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NOTE: This is on a 540i, not an M5. However, the coils are the same for both cars, so I thought it would be useful to post here.

Here goes, my review of the Bilstien PSS9 Coilovers for the 540i/M5. These went on my 1999 540i non-sport. I've had the coilovers on for about 6 months and 7,000 miles. I've been through 4 suspension setups in total on my car now, ranging from stock, then H&R "sport" springs with Bilstien Sport struts, then swapped to the H&R "race" Springs, now finally to the Bilstien PSS9 Coils. I kept getting progressively stiffer and lower, because my main goal was to get "low", while stiff being functional and able to be good at the few track events I do a year. Comfort was a concern, but I'm a college student, so it was not a top priority. I'm not driving around my grandmother or infants.

I was searching around on classifieds and found these unused from a guy who sold his M5. My main reason for buying these because arguably they are the best coilover made for our cars. I'm sure I don't have to tell you all about the motorsport history that Bilstien has.

As far as performance was concerned, the Race springs paired with the Sport struts were perfect. Stiff enough that they eliminated alot of body roll on spirited drives, but still decent around for daily (pothole filled) driving. But they were simply not low enough for my taste.

Supporting Mods: (For Reference)

* Dinan Adjustable sway bar (on middle setting)
* ACS Type III 18x8.5
* 255/40 Bridgestone RE760 Tires all around


Price: I got mine for something a little over a grand if I remember, but they were "used". From any major vendor you can expect to pay +/- $2,500.

First Impressions: NICE. All the welds, powdercoating, everything looks amazing. Everything feels "heavy", and high quality. Exactly what you'd expect to find from Bilstien and at this price point. Comes with wrenches and a small card on how to adjust the height and dampening. They come with 9 settings (PSS9), 1 being full stiff and 9 being full soft.

Install: Smooth and easy, nothing out of the norm to report. Everything came pretty much ready to go out of the box. I got it done in less than 3 hours, including a small lunch break and semi-constantly getting distracted by ESPN. However that was my 3rd time doing my suspension, plus I had another experienced mechanic helping/distracting.

Height: It's adjustable, but I thought it was worth mentioning. My M5 front bumper is about 4 1/2 inches off the ground. Front wheels are 13inches from center of the wheel to the fender, while the rears are 12 inches center to fender. Compare that measurement with over suspension setups at the following link: BMW E39 Suspension Survey And I still have room to go lower on the strut.

Daily Driving: I keep these on 7 F/R. Not too bouncy, and on normal driving roads the ride is perfect. Enough to feel the road, without chattering my teeth. My dad drove my car and his words were "Tight and precise". Only person who complains about the way it rides is the wifey-to-be, but I don't consider that a real complaint because she has always hated how my car rides.

Track Day: Put these down to 1 F/R. On a flat track environment, these were awesome. Not body roll, predictable, and simply amazing. Just a little bit of oversteer, but it would grip and grip and then slowly let go, so it was very manageable. Check the picture below of the track day, that picture is going ~30MPH on the very edge of grip. Simply Amazing.

Pros:

* Great build quality.
* Transformed the car's handling.
* The ride is AMAZING
* Shocks can be sent back to Bilstien to be rebuilt
* 0 body roll when put on stiffest setting
* Dampening adjustable
* Can go pretty low.
* Rides like stock (I think) if put on softest setting
* Lifetime warranty

Cons:

* No Install instructions (not a big deal)
* Bought used so no warranty card, not in original box, etc
* PRICE. Expensive if bought new.
* Not PSS10
* No in-car dampening adjustment


Install



Picture is on the lift - I doubt it goes up that high haha.



Ride Height:



Only rubs at full lock:



 

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Discussion Starter #3
Nice write up!

The company's name is BILSTEIN,btw........
Ah, right. I'm actually very dyslexic, haha. Oh well.

Maybe a mod will be so kind to change the thread title around so those that search can find this thread?
 

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It is something that i am considering at the moment, but concerned with comfort for daily driving (and I want that comfort). I wonder if at position 9 it will be close to OEM in terms of smoothness.
 

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Thanks for the write up. Likewise, considering this path for the tired, nearly 100K suspension.
 

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That's okay fellas about the spelling. Even though I have the complete Bilstein PSS-9 box in my house, I still spell this great companies name wrong sometimes... ! ouich
 

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It is something that i am considering at the moment, but concerned with comfort for daily driving (and I want that comfort). I wonder if at position 9 it will be close to OEM in terms of smoothness.
You don't need to ride on full soft (9) to get OEM "comfort." I would actually equate PSS9 setting 6-7 to be very OEM like in terms of comfort and dampening.
 
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Altering settings for street comfort and track flogging is largely a waste of time. The optimal setting for all duty will be roughly defined by the chassis' weight & f/r balance in conjunction with spring and swaybar rates. This holds true even if you're changing from street to race rubber. When you can generate greater G's with track tires, both stiffer dampers AND springs are the fix. If dampers need tightened up for track to prevent bottoming and reduce chassis movement, the ride height and/or spring rates are wrong. The result will be inferior.

Setting the dampers softer than optimal will cause poor control (heaving and pogo) that will not make the ride more comfortable. Setting the dampers stiffer than optimal will degrade handling in all cases and this will actually become dangerous on varying or slippery road surface.

Setting a car to stiffer settings than optimal for track use will make the car firmer and flatter, but slower and more difficult to control. Dampers should never be used to achieve flatter cornering. When dampers are cranked above optimal to work like a helper spring, the instantaneous wheel rates vary wildly and become so unpredictable that an expert driver can no longer drive near the limit of adhesion. The car will continually get loose as the wheel rates change. Compliance and suspension responsiveness is a good thing.
 

