Automobiles compete against “similar” cars as determined by the classification scheme adopted by the SCCA with input from its members. These classes are divided up broadly into Stock, Street Prepared, Prepared, and Modified classes. Anyone serious about this sport will consult the current rule book for (crucial) details; this outline of the general classification scheme is mainly for newcomers curious about where their car might fit in and is not a complete list.
The basic SCCA value of providing an economical way for everyone to become involved in competitive motorsports at a grassroots level is reflected in a hierarchy of classes where increasing amounts of preparation (and hence money or time) is required as you move up from the Stock category. Below I will list some of the vehicles commonly found in each of the stock classes and outline what it means for a car to be considered “stock” in Solo II. I also give a separate description of the levels of preparation associated with other classes.
It is important to note that these classes are mandatory at divisional and national events; local regions can and do run additional car classes to accommodate interests at the grassroots level.
Below is a “brief’ description of the classes just to determine where you might be. For more detailed information on SCCA classing. Click here.
Stock Classification Rules
The rules on what constitutes a “stock” car in SCCA Solo II competition are very strict and often the source of much discussion as well as protests, appeals, and requests for clarification at the national level of competition. The 1996 Solo II Rules included a new appendix listing some of the interpretations from past clarifications and protests, especially concerning what constitutes “comfort and convenience” changes that always pose an interpretation problem. (Effective with the 1997 rules, only published clarifications carry over from year to year; private letters from the SCCA expire at the end of the calendar year.) My favorite clarification: a camshaft is not the sort of part that is replaced from non-OEM sources due to normal wear and tear on the car.
The operational rule is: if the book does not say you can do it, you cannot do it. The book does not allow you to do very much, in the spirit of keeping the cost of competition down.
Allowed modifications in Solo II Stock classes are pretty much limited to the use of “treaded” DOT-approved racing tires (but stock size and offset rims must be used), replacement of the front anti-roll bar, suspension adjustments possible without modification of mount points, and replacements (air filter, shocks, muffler, spark plugs) that are considered commonplace. Ride height cannot be lowered and the computer chip cannot be replaced. The air induction system cannot be altered in any way, but anything can be done to the exhaust after the catalytic converter.
Most local regions will not give a new driver much grief about running a car in Stock that is technically only eligible for Street Prepared, at least on the first few outings. Everyone knows that an extra body brace will not make up for using street rubber, as an example. A novice driver has enough to worry about anyway. Friendly advice about the car will guide later decisions about how to campaign the car. Our region also ignores minor technicalities (removal of my front holddown hooks to install a front grill) that would not be tolerated at the divisional level. We come out to play, not litigate.
Any modifications beyond those allowed by the Stock rules push a car into one of the prepared classes. A few cars, mostly the special after-market race-prepared street cars, are put directly into SP in their ‘stock’ setup. I will only summarize the broad categories. Suffice it to say that there are a series of classes in each of the categories that tend to follow a similar scheme of power-to-weight and handling potential to equalize competition within a class.
- Street PreparedThis is a class whose philosophy is to allow only a specific list of modifications that might be commonly found on street cars that have been hopped up in some way. Wider rims, rear anti-sway bar, cold air induction, and computer changes are some examples of changes that move you from Stock to Street Prepared.
- PreparedThese are cars that have the original engine and body type of a production car, but have been significantly modified for racing. These cars are usually not street legal. Most have been gutted so the interior consists of a roll cage and racing seat so the car is suitable for Club Racing (wheel-to-wheel) or the more agressive forms of Solo I competition (such as hill climbs). They must be carbureted and meet a minimum weight.
- ModifiedThese are essentially pure race cars. A streetable car that has had its engine replaced with something not possible as a standard package from the manufacturer will also fall in this category.