jack.pe

I'm running Intrax shocks on my 964, with their Anti roll widget which is supposed to keep the car flat and supple while still running softish springs.

Current rates are 30N/mm on front and 70N/mm rear (170lbs and 400lbs) (same as Kw V3 springs) with H&R anti roll bars. Since the car is mainly going to be used on track i'm finding this set up too soft and am sending them back for stiffer springs.
Question is what to go for? Car will be used 85% on track with sticky R888 type road legal track tires.

Intrax suggested 40N/mm front and 90N/mm rear but I think thats not different enough. I saw that KW Clubsports are a good compromise and their rates are 60N/mm front and 120N/mm rear (in US terms 345Lbs Front and 685 lbs rear).. Does this sound like a decent compromise to everyone? Car is not quite fully stripped but pretty light with carbon bonnet, no stereo, sunroof delete, buckets....etch. Am getting it weighed in a few weeks but think I have lost about 150- 200Kg in all. That's from a C4 weight originally and includes the C2 conversion.

Also saw the Ohlins Road and Track run 60N/mm front and 90N/mm rear (345Lbs and 515lbs).. really respect these guys from my bike riding days and wonder if going for a smaller split like this would be better than going for the Clubsport spec?

I've read the previous threads on here and most of the hardcore guys for much higher rates but with my track day non-slicks not sure I need that level of stiffness,

Spyerx

there is a lot of depends here.
I'm running about 350/550 and well, I am probably going stiffer and my car is reasonably light at about 2700 lbs.

Bill Verburg

look at the difference f/r not the ratio

jack.pe

Thanks Bill, very interesting. When I last drove the car on track it was extremely tail happy, unfortunately I've since changed some settings but the subsequent track day fell through so I've not been able to observe what effect the changes have had. It was set up with a tail up stance to put weight not he front and minimise understeer as a C4, as a C2 it was too front endy. So I changed the anti roll bar setting at the front to the stiffer one and also lowered the suspension all round but only 10mm at front and 20mm at the back. In theory these changes should already have changed the balance and made the car less oversteery but unfortunately I've not been able to test it since I made the changes and I won't have the chance before the shocks need to be sent off. Geo wise it was quite close to RS spec from what I can remember but that will be redone too...
The delta on the KW club sport settings seems high at 60.. but I guess that can be tweaked with the anti roll bar settings and the damping too. i would hate to have an understeery car again.

Bill Verburg

Changing rake(tail up) doesn't appreciably change weight distribution, of course if you go to an extreme tail up it will be noticable, It also reduces flow under the car(good thing) and increases the effectiveness of a rear spoiler(good thing), Generall a small amount of rake will be helpful.
stock 964 has a deta of 4 or 5 depending on the year, the sportier RS has a delta of 34 right in line w/ the 964 Cups.
Yes swaybars also affect over/under steer, I like the cars basic setup to be good, then you can tweak for conditions or track layout w/. the sways, Sounds like you feel the car has too much over steer, changing your sways up in front and down in back induces more under steer
The Ohlins @ 60/90 delta 30 is probably right around where you'd want to be, though a bit light 450/650(79/114) is probably better for an 85% track , 600/800 105/140 for 100% track, start w/ the sways in neutral then tweek to suit.

RallyeChris

I'm running 400/600 on my C2. Totally streetable, though somewhat firm. Excellent on the track. Moton Clubsports. Porsche Motorsport adjustable sway bars. I do 80% track, 20% street. I may go to 600/800 next season.

Bill Verburg

High end digressive shocks like yours talk a huge amount of the pain out of stiff springs on the street, and are magical on track

kos11-12

Hi Jack
mine are
50/70 (300/450) on my C4 with the V3 shocks, I only change the front ones for stiffer spring,
with standard front roll bar, H&R stiff at the back.
rake more or less +10 mm compare to RS
a bit hard on road,
I gues for a C2 track car and if you keep the back springs, you may need 350/450
from what I understood ratio would be about 1,5 for C4 and 1.3 C2

DD GT3 RD

jack.pe

Thanks all for your replies.. am edging towards 60Nm front and 100Nm rear. This will keep the same Delta of 40 as i have now with 30Nm/70Nm
Rear a bit softer than the 120Nm on Clubsports but I think I can dial out any resulting understeer on the front sway bar or with damping alterations on the go..

ThomasC2

My car is set up for track use and I put in on a trailer when I'm going to a track day. But....I used to drive it on the street with the same set up, Even going on long trips from Stockholm down to Nürburg Ring and Spa. Around town it's a bit harsh with pot holes etc but for country roads and Highways it works just fine. But most importantly...on the track it is amazing! More or less neutral and a rock solid in high speed corners and it reacts very well to different settings of the sway bars.

The suspension is factory Bilstein 964 RSR dampers with 160Nm front and 200 Nm rear. The car is 1180 kg with 10 L petrol,

ALSPEAKE