ERP bump steer on the street?, Will those hiem joints last? Options

[blabla914]

Does anyone here have experience using an ERP bump steer kit on the street? I'm concerned about wear. I drive my car quite a bit (5-10k/year) on the street and I'm worried about them wearing out quickly since they aren't sealed. Anybody have experience with this?

Kelly

[Aaron Cox]

i read they are track only, and have seen the pics of one failure on pelican....

whats wrong with turbo tie rods and rasied spindles and rack spacers?

[DanT]

I have been told that you only need to do rack spacers if your tie rods are parallel to the ground. If you have any angle on them be it up or down the bump steer kit is not necessary.

My car is very low and I have an upwards angle on the tie rods to the outside of the car.

I have absolutely 0 bump steer. No rack spacers.

Car handles great with no kick back in the steering wheel.

Why do you feel you need a bump steer kit? (IMG:style_emoticons/default/unsure.gif)

[blabla914]

Thanks for the replies guys,

My understanding, and I've looked at it a bit, raised spindles will increase usable suspension travel and increase camber gain, but the steering arm will still be up too high. It's the upward slope of the tie rods that creates bump steer problems. The closer you can get the tie rods to level, the less bump steer will you have.

I'm not certain I need the bump steer kit. I just want to know if the ERP kit is even an option, which it sounds like it isn't. I'm going to pull the torsion bar and run the suspension up and down and see what the bump steer actually is. I think I have more than I'd like. If I run less than 1/16" toe in on the front the car becomes quite unstable over the bumps. My thought is as the front wheels are going up in bump I am getting toe out. If I run a bit more toe in the effect is minimized, but less toe in makes a big difference in the middle of the corner for me.

The car is low. I've got 5 1/4" from the rocker seam to the ground at the jack point. I am running 205-50-15's on 7" wheels with stock struts and the rack spacers in place. If the ERP's are not an option I may just raise the car up a bit.

Kelly

[Aaron Cox]

Thanks for the replies guys,

My understanding, and I've looked at it a bit, raised spindles will increase usable suspension travel and increase camber gain, but the steering arm will still be up too high. It's the upward slope of the tie rods that creates bump steer problems. The closer you can get the tie rods to level, the less bump steer will you have.

I'm not certain I need the bump steer kit. I just want to know if the ERP kit is even an option, which it sounds like it isn't. I'm going to pull the torsion bar and run the suspension up and down and see what the bump steer actually is. I think I have more than I'd like. If I run less than 1/16" toe in on the front the car becomes quite unstable over the bumps. My thought is as the front wheels are going up in bump I am getting toe out. If I run a bit more toe in the effect is minimized, but less toe in makes a big difference in the middle of the corner for me.

The car is low. I've got 5 1/4" from the rocker seam to the ground at the jack point. I am running 205-50-15's on 7" wheels with stock struts and the rack spacers in place. If the ERP's are not an option I may just raise the car up a bit.

Kelly

it is almost protocol, that when you raise spindles, you heat and bend the pitman arm down.....

[blabla914]

it is almost protocol, that when you raise spindles, you heat and bend the pitman arm down.....
[/quote]


Ah, got it. How much does this lower the tie rod connection point?

Kelly

[Aaron Cox]

[quote name='blabla914' date='Jul 2 2006, 12:11 PM' post='718277']
it is almost protocol, that when you raise spindles, you heat and bend the pitman arm down.....
[/quote]


Ah, got it. How much does this lower the tie rod connection point?

Kelly
[/quote]

as much as you please. heat beat repeat (IMG:style_emoticons/default/smile.gif)

seen anywhere from 05-30mm.....

[TimT]

the ERP bump steer stuff will last a good long time.

Do you need it probably not, measure what the bump steer is before you even invest in something like this..

That failure that was posted on Pelican, appear to me as a case where the owner was unsure if the kit was installed properly.. I remember pics of the brocke bolt and there were traces of rust apperent along the failure. ie the crack took a while to propogate.

In any event the ERP kit will last a long time especially if you are a DIY person, and get an eyeball on the components more frequently than the average owner..

That is all

[Jeroen]

I hate to say it, but do a search on the PP 911 BBS
You'll find lots of good info on bump steer, raised spindles and bumpsteer kits
(including the thread on the ERP kit failure)

your tie-rods need to be parallel to your a-arms (NOT parallel to the ground)
or as close as possible, since your tie-rods and a-arms have different pivot points, you'll never get them 100% equal

[Brad Roberts]

They will last just fine on the street. Check them each time you jack the car up. Treat it like a race car. Put an "hour limit" on high wear items and track the hours. You can easily replace them as they "hour out".

I forget who did it for me, but somebody made me an Excel sheet showing how much bump would occur withing 1.5 inches of travel in the suspension.

This is a HUGE issue right now in the Boxsters and 996's. It is burning up power steering pumps.


B

[Jeroen]

You can easily replace them as they "hour out".

After how many "hours" would that be?
Do you only need to replace the bolt/nut that holds it all together or the complete unit?

[Brad Roberts]

Bolt will be fine. Replace the nut every time you remove it for any reason. I wouldnt put any more than 40hours on any heim joints in a suspension situation.

Factory Porsche teams replace some suspension components after every race weekend.

Safety is the key here.



B

[ChrisFoley]

How much does this lower the tie rod connection point?

Kelly

When I do a raised spindle mod I bend the steering arms down so the tie rods are lowered the same amount as the spindles were raised. Most common amount is 19mm.