guznax

Hi Guys,

The suspension on my manual '85 928s is still stock. I would like it to be a little stiffer without changing ride height.
I'm very pleased with the stiffness of the Bilsteins on my 911sc. It makes the car a bit more sporty and that is ok because it is purely a hobbycar for me, so I would like it a bit more stiff without my theeth falling out
I found out that the Bilsteins are offered by www.928intl.com, but sadly no Eibach springs anymore.

What upgrade in your opinion is a good compromise for a '85 928s?

thanks and greetings,

Xander

Mrmerlin

IMHO leave the springs you have on the car alone ,
putting on stiffer springs will rattle the car loose.

The 928 is a GT machine not a racetrack runabout
thus its sprung for long distance comfort.

Every 928 I have ridden in that had stiffer springs lost its long distance comfort
My 88 S4 is great for going 3 states away bilstiens with stock springs.

guznax

Thanks mr Merlin,
So swapping to bilsteins alone allready made a noticeable difference compared with the stock dampers in stiffness?

Mrmerlin

yes the hi speed stability that the Bilstiens give make the chassis very competent at speeds near 100 MPH or more

GregBBRD

Definitely.

I have to be careful about shock selection for my clients. Bilsteins can be too stiff for some people, especially on cars with either 17" or 18" wheels! (The tire's sidewall is part of the spring rate of a car, also....shortening the sidewall changes the spring rate of the entire car.)
​​​​​​
Most 928 owners are oblivious to the fact that the front lower control arms are a huge percentage of the spring rate/dampening, in these cars, and that they deteriorate with time and use. This is extremely important! Make sure the rubber bushings are intact and still vulcanized to the control arms (and the front most mount) when you do the shocks.

Note that these rubber bushings take a set with time, meaning that the lower control arms must be replaced in.pairs to get equal effective spring rates on both sides of the car.

guznax

Thanks for your advice Greg!
The bushings and control arms have just been replaced as far as they were worn.
Regarding the wheels, we like to stick to the stock rims (teledials in our case) with Porsche approved tires with the stiff sidewalls (conti's)

In my opinion behaviour steering on our 85 is quite precise and no rolling, but it could use a little more 'feeling'

guznax

Thanks Greg,
I will stick to the stock teledial wheels.
Thanks for you advice on control arms and bushings. I will check them and replace them first in case they are worn.
grtz,
Xander

guznax

And how is the behaviour in bends on winding roads?

bureau13

I just put Bilsteins on with stock springs on my '86.5 and it's made a huge difference. Mind you, I had old worn-out Boges (stock) on prior, so I can't compare it to new Boges. But I don't think I'd want it any stiffer, to be honest.

Note to Greg's point, I have 17" rims, not the stock 16"

guznax

Thanks Jeff!
Is the steering more direct as well?

Speedtoys

Sway bar can make a big difference here, but is A) hard to find, and B) needs a rear bar with it, and also hard to find.

the day I did my rear bar I had my stroke.



...not that the two are related..but...

bureau13

Tbh I haven't really noticed a problem with the steering, until one of my tie rods started going bad. I fixed that, and of course it's back to the way it should be. I know my rack bushings are allowing too much movement as well, but I don't really notice that while driving.

guznax

Thanks!. I'll leave the swaybars stock.

Thanks! I'll have a look at that!

jpitman2

I have M474 from factory on stock 16" dish wheels. Replaced the fronts with new Bilsteins @42k(front was LOW!), and had the rears rebuilt by local dealer @48k. The new fronts came with adjusters, and ride height is all in spec. On poor suburban roads the ride is hard but not harsh IMHO. At speed its terrific, very taut, but nowhere near harsh - on good blacktop its like a magic carpet. Highly recommended if you like taut.
The spec book calls up different springs for Bilsteins. It also says that if Boges are replaced by Bilsteins without changing springs the front will rise ~ 10mm. It recommends use of the white/green springs - these are listed at 6377-6630 N @ 205mm length, where the white marked springs are listed as 6377-6573N @211mm length. Also have Bilsteins and matched springs on my Subaru gt wagon - similar ride and handling.
jp 83 Euro S AT 57k

guznax

Thanks JP.
The drive quality you descibe is what I'm looking for.
Did you replace the stock springs in the recommended springs as well or did you leave them stock?