bob944

Hello all....I'm seeking suspension input from anyone that can help.....especially the experts including John H. and Skip G. that have offered me suspension advice in the past.

I have DE'd my completely stock '84 944 for quite a while, and I'm well overdue to install suspension upgrades that have been in the works for some time. I bought a set of gently used Leda coil-overs along with Weltmeister sway bars, and they have been patiently sitting on the shelf awaiting the completion of my safety equipment upgrade (just finished!). I only intend to do this suspension project once, so I'd like to get it right. The car is a "street-legal" DE car that is rarely driven on the highway (tech-insp, auto-x, etc.) and I have no intentions of racing it in the immediate future.

My tentative plan was to install the Ledas front and rear along with the Weltmeister sways, and completely remove the torsions in the rear to make this a one-shot deal with no re-indexing hassles, and easy ride height adjustment. I already have poly bushings in the front, and I have heard the delrin torsion tube bushings are essential in the rear if deleting t-bars.

My real problems are with the rear....I did not realize at purchase time, but my Leda's are intended for the late model cars with alum trailing arms. The oil filled shocks must be mounted inverted, meaning that the large adjusting **** interferes with the steel "cup" that forms the lower shock mount on the steel arms. John H. got around this same problem by welding a custom lower mount, but before I start fabbing I'm investigating a "bolt-in" fix. I mocked the shocks into place and discovered that I could possibly drill a new lower mounting hole 90deg off, and about 1" above the stock bolt hole (See white dot in photo). This raises the adjustment **** just above the cup and seems like it would work. The biggest concern, however, is the decrease in suspension travel before bottoming out on the shock-shaft-bump-stop. With the car at stock ride height I measure approx. 2.75" of travel between the factory bump-stop and the chassis, as well as about 2.75" of travel between the shock body and the shock-shaft-bump-stop with the proposed new mounting location.

I would obviously need to lower the car for best performance, but that gets into extremely low suspension travel with the above plan.

IF the new mounting idea hole won't work my options are:
1.) buy correct early model Ledas (expensive)
2.) fabricate new steel lower mount
3.) update entire rear trailing arms (or complete rear suspension) to the late model parts.
4.) abandon the plan, buy 30mm t-bars and slap the Koni yellows back on the rear

I am open to ANY and ALL suggestions for solving this problem, preferably by using the Ledas I already have, and ideally ending up with the benefits of coil-over adjustability.

Several questions:
1.) Will the new mount hole idea cause problems, especially with the reduced travel?
2.) How much should a 944 ideally be lowered F/R for best track performance (16" wheels)?
3.) Should I delete the t-bars as I planned, or reindex them and go the helper spring route?
4.) I have been told deleting torsion bars will not cause other problems....anyone disagree?
5.) If t-bars are deleted, are the delrin bushings a necessity?
6.) I believe updating to late alum arms will also require calipers, rotors, hubs, axles, wheels, spring plates, and not sure about torsion tube, parking brake, etc.?????)
7.) If I ever get full coils working, what spring rates.....300F, 550R ???

Thanks in advance for your feedback!
Andy
'84 944 (new safety equip, in suspension dilemma)

Serge944

As long as you have a high springrate in the rear, the 1" decrease of shock travel will be irrelevant.

350/550# springs will work very well as it comes out to about 350/330 Effective. You could also go to 600# springs in the rear and use the swaybars to dial out any extra oversteer.

I reread your post - yes, 300/550 should be alright too, but if you plan on mainly doing DEs with your car, the extra springrate from the previously mentioned setup will do a better job of keeping the car flat through the corners.

Manning

Just throwing this out for consideration, but won't that place the lower heim joint in the wrong orientation in regards to rotation front to back and side to side? I doubt that lower joint is a high misalignment piece. I don't now how much rotation you actually need, but if you need much at all your going to damage that lower eye/joint/mounting point.

bob944

Thanks for the input Sergey and Michael....I had not actually thought of the lower heim being off axis. I do not think that joint is a high misalignment part, but even a BIT too much will destroy it.....and it's difficult to tell for sure....at least without pulling the t-bars I guess.

