hey guys need some info on how to get rid of most if not all the bump steer.
im currently on H&R coilover and im sitting pretty low. i have gt3 arms in the rear to help get the alighnment in. car is great in corners and on a nice flat road but thats very far and few here in ny so it gets bad sometimes when i open it up and hit a good bump. any info and set up tips would be great thanks in advance

 

I used to run H&R coilovers on my car a couple of years ago. They're a great street / mild track set up and work well at low ride heights unlike the Bilsteins. With that said, bump steer was always an issue and will always be to a certain degree when the TT is run at low ride heights. When I swapped to a JRZ suspension, bumpsteer was reduced mainly due to the fact that the spring rates were much greater which reduced the amount of suspension compression (especially in the front) in turn reducing bump steer. The biggest problem child is the fact that the geometry of the front TT AWD uprights is pretty f'd up. Not only are the TT hubs designed for a much higher stock ride ride height (compared to what you end up running with a low set of coilovers), but the pivot axis is also not centered on the hub due to clearance issues of the front drive shafts. A bumpsteer kit will help but won't eliminate it. When I removed the front TT uprights and installed GT3 Cup uprights, bumpsteer was all but eliminated as the suspension pick up points are much lower in the Cup parts designed for ride heights over 2" lower than that of a stock turbo. Converting the uprights is the proper way to go but it will cost about $3K and you can NOT run the front drive with it. It turns into a bit of a slippery slope as the RWD set up will necessitate an LSD. It does really transform the handling of the car and makes a huge difference especially if you track the car. Hope that helps...

 

Pwdrhound, thank you got a great explanation. On another topic, I prefer your previous avatar.

 

I had to change my avatar as it's been snowing pretty hard early season and I'm getting myself pumped for some fresh pow this year! 27" of new snow in Vail over the last week. Hopefully it's gonna to be a good winter....

 

http://www.tarett.com/items/996-997-...bmp-detail.htm

I believe ERP make a kit also. Give Stable Energies a call. http://www.stableenergies.com/

 

Beaver Creek next week.

 

The toe arms in the tarret link above are actually ERP parts. Good stuff. I have the Tarett parts on my car. When it comes time to replace, I will be using the new 997 PMNA toe arms. The new 997/991 PMNA stuff with the "pinch" collars is absolutely beautiful. You almost don't wanna install it on the car but hang it on the wall instead. Pricey, but the best..

 

Oh yes those are works of art. Plus a dream to set up as there is no jam nut to push out on your adjusting arm.

 

You're gonna have a ball. Snow is great so far this year. When I was living on the east coast I was skiiing 40 days each year in Colorado but living out here I do barely half that as you get spoiled and only tend to only go up on the big snow days. Unfortunately we haven't had many of those lately. Only a few big dumps last season.

This was one of them. Jan 31,2013.....Red Square, Vail.

 

RSS also makes a kit. Had it on my car with good results.

 

Let's clarify some information as people will get confused. Bumpsteer is not when your suspension does not settle over bumps. Bumpsteer is when your rear toe changes due to change in load. Front can change too, but that is usually used to ones benefit via ackermans steering principal.

What you are dealing with is a spring/compresssion issue, and will not be solved by a bumpsteer kit. Many people have tried, thinking what the kit says is addressing what they are thinking in their head and the two issues are altogether completely different.

The best thing you can do with what you have is soften the spring rates, otherwise you need to soften compression/rebound on a coilover system if you have one, after that, you just need better dampers. Entry level dampers are only made to lower your car a certain amount before they start bottoming out on big bumps and losing almost all effectiveness. They are also just not that great in damping ability to begin with. JRZ,Ohlins, Moton, MCS are usually better, higher quality designs which can handle these undulations much better.

But a bumpsteer kit will do absolutely nothing for your car's ability to go over bumps. Many guys have paid 1k for parts and almost a thousand for install and setup to find that out.

TT uprights are designed for higher ride heights but I run mine at near cup car heights and they do well, but at this height, a rear bumpsteer kit is mandatory, but sufficient.

 

Thanks everyone for your feed back and I'll be looking into a few things.