Project Mazdaspeed3: Building a Stock Class Cone Killer- Introduction and Installing Koni Shocks
Autocrossing is a ton of fun. It’s super cheap, you can take almost any car under the sun, it’s fun, and the crowd is very friendly. Personally, it’s my go-to for a quick motorsports fix. Also, here in Kentucky the number of tracks that have both asphalt and right turns is limited, so autocrossing is one of the few legal ways to get your speed fix. Within 2 weeks of laying claim to a 2008 Mazdaspeed3, we were dodging cones.
The Speed3 is a great Street Class car, with lots of grip, tons of torque, and low gearing to take advantage of that torquey, turbocharged Mazda MZR engine. See, the things that make the MS3 a not-so-great track car (short gearing, small turbo, and heavy front weight distribution), make it a great autocrosser. That small turbo runs out of breath at high RPM, but it makes for a no-lag torque monster. Those short gears that force a 2-3 shift in 0-60 tests are perfect for tight Solo tracks. And, that front bias puts a lot of weight on the front tires, giving them extra traction. While this would overheat the tires on a track day, on an autocross track, it’s perfect for getting the most out of the 60 seconds or so you’re on the gas. In other words, a Mazdaspeed3 (or a Ford Focus ST, which is built on the same platform), makes for a great cone killer.
Street Class is for stock or near-stock production cars. After chatting up some of the veteran Central Kentucky Region (CKR) autocrossers, we found out the original owner of this car was also a cone dodger, and they were quite familiar with this particular 3! That would explain why 1st and 2nd are a little sticky… Anyway, we wanted a practical daily driver and as purchased, our 3 was already a quick little car. So we decided to leave it in Street Class and just have fun with it! That said, there are a few mods you can make to a Street Class car, and that is exactly what we did. The best mods are wheels and tires, a high-flow air filter, a high-flow catback exhaust, adjustable struts, a short throw shifter, sticky brake pads, and stiffer sway bars. Here’s how we attacked each area.
Wheels, according to SCCA rules, must be the same width as stock, but can 1” larger or smaller in diameter, with an offset within 7mm of OEM. Tires must be the same width as stock and must have a treadwear rating of 200 or better. While browsing our favorite car parts site, we found a set of lightly used O.Z. Allegrita wheels with a set of Yokohama Neova Advan tires already mounted and in the right size. In fact, after talking to the seller, we found out these too came off a Mazdaspeed3, which meant we could be sure they’d be legal on our car! Jackpot! We picked up the wheels and tires for a paltry $600, a third the cost of new. The wheels were dirty, but round, and showed very little wear and tear. The tires were pretty well used up- the rubber had been heat cycled many times and was getting hard. However, this was to our advantage: technically the Advan Neova is a 180 wear tire and no longer legal for SCCA Street class. At a local event, the heat cycled tires were definitely not gripping as hard as they should have, and the tech guys let us slide. Still, these were perfect for the job. The Allegritas are super light and strong. The entire package is about ? lighter than the Mazda wheel/tire combo. Even with the worn tires, our times dropped by about a second bolting these on, and the breakaway behavior was much more predictable.