Today I spoke to someone at the Prodrive race-department, and I asked him what I could do to avoid understeer on my MY98 scooby. His answer is:
1) prodrive geometric settings, but you can have extra wear on the inside of the front tyres.
2) stiffer springs rear, but the suspension becomes harder and less comfortable.
3) best sollution: a bigger rear anti roll bar.
My question: do STI-versions have a bigger anti roll bar at the rear than standard turbo sportswagon? Has someone already tried this sollution, what are the results of a bigger anti roll bar? It seems to be that Graham Goode sells a 20mm anti roll bar, is this one bigger than the original or is it an STI-type???

If you have a look on MRT's web site I dont know the website address at the moment! They do an Adjustable rear antiroll bar that you can get from Scoobymania. There are also a number of other possible change that I am looking into along the same lines these include replacing the plastic rear links with metal ones and replacing the standard rubber anti rollbar bushes with Polyurethane ones.

Doing these 2 changes would make the existing roll bar more effective and that may well be enough to sort you understeer problems without a new Anti rollbar.

I would first of all get the geometry changed and see if that sorts the problem out enough for you.

The main reason I am looking at these changes is that at Donington I was getting problems with the inside front wheel picking up and spinning so I am trying to control the rear roll to keep that end down!!!

Darren

I've read the following...

"...that upgrading the suspension to "race car hard" may affect reduce road holding. Especially when cornering on rough surface, the tires may not maintain good contact with the road and your car will hop sideways when hitting a bump and cornering.

Reducing roll should be done by fitting stiffer anti-roll bar, not increasing suspension stiffness..."

Does this sound right? I also want to improve the handling of my STi (too much body roll), but I keep reading conflicting info :-(

Cheers
Andy

Andy

Yes it does sound right, anti roll bars are a good starting point but under differing loads it gets very complicated, see it as a partnership approach which requires high quality input from all contributors.

Not much point changing your rear anti roll bar if the part holding it on at the back (drop links) are made out of chewing gum. http://bbs.scoobynet.co.uk/smile.gif

MRT are

I have a 94 WRX which understeered very badly. Body roll did not seem to be much of
a problem.

I took my car in to have four new tyres fitted, fit the Anti-Lift Kit (£120 approx) and rear sway bar links. They also did a wheel alignment.

This has transformed the handling - understeer has been almost eliminated. There is now hardly any lift under hard acceleration and the car will even oversteer slightly if deliberately provoked.

The sway bar (anti-roll bar) links allegedly increase the effectiveness of the roll bars by 50% (according to MRT). They cost £30 approx.

It's also worth taking a look at Whiteline's web site (who produce the MRT kit):

Just fitted the rear Sway Bar links, although currently have the original STi Sway bar bushes in place.

The effect of a £35 upgrade is excellent. The rear feels much more secure and turn in is improved (increased rear roll stiffness pushes weight forward to the front wheel).

The car on initial testing has much less of the STi V 'nervousness' and makes me feel more confident in a corner. And before anybody comments on wet weather grip - this was all in the p***ing rain! I feel the improvement comes from the consistency of the roll stiffness, you are not waiting for the plastic link to load up before engaging the sway bar.

Also there is no obvious deterioration in the ride.

Tomorrow - stage II - I will be fitting the ALK - on the basis of results so far I am looking forward to this one!

Cheers,

David