bj

Hi All

Is there much difference in the performance between Bilstein heavy duty and Boge which are currently on the car? If I go with Bilstein do I loose the adjustment which is currently on the Boge?

Thank you for your responses
Bill
90C2

Adrian

Dear Bill,
No you do not lose the adjustment. The spring perches can be transferred to the new parts if they do not have them already.
The Bilstein HDs are stiffer than the Boges but I cannot give you a quantitive figure. The question is what do you want to achieve by changing your suspension components?
Ciao,
Adrian
911C4

Drew_K

I just had Bilstein HD's installed, and they come with the spring perches.

FYI, if anyone is considering using TRG camber plates with Bilstein HD's, they're not a direct fit and require some machining.

I don't know how well the HD's match up with the stock springs, but I suspect they'll last longer than the OEM Boges.

bj

Hi Adrian

My left rear Boge shock recently lost all its' oil and it has to be replaced. I could just replace the broken one with a new Boge but I was entertaining the idea of replacing both and maybe getting a little more performance at a slight cost increase by putting Bilsteins on the rear. I've noticed when I take a corner a bit agressively and the rear end is starting to break loose it feels a bit choppy (this is the best way I can describe what it is doing) where the rear gets traction then looses it intermittenly. It maybe the tire/rim combination (i.e 16" 928 style rims and BF Goodrich TA's) which is causing it but I was hoping new shocks would solve some of the problem. For a $100.00 more for each shock I can upgrade from Boge to Bilstein and I would only be doing the rear shocks right now and leaving the stock Boges on the front. I like the stance of the car as it is with Boges and I don't want to change that if I go to Bilsteins.

Your thoughts are welcome
90C2
Bill

Irishdriver

I thought I'd be very clever and fit the Koni sport adjustables.

Great shocks but.....the top of the strut is in the engine bay and, short of removing the complete air intake system, adjusting the shock can only be done by a double-jointed-vertically-challenged-gynalogically-trained octapus.

be warned - set the Konis to the setting you want before fitting - the left one is the worst.

Adrian

Ah Irishdriver the hassles of owning a post Oct 31st 1990 build 964. I have no problems with my Konis at the rear adjusting them.

Dear Bill,
I do not advise changing the balance of the by just changing the rear shocks and leaving the rest. If you like the Boges stick with them or get rid of front and rears.
I would certainly advise you lose the tyres as well. I do not like the design of the wheels either but that plays no part in handling.
My advice is to stick to Boges and invest in a decent set of tyres.
Ciao,
Adrian
911C4

bj

Hi Adrian

Thanks for the response. Do I understand you correctctly? Are you saying if I replace the shocks in the rear with Bilsteins and leave the original Boges in the front that I may change the stance/attitude of the car. I thought it would be the springs which would affect the ride height. Also, because my car is a 1990 the issues Irishdriver experiences with his Konis on a post 1990's 964 is not a concern with mine. I know the tire/rims are not the best but I was planning on changing them eventually - one thing at a time.

Thank you
Bill
90C2

Adrian

Dear Bill,
I did not mention ride height I mentioned balance. If you stiffen up the rear with Bilsteins and do not compensate then you will have additional handling problems.
Now you mention it I should remind you that ride height is determined by the compressed length of the spring and shock absorber assembly. A stiffer shock absorber at 1990 pre-tension levels will not compress as far. The weight of your 964 might not compress the shock absorber to the correct ride height either. You may have to do a new ride height and corner balance adjustment.
However my main concern is that I am not comfortable with suspension changes like this.
Ciao,
Adrian
911C4

Drew_K

Stiffening up the rear will dial in more oversteer. That may be what you want, but just FYI.