Wheels and Tires
Time to go with race tires. Hoosiers rule in autocross, and the hot setup for EF/EG is 275 35 15" Front and 225 45 15" rear. Of course 1) you have to find wheels that work with this size and 2) you have to make them fit on the CRX.
After a lot of looking, the most attractive wheels, in our opinon, are from 949 Racing. Emilio Cervantes who owns 949 saw a need for a reasonably price competion wheel for Miata's. So he designed and has built, in small batches, 15" wheels with 4X100mm bolt pattens with very wide widths, perfect for our application as well. You may have to wait a while to get a set, they are produced in small production runs, but they are a great deal and awsome wheels. You can read about them on his web site, but they are optimized for 4X100 and only 4X100. This makes them light, yet strong. The +36mm offset is perfect for the CRX, and the prices make them a bargin. We went with 15" X 8" for the rears where we will mount the 225 45s, and massive 15" X 9" for the front with the 175 35s. We received the wheel right before Christmas after about 2 month waiting for the production run. It was well worth the wait, they are gorgous wheels, and what a great price. We got the Hoosiers mounted and a quick test fit in the rear shows they actually clear the rear trailing arm by a few mm, we had initially expected to have the shim the rears a bit. Of course, we have not looked at the rear fender clearance, there is sure to be work done there. And the front can't be fitted till we get the engine and drive train back together. But all it all, we think it will work. Psyced!
We will update you with details and pictures and most importantly, how we (will) fit them on the CRX soon.
Fitment
We tested fitted the new wheel/tire combo with the car up on jackstands and the coilover spring perches set all the way down. This allowed us to mount the wheels and use a jack to lift the wheel all the way to the shock bump stop and check for clearances. The 949 racing 8" rears with the 225 Hoosiers had the perfect offset and just clear the rear trailing arm by 3-5mm. The outside of the tire just hits the "lip" of the rear fender. We used an Eastwood fender roller and a heat gun to carefully roll the lip up into the fender well. This worked great, no paint cracking, the clearance is perfect, and it actually looks good too. We have no evidence of tire contact after 2 hard days of autocross events.
The front was not that simple, but we knew that. First, we determined we need to use a 10mm spacer to allow the 9" 949 racing wheels to clear the knuckle. We used H&R aluminum spacers but you also need to go to longer wheel studs, which means taking the front end apart and pressing out the old and in the new ones. We used ARP extended length studs and Blox Racing chrome moly lugnuts, necessary to fit over the extended studs. Note we used chrome moly steel lugs, I can't imagine using aluminum lugnuts, especially when changing between wheels regularly, scary.
The next problem was there was no way they would fit under the stock front fender (see the pics). So after much deliberation, we bought a set of inexpensive stock replacement fenders from RockAuto and cut them up about an inch with a dremel tool to clear. We put away the nicely painted original fenders in case we ever go back to a non-race setup. In the meantime we are running the fender primed naked, but will get around to putting a universal flare on it and painting it to match.
Results? This is just an awsome setup on this car, the cornering and braking are unreal. You can get on the brakes so much harder and never lock up the wheels. There is still way to much power with the boosted K20 and you have to be careful to modulate the throttle or you will cook the fronts, but the acceleration in second to redline is like 30-65 MPH in a second. We are still playing with tire pressures, and I am astonished at the wear rate in the front, it could be an expensive season, but well worth it.
