TelBoy

Can someone please tell me in simple terms what the bumpsteer modification is? What is actually removed from the car?
Why don't Scoobs or other performance cars have it done at the factory if it improves handling so much?
What are the reasons for NOT getting it done?

ta much,
Terry

mutant_matt

SImply put, Powerstaion shim your steering rack to change it's height in relation to the steering joints. This stops the designed toe out of the front wheels when the suspension is loaded up.

This will reduce the designed in understeer, make the steering firmer and provide a much more planted front end when cornering.

The reason that Subaru designed in the understeer is to make the car as easy to handle as possible for the lowest common denominator driver

Do it, you won't regret it!!!!

Matt

StuBoy

Have a look at this site explains exactly what it is.

http://www.drivingtechniques.co.uk/ShowPage.asp?Activemenu=63&PageID=56

Hope this helps.

StuBoy

solmob

OK, so I've read the driving techniques explanation of what this bumpsteer mod does, but I would like to know exactly what the likes of Powerstation do. I am in Sydney and no one here seems to know about this mod. Maybe we don't have the same bumps here, or maybe the cars react differently in the southern hemisphere!

How much is the steering rack moved, and in what direction? Are new rack mounting blocks fitted? Is anything else done apart from moving the rack?

Any information would be appreciated.

Graham.



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DavidRB

Due to manufacturing tolerances, it is often different for each car. In my case, the steering rack was unclipped and dropped 3mm. The clips were also shimmed so that they weren't bent when reattached.

Powerstation use their laser-alignment equipment to measure the bumpsteer by looking at the amount of toe-out that occurs when the suspension is compressed. This tells them how much they need to move the rack.

I've been very happy with the results so far.

Zahnster

In the same vein. Here in the US I've never heard something mention this modification. It sounds like Powerstation is the only one who can do this to your car. Any ways to do it without them?

mutant_matt

You can do it as long as you can work out how far it needs to be dropped. I think mine was dropped about 5mm.

Matt

chiark

It's just like matt says. You need to measure the amount of bump steer you've got to start off with then shim the rack an "appropriate amount" in order to correct it.

No-one apart from PowerStation in the UK is doing this. I am quite surprised given it's popularity.

I thought Cheltenham was a long way away. It's worse for you guys

Must get mine booked in sometime...

john banks

Falkland Performance in Glenrothes now do this also to good effect.

chiark

aah, there you go. John always feels it necessary to prove me wrong

john banks

No Chiark

Just thought I would update you I asked Falkland to do it on my car as a guinea pig after demand in the Scottish forum. Results are impressive.

sasim

I was Falkland's second guinea piggy, must say I'm impressed too

Stuart

[Edited by sasim - 5/30/2002 10:14:07 PM]

hmhaga

DIY?

All cars have bumpsteer from factory, so if I drop the rack 3 mm - it'll improve things EVEN though it should have been dropped e.g. 5 mm to get it right?