Originally Posted by Rancie

RS ride height -20mm with a little addtional rake etc..

Originally Posted by Rancie

Thank you for the replies Gentlemen. Some good information.

I arrived at the set up after a few days testing. I wanted to keep the car as stock as possible so have tried to achieve a chasis balance without changing the front uprights to the better 993 Evo units. I run the car low with a little more rake than usual and on rlatively stiff springs which minimise front suspension travel. I drive the car on it's nose like a contmporary cup car. The set up works well, it has a nice balance but it does rely on help from the diff during the braking phase. Currently I have a standard factory Limited slip unit which is adequate but only just. Soon i'll be fitting a Guards GT tranmissions unit with a little extra preload which will make things a little easier to balance during a trail. Braking is 993 turbo fronts and 993C2 rears without any bias adjustment so it's heavily front biased. I know that this would not be everyone's taste but it suits my driving style. Pace wise the car is quick by race standards and it still has electric windows and aircon fitted so I'm happy with that.

So basically i'm happy with the set up but when the car is at 10/10ths on the circuit there is a vaigueness about it common to any reasonably heavy car with rubberised bushing. Although I can drive a balance into the car, I can feel it floating as the bushing loads and distorts. Changing the engine mounts to RS units has made a decent difference. The standard mounts were hopeless and promoted oversteer on exit as the engine rotated on the loaded mount. The other problem that I am getting is accuracy of rear toe adjustment which my race shop are struggling with, which is why I've purchased the Tarett spring plates.

Great info re; the washers on the bushes. I've checked the Elephant items and they apprear to accommodate this concept which is encouraging. I'll definately look at the steering rack bushing also.

Thank you again for your input. This forum is extremely helpful

Originally Posted by Juha G

Running it that low with C2 uprights and outer tierods is a disaster to be honest.

Originally Posted by Bill Verburg

Another thing that you might want to address is the dual spring set up used on the kw's.. with a main and tender the suspension has 2 very noticeable set-points.

Originally Posted by Rancie

You would think so but I get no understeer issues at all - have a look at the video - and its a relatively easy car to drive at 10/10ths or 11/10ths. Much easier to find the last few 10ths than say a 997 Gen 1 cup. It would be a very easy car to race by comparison. On saying that, the car is set up for minimum suspension travel as I was aware of the potential bump steer issues. Its also fine on the road. I driven most road and race 911's on circuit and it's one of the easiest on the limit.

Originally Posted by porsche mania

We have nearly identical setups, different make shocks but same kind of spec and I also have the rs uprights. I am rs -20mm as well. My car is dual use but obviously set up to make the most of the track. When my Geo was done I struggled to get the camber I wanted on the rear without gaining excessive toe in so have been considering spring plates for the rear as well. I still have one issue to sort on the car and that's a vagueness as the car loads and unloads the rear in fast committed corners, I've put this down to the rear trailing arm bushes flexing but after having new tyres put on, another set of ps2's, and feeling how flexible the sidewalls are I'm wondering if that's the reason. At my next track day I am going to up tyre pressures from 36 hot all round to 38 hot in the rear and see if that helps. Next step will be some Toyo 888, if the problem still persists then I'll buy the spring plates. Hoping I'm at the bottom of the slope now, there can't be much further to go!

Originally Posted by Juha G

How a car feels vs. how it really performs are naturally two completely separate things.

Lowering the front that much without correcting the geometry means your tierods and lower control arm angles are seriously out of whack and the suspension does not work anymore how it's meant to be working.
You might be compensating this with stiffer springs etc. but it's a bandaid fix and takes away from the performance of the suspension in other areas.

There is a very good reason the factory race cars (as well as the RS versions) used different wheel carriers and outer tierods.

Originally Posted by Spyerx

look at my build thread :-)

what spring rates are you running?
If you want control, you remove all rubber from the suspension, steering, get 993 uprights for proper front Geo, ensure you have a proper alignment/balance

Even with all monoball everything, with a compromise spring rate and shocks adjusted as such the ride is quite compliant. You do get some NVH, and the steering can be very sharp, but that's due to the agressive camber/setup on my car.

But for me, it's quite tolerable.

Originally Posted by Bill Verburg

#3 2x 3mm washers

Originally Posted by Rancie

That is interesting. We seem to be experiencing similar problems. How are you driving the car on circuit? ie; are you off the brakes at turn in or carrying a trail into apex?

Originally Posted by Goughary

Bill- that's interesting. The stock oem trailing arm bushing has a similar washer on both sides. Is it simply thinner? I'm guessing 2mm?

I may have one around. I should go measure.

Originally Posted by Vandit

The OE spring plates are designed to flex and pull and push and be all over the place. They called it the Weissach effect, it's Porsche's take on active suspension geometry in the 80s. Swapping for the monoball pieces goes a long way for getting the car to act right in the rear axle.