustangs, Camaros, GTO, G8)
CAM-T (Min weight: 3000lbs) Cars from 1948-2000 as well as 4th Gen F-bodys to 2002 and New Edge Mustangs to 2004
Solo Spec Coupe
Solo Spec Coupe was designed as a spec class for the 2013-2016 FRS/BRZ. You can run the car 100% stock, or you can change the bits in the SSC package from Tire Rack, but you can not make any other change to the car. Wheels must be OEM size and weight. Tires must be the current spec, which as the writing of this is the Falken RT660. Full rules: https://www.scca.com/downloads/51719-2020-07-08-solo-spec-coupe/download
Street Prepared can be thought of as “Street Touring + Race Tires”. Wheels are unlimited. Tires must be DOT-Approved, but no treadwear minimum. This is the lowest class where ‘Slicks’ like the Hoosier A7 become the dominant tire.
Additional things that can be done in street prepared beside the tires are adding a front splitter and rear spoiler as well as lighter flywheel/clutch assemblies.
SP is broken down into SSP, ASP, BSP, CSP, DSP, ESP, and FSP.
Modified is for non-car based race cars, like Formula Ford, Formula Vee, F500, e
Street Modified opens up engines – swaps and building (internals, adding forced induction). Body work can be altered. Aero is allowed. There is a lot more to it, to if you find yourself interested in this class, check the rulebook. Once again, to be competitive here, you should be on slick tires like the Hoosier A7.
SM is broken down into SSM (2 seaters) , SM and SMF (FWD).
Prepared is where you end up when you want to gut the interior. Class allows ANY race tire.
Modified is for non-car based race cars, like Formula Ford, Formula Vee, F500, etc.