Hey everyone, I posted a while back about running issues for my 88' Turbo S. Got that solved, had the DME rebuilt and she's running great! I did find an Authothority Chip in the DME, so I'll probably dyno the car and make sure it's safe to drive. Advice on that front is welcome as well.

I'm posting because the original Koni's are worn out, the car wallows all over the road. I've unfortunately raced a few cars with shock issues and am very familiar with what blown shocks feel like... I plan to have them rebuilt to keep the car original, but the car is my daily so in the mean time I plan to put a set of Leda coil overs that I bought off a friends race car. They're valved for anything from 250lb springs to 700 lb springs, and they currently have 600 lb springs on all four corners. My question, is what spring rates should I run?

The car is a daily and will likely see some track use, and I don't mind a sporty/stiffer ride on the road. The car is entirely stock otherwise, so slightly stiffer than the stock rates would be fine, but I don't want to miss the opportunity to get the right spring rate that can be used once I decide to rebuild the original shocks. The Leda's are double adjustables, and pretty used, but likely dampen much more effectively than the current setup!

Also, I intend to keep the T-Bars for the time being, as I'm not quite confident enough in my own ability to install the suspension (and don't have the time...), and would like for the install to be as cost effective as possible. That being said, what rates would you all recommend for a track ready daily driver, that still has torsion bars in the rear?

Thanks!

- Andrew

 

 

200lbs to 250lbs is the maximum that I would suggest on a street car in a front. I myself have 250lbs springs with 27mm TBs and 30mm and 19mm sway bars and it is still fine on street and works also for the track. For the rear you have to apply IIRC 65% coefficient if you put the coilovers, thus to match the fronts of 250lbs, the rear coilover springs should be around 380lbs. Double check it by searching the forum. If you keep the TB, you have to consider that - standard ones were around 140 lbs.

 

I had 200 (I think, maybe 250) years ago on a street 944. It made it fun enough at auto-x and spirited driving, and mostly bearable during street driving. Wouldn't go much stiffer...

 

 

Think it's as much about the shocks / valving than the springs. Ran 628f and 710 r (in concert with T-Bar) for a few years with KWs and the car was fine on the street.

 

I have 300 up front. That in conjunction with the sway bars will loosen your fillings. I would go lighter.

 

As you can see, there is no consensus for DD spring rates. It boils down to your personal tolerance and acceptance of discomfort to find the best handling/comfort compromise. Yes good shocks make a difference, and it's nice to see you plan to change the suspension in the near future- this will give you a chance to change the spring rate if you don't like your first choice.

Personally I've been through several spring rate changes and my tolerance has changed over the years. I got my 87 Turbo with stock springs and M474 Konis set to the softest position. That was way too squishy. Next came 225 pound springs up front with 27mm torsion bars. That was a great improvement but I still had to hold back when cornering aggressively. Then I got 275 pound springs with 28mm torsion bars and M030 30/19mm swaybars. That was a very nice combination. It was probably the best I've experienced for a DD that is used for autox and fast backroad driving.

Then I got a 97 BMW M3 with crappy suspension and I realized I was being a *****, so I installed 350 pound springs up front on my 951 and I love it. It's a little too firm for DD use but it's amazing in the backroads.

 

I appreciate all the responses. This definitely points me in the right direction. I think the general consensus is that the 600lb springs on the Leda's are probably a little much for the road. It sounds like I'm gonna end up somewhere in the 250lbs-350lb range. These shocks do have a wide range of adjustment, so it's likely I tune it to be nice on the road, and then crank them up a little for the track.

I keep finding other items I need to address before doing the suspension though... Found out the Autothority Chip is causing it to run rich before the turbo comes in, and it's running 19 psi of boost, seems as though the waste gate is the suspect there. 250 whp and 300 lbs torque on an 160,000 mile motor is pretty impressive though. I probably need to dial that back a bit before I address the suspension now!

 

Another data point. 300lb springs up front, 400 lb on the rear (no torsion bars) with koni sports. 30/19 anti-swaybars.

weekend fun toy, and 4-6 autocrosses a year. Still playing with springs

 

Just did some Dyno time, looks like I need to sort out a shot wastegate and old Authority Chip that is causing the car to run super rich at low rpm. I'll probably have to sort that before I do suspension. Might start a new thread asking for more advice on that...

 

I have 450 front/400 rear with stock torsion bars. I had 400 all around but thought I could stand a little stiffer so put the 450's in. The car is stiff, very stiff but I drive it a lot and actually have driven from LA to Nashville 3 times so far and my kidneys are still intact. Also, my shocks are Bilstein Escort with the stiffer race valving and I think that's where the stiffness comes from mostly.

You can live with this everyday but it will beat you up, depending on your streets. And passengers will hate you. Or at least complain non stop. Bumps and dips aren't so bad; potholes are killers. I wouldn't go any stiffer....Well, maybe 500, but that's it....ha ha!

I can't imagine 250 being enough. If you can tolerate a stiff ride, I would lean towards the stiffer end of the spectrum you mentioned. Plus, you can play with the shock dampening to get what you like.

Happy springing!

 

 

I think if the T Bars were kept the rear would be a little stiffer, I believe these were run previously with no T Bars.

I can find some info on them online. If you want to connect via private message I can send pictures etc..

They came off of a racecar that was run for ~2 seasons, so I can't speak to their condition (as far as using them goes at least), but they look like a set of used shocks. Still 100% usable and very very high quality pieces.

Gotcha, I like KW's and would certainly be interested in trading.