Bump Steer correction procedures - Need tips!!

[Northwestvoodoo]

I am running Eibach springs with one coil cut on the front and Tokico struts all round. The bump steer is horrible and needs to be corrected.

As I understand the issue - I need to shim the steering rack up as far as I can, about 1/4 - 3/8 high or until I run out of threads on the bolt to still be safe. Slot them if I need too get them in.

Also, I have read that I can trim about 1/2 inch off a set of aluminum sub-frame mounts to raise the whole shittery up as well.

Generally speaking - If both of these procedures are invoked, should this be enough to bring the angles back to a more reasonable position?

Any insight would be greatly appreciated as I need to start repairs ASAP as I hate driving the car this way.

Thanks!!

 

[kevinspann]

You could use gen 3 steering rack bolts, in order to shim it up a larger amount, as those are longer.

 

[St Louis SHO]

Yup. Shim the rack up.

 

[Northwestvoodoo]

Thanks guys.

If I was to raise the sub-frame up, would that help ease the angle on the output shafts to reduce wear or is there some other methods I should consider? There is a aluminum set available locally. Would it be prudent to pick them up and do both methods at once or try the Gen 3 bolts first and see what happens? There must be tons of guys that have come across this issue and I may document the whole procedure and post at a future date. I was hoping for a sticky on this and didn't find one....

 

[rubydist]

can you raise the whole mess 1/2" w/o having the intake and the hood in contact?

 

[Northwestvoodoo]

Perhaps with no mat and possible zip wheel usage?

Has the raised rack solved most guys problems? If so, I will happily only do that mod and be done with it.

 

[zach44102]

I have cut intrax and im not sure if I experience any bump steer unless what I mistaken for throttle lift understeer is bump steer. Or is it the same thing? Sorry for the thread hijack.

 

[Northwestvoodoo]

Bump Steer is when your wheels steer themselves without input from the steering wheel. The undesirable steering is caused by bumps in the track interacting with improper length or angle of your suspension and steering linkages.

 

[Shoaz]

Shim the rack, and don't go too crazy to start with. Use the big, hardened washers. 1/4" is a good start.

 

[AREA 91]

I used the big washers for the outer cv shaft on mine.

 

[yamahaSHO]

Has the raised rack solved most guys problems? If so, I will happily only do that mod and be done with it.

I've had my rack shimmed for years and haven't noticed an issue, even with track use.

I have cut intrax and im not sure if I experience any bump steer unless what I mistaken for throttle lift understeer is bump steer. Or is it the same thing? Sorry for the thread hijack.

Lift-throttle understeer?

 

[NEp8ntballer]

I think that's when you defy physics and when letting off the throttle the front end of the car gets more weight and refuses to turn. although it might also be confused with going into a turn too hot and the car not having enough grip to make the turn at the speed you want it to on the line that you want it to.

 

[yamahaSHO]

I think that's when you defy physics and when letting off the throttle the front end of the car gets more weight and refuses to turn. although it might also be confused with going into a turn too hot and the car not having enough grip to make the turn at the speed you want it to on the line that you want it to.

What I think he means is lift-throttle oversteer.

 

[Shoaz]

I think that's when you defy physics and when letting off the throttle the front end of the car gets more weight and refuses to turn. although it might also be confused with going into a turn too hot and the car not having enough grip to make the turn at the speed you want it to on the line that you want it to.

What you're describing is a talent deficiency, not a setup problem.

 

[Northwestvoodoo]

I'm hoping to have a go at shimming up the rack this evening and am quite excited about not driving in fear every time the boost kicks in. As is - keeping this thing in it's lane is a nightmare.

Thanks for all the input guys.

 

[NEp8ntballer]

What I think he means is lift-throttle oversteer.

I know, but that still wouldn't point to an issue with the steering system

What you're describing is a talent deficiency, not a setup problem.

I guess it was a poor attempt at humor. but if some stickers add HP can you add some hotchkis stickers for some improved lateral gs?

 

[yamahaSHO]

I know, but that still wouldn't point to an issue with the steering system

Not quite. It has more to do with weight transfer and traction to the rear wheels. When you lift the throttle and the rear end comes around, it really has nothing to do with the actual 'steering' system.

I'm hoping to have a go at shimming up the rack this evening and am quite excited about not driving in fear every time the boost kicks in. As is - keeping this thing in it's lane is a nightmare.

Thanks for all the input guys.

This won't get rid of tourqe-steer.

 

[zach44102]

Yes I meant throttle lift overstear. But Mainly I was asking if the weight is coming back down on the front wheels making the suspension in the front compress changing the steering geometry considered bump steer? Or is this just oversteer? Im just asking cause my rack is not shimmed and I dont think I have ever experienced any bump steer.

 

[Northwestvoodoo]

Yes I meant throttle lift overstear. But Mainly I was asking if the weight is coming back down on the front wheels making the suspension in the front compress changing the steering geometry considered bump steer? Or is this just oversteer? Im just asking cause my rack is not shimmed and I dont think I have ever experienced any bump steer.

Zach - You would know if you had bump steer cause you would be all over the road, at least I am! It feels like your steering is loose and you need to make constant steering inputs. It get seriously exaggerated when under power or lifting off.

Alex

 

[frosho]

I really need to do this too. I might just wait until I put in a ZF though. It's much less pronounced with the current 16" 215's than it was with 17" 245's.