1989 944 Turbo S suspension upgrade

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1989 944 Turbo S suspension upgrade

Postby LUCKY DAVE on Wed Feb 27, 2008 10:32 am

I'm going to move my 944 Turbo S from kss to ks (8 points)
Looking at the endless vendors on the web, I see coilover assemblies without remote reseviors (only 2 points right?) made by H+R, JRC Cross, and others. It looks like I can get spring rates of 400 lb front, 600 lb rear with coilover assemblies.
Is this the way I want to go? Who makes the best ones? Whose products do I avoid? Do I want to stick with torsion bars for the rear in the first place?
Also, since there are only about 12,000 sway bar choices, I need advice there too.
What wheel/tire sizes can I fit without changing the front fenders?
I know I'm asking for car chassis parts vendors 101, but hey, I'm a motorcycle roadracer. If any club members need to know anything about bike chassis dynamics or vendors, I'm an expert, and happy to help.
But cars......I'm clueless.
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Postby 944 boy on Thu Feb 28, 2008 3:04 pm

The Escort Cup coil-over set is the best bang for the buck. I don't know anyone who has those and hasn't loved them. JIC (cross) would be my next choice because they have a dedicated hight adjustment separate of the spring pre-load. Those are nearly 3K however. You can go up to and beyond 8K for triple adjustable Ohlins.

I would Stay away from more than single adjustable unless you really know how to adjust suspension or are willing to to pay someone top dollar to constantly adjust you car.

Ditching the t-bars makes it easier to set up the car, corner balance and whatnot. It may add more points though. I plan on ditching mine eventually. You can also leave the stock bars in and add a lighter spring to the rear and not have to deal with dropping the whole rear suspension.

I have 375lb springs in the front and 30mm t-bars in the back which has proven to be a good balance. Here is a link to a page that has spring rate conversions for the rear.
http://www.tech-session.com/kb/index.php?article=39

As for sway bars there are really only 2 aftermarket choices. The Weltmeister 28front and 22 rear, or the Tarrett/Koklen adjustable bars. The cheaper choice would be the 968 M030 factory option, only 3 way adjustable but light and a good balance. I have the Weltmeister bars and like them other than their weight.

Good Luck!
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Postby lrayner on Thu Feb 28, 2008 5:29 pm

Paragon has a package suspension deal that saves you several hundred dollars over buying stuff seperately. It includes front and rear koni sports, coil over kit for the front with choice of spring rate, front and rear weltmeister sway bars and rear torsion bars. I notice 944 boy is a spec. racer. I have a similar set up on my 924 S with 350 # front coilovers and 30mm rear torsion bars. But I think the Spec cars are quite a bit lighter than your KS car so you might want to check with some turbo guys on what to run... Jad?
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Postby LUCKY DAVE on Thu Feb 28, 2008 5:47 pm

Jad's advice is "remove the entire interior (use the 8 points to make the car as light as possible)and install aftermarket swaybars and front fenders to fit 275's.
The car is still pretty however, so I'm trying to get equal performance without cutting the car to bits.
I'm thinking of using the 8 points to change to coilovers with camber plates (4pts) change the swaybars (2pts), and change the seats (lighter, 2 pts). Bigger tires not exceeding 260's are free.(I think)
Am I dreaming? Or not reading the rules correctly?
Informed advice encouraged.
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Postby ttweed on Thu Feb 28, 2008 8:35 pm

LUCKY DAVE wrote:...change the seats (lighter, 2 pts).
The first increment for weight reduction is removal of 51-150 = 4 points, so I don't know how you'll spend only 2 points on weight reduction. If changing the seats removes less than 51 lbs., they're free, otherwise you're at 10 points with your plan.

Bigger tires not exceeding 260's are free.(I think)
That's correct, as long as they are 140 treadwear or greater, and are on rims that don't increase your stock track width more than 2". Frankly, I don't think there is any more important improvement you could make in going to KS than to use a 4-point tire. You will be faster that way than changing spring rates and adding camber boxes for 4 points and still using a 140 treadwear tire, IMHO.

