Zuba951

I want to put a Bilstein Firehawk Suspension on my 86 951 and I’m having a difficult time finding the information I need.

The Bilstein Firehawk Set consists of: Front gas struts 380/150 rebound/compression and Rear gas shocks 400/200 (no coils)

I’m planning 300 lb springs in the front and 28 mm t-bars in the rear

Chart on spring rates vs torsion bar size from Sway-a-way.
22m = 98.03 lb/in
23mm = 117.11
24mm = 138.84
25mm = 163.47
26mm = 191.24
27mm = 222.40
28mm = 257.22
29mm = 295.98
30mm = 338.97
31mm = 386.47


Questions

1. Spring length: how long or how short? The Information off the eshocks.com web page says “As a general rule, you need a total spring length equal to twice the shock travel” this is spring + spacer +helper (I want the thing to stay all together when I jack up the car) I was thinking a longer spring than a shorter one (do you get a different ride?)

2. Spring Diameter 2.25 or 2.50?

3. Rear 400/200 I spoke to Jack at Bilstein (shock tuner guy) and he said to put the suspension on the car and try it out for a while and send it in and he will re-valve it. He recommended (digressive valving)? And and changing the numbers a little but he said to check it out first. There is a form on the Bilstein web page under services…easy enough…he also said the 400/200 were to stiff for the 28mm bar (257lb) and to have them re-valved to something like 400/135. (I have to check the number )

4 Bilstein HD rear shocks the valving is 235/119 and Jack from Bilstein said to try them out they might work fine on 28mm (257)rear T-bars. Has anyone ever tried this?



Thanks

Brian
86 951

2bridges

Hey brian -

a 300# front spring with 28mm bar will be a push setup.
why not stay closer to recomended balanced setup - 300# w 29mm bar.

As for spring diameter I would run the smallest reasonable to allow widest tire fittment

Zuba951

I was thinking the front is 90% because of the angle and gives me like 270 (300) to 257 (28mm) I don't want it to be tail happy...Does that sound right? Right now I have the stock sways 24 in front and 18 in the rear...

Now that I think of it the F 130 to R 126 stock set up was a push so are people saying to go larger in the rear anyway because of the way the car is...

Brian

2bridges

A push setup is great for novice safe setup. You will definately give up alot at the track. Push will keep you from rolling in the throttle as soon. With turbo car especially you will pay waiting for spoolup on exit. A balanced setup would be better suited to a reasonably experienced track driver.

I am installing a 325# front and 29mm torsion bar setup. Cannot yet comment as only front installed yesterday. I expect a very slight push with this setup and 30mm 968 m030 front sway with adjustable 22mm welt rear. Did tons of research and consideration for my use. Ultimately made a "best guess" after considering lots of different experience/opinions.

I went with rebound adjustable koni. Originally planned for escort cup.... after lots of reading and carefull consideration I changed plan.

I expect a good amount of track use, but will see lots of street use. The koni rebound adjustability - soft shock setup for street - I am hoping will allow for decent spring rate without busting my kidneys. Will still be plenty firm no doubt, but far more reasonable than the escort setup from what I have read.

I have driven a rough stretch of road with fronts on full soft and firm, huge difference. I think I will be pleased with adjustability for street.

I am going out to tear into the rear now best of luck.