I recently gave my opinion, and that of Bilstein, regarding the PSS-9 system. It seems that there was some difference in opinion regarding the rear perches.

I have taken the time to photograph the problems encountered using the factory perch vs a monoball perch. What you will see is that the factory perch is concave, and therefore the seating surface for the hat supplied by Bilstein rests not on a flat surface matching the hat, but only on the raised portion of the perch. This amounts to a seating surface that is only 1mm wide with a 50mm diameter. The monoball has a mounting surface that is 8mm wide with a 28.4mm diameter. with the weight that is carried, the factory perch will cut into the hat due to the thin edge.

We have not, and will not install the system using the factory perch for the reason stated above. We would be doing our customers a disservice if we installed a product knowing there was a very high chance of having problems down the road.

I hope this is helpful to those who have installed or will be installing the PSS-9, which by the way is a great system.

<a href="http://germanmotorcars.com" target="_blank">web page</a>

ps: I hope the image link work, if not it is <a href="http://germanmotorcars.com/PSS-9.htm" target="_blank">http://germanmotorcars.com/PSS-9.htm</a>

 

Hi Forry,

In a nutshell, you're saying that monoball perch is a must for those who have PSS-9 on their cars?

Where can we get these monoball perches by the way?

Thank you in advance.

 

Forry,
Thanks for the heads up on this install!
My understanding is monoballs will make a lot of noise and make the ride harsher. Can you mount the monoballs in the rear only and how will this effect the ride/noise? or should monoballs be mounted all around? I have not installed my PSS9's yet and would like to make sure the shop does the right thing.

 

Steve, I'd love to get your input on this issue. Mr. Hargitt makes a sound argument, and several Rennlisters seem to be experiencing unusual sounds in the rear suspension following the PSS-9 installation.

 

Forry,

Thanks for the photos and feedback. It would appear to be an imperfect mating service with the factory perches. I'd be very interested in hearing other opinions and solutions (could I modify the OEM perch?) prior to my PSS-9 installation.

MC

 

In my opinion, the PSS-9 can be effectivly used with rear monoballs replacing the factory perches. The monoballs really are not going to make the ride any "harsher" then using the factory perches, as the way the hat contacts the perches, it is a metal to metal contact with most of the cushioning effect of the factory perch "eliminated" due to the spring not riding in the rubber cushion.

By using the monoball you are also getting the added benifit of having the rear shock being able to articulate more freely. I must add that we are also changing the hats supplied by Bilstein to ones that fit the monoballs better. This is probably not as important as the perch vs monoball, but I believe a good change.

To get the fullest advantage out of the PSS-9, you would install camber plates in the front, though not a requirement in my opinion. If camber plates are used, the hats should be changed also.

As for the cost questions, we sell the monoballs for $580 for the pair.

<a href="http://www.germanmotorcars.com" target="_blank">German Motor Cars Homepage</a>

 

PSS-9 correct rear inst.
Using monoball $ 580.00
Andial kit $ 72.00
Using expert Rennlist advise $ 0.00 but living with noise and parts failure at later date.

 

Pete,

Could you please describe the Andial kit?

 

I just spoke with Andial, they make a set of washers/spacers to take the place of the monoball set up. However, like most Andial products that they develop in house, it is not for sale to the general public, only customers