SSM
SSM is short for Super Street Modified, which is the Autocross class that we're building this Miata for. The 2011 PAX index is 0.875.
General Guiding Solo Rules
Street Modified is a ruleset built up on Stock, Street Touring, and Street Prepared. Anything allowed in any of those 3 rulesets are allowed in SSM in addition to anything added by the Street Modified ruleset. Some of the more interesting things added by the SM ruleset are below:
Minimum Weight
For RWD SSM cars, the minimum weight is 1600 lbs + 200 lbs/liter of displacement (+1.4 liters added if forced induction is used) - 200 lbs if your tires are 275mm or less all around (as ours are). This gives us some likely final minimum weights of:
- 1.6L FI: 2000 lbs
- 1.83L FI: 2046 lbs
- 2.0L FI: 2080 lbs
- 2.5L FI (KL): 2180 lbs
Minor Modification
16.1.P. Any minor modification, intended to allow or facilitate any allowed modification, is permitted as long as it does not provide any intrinsic performance benefit in and of itself, does not provide a weight reduction of more than 1 lb, and is not explicitly prohibited elsewhere within these rules.This rule is intended to allow minor notching, bending, clearancing, grinding; the drilling of holes; affixing, relocating, or strengthening of brackets; removal of small parts, and similar operations performed in order to facilitate the installation of allowed parts or modifications. Minor strengthening, without relocation, of original chassis/suspension pickup points is allowed. Examples include welding washers restricting control arm mounting bolt movement, local reinforcement of control arm chassis mounts, etc.
These allowances do not permit extensive modifications to a subframe or cross-member to lower an engine which would otherwise not fit in the engine compartment.
Competitors are strongly cautioned to make the minimum amount of modification required to affix a given part, and to not make unduly
tortured interpretations of this rule. Modifications to the firewall in order to allow for increased engine setback, and any modification that changes the location of a suspension pickup point, are explicitly forbidden. Plastic under-trays and covers below the vehicle may be removed or modified as necessary to facilitate other compliant modifications, but not added or enlarged.
