We caught up with Tamra Hunt, 2015 SCCA Solo Rookie of the Year and National Champion in C Street Prepared Ladies, to share advice on how to get faster in autocross. She recommends we start with car setup, “because that’s more fun than criticizing our own driving,” she perhaps accurately stated. But stay tuned next week for part two on “How to Get Faster: Driver.”
Basic Car Setup
Regardless of your current class, there are some basic things all cars need to perform their best. Tires, and alignment are the #1 methods of making your car faster. There are many forums online (take the feedback with a grain of salt, but we find forum.miata.net to be one of the best) with car and class specific threads offering great setup advice for your specific platform.
Maximizing the Rules
Begin with the right car: For starters, not all cars are competitive. If you want to be a serious competitor, starting with the right car is critical. Thankfully, Mazda’s are competitive in a large variety of classes to suit most people’s needs. That’s one reason more Mazda’s are raced on any given weekend than any other brand.
Do you want to autocross your daily driver? I recommend sticking with the street classes, which limit the modifications and run street tires that you can daily drive (BFG Rival S is a popular choice). For example, an NC (third generation) or ND (fourth generation) Miata or an RX8 are competitive cars in C Street (CS). Do you want to do some fun modifications, but without too much compromise? Perhaps Street Touring (ST) is a good option – where you can lower your car and run wider wheels, but still on street tires. The NC and ND Miata’s excel in the Street Touring R (STR) class, the RX8 in the Street Touring X (STX) class, Mazda 3 in Street Touring F (STF) class, and the NA Miata (first generation Miata) rule in Street Touring S (STS).
Do you like the idea of going fast and running race tires, but still limiting the cost? Street Prepared (SP) and up might be your place to play, where Miata’s dominate B Street Prepared (BSP) and C Street Prepared (CSP), and the RX8 is a great platform for D Street Prepared (DSP). If your budget is larger and you like the idea of big power and more extensive modifications, Super Street Modified (SSM) is home to Miatas and SM to RX8’s. Another thing to keep in mind is that some cars are competitive in certain classes, but not others. For example, a Mazdaspeed3 is competitive in G Street (GS), but tends to struggle in the Street Touring (ST) and Street Prepared (SP) classes.
Car Setup: Street. Street is the most limited prep level, permitting modifications such as shocks (but not springs), one sway bar, lighter weight wheels, and any exhaust from the cat back (as long as it meets sound requirements). Initial setup includes getting the best 200tw tires (do your research, it’s a competitive market with new top tier tires coming out every year. BFG Rival S is a hot ticket tire for 2016). Second, upgrade your sway bar. On rear wheel drive cars, the typical option is to go to a stiffer front sway bar to settle the rear end and improve transitions. Many people stop at these two upgrades and can be very competitive on a regional level. However, if you want to take your car to the next level (e.g., national) upgraded shocks would be the next most critical improvement to your car’s handling. In street class trim, you are limited to the OEM springs; so shocks with proper damping become critical in finding tenths of a second. There are a variety of options out there and they are not all created equally, so this is definitely an area where you can optimize your car setup. Some of the final steps to having a full prep street class car include weight savings through lighter weight wheels and replacing your cat back with a lighter weight option, which can also potentially gain a little power.
Car Setup: Street Touring. Street touring permits modifications such as coilovers, cold air intakes, a tune, race seats, Idemitsu lithium ion lightweight batteries, wider wheels, high flow cats, headers, both sway bars, and more. A full prep street touring car will require more funding and setup work than a street class car. Initial setup includes all of the same items for a street class car, but the shocks must be valved to handle the higher spring rates. Therefore, most people buy a new suspension package and/or get their shocks revalved. Shocks that are not damped properly for the springs will allow for inconsistent handling and terrible ride quality, and will quite possibly make you slower than a street class car. In addition, you can corner balance your car to set ride heights and improve handling. The most critical modifications in this class are the coilovers and wider wheels, which should make for a regionally competitive car. To optimize your setup, power adders and a tune are next on the list, followed by weight savings such as race seats and a lightweight battery, such as Idemitsu Lithium Ion batteries.
Car Setup: Street Prepared. Street prepared is the first class that permits race tires (Hoosiers are a popular choice). If you like to tinker with your car and want insane levels of grip, this is the class for you. Street prepared permits all of the modifications of street touring, but adds in the options of update/backdate (more on this in a minute) and fender flares to accommodate wider wheels and tires. Cars like NA/NB Miatas rule in CSP and are a more extensive build due to the update/backdate rules (not uncommon to find a first generation dash without the airbag put into an NB chassis that has ABS brakes, or a later NB generation VVT motor for more power), and wide tires that can fit when you flare the fenders. A car such as the RX8 is a simpler build for DSP due to less update/backdate allowances and the fact that the car can fit wide tires under the fenders without cutting. The most critical modifications in this class include all of the Street Touring Prep, followed by wide wheels and race tires. The intricate rules of this class allow the engineering/tinkering types to have a lot of fun maximizing the rules while still on a limited budget; I recommend you take a look at the SCCA handbook.
Car Setup: Street Modified. Street modified is the first class that doesn’t really build on the previous ones. You are permitted to run any engine from the same manufacturer (so any Mazda engine in any other Mazda), and more extreme suspension modifications are permitted that may require some undoing from the other class rule sets. Other significant power adders such as turbos or superchargers are permitted. Aero such as large wings and splitters are common place. Most of the cars in this class are no longer street driven due to the compromises made to build to the rules. It is difficult to maximize a car to the rules in Street Modified, as the allowances are extensive. The most critical components to building a car to the rules for street mod are to start with really good suspension, wheels/tires to maximize grip, power adders (turbos, etc.), and aero (which can be a huge can of worms to optimize air flow for downforce). People who enjoy fabricating, engineering, and want big power will be attracted to this class. If you decide to join this class, you’re going to become close friends with the rule book and the bottom of your pocketbook.
Car setup: Prepared and up. At this point, you are at full race-car status. Interiors are gone and insane modifications that you see nowhere else on planet Earth have occurred. If you’re in prepared or up, you probably aren’t reading this article.
Conclusion: In all classes, if you want to get faster by improving your car you will have to read the rule book closely and learn how to optimize your setup. Spend time researching setup on forums and talking to experienced competitors. One of the most overlooked setup points is a good suspension. However, keep in mind that there are sometimes allowances that don’t really gain you much for the effort/money/compromise. For example, removing the air conditioning of your car is permitted in street prepared, but the weight savings are minimal. Unless you are chasing tenths of a second (or less), this modification probably isn’t wise. Finally, one of the best ways to optimize your car setup is by fixing your existing setup to handle better. I recommend talking to other drivers in the same class and exchanging setup notes, or even car hopping to give each other feedback.