Evil Bunny

Looking for a steer in relation to spring rates, main & tender for a 996 C2. – About to fit new dampers.

The car will be used 70% track, 30% road, so I appreciate the setup will be compromised.

UK based so circuit asphalt is good, Silverstone, Brands Hatch, Donnington etc – Roads, similar to LA, some good some not so.

Tyres: Yokohama AD08R
Shocks: JRZ Motorsport 11 series, 2 way remote cans.
Car Weights: 1300Kg (Including driver)
Ride Height: 115mm front, 128mm Rear

I want the handling to be progressive and predicable, particularly on the limit and would be willing to sacrifice a little out and out pace, to achieve this.

I will head to my local shop but am looking to collect as much data, particularly first hand.

So what would you recommend and what is a step to far, i.e Are cup settings for the road a big no?

Thanks

jdistefa

softer spring i.e. 600/800

with a lot of bar

this will give you reasonable ride quality for the road with combined higher spring rate (sways) for corners

dampers will have a wide range of adjustment to accommodate road/track adjustments and you can bump can pressure at the track if you want a bit more 'spring'

jrgordonsenior

Agree with Matt above but can you drop the front any and stay "streetable"?
You f/r rake is only 13mm and 996's like something more like 20-25mm rake....

AudiOn19s

+1. My first thought in reading your post was not enough rake. I run 20mm on my car.

I did 600/750 on my car for years as a dual purpose car and it was good on relatively sticky rubber (nitto). Currently have 750/900 and honestly I can barely tell the difference on the street.

Evil Bunny

Thanks for the input.

In relation to rake, what heights would you recommend? - I am running a cup splitter which I would like to remain on the car

In relation to spring rates I am leaning towards..,

F; 700 with 150 tender
R; 900 with 250 tender

Thoughts on this from a street perspective? drive-able?

AudiOn19s

I run 106 / 126 with the OEM cup splitter.

You have to be careful with it on the street but I've had the same unit on there for 3+ years. It's pretty beat up but it's still there.

Evil Bunny

Thanks again.

I now have my suspension to hand, top mounts are monoball front & rear, fronts are Porsche GT3 not sure about the rear.

The dampers are JRZ, however there is a sprinkling of KW present.

The main springs are H&R, they appear to be Cup springs, while the tender/helper are KW, as are the bump stops.

H&R 130 – 260nm (Main) & KW 20-60-80 (Tender)
H&R 100 – 240nm (Main) & KW 10-60-80 (Tender)

Has anyone ever seen this setup previous and are there any issues, the front springs look very short.

Judging from the feedback I am assuming these will be unsuitable for my needs? Has anyone run a car on the street with springs this stiff?

Should I soften the springs I am assuming I will need to re-valve the shocks?

Are the tenders suitable for softer springs or should I be looking to change those out too?

All input welcome!

jrgordonsenior

Those are cup springs at basically 1300/1500 rates. Way too much for a street/track car. Use the tenders, but go with something like 600/800. The lengths are 4" fronts, 5" rears (+/-) which should work just fine....

Drop that front ride height to 108 or less....

Evil Bunny

Many thanks!

Will the dampers need to be re-valved when the spring rates are dropped to 600/800?

Also H&R springs, is there a big difference in their HRF & RF ranges?

AudiOn19s

I've never made a big enough of a swing in rates on my setup to think about re-valving them. The JRZ's have such a wide range of adjustment I'd think you'll probably just end up running them on the softer side of the adjustment range and still be OK. I'd check with a professional on that though. When was the last time they were serviced???...if not in the last 2 years it's best to just service them now anyhow....at least get the oil changed if nothing else.

IDK on the springs I use Eibach on mine...I believe from the markings your springs are 60mm which means you can run Swift springs which everyone seems to rave about.

I have 5" springs front and rear on mine, I know alot of people who have 6" springs front and rear. Ultimately there is enough adjustment on the coilover body that you can run just about any length of spring without worrying about it too much.

Evil Bunny

Many thanks for the info.

I was concerned that the springs looked particularly short and given the cup rates I am assuming that they are all but 996 Cup dampers.

With this is mind I feel the ride will be to low, would going from 4" & 5" springs to 5" & 6" increase the base ride height?

I understand that I have height adjustment within the damper but would rather the base line be more central in terms of adjustment as oppose to one extreme or the other.

I will be taking these to a shop, but would like to have a basic understand prior to doing so.

AudiOn19s

Lot of variables start to come into play as this turns more to a theory discussion without more base info.

Do you know:
Were these for sure on a cup previously?
Do you know what heights that car was run at?
Do you know if the spring perches sit now where they sat on that car?

The answers to those questions will help guide you.

Evil Bunny

The background, I had no intention of buying a new suspension setup this year, I intend to run as is through the summer and research upgrades in the winter.

However, a deal came up that I thought was to good to pass up on, and due to the speed it happened I did not have the oppertunity to do the diligence, hence the questions.

What I know. - The suspension came off a 996 GT2, the car only has travelled 7000 miles and this setup was on the car for 4000 miles. (Road & track use) - I do not know the ride height, I asked this but did the owner did not know.

I picked up the dampers, springs, mono ball top mounts and drop links for under $1000, which I think is a good deal.

I have included an image that I hope may help! - Thanks again for the input.

Slakker

I would try them out like they are, adjusting only the height, and then go from there. If they are Cup dampers they are about 3/4" shorter than the C2 dampers and so you'll need to run them a little lower. If you want to post the piston length I can check for you.

The height recommendations above are spot on.

Aspen Autosports

Those rates are absolutely too stiff for the street. 600/800 seem to be the sweet spot. You will likely want to have the dampeners revalved and rebuilt especially if you do not know the last time they were serviced.