Bilstein PSS9 (B5 S4) dyno results, and suspension ramblings.

[Tomasz@Startup]

I posted few days ago about the single Bilstein PSS9 I dynoed. At that time I warned that the results may not be representative, as I was still waiting for results of the second shock. Now that I dynoed both, I can speak more openly.

I believe that this problem is affecting all B5 PSS9s and potentially all PSS9s.

Here are the dyno results for the front and rear shocks:



As you can see these shocks only offer two adjustment settings, not the 9 that are commonly advertised. There is no difference in the shock performance in the middle settings, only the two extremes matter. I also believe (and this can only be proven by track testing) that these shocks will deliver harsher ride and sharper response at the stiff setting, but with that much rebound less traction and ultimately slower cornering speeds.

I was hoping that with the PSS9s we had a good offering in the sub $2,000 range, but I am confident now that Penskes and Ohlins deliver quite a bit more value.

Until proven otherwise I believe that there are two generic categories of coilovers there: low cost, high durability street optimized twin tube coilovers like Vogtlands (my preference) or Konis, and high cost, rebuild able, race track optimized mono tube coilovers like Penske and Ohlins. Both will deliver lots of value per dollar. Unfortunately the middle ground seems to be a compromised solution... acceptable to many, but still a compromise.

To get the above results I had to spend little over $200. If you are interested in having any other shocks dynoed, please e-mail me. Maybe we could get small donations from a group of enthusiasts and dyno few more offerings. To kick this off I want to share the results from dynoing the B5 S4 Vogtlands:

[akula-ssh]

[bhvrdr]

compared to the street coilovers you mentioned IMO. Sure you dont get perhaps a full range of 9 settings but as you can see on the stiffest setting the valving is doing exactly as it should. It is easily able to surpase the street setup like the vogtlands dynod there as it should with its slightly higher spring rates making it not pogo like most of the street setups I have tried that rely on much smaller dampers. The handling is fantastic for track duty and the street feel is only slightly more harsh than the OEM S4 suspension as those members will report and I have seen (quite a bit stiffer than the OEM non sport suspension of an A4 though). Then if you prefer the feel of a soft spongier ride for the inlaws when in town you just crank them down while still on the car and you have an almost non sport suspension feel. For $1450 (the price now Autozone and many other sites are carrying them for) it really was the only way for me to get a performance level similar to what I wanted but not having to pay almost 4 grand. Would I prefer a motorsport kit? Sure I would. Would I prefer street coilovers? Not at all. Even for confort I find the PSS9 is fantastic and it really does perform well on more harsh tracks.

cheers! Mike

[Ray Khan]

[Tomasz@Startup]

Just wanted people know what I knew though.

[Mike@StartupRacing]

[bhvrdr]

[Tomasz@Startup]

[Pie4Foo]

FWIW, today I changed my PSS9s from "3" to "9" and noted a difference. Significant? No, but it did come out in road undulations and freeway expansion joints.

I don't fully understand the technical discussion here, but I would like to understand what was done and how changing the dampening would have an affect on spring rates.

Can a Bilstein representative be contacted to comment on this as well?

[Tomasz@Startup]

Graph shows the force in lbs. that the shock excerts at different speeds.

Key here is that PSS9 does not change between most settings. It is what it is. Not judging here.