Notching the steel trailing arm to create enough clearance for the shock **** might work, but it would involve some very creative bracing that would have to be fabbed to restore the strength. I had also thought of building a sort of "U" shaped extension bracket that would allow me to bolt the bracket to the stock mount, and the shock to the bracket (effectively raising the mount point). This would still have the problem of shortened travel, but would eliminate the need to modify the steel arm. (I can attempt a drawing if this makes no sense)

I intend to run the highest reasonable spring rate that I can in order to have good track performance, but not rattle fillings loose on the street. I was thinking 300 or 350 front would be close, and probably the 550 or 600 in the rear as mentioned.

Any thoughts? I'm open to any criticisms.....THANKS!

docwyte

Do the late model arms bolt in? If so, source a pair from a junkyard?

Manning

Did you just buy these things? Other thanthe fact that they may have some blemishes on them now from test fitting, can't you send them back and get credit toward the correct parts? How much would that set you back? Or yeah, maybe look into converting over to the later trailing arms.

RobNL

I don't have my Ledas in front of me, but is it possible to remove the ****, and create an inspection hole where the **** would be when installed and replace the **** with something smaller, for example what you can alter with a screwdriver or allen key?

bob944

Now the ideas are rolling in!

Unfortunately, returning them is not an option. I have had them sitting on the shelf for a couple years now as other things delayed building the track car. I got a nice deal on them slightly used from a national level SCCA auto-x'er. I made the mistake of buying the late part, and now I'm trying to salvage the deal without buying new shocks.

Drilling an access hole for screwdriver adj. is a great idea, but not really possible. The Ledas have a huge metal **** welded to the shock body with a plastic cover. (See pic) Any attachment using the factory bolt hole will require a huge notch out of the mount, which will need lots of reworking to support the load.

This site gives a nice breakdown of the update/backdate options. As I suspected, the alum arms are longer necessitating a swap to late brakes, hubs, axles, spring plates, and wheels. Unless I find a deal on a local car being parted that I can bolt in the entire rear suspension, this option gets very pricey.

http://members.rennlist.com/m758/944suspension.htm

Lemming

Andy,

I just installed the Leda's on my 924S. I went with 400/450 and deleted the T-bars. I also have M030 sways front and back, but even on the softest rear setting I found that I had too much oversteer. I'm going to pull the stock sways off my 968 and give them a try on the 924S. If that works, then I can install the M030s on my street car that is way undersprung IMO.

As for ride height, I'm running right at 23.5" to the top of the wheel wells (IIRC). I'm on 15 inch wheels so it may differ. I believe that I could go about 1 inch lower, but that makes it a pain to get a jack under and to get on my trailer.

I did not switch to the delrin bushings in the rear, so far so good, but I only have about 6 track days with the new suspension. Which by the way is worth every penny.

tifosiman

He's not local, but "nine-44" here on the board (also another "Andy") is parting out a car now and has everything you need. You might want to send him a PM, it may not be as bad as you think regarding expense.

r1moto

Could you cut a semi-circle from the top of the cup to allow for the **** and use the existing hole?

Kurt R

I'd strongly discourage any cutting of the mount, especially if you intend to use coilovers. I'd either swap in a late rear setup, or have a fabricator look at it to see if he could cut off the old mount and come up with something new that allowed access to the ****.

I was going to offer up a swap for my Carrera's, but I took a look at the rears tonight and I think the hose to the remote would come out about the same place as the ****. SCCA changed the rules since the PO bought the shocks, remote reservoir and adjustment ***** on the remotes, but I can't use them now.

bob944

I've seriously considered cutting the mount, but it's not a simple notch by any stretch. The factory mount derives its strength from suprisingly thin stamped steel, and the particular shape of the lip clearly adds much of the strength. Cutting into that area would be required to clear the ****, and that would automatically weaken the mount beyond use. It would have to be almost rebuilt with lots of new bracing welded in place to form a new lower mount with the integrity to support the entire rear of the car. Even if the **** didn't exist, it is even questionable if the factory mount is up to the task of holding the load of 500-600# springs which the original design didn't account for.

Along these same lines, I've also stumbled along the idea of completely hacking off the steel "cup" and then welding a beefy nut right into the steel trailing arm so that it would function the same as the tapped hole in the alum arm. I'm not sure if the angle would remain correct, however. My shocks even have have the racers edge bolts that allow the heim joint to easily mount to the tapped hole in the alum. arms.

Thanks again to everyone!

Manning

I imagine if you are worried about hacking apart the mounting cup because of how it would be weakened, would it not also bother you to mount a heavily sprung coilover shock on a single sheer mounting point?