NorCal Miata TT Challenge Rules
Vehicle Rules
Safety equipment regulations are in force during all on-track sessions. Not just timed sessions.Deleting OEM steering wheel airbag will require SFI/FIA approved HNRS, 5/6pt harness and fixed back-one piece seat seat.All drivers in cars with out airbag must wear HNRS during all sessions.All drivers using 5/6pt harness must wear HNRS.HNRS is an FIA or SFI certified rigid collar that attaches to helmet via lanyard on either side, held in place by driver harness. Foam neck rolls are not only not HNRS, they are banned.All years of Miata eligible.Update/backdate allowed for all USDM parts between NA-NB except engine.Vehicle must retain the entire tub between rear bulkhead and firewall or be an Exocet to be eligible.Fire suppression definitions: “Bottle” is a handheld fire suppression device. “Automatic” is integrated system for the whole car using a remote activation switch on the dash.Mufflers (axle back), battery, hubs, brakes, seats, intake piping/airbox are free.Vehicles must meet sound limits required by some tracksHardtop shape and material are free provided it does not provide downforce or extend over OEM trunk.Diffuser: any non-OEM under panel behind rear axle intended to affect airflow.Flat bottom: Any non-OEM under panels between axles of more than 2 square feet.Front undertray: Free up to front axle centerline.Splitter length is defined as distance past reference plane. Reference plane is vertical from OEM bumper skin measured at any point. That means center (forwardmost point), sides and ends near wheel opening. A splitter that is square when viewed overhead that is less than 2″ past OEM bumper in center but greater 2″ at any other point of the OEM bumper takes >2″ pts. To remain inside of 2″ requires a splitter that matches the outline of the OEM bumper.All cars must have front and rear tow hooks.Passenger seat is defined as fully intact OEM or race seat. Toy or non functional seats are not allowed. Let's not have something that can be described as a "seat".Passenger and driver seats do not need to be SFI/FIA certified. However, they must be FIA rated to obtain pts reduction.Any proposed rules change will be published no less than two events before being enacted. Exceptions may be made for safety related concerns.Free mods: axle back exhaust, battery, intake piping and airbox (n/a), FPR, fuel rail, fuel pump, radiator, oil cooler, transmission or diff cooler, side mirrors, headlights, brakes.Camber correction is free. Only one front location (FUCA, FLCA, ELBJ, OKB) may be altered without taking 2pts for control arm bushings.Unlimited class cars must have fire bottle reachable from driver seat with belts on or automatic system. Must also have master cut off switch, door bars, dash bar and front anti-intrusion bars.Vehicle Classes
The following table outlines the available vehicle classes and the modification points allowed for each class.
| Class | Modification Points |
| Street | 40 |
| Super Street | 80 |
| Super Modified | 120 |
| Unlimited | 121+ |
Challenge Point Allocations
The following table outlines points allocated to competitors based on their placement. End of year challenge placement will be based on the points allocated from the sum of the best of 5 events for each individual within a class. To break ties, the end of year challenge placements will be put in favor of the individual with more event wins throughout the year.
| Placement | Point Allocation |
| 1st | 21 |
| 2nd | 13 |
| 3rd | 8 |
| 4th | 5 |
| 5th | 3 |
| 6th | 2 |
| 7th+ | 1 |
At each event, only the first three sessions count towards the competition. An awards ceremony will be held immediately after the third low intermediate session. All sessions throughout the day will count towards class records.