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Nice thread. Just picked up an 02 with the PSS9s thoughtfully provided by PO.

I'd like to get her up in the air this weekend, check settings and possibly adjust. I've read the spring perches have three settings.

Question - if I adjust height via the spring perches, I don't have to get an alignment, do I?

Thanks in advance.
 

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Altering settings for street comfort and track flogging is largely a waste of time. The optimal setting for all duty will be roughly defined by the chassis' weight & f/r balance in conjunction with spring and swaybar rates. This holds true even if you're changing from street to race rubber. When you can generate greater G's with track tires, both stiffer dampers AND springs are the fix. If dampers need tightened up for track to prevent bottoming and reduce chassis movement, the ride height and/or spring rates are wrong. The result will be inferior.

Setting the dampers softer than optimal will cause poor control (heaving and pogo) that will not make the ride more comfortable. Setting the dampers stiffer than optimal will degrade handling in all cases and this will actually become dangerous on varying or slippery road surface.

Setting a car to stiffer settings than optimal for track use will make the car firmer and flatter, but slower and more difficult to control. Dampers should never be used to achieve flatter cornering. When dampers are cranked above optimal to work like a helper spring, the instantaneous wheel rates vary wildly and become so unpredictable that an expert driver can no longer drive near the limit of adhesion. The car will continually get loose as the wheel rates change. Compliance and suspension responsiveness is a good thing.

Lscman - great post and to the OP, nice writeup... I installed mine straight up with no changes to the factory damper settings. However we did remove the front tender springs to get the spring perch higher. Over bumpy corners the car will pogo just a bit but too much for me. Bumpy straights are fince since the car isn;t already loaded side to side. I'll probably adjust a click and see what happens. Other than that no complaints about ride quality from anyone so far. I;ve run/installed many many PSS kits oin all different BMW's and have been very happy with them. I'm glad they do not paint the dampers, the coating is much more durable.
 

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Definitely a great thread; good remarks from everyone. I just installed a PSS9 set on my 2003 M5 and have a few remarks to add to those mentioned thus far.
1. Bilstein's instructions do not indicate in their parts blow-up or in their non-existent text the "plate" P/N 31 33 1 096 068 which acts as a stop for the rebound bumper portion of the upper strut mount. This part definitely needs to be reused (no need for a new one) and included as part of the front strut assembly! Without this plate, any rebound is going to be absorbed by the mount rubber at the metal sleeve where the strut's threaded shaft protrudes thru the mount instead of onto the body of the strut mount's rubber slug, surely resulting promptly in a failure of the upper mount.
2. The two OE parts indicated for reuse on Bilstein's instructions for the Fr. struts are not indicated quite as clearly as they could be. The strut mount itself is of course the strut mount, and it looks like one, but the plate below it that looks like a shim is in fact P/N 31331090612; the axial cage bearing, necessary to allow turning of the strut for steering. It comes (from BMW via RealOEM.com info.) as the "UPPER SPRING POCKET W/AXIAL CAGE BEARING" but the pocket portion is replaced by Bilstein's own upper spring perch. Insert the old (or new, why not) bearing into the underside of the strut mount and away you go . . . .
3.The front strut can be installed in any orientation (i.e.: decal in, front, or out) but the real decision to make on this is how you want the adjustment dial to face. There is a hash mark on the fixed portion of the dial which is useless if you face the 180 degrees of dial travel in towards the brake backing plate. Counting and recounting clicks back and forth from the stops at "1" or "9" in order to make sure you are on "5" or "7" or whatever is tricky and not immediately conclusive since the click detents are shallow, they are closely spaced, and the drag on the dial is high. Face the strut so that whether you are going to be making adjustments from on a lift, or on the ground from from behind or in front of the wheel, you can see what you are doing. The car itself doesn't mind nor will know how the strut is aligned.
4. On the rear shock replacement, I did not need to remove the plastic wheel arch liner. I did uncouple the "wishbone" (it's certainly not a forked 'wishbone' but that's what they call it . . . .; it is a 'rear upper link') P/Ns 33 32 6 767 831 / 832 for L & R at the outer ball joint where it connects to the wheel bearing carrier and pulled it back and upwards to give clearance for removal and installation of the shock. Additional benefit is that if the inner bushing or outer ball joints are at all soft or loose, you can tell that this is a good time to replace the link. The adjustment dial on the Rr. shock only can face the one good way; no choice here. The rebound bump plate is indicated here, properly on the top of the mount under the top lock nut.
5. Disassembly of the rear parcel tray behind the rear seats, necessary for access to the Rr. shock mounts is only a pain. On my car, the wiring for the R. Rr. speaker was seriously frayed where it passed under the frame from the wiring harness bundle (running along the side of the rear seat bolster) to the speaker itself. It was a simple matter to thread it back out to the point it leaves the harness, repair it, and reinsert it where it wants to go. The frame underneath which it passes has a sharp edge which is not good for wiring but there it is. I made sure there was plenty of slack in that area and that the twisted wire pair was not in contact there. Once installed its not going to shift around much if at all (?!) This was the only mal-designed part of the entire car, shock set-up or installation process that I noted during this job. The E39s are definitely heads and shoulders above the E34s in this respect, as well as most if not all others.
6. My PSS9 set seemed to come pre-set for stock ride height. Whether this was by chance or design I do not know but it was a very good place to start from. I ended up lowering the car 1/2" Fr. & Rr., not much by design as much as in making sure the L & R side ride heights were equal after fiddling with the units immediately after taking them out of the box. It might be wise to avoid monkeying with them at all and making sure the perch locks are locked before installation.
7. ENJOY!
 
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