Hi,
I've been tracking my 951S with 968 M030 sways a bit and the more experience I get, the more I notice the car feels quite soft. I was at NJMP Lightning a few days this summer and this track really brings that quality out. The car feels floaty when cresting Turn 1 then again turn 5. Transition on Esses like 2,3,4 seem a bit overly dramatic in terms of weight transfer.

I'm comparing to my BMW e30 with J-Stock suspension which is really flat and tight, the Porsche seems to turn in slow, and requires alot of input to really get it going.

Is this an inherent 944 quality or can it be dialed out with a good coilover set up?

 

I run the same sways but have doubled the effective spring rate on all corners as well as lowered the car all round by about 1.5 inches, it killed a lot of the undesireable track behaviour you describe.

 

I have Leda single adjustable coilovers on all 4 corners, heavier springs (650 lbs in my case), and Racer's Edge solid suspension bushings, front and rear. 968 M030 sway up front (solid bushing also) and a 22mm adjustable sway in the rear. I also use solid bushings on the steering rack mounts. The car handles very well. I'm sure there will be comments from others, especially concerning spring rates and adjustable coilovers.

My car handling was not too great either with the original rubber bushings, stock turbo springs, torsion bars and koni yellows. The bushings made a big difference, especially with turn in and braking.

 

Rubber in the suspension is definitely worth mention! I no longer have any, solid mounts and heim joints everywhere. Really sharpened things up, however it is a track car, if its your daily driver this may be a bit much,

 

http://www.clarks-garage.com/ has suspension and upgrades section which is great.

 

You definitely want all rubber out of the suspension. The faster you are, the stickier and the wider the tires, the bigger the issues becomes. And this goes for all suspension joints as well as the rear torsion bar carrier.

Shameless plug > I have the solid mounts for the torsion bar carrier for sale as well as some used late A arms that have Delrin bushings installed as well as some spring plates that already have the solid bushings installed :-)

As far as spring rates go..... just note the 53% rear and 91% front (approx) effective spring wheel rates when you choose your springs. For a dedicated track car that is full weight, I would start with at least a 550lbs front and 750lbs rear spring as a starting point. Start with the rear bar disconnected and if it pushes reconnect the rear bar and tighten up from there.

TonyG

 

Also don't forget that when people are discussing spring rates some might be talking coilovers all round where others, like I assume the O.P. are still running torsion bars. ie you need to calculate with or without T-bars.

 

Looks like I'm going with;

Escort Cup
http://www.lindseyracing.com/LR/Parts/944SUSESCORT.html

and
Tarett Adjustable Sways Front & Rear
http://www.tarett.com/items/944-seri...sba-detail.htm


any input?

 

how about this item? http://www.tarett.com/items/944-seri...arm-detail.htm

What do they mean about causing the suspension to feel "out of whack"?

 

when lowered, the front suspension puts a lot of torsional force around the balljoint, and warps them down... they can eventually break.

i can't remember the details, but i recall reading somewhere that stock a-arms aren't allowed in certain competition classes. anyone know offhand?

 

Correct about lowering the car. It causes the stock ball joint pins to contact the side of the A-arm cup and possibly break. Rennbay offers a couple of kits to replace the stock ball joint pins with a longer ones. To use the 19mm pin you'll need to have the steering knuckle machined. I've been using the 19mm pin for about 6 years without a problem. That means I'm using the stock A-arms. In PCA they are legal in the Stock classes and SP3, where the 951 competes. I don't know about other venues. You do need to consider using the longer pins for safety if you are going to lower the car.

 

Try contacting Pete at RS Bran - 215-968-2599 for your set up concerns. If you don't want to bite the expense of gas filled coilovers yet, Bilstein turbo cup shocks are digressive valving and have hugh cartridge size, offering increrased strength. They function like a gas shock at a much reduced price. Far too many tweaks to mention here, but it is all an expensive proposition to not discuss with someone who really knows about front engine p-cars.

 

Eh...

The Bilsteins are great. I'd go with the Weltmeister front with the competition drop links and the stock or M030 rear bar.

And, get all the rubber out of the suspension and the torsion bar carrier.

Go with a 550lbs/750lbs spring rate combo.

Does the car have LSD?

TonyG

 

Not really.

Torsional forces are twisting forces. And the ball joint rotates freely. Thus there are no torsional forces applied.

TonyG

 

Nope.

The A arm, starting at a stock height where the A arm is level, has 6" of upward travel before the ball joint runs out of travel and binds.

6" of A arm travel generates probably another 1"+ of wheel travel (I don't know the exact amount). Even more on late offsets cars. Remember... This is just the UPWARD TRAVEL FROM A LEVEL CONTROL ARM.

Even with lowered cars... with stiff springs, you might get 2" of wheel travel upward from where the sits at rest. So even if the car is lowered 2" from stock, and 2" of wheel travel up from rest, you won't get to the end of the A arm/ball joint travel.

I race a lowered extremely fast LS6 951. It's got stock A arms. I run sticky 315 front wide tires with massive 996 GT3 brakes. And I've run from between 450lbs front springs all they up to 750lbs front springs.

I've done this for over 50 track days per year since 2007.

I've jumped many a berm, fully loaded the suspension at 170mph on super speedway high banking, and gone airborn at Pahrump and Laguna to bottomed out and fully loaded. Over and over.

I've changed the A arms once "just because". I had them magnafluxed with no cracks.

If the ball joints were going to break... I'm the one that would have broken them. And they would have broken long ago.

Not only have they not broken... but the stock non-rebuilt A arm ball joints are very durable and will stay nice and tight for at least 3-4 seasons.

TonyG