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Postby LUCKY DAVE on Thu Feb 28, 2008 9:22 pm

You may well be right.
But.....the body drags on the ground with the stock tires.......with stickier ones the door handles may drag....
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Postby ttweed on Fri Feb 29, 2008 7:54 am

LUCKY DAVE wrote:.....the body drags on the ground with the stock tires.......with stickier ones the door handles may drag....
Bigger ARBs and higher spring rates should help with that. My 8-point formula for S class would be 2 points for spring rates (leave out the camber boxes and dial in as much negative as you can get with the stock adjustments), 2 points for ARBs, and 4 points for Hoosier A6 tires (preferred over the V710 in your case, as they make a 255, which would max you out with no width penalty, although it is a pretty tall tire).

Put in the race seats, but ballast back up to within 50 lbs. of stock if nrcessary so as not to take any points for weight reduction. 4 points for a mere 150lb. weight reduction is a ridiculously onerous penalty, IMHO, and not worth the result in lap times.

YMMV,
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Postby LUCKY DAVE on Fri Feb 29, 2008 8:35 am

Put in the race seats, but ballast back up to within 50 lbs. of stock if nrcessary so as not to take any points for weight reduction. 4 points for a mere 150lb. weight reduction is a ridiculously onerous penalty, IMHO, and not worth the result in lap times.

I agree about the weight penalty being unreasonable, but the rules are what the rules are.
My guess is that by the time I remove the (very heavy all electric) stock seats and replace them with light weight race seats, then add proper belts and a cage, weight won't be a problem.
I haven't heard an opinion on replacing the rear torsion bars with coilovers or adding coilovers to the rear, and how legal it is/number of points involved. Is this just considered a change in spring rate? The units I'm looking at feature adjustable ride height/spring rate and the fronts have hard (monoball) top bushings integralk to the design. There are no external reseviors or welding/machining required for installation.
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Postby Jad on Fri Feb 29, 2008 9:37 am

Dave and I have had numerous conversations on this. He asked how to make the car as fast as possible in KS. My answer was based on making the car as fast as possible, not keeping it pretty. Lots of weight can come out for zero points, flared fenders in front, zero points as 255's may or may not fit stock, lose the cat, and muffler, intercooler ducted nose, custom built shocks, etc, all ZERO points, then do springs all around for 2 points, GOOD sway bars and tires. All the free stuff makes the car fast, just not pretty and stock which is a bit of a dilema.
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Postby LUCKY DAVE on Fri Feb 29, 2008 9:42 am

I know Jad is right (his track results speak louder than words).
Now if only the car had some dents in it, or the interior was flogged. Neither is the case, and until it is, I just can't bring my self to play sawzall savage with the poor thing.
Of course, not winning anything might change my view considerably......
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Postby ttweed on Fri Feb 29, 2008 2:54 pm

Jad wrote:Lots of weight can come out for zero points...
Jad-
Is this because the 944 Turbo is always over the stock curb weight specified in the manual?
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Postby LUCKY DAVE on Fri Feb 29, 2008 6:30 pm

Jad-
Is this because the 944 Turbo is always over the stock curb weight specified in the manual?

It this true? How much (how many pounds?)
Does it depend on an individual car's option list?
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Postby Jad on Sat Mar 01, 2008 11:47 pm

yes, the turbo S uses the turbo weight but has a lot of required? options? You need to weigh it to see where you actually are, mine was about 200lbs over, plus we have gas rules (21 gallons) and spare tire etc. It varies, but they are all well over.
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Postby lrayner on Mon Mar 03, 2008 12:41 pm

My 944 S was way over the weight stated in the manual. Fill the tank, put the spare in and have it weighed at a certified scale. There is a lot of weight you can take out without wrecking the looks. It will just get louder inside :cry:. Weight everything that you take out then see how close you are to stated weight less 50 pounds.
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Weights

Postby Greg Phillips on Mon Mar 03, 2008 9:42 pm

lrayner wrote:My 944 S was way over the weight stated in the manual. Fill the tank, put the spare in and have it weighed at a certified scale. There is a lot of weight you can take out without wrecking the looks. It will just get louder inside :cry:. Weight everything that you take out then see how close you are to stated weight less 50 pounds.


I think is simpler, or more complicated, depending on your outlook. The weight he has for a benchmark is not his car's actual weight, but the published factory curb weight for his model. Usually the curb weight is lighter than the actual weights and you have a fair amount of weight you can lose before getting below the 50 pound threshold to take points.
I see 1400 kg listed on the Porsche website for the 1989 Turbo (S)
Also the driven weight can be even less with the removal of jack, spare, tools and less than a full tank of gas.

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