My Motorsports Passion
What a blast!
February 2007: This past winter, I did not have much to do on the RX-8 racecar and consequently, I had quiet a bit of time to invest into this fun little car.
A lot more power, better brakes and better handling.
Below is the comparison of the original normally aspirated 13B 4-Port with the Delorto carburetor and one of my old 1/2 bridge ported 13B Cosmo race motors, normally aspirated Dyno chart.
Since purchasing the car in September 2000 with 497 miles on the odometer, I have driven it no more than 1,500 miles and I learned that the suspension setup was really bad and so were the brakes. Last summer, I swapped out the original drum brake rear end for a limited slip, 1984 rear end with disc brakes (thinking this would help the braking) and I removed the carburetor and converted it to fuel injection with an old intake manifold I modified to fit the 4-port 13B, a 50mm TWM throttle body with two 550cc injectors and an old Haltech E6K ECU. I tuned this setup on the road driving around and logging air fuel ratios. Rather crude but I didn't have the time. This made quiet a bit of difference in power and torque and I soon learned that the suspension setup was really bad and the brakes were still horrible. I had to really push hard on the peddle to stop.
The transformation as the car is today is a result of being introduced to a few road race guys in my neighborhood one Saturday afternoon in November who looked, pushed and felt the suspension, listened to my explanation of how the car drove (on the street). The main thing were the shocks and the old, original tires that were really hard. The car was way too soft in the rear and obviously, I had to do something to improve the brakes. One of these guys, Jay Carley invited me to spend that next Sunday at a local private road coarse called Motorsports Ranch in Cresson, Texas so I could "see what it could do". With a few recommendations on what to do, I went home and immediately went to work on taking the coil over shocks off to see what shocks were on it and how the car was sprung.
To my surprise, the shocks were Koni's with the valving set so that there was hardly any dampening at all. One at a time, I took the springs off and cleaned up the shocks then figuring out how to adjust the dampening. I believe there must be a problem with the valving, however I had to do what I could because of time. I adjusted so they were a lot stiffer and put them back on the car. As for the brakes, I bled the system with new brake fluid. Sunday morning, I loaded the car in the trailer and headed for the track.
After my first half hour session, I had spun the car around four times almost getting T-Boned in the process once because of the old tires, I still had really bad brakes, it started leaning out at the end of the session and the car felt a lot better in the corners. That was a lot of fun even though was not in good shape to run fast. There was not much I could do about the tires and brakes and it turns out that the fuel filter was clogged full of dirt from the continuous circulation of the fuel injection. I cleaned the filter and went out for the last session to have some more fun. Half an hour later I was worn out trying to control the car as if it were on a slick track. Fun I had for sure! There was no doubt that new tires were imperative as the old 1987 BFG t/a radials had developed cracks because they were so hard.
Inspired by how much fun I had, I decided that I would build a new engine, purchase new tires, change the seat and find out what was wrong with the Pinto front brakes.
I elected to use the slightly used parts from the first RX-8 motor Jesus Padilla built with the exact same porting, high compression 9.7 rotors, a 1993 intake manifold and throttle body with a light aluminum Turbo II flywheel. I then modified a 1987 Mazda Turbo II transmission I had laying around to replace the old style transmission. This required shortening the shifter control and manufacturing a new transmission mount as well as having a new drive shaft made.
I replaced the tires with a new set of Toyo Proxes RA1's, the same tire used by the spec Miata and RX7 racers in SCCA competition. Talk about a day and night difference.
Another modification was to build a free flow setup and get rid of the original exhaust system that was very restrictive for a rotary. More to follow here.
The day I Dyno tuned the new engine combination with the help of Chris Ott at Rotary Performance, I received a call from Jay saying that they were headed out to drive on a brand new race track about 20 miles north of here. I drove the car out to the brand new Eagles Canyon Raceway. This is going to be a fantastic new road coarse in North central Texas. Here I felt the difference in the new horsepower and the new tires. Wow, this little car is fast and nimble now. All I had to do was get it to stop!
As for the brakes, I learned that the brake pedal assembly consisted of dual remote master cylinder with an adjustable bias bar. I disassembled the master cylinders and check the over but did not find a problem. After reassembling the master cylinders, I checked the front calipers but they were working OK. Not knowing if the braking system was designed correctly, I started asking questions and looking into replacing the front brakes with a set of aftermarket kits. This I could not do due to the 13" wheels so when I looked into racing brake pads, I learned that my problem may just be the original pads. The recommendation was to have the rotors turned and install a new set of pads. I did that and bingo, now I have good brakes. Who would have thought that the pads would be the cause? I will wait and see how they perform at the track now.
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