'84 Fiero - Need suspension help

[Gearheadotaku]

I know, I'm asking for a few hard knocks, but here we go...

I'm co-driving an '84 Fiero in ITB, and need some help with suspension tuning. I know that these are bump steering wonders and little can be done that is IT legal.

Front suspension has been rebuilt with solid lower bushings and poly uppers, larger sway bar and bilstien shocks. Springs are stiffer, but unknown rate.
align specs: -3.5 degrees camber on left,-2 on right. zero toe. Camber is maxed on both sides.

Rear has stiffer springs (unknown rate again) bilstien struts and poly bushings.
align specs -2.2 degrees camber 1/16 toe-in

The front sticks well, but the car oversteers at odd times without warning. Sometimes the whole car will run wide, but not one end faster than the other. Tried a large (7/8?) rear sway bar, little change if any.

The front has little travel 3-4 inches maybe, the rear will sag dramaticly if up on a jack hanging freely. (I can put a Coke bottle on top of the tire with room to spare)

Can't get more rear camber without cutting and such, will have to check the book for legality. Can only go so far before the spring hits the body.

Any thoughts?:shrug:

EDIT: Help! can a mod please fix my typo in the subject line!?!

[rrb71]

I don't know anything about Fieros, but if the car seems unpredictable the first thing I'd check for is a dead shock. Assuming you've already checked for obvious loose bolts, etc. Take 'em out, put one end in a vise and then push and pull them thru there full range. What you're looking for is smooth even resistance. If there's any dead spot where the shock moves without resistance, there's the problem. I had a similar problem with my ITA RX-7. It would push one moment and then go loose the next all in the same sweeper. It's at least worth a try and won't cost anything.

[924Guy]

Another thought - make sure you're not bottoming out the rear suspension, such as hitting a bump stop or coil spring bind or the like. My 924 used to do the same thing, till I figured out we'd lowered it enough that we were hitting the rear bump stop on-throttle. Simply putting a paint mark on the top of the bump stop was enough; the paint was gone after 1 race!

[Weaver7]

I don't know anything about Fieros, but if the car seems unpredictable the first thing I'd check for is a dead shock. Assuming you've already checked for obvious loose bolts, etc. Take 'em out, put one end in a vise and then push and pull them thru there full range. What you're looking for is smooth even resistance. If there's any dead spot where the shock moves without resistance, there's the problem. I had a similar problem with my ITA RX-7. It would push one moment and then go loose the next all in the same sweeper. It's at least worth a try and won't cost anything.


Ditto that our first Gen did the samething scared the hell out of one of our drivers. Swapped them our and the car handled great.

[924Guy]

Ditto that our first Gen did the samething scared the hell out of one of our drivers. Swapped them our and the car handled great.

LOL... took me a minute to realize you were talking about swapping shocks, not drivers!!!
:eclipsee_steering:

[iambhooper]

hmmm fiero's.... tempting.... must fight urge to build ITA car....

anyway, agreed on the shocks. also, i think you need to go with the Koni on that car, and I believe they are reasonably cheap. spring rate is very important... there might be a stamp on the spring that would tell you. If your getting -2.2 deg camber in the rear, then i'm assuming you have slotted the bolt holes? the only thing more would be to actually install some camber plates.

do you have poly or Aluminum cradle bushings, and are the rear bolts torqued properly (the nut tends to pop from its tack weld inside the rear frame and it can be hard to thighten that bolt)? what about the dog bone mount, is it the originall one? also, have you added a second stay rod per the GCR?

yes these cars are notorious for having bump steer, and there are only 2 fixs that i am aware of... 1) the Held bump steer kit, which is likly not within the "spirit" of the GCR and 2) finding yourself a cradle form an '88 car.

also double check all your tranny and engine mounts... if original, or even questionable, replace them. this will eliminate much of the feeling of the rear sliding from side to side.

i really should build one.... if only they weren't 20 years old!

hoop

[924Guy]

I wouldn't "upgrade" to Konis from Bilsteins... no improvement IMO, I've long since chucked the Konis and upgraded to Bilsteins. But the big question there would be what kind of Bilsteins are you running?? Off the shelf, or custom? Maybe it's time for you to upgrade to some custom race units? I'll drop you an email...

[Gearheadotaku]

Thanks for the suggestions everyone!