Bajie

Hi All
I have Prodrive suspension 'complimented' by an anti-lift kit.
At Donnington I found the rear wanted to snap out constantly, checked the tyre pressures and had 40 all round. I had put 38 all round two days before.
Tyres Northampton reduced the pressures to 36 on the front and 32 on the rear but once heated the back was still twitching.
Phil Bennet drove the car, what a revelation! Tod me to get stiffer springs and nothing would catch the car.
So, which springs do I get? Any suggestions?
Prodrive, Leda, HKS ???
Also, is the anti-lift kit contributing to the rear end problems.
On the road I have no problems.
On the track, well still seeing that Honda sign getting ever larger.
Both Blowdog and Phil said I'm a bit too violent with my steering inputs so I am trying to address my driving 'style' also.
Followed Blowdog after Phils session and there was an improvement.

Stef

Bajie.

Just seen some video footage of your car, and was amazed how much roll there was!
Doesn't the Prodrive suspension already have stiffer springs?

Stef.

Blow Dog

Hey Baj,
It appears that the fully adjustable Leda kit is the most popular choice. The 22B's seem to go with them aswell and they seem to be the ones with the disposable income

I would personally go for the Leda kit, only coz I find Scoobysport products to be top notch. They ARE the most experienced around after all.

One thing I would say though, you car doesnt have a 'bad' set up at all. Your car is set up mainly for road use and you gotta consider which takes precedence. At the begining of the track day, youre steering inputs were far too violent and it seemed you were inducing excessive body roll, causing oversteer and powersliding. This can be great fun, but doesnt mean the fastest times. At the end of the day, I was finding it difficult to lose you, but I am running standard suspension and average brakes.

If I were you, I would go and see Pete, get him to take you for a ride down the Scoobysport test track, I will come with you if you want, get him to shoe you the Leda kit.
Cem

GavinP

Bajie,

As you have already replaced the suspension, I would second Dave in suggesting that anti-roll bars and possibly geometry are the things to look at.

Scoobymania sell an adjustable rear anti-roll bar which would allow you to "tune" the responses of the back-end - at relatively low cost.


Thanks

Gavin

andyp

Bajie

Do you mean Prodrive Geometry Settings rather than Prodrive Suspension?

I have the Prodrive kit and it comprises of new AR bar (I was upgrading a MY95 with the thiner bars), Bilstein dampers, Eibach springs (firmer and 20mm lower) and a geometry setup. As far as I know the Prodrive springs are quite hard for a road setup, although they may be too soft for serious track use. If your Prodrive springs are too soft then it's probably worth considering the LEDA adjustable setup - because IMHO you wouldn't want anything too much harder than the Prodrive ones for the road.

Andy

Bajie

Firstly thanks all of you for the input.
Just got back from having the car checked out. Underneath is ok so just cosmetic damage.
Anyway, Mark took the car out and suggested anti roll bars too. More importantly he told me to get the suspension settings realigned as there was a lot of roll.
My only problem (?) with getting adjustable suspension is I don't want to be spending too much time setting the car up to go out and then after some laps come back in and go through it all over again.
The car goes to Lavender Hill tomorrow so I may ask them to look at the settings if they have a chance. Fortunately I had a knock coming from the front left strut which they are replacing under warrantee.
Perhaps anti-roll bars with realignment is the way to go.
I spoke with Mike toward the end of the day and he had some kit. Maybe I should have taken it.
How much does the Leda kit cost anyway.

Blow Dog

Between £1200 and £1300. A drop in the ocean for you.

Darren Soothill

It depends what you mean by a problem at the rear end.

Fitting a bigger anti rollbar at the rear will reduce the amount of grip at that end.

When is the last time that you had the geometry checked?

What is the camber at the rear end? This could be alot of the problem if you dont have sufficent rear camber.

Probaley created more questions than answers!!!

Darren

Mike Tuckwood

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Darren Soothill:
<B> Fitting a bigger anti rollbar at the rear will reduce the amount of grip at that end.
[/quote]

Not true. This has been covered before, especially on IWOC, by Jim at Whiteline and it is massively complex. Fitting the adjustable 22mm Anti-roll bar could help.

There will hopefully be more info. available after the test day at Mira this month.

Mike.

Steve Wilson

Just to add my two pence worth -

I have a 5 door Sti4. On the original suspension body roll was very pronounced. To the point that I would get fuel starvation problems with less than half a tank of gas.

Changed over to prodrive kit reduced body roll dramatically. FACT. There is no debate over this, and is I assume, down to stiffer springing but particularly due to much reduced possible range of movement of the dampers. (Most noticeable at the rear). Also no more fuel starvation problem!

A point to note is that 5 door cars require heavier springs at the back than others due to extra weight. If you use 4 door springs on a 5 door you will get a lot of understeer. (Voice of experience)

I have had the generally available anti-lift kit fitted and found it a great help. It does reduce the lift of the front of the car when accelerating in low gears, but what I like is the the way the balance of the car is changed towards what feels like a more rear wheel drive set up.

Darren Soothill

Mike

The reason for fitting the bigger Anti Rollbar is to reduce understeer. This is the reason that Whiteline where suggesting it. In this particular case Bajie is complaining about a loose rear end.

I was involved in the discussions on IWOC about this very subject. I also had a number of discussions with Jim offline about this.


Darren

R19KET

I have to agree with Darren. If we increase the front cambers to reduce understeer, then by either reducing the front camber, or probably a better idea, uprating the front ARB, it will reduce oversteer.

I have uprated the rear ARB, and increased the front cambers, this dramatically reduced understeer. Reversing this will reduce oversteer.

Re ALK's, both Bob Rawle, and I both suffered an INCREASE in understeer with it fitted. I have a Leda set up, Bob's car is standard.

Mark.

Mike Tuckwood

To be fair though Mark, am I right in thinking that Bob's steering alignment had not been fully sorted since fitting the ALK?

Mike.

AndyMc

I have played around with the geometry on my standard my98 and found that the amount of rear toe had the biggest effect on rear end stability,I would definitely get this checked.

I have since fitted an ALK which has reduced both understeer and oversteer on my car !!!(ie more neutral)
Also fitting the ALK added a load of toe-in on the front which made it understeer badly until it was reset.

Bajie

Thanks to all for the help/advice in this thread.
The car is in Lavender Hill having the front suspension replaced under direction from Prodrive, who will then reset the geometry settings front and rear.
I am definitely under the impression the suspension was knocked out of alignment somehow, though not at Donnington!
The Prodrive setup is stiffened shocks and springs and dampers but not roll bars so this may be the way for me to go.