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Suspension Mods - (Rewritten) I was up in the air on this for quite some time. I even surveyed the Rennlist group to see what everyone was running. Here is the SPREADSHEET with everyone's numbers. I finally settled on 400# front springs and kept the rear torsion bars and added 300# Hal coil over shocks. Here is how it went. The fronts: Below are the components for the front M030 strut conversion to 2.5" coils. I'll see if I have a constructed picture.
The fronts are a piece of cake. I had M030s with threaded struts. I moved to 2.5" coil springs so I ordered the .5” coil over kit for M030 front struts. It replaces the stock spring perches. Purchased from Paragon Products. Talk to Jason. Those without M030s can get a kit that actually costs slightly less and does the same thing.
Rears: I kept the 25.5 mm torsion bars. They were already too low, I had adjusted them as high as I could without reindexing (again) and still too low. So if figure I had about 1" of preload to put onto the coilovers. If I wanted to, I could swap the front and rear springs (if it was too stiff or if I needed to get rid of the torsion bars.) (EDIT: Stiffness has not been a factor, plus I feel more comfortable with the torsion bars in there in case I break a shock mount, read on...) I went with HAL shocks. Now know by QA1. www.halshocks.com These are the same shocks that Huntley sells. The difference is that Huntley has engineered proper mounts for the upper and lower mounts. The price difference is about $400. I made my own mounts.. These are the components for the rear coilovers.
Here is the research I did on these shocks... On the bottom mount I used the Poly bushing kit that came with the QA1 shocks and the 5/8" sleeve (they didn't have a 9/16" sleeve). Then used the stock 14mm bolt with metal tape to expand the diameter so that the fit was tight. So far that has held up well. I'd like to go with the Racer Edge shock mounts, but they were out of my budget. The spacer needs to keep the shock from rubbing on the lower mount. Mine doesn't rub like this picture. Here is another solution. Using a stud instead of a bolt. (same picture if you look close)
High dollar solution to the lower shock mount. Very Strong. http://www.racersedge-inc.com/bushparts.htm
Top Mounts. This is where it gets a bit weird. Please turn back now. It's almost too much to take... I used the swivel mounts as shown in the pictures below. Added shims to the side to compensate for the difference in width. Tough to get in there, but solid. Then the shock mount had a 1/2" tube, and the bolt was 12mm. I wasn't comfortable with the slop, so I found some metal tape used in duct work. (not duct tape) This is actually metal that I lined the inside of the tube to create a smaller gap. I told you it was wierd.
Here is more information on parts and such.. HAL
Rear Coil Over Shocks for Porsche 944/951 This write-up describes my experience with installing HAL coil-over shocks on the back of my 86 951. From another Lister who's
"been there". Here
is the information that you wanted - The shock is made by HAL and the model is
called Proma Star. Best price is $179.95 (169.95 now) each from Summit Racing
Equip (800-230-3030) - part number HAL-DR4855B-1 The correct size for our cars
is the 14" extended / 10 1/8" compressed size. I got the other parts
directly from Carrera http://carrerashocks.com/catalogs02.htm
click on the road racing catalog - To make this fit perfect you will need a
3/4" shock extension, Carrera part number 1949A (the shocks have a 9/16 x
18 thread.) On the top end you will need a set of Carrera #1815G reducer
sleeves. You will have to grind off a little to fit in the stock mounting area
but it will give a nice fit. The lower bolt is a 14mm bolt so you may need a
reducer and a special rod end. The set I got from Huntley had a different rod
end installed already. Check the Carrera web page for the road racing catalog,
lots of good parts there. Mounting questions - The shocks are mounted 'upside down' - the adjustment knob is at the top. The extension goes at the bottom. The sleeve (1815G) is a set of bushings that adapt the upper mounting bolt to the same diameter of the spherical bearing - you will need 4 altogether. I have a set of the racers edge mounts on my track car - they are the way to go if you are going to really stress the car. (BTW - I am a racers edge dealer so I can get you a set if you want).
NOTE: I talked to the
tech at QA1, (Hal Shock Mfg) I asked him about the drag racing description in
the Summit Racing catalog. He said
that these shocks were not valved strictly for drags. (Drag shock valving is
unique). They are double adjustable, with a single knob. Both the rebound and dampening get adjusted at the same time.
http://www.halshocks.com/shocks/promastar_al.html The only other hardware that you will need is a 1" spacer to fit between the lower rod end and the aluminum arm so that the coil does not hit the arm. As for the coils - use any 2.25 ID spring you like. I have 550 lb Eibachs (9") on my car and found them to be pretty nice with the 350's on the front. It looks like you can put the whole thing together for under $500 a pair with all the hardware. Another option for the lower mounting point is the racers edge mount which looks like a nice (but expensive) piece. High dollar solution to the lower shock mount. Very Stong. http://www.racersedge-inc.com/bushparts.htm
QA1 Motorsports/HAL Shocks externally adjustable coil overs
are adjusted by rotating the knob at the base of the shock. The knob rotated
fully counterclockwise is the softest setting. As the knob is rotated clockwise
the resistance on both the bump and the rebound sides of the piston are
increased. There are 12 settings. Torsion
bars with Coil-overs. The
real problem with the 'combo' set up is that the spring rate changes drastically
under certain conditions. If you are cornering very hard and the inside rear
reaches the point where the coil is not loaded then all of a sudden it is seeing
only the torsion bar spring rate. Since both sides of the suspension are
'joined' together by the sway bar the rates can do some pretty weird things.
Some folks use that type set up and don't notice any problems. My fear is that
you could never really get he car totally dialed in. In
your case you are in pretty decent shape with the 1 1/2" load on the coils.
Most folks can't get any load. I originally set up my track car for stock class
- I took the torsion bars to a local machinist and had them turned down to 10mm
- 4 lbs per inch(!) and that cost me $50.
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