P-track

Just finished the install of a new suspension and thought this info might benefit others thinking of upgrading their suspension.

After literally days of browsing Rennlist, sleepless nights and nightmares where Ferdinand Porsche haunts me for not using Porsche original suspension I finally opted for Bilstein HD and H&R springs. And decided to fit some Walrod bushing on the A-arms as well.


And yes I I know that:
Bilsteins HD are for wannabe’s not willing to get a real suspension (aka PSS10).
H&R springs are painted pink for a reason……
Shopping carts have lousy handling because of Walrod bushings....

Anyway, I used both the intructions form Gert and the DIY install guide by Jeff, available here on Rennlist for a small fee. With these manuals the install itself is not that hard, and I did not have any serious issues apart from not having the correct tools at first.

Just a few notes that maybe will help others.

Car: 1994 ROW 993 C2 narrowbody ( 65 K miles)
Struts original: ROW standard BOGES
Setup: Bilstein HD with H&R lowering springs and Walrod bushings ordered through Gert Carnewal.
Install time dampers and springs: 8 hours
Walrod bushings: felt like 5 years but was only 4 hours.

• My car is a 1994 ROW model and was still fitted with the original Boge (!) dampers. The only difference to the Monroes is that the topnut on the frontstrut is 22mm iso of 21.

• Instead of the special HAZET tool you can also use a VAG tool number 3078. It is a direct copy of the HAZET tool only half the price!

• The 2012 model Bilstein dampers have a slightly different mount for the droplink, you need to unscrew the droplink mount from the strut to install the droplink to the strut. You cannot install the droplink with the strut on the car!

• The fronts are adjustable with everything installed on the car so you can just experiment until you have the correct height. With H&R springs I needed about 220 mm measured from the bottom of the locking collar to the bottom of the strut. That gave me a ride height of RS +10mm.

• The rears can not easily be adjusted with the struts installed. To get a RS+10mm ride heigth the distance between the locking collar and bottom of strut was 125 mm. See photo ( should be 125 mm )

• Although it is possible to install the rears without taking of the filter cover and blower housing it makes it lot easier when these items are removed. It’s only 10 mins extra work but so much more room to work with ( and still quite cramped…)

• The eccentric bolt on the lower control arm has to come out to remove the rear lower control arm. On some cars the left heat exchanger prevents you form getting the bolt out of the way. I read some people make a dent in the heat exchanger to create more room for the bolt. On my car I only had to lift the engine a little to give me just enough clearance.

And it is very cliche but after about 13 hours of work the car has transformed, like many others have said the difference is unbelievable!!!!

Here are some before and after photos and some pics of the dampers:;

JonasO

Nice, you have the same rideheight as me, I have a H&R clubsport kit on my car. And as you say, it's a different car.

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SC2993

Nice write-up, thanks for sharing! What are your first driving impressions with the new set-up?

P-track

Haven't had a chance to really test the new suspension but the car feels more solid, even on the many cobblestone roads we have here in Holland. The ride is firm but not harsh at all. I will report back wehn I have done more miles, I also have a trackday planned this month.

Mark Harris

Nice job! I had Bilstein HD's/H&R's on my 96' 993. Loved the set up. Sold the car. (mistake)

Bought a 97' and picked up some used PSS9's. No real difference to me. I don't track but couldn't pass up the deal on the PSS9's. Having had both set up's the only difference in my opinion is you can adjust the PSS9's (which I doubt many do) and bragging rights.

Your set up is an excellent choice.

Ed Hughes

Nice! Looks similar to the one in my Avatar now.

I think I need ARB's next....

Ed Hughes

PS-I had to shorten my droplinks.

993KT

I have the H&R + HD setup on my '97 NB also from the PO. The ride was acceptable with the 17" Cup II wheels, but I think it is way too harsh with 18" BBS LM (225 front and 265 rear). The ride is busy on anything other than newly paved asphalt, and the car just gets tossed around on any size bumps. This is all with stock ARB. The H&R spring rate is not as high as KW or the RS setup, so I suspect my HD's might need a rebuild? Does anyone else have similar experience?

Bill Verburg

I'm not sure that Bilstein HDs aka B6 or the H&R version can be rebuilt or even revalved, AFAIK they have crimped cases,

The only Bilstein 993 Cups that I know can be rebuilt and revalved are the Cup versions.

These are custom valved Cups and they are the nuts w/ 660/750#springs, even acceptable for street use

bruce7

According to Juan at Bilstein in San Diego, the HDs can be custom re-valved at a cost of $75 with a 6-week lead time. You can pay more to get them faster. BTW, according to him, the HD shock already comes with a digressive valve stack. I got the impression that if you are staying with one of the standard factory spring sets, there would little to be gained by further customization. With the H&R springs then yes there would be a benefit to re-valve them.

Bill Verburg

That's interesting, I had always thought that the HD was a rebuildable shock, the HD and Sport shocks on my '76 are certainly rebuildable, but I have recently been told that the HD are not. I guess I'll have to take that up w/ the source.

Also good to know that they come w/ digressive vales oe.

It is my understanding that the Cups which I come w/ the old fashioned linear valving which can be extremely harsh, I've been told that the experts are appalled at the stock Cup valving,

Anyhoo, the Cups w/ custom digressive valves are perfect IMO.

ToSi

Did you get dyno plots with your revalved shocks? Could you post or PM a front & rear please? thx-

Bill Verburg

No, that's proprietary and not for publication

you can get an idea from the current 997RSR plots
late 997RSR w/ digressive valves


compared to original 993 Cup/RSR w/ linear valves