Bump steer. (Page 1/1)
LS4FieroGuy APR 05, 01:33 PM
So I know the 88 has less bump steer but wow during hard cornering it still does have quite an aggressive jerk. Anyone find a way to dampen that? It would be really nice especially when shifting in a corner.

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Joshua Seeger

cartercarbaficionado APR 05, 02:51 PM

quote
Originally posted by LS4FieroGuy:

So I know the 88 has less bump steer but wow during hard cornering it still does have quite an aggressive jerk. Anyone find a way to dampen that? It would be really nice especially when shifting in a corner.



a. what wheel offset
b. alignment front and rear. i believe we set it to 0 toe maximum positive caster and 2.5 degrees of camber on sll 4 wheels for our 88 and it would rip around corners at 80 plus afterwards (talking like neighborhood style corners too) but we quickly discovered the poly bushings are kinda trash and gave them alot of extra lube to mitigate the harsher ride quality and they end up putting extra strain on the 88 steering rack over time, 5k miles after that bushing replacement the bushings in the rack were trashed so we replaced them and gave it that alignment so keep that in mind for bump steer as well
olejoedad APR 05, 05:30 PM

quote
Originally posted by LS4FieroGuy:

So I know the 88 has less bump steer but wow during hard cornering it still does have quite an aggressive jerk. Anyone find a way to dampen that? It would be really nice especially when shifting in a corner.




I've driven an 88 Formula V8 for the last 17 years and have not experienced what you describe.

The Fiero doesn't have 'bump steer', but it does have 'drop throttle oversteer', which most mid engine cars exhibit.
Brian A APR 05, 05:53 PM

quote
Originally posted by LS4FieroGuy:

So I know the 88 has less bump steer but wow during hard cornering it still does have quite an aggressive jerk. Anyone find a way to dampen that? It would be really nice especially when shifting in a corner.



If you are near the limit of traction, it is a really bad idea to unsettle the car by shifting gears while in a corner.

My track car is a 1987 GT (albeit with stiffer suspension and much wider tires), but I don't seem to have enough imagination to feel bump steer in the car.
fieroguru APR 05, 05:55 PM

quote
Originally posted by LS4FieroGuy:

So I know the 88 has less bump steer but wow during hard cornering it still does have quite an aggressive jerk. Anyone find a way to dampen that? It would be really nice especially when shifting in a corner.




You probably have a rear suspension link loose.

What you describe is not normal 88 fiero behavior.
Dennis LaGrua APR 06, 06:05 PM
Not an 88 but when I first bought my 87GT, hitting a bump or pot hole pushed the car sideways a bit. Had the car aligned and the bump steer almost want away. Installed ADDCO front and rear sway bars and now there is no bump steer at all.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
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" ON THE LOOSE WITHOUT THE JUICE "

Frenchrafe APR 08, 07:40 AM
'87 as well, with a rear sway bar: no real bump steer to be noticed.

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"Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero
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olejoedad APR 08, 10:20 AM
My old 86 SE had Eibach lowering springs, KYB shocks and struts, TFS front and rear sway bars, poly front bushings, GT steering rack and had no unsettling behavior other than a bit of drop throttle oversteer.

If it started feeling sketchy in a corner, just give it more throttle.
LS4FieroGuy APR 08, 11:52 AM
I am currently in the middle of completely overhauling my suspension, engine, transmission, brake system, clutch system, interior, cooling system, repairing my cradle, and doing a lot of rewiring so I'm sure a lot will change in the next month or two.
82-T/A [At Work] APR 10, 12:19 PM
There were a bunch of kits you could buy back in the late 90s and early 2000s. The Big Fiero Parts Book, which I still have... had like 4-5 companies all who were offering "bump steer" corrective kits. Some of them were those ball in socket replacement end-links, to thicker tie-rod ends, to completely redesigned suspension components that still used the stock frame and rear steering knuckle.

I'd say that even on the 84-87... the bump-steer issue is mostly corrected when your suspension components are new or in good repair. You really shouldn't be getting any of that in an 88 as they basically completely eliminated it. In my 87, when the suspension was getting worn at around 90k+ miles back in ~1998... the rear end would go all over the place when I drove over ruts and grooves in the road. The 88 redesign was supposed to completely eliminate that, from what I understand (I've never owned an 88). But if you are experiencing something like that... the bushings on your suspension are probably getting a little tired.

We're rebuilding my daughter's car, and even without a formal alignment, we completely rebuilt the entire rear-end and got it as straight as we can in the garage. It drives amazing, and we see absolutely no bump-steer at all... it's totally solid in the back... and that's a 1985. So my guess is you just need to freshen up your suspension bushings.