Our race team has encountered our first design question for our car.
The Chevette is an economy car, and as such was never meant to be driven at speed. The speedometer only goes up to 80 and the engineer was being extremely optimistic about that number. With economy, light weight, and light duty in mind this car sports some extremely small brakes. There are disks up front and rotors out back, there is no brake booster, and neither half of the car sports cooling features for the brakes. This is not the recipe for a race capable brake system, especially an endurance race system that will see high temperatures for extended periods of time.
The rules for the endurance race series we plan to enter are pretty generous towards brake modification as that is an extremely important aspect of safety and racing. This leaves us with plenty of options.
A little bit of research on the intertubes has revealed that the Chevette and the Fiero front suspension are basically the same. This is an extremely easy brake upgrade to perform, but has a large drawback. The Fiero sports a 5 lug bolt pattern for the wheels, while the Chevette is a 4 lug. We ran different bolt patterns on the front and rear on our last car and it’s something we want to avoid. It complicates wheel and tire replacement at the track and forces you to spend more money on spare tires and wheels. Drilling the rotors for the Chevette bolt pattern is an option but adds to the price. I’m also unsure if any of the Fiero’s came with vented rotors, as information on the stock brakes are limited. It appears that in 1988 there may have been a model with vented rotors, though more research is required.
Retention of the stock rear drums is also up for debate. Rear disks would be be nice as we are more familiar working with disk brake systems and the upgrade would reduce the amount of braking duties the front brakes would be required to do. Putting too much rearward braking capability in the car can induce a tendency to lock up the rear tires, but the massive fuel cell we plan to mount behind the rear axle should provide a decent amount of weight to help prevent that possibility.
Addressing the brakes to handle the rigors of endurance racing is something that needs to be thought out, implemented, and tested to ensure trouble free performance lap after lap. This is an issue that we must carefully consider in the upcoming build process. Stay tuned for updates.
Hey, I’m not sure if you got these in the States but try the Isuzu Piazza front rotors/calipers – they are vented and come in a smaller size for the non-turbos which will fit under 13″ rims, or larger diameter for the turbo models which need 14″ rims or bigger. They retain the same 4x100mm lug pattern. The Piazza is essentially based on the T-car. You can use Piazza rear diff too and they are disc braked and some come with LSDs, however they are a little bit wider and the later model ones did away with the torque tube and were mounted differently.
http://en.wikipedia.org/wiki/Isuzu_Piazza
AKA Isuzu Impulse! Now you just gotta find one in Minnesota that hasn’t rusted into a pile.
I meant the first generation which was RWD. I don’t think second gen FWD Impulse stuff would work. First gen Piazza stuff is common in Australia but I guess freight over there would wreck your budget.
Oh whoops I didn’t read the wiki article thoroughly enough, I thought the second gen was named the Impulse rather than the first gen also. Disregard above please, and also good luck finding the Impulse stuff
I did the front brake swap back in 96 0r 7,you owe me $100 for R&D,lol…
The Impulse/Piazza rear ends are practically bolt-ons.
The 3-links are open and the only LSD available is the Quaiffe ATB,$1300,(yikes!)
The turbos have LSDs,but I’m not sure if they all have it.
They are about an inch and a half wider,with a stock pazuzu 14×6,(25mm offset?) aluminum wheel and a 195/60-14 you’ll be right at the edge of the fender.
Anyway,you will need to remove the brake line,flip it over and gently reshape it,or make a new one. You will have to disassemble the e-brake to attach the stock Chevette brake cable.And you will need to drill 4 holes in the floor pan to mount the anti roll bar. Use your Chevette lower links,panhard rod and shocks.
For the 3-link,you can either cut the torque tube mounts out of the brackets and swap them,weld the Isuzu in the Chevette.
Or you can make some L-brackets and bolt the entire Isuzu unit to the floor pan.(probably safer,use big washers or reinforcing plates on the inside.)
For the 5-link,the upper link attaches to the body via a stamped bracket spot welded to the rear “frame rail”.You can drill out the spot welds and spot weld it to the Chevette “frame rails”. The pazuzu and Chevette frame rails are the same distance apart.
Or you can make some (adjustable?)plates and cross-bolt them through the frame rail.I would sleeve the bolts to prevent crushing or distorting the frame rail.
If you make your own brackets you can adjust your pinion angle and,on the 5-link,move your instant center rearward,maybe forward.
Driveshaft? I didn’t get the far,I had to sell it.
Thanks,Scroat