Cosie Convert

My 96 WRX RA suffers from understeer when pushed hard. (They all do that sir) I was considering fitting a 22mm rear arb to transfer more weight across the rear wheels, helping the front to turn in. Anyone have any comments ? Anyone tried this ? Think it might be too much and result in terminal oversteer ??
Opinions welcome

regards CC

milo

what suspension mods do you currently have?

if none, anti bump-steer and a good 4 wheel alignment will help reduce understeer

the arb is good thou... make sure you get uprated links with it though

Mo

Good alignment is essential on an Impreza.

Something else to consider, it really helped me, is to change your driving style to suit. Sounds stupid, but it works!

Adam B

Hi CC

I've got a MY00 RA and have had the Powerstation boys do a little bit of work on it.

White line anti-lift kit, bumpsteer removal & geometry setup.

Result:

Fantasticly neutral car with a hint of oversteer when pushed. I'd definately consider this before the ARB, but give them a call ... bit of a way though

Cheers

Adam (no links with Powerstation etc....)

Cosie Convert

What style do you suggest Mo ? I used to circuit race a 3door Cosworth and the sequence there was - turn in on the brakes, the back end goes light, quickly on to the power to get the boost up before the front washes out, then control the mild oversteer on the throttle. Seemed to work, won the Scottish championship !
Tried that on WRX and front pushes wide, tried brake early and mild power ala FWD but it feels slow and still understeers as soon as power is applied.
PS We are talking wet roads here with Toyo Proxys. The car is standard however it had a 4 wheel alignment done recently.

Just can't unstick the rear !! Maybe need to try left foot braking !!!!!

cc

daw

I have a 22mm adjustable on the rear. I generally keep it on full stiff setting. It makes an incredible difference. Especially beneficial on the track.

Keep the front as stock.

Understeer disappears and you can use easily controlled lift off oversteer to get through tight corners at a higher speed than you normally would.

Also, you don't need uprated links with 22mm bar. Standards are fine.

HIGHLY RECOMMENDED! and a no brainer for the $.

Regards,

David

Cosie Convert

Thanks David, glad someone found that it works ! Is the adjustment on the bar end pick up point ? Is it a sliding bracket or a selection of bolt holes ?
I live a bit out of the way and all my parts come mail order so I like to know what I'm buying first !

cheers

cc

daw

CC,

Check this out, there's some good pics that should make it all crystal clear :-)

http://www.azscooby.com/mods/AZScooby/whiteline.php

This guy is using a Whiteline adjustable. As you can see from his setting he's a bit of a softy though. I have a similar bar to this one only mine's set to full stiff.

Go for it!

Regards,

David

SDB

Hi Cosie

Some REALLY good advice on this thread.

As you said, the ARB will increase load transfer at the rear so will effectively reduce cornering grip at the rear in comparrison with the front.

However..

In comparisson with the cossie (i have a 3 door too) the scoob requires a totally different driving style. It is difficult to convince yourself of this, especially if you are (as you obviously are) an accomplished driver, used to RWD (correct wheel drive).

The reason I would suggest looking at this before the bar is that you will probably be removing some of the benefits of the standard chassis just to get round the problem.

If you have ABS, it's a little more tricky, but you need to do lots more work on the brakes. It is possible to get a scoob MORE than 90 degrees sideways and still bring it back (don't try this at home!) so you can really pitch the thing into corners and deal with it on the gas.

You can't adjust the car on the gas as you can a RWD car, that's just a fact, so the work has to be done on entry / turn-in.

I do however think you would be stunned as to the difference with the bumpsteer removed.

All the best

Simon

dmel

Before moving on to more complex or exotic solutions why not start with basic geometry setup?

Have you tried reducing rear-toe? My car initially had 4mm(!!) overall toe-in at the rear. No wonder why it was extremely difficult to make the rear end become unstable.

I now have 1mm overall toe-in at the rear and -0.75 camber. A new car.

If you require more tail-happy behaviour you can even use a bit of toe-out as Whiteline recommends.

Cosie Convert

Thanks guys, I guess the 22mm ARB could be a quick fix but possibly a bit of a compromise.
I always believe that you should work on making the loose end stick rather than unsticking the gripping end to get balance !
In the short term it would probably be quicker with the 22mm bar due to better balance but ultimately I need to work on improving the front end grip.
An anti lift kit would appear to be the favourite for this. Am I correct in saying the ALK raises ?? the rear pick up point on the bottom arm, which in turn increases the castor slightly.
My car is a WRX RA with the alloy bottom arms, I read elsewhere that RAs have different steering geometry (no bump steer was the claim)
Is the ALK still effective on the RA ?

questions, questions questions !

cheers

cc

daw

Simon,

Have you done back to back testing on a track between a stock WRX v one with a 22mm ARB?

I have yet to see anyone make this mod without a fairly significant drop in lap times.

Yes you can apply trail breaking to improve the standard car's cornering and this is certainly the way to get the best out of the standard car but you can definitely carry more speed through corners with the uprated ARB.

Regards,

David

Adam B

Hi CC

Re. RAs and Bumpsteer :

When mine was measured it had a HUGE amount of bumpsteer ! So at least in my case the claim seems false ... You maybe getting confused with the 'quick-rack' that they share with R's (and also 22b's I think).

The ALK lowers the rear pickup point on the wishbone and gives more castor (I think).

Very effective on my RA at least, almost ridiculously good at putting power down coming out of bends. Combined with the bump and geom changes ... the best upgrade on the car so far !


Cheers

Adam

PS I should point out that prior to these changes I thought the car handled pretty well !

Cosie Convert

Adam
I would have thought the rear pick up was raised on the AL Kit ?
Lowering it would promote dive under braking as the wheel moves back an up and therefore lift the chassis under acceleration as the wheel pulls forward and down......I think ?

Did you need the rack moved on your RA to eliminate the bump steer ?

cheers cc

Adam B

Hi CC

I'm pretty sure it was down (and out slightly) <shrug>. Take a look at : http://www.whiteline.com.au/ and or give the guys at powerstation a bell : 01242 238400 (Enquires@powerstation.org.uk).

All I can say is there's no dive under braking and no (perceptable) lift under acceleration.

Yes, the rack was shimmed (only very slightly).


Cheers

Adam

AndyMc

Hi

The ALK does move the rear pick up point down and out slightly.The extra caster comes from moving the pick up point out as this moves the wheel forward in the arch creating more caster.Also the stiffer bush in the kit distorts less than the standard bush so the caster angle is maintained when the suspension is under load.

CC when I was first interested in the ALK I asked the same question about it increasing the dive and the answer is that it does, however in practice I didn't notice it even though I have AP brakes ,on the other hand the reduction in power understeer is quite remarkable.
Saying all that I took the kit off a couple of months ago after nearly 2 years( because the bushes had worn) and the car doesn't feel nearly as bad as I thought it would,in fact although the car will now power understeer more easily it seems better in other areas,I certainly won't be putting it back on.I know this goes against what other people say but is just my experience.

Andy