jdufour wrote: ↑Wed Jan 11, 2023 1:54 pm
Hi,
We are considering build a 280Z race car for the ChampCar Endurance Series. It's amateur racing. We are concerned about the rear suspension. How did you configure your rear suspension? Is your rear suspension stock? Or are you using an aftermarket rear suspension? How large are your rear tires? Was your choice of tire size influenced by your rear suspension setup?
Thanks,
John
Hi John,
My rear suspension uses the stock the components that have been heavily modified/strengthened.
- Rear crossmember has had inner mounts slotted vertically to allow camber adjustment.
- Rear crossmember bushes changed to solid/sleeved plastic ones.
- Rear arms were shortened and then rod ends added, so they can be adjusted in place, i.e. Left/right threaded. (in/out)... to adjust toe.
- Rear shocks/coil overs are from Koni Racing and are adjustable.
If I was to do it again, the APEX Eng. set is probably a cheaper way to go, and will offer similar adjustment. Though they did not exist when i started this project, and i wanted to keep it as close to the GTU car as possible.
If i didnt do the APEX thing, I would probably have gone complete custom rear like the GTO cars... but big bucks!
https://www.apexengineered.com/s130---280zx1.html
With the wide rear guards, I went with 11" wide wheels.
The original works GTU cars were running 16" x 12" wide wheels from memory.
Currently the car is fitted with 280 wide (300mm overall) x 650-18 slicks, but I will also use 295/30-18 Dot Semi-slicks (or 315/30-18).
My wheel offset is about 1/2" to far inwards, so I could have gone to a 12" wide rim, or at least 11.5"... but with two sets of wheels I'm not changing.
My tyre size is really influenced by the original car, and the amount of room I had under the guards.
Based on the average 8~10 lap race, the tyres are probably oversized for the car, but it looks cool!.
I'm only running 9" wide on the front (235 or 240 wide tyres) because my front guards are not as wide as the official GTU cars were.
We have done a few complete wheel alignments so far during the fabrication, and the front & rear camber/caster/toe all looks perfect to what you would expect (touch wood), though time well tell.
Photos below are before final powder coating.
Anything let me know, and good luck with your race car build!