maci911

hi i am deciding in getting some coilovers pss9,pss10.....but thinking about it i ask if u lose suspension travel when adjusting the hieght(lowering),thus affecting the ride quality and performance.

ivangene

cool new avatar

Jon996

Greetings from Stillwater, MN! Wow, nice week (last week) for driving the cars around here.

I will just give you my experience based on 1 P-car. Sure others will chime in too.

I went from stock C4S suspension to PSS10s. Both my wife and I noticed a much better ride quality. Perhaps my stock shocks were bad. The old suspension seemed rather "jarring" over bumps. The new one seemed much better dampened. We tested the PSS10s at settings from full soft (0) to sport (10). Even at 10 the ride was better than stock. I decided on 5 front and 7 rear.

I relied on my shop for settings, just giving them directions that it was for street use. Fender height as purchased was 27"F and 26.5 rear. With the PSS10s we went to 25.5" front and rear.

My experience with the lowered settings is this: No problems driving, even hitting some of the major potholes this year (worst year ever here in the metro, IMHO!). I never had the feeling that I had hit the stops on the shocks.

You DO need to be really careful of the front spoiler when turning onto a steep driveway. I have a stock C4S spoiler which, luckily, is not very expensive.

maci911

i think my question would be ...is there any coilover system that can adjust the body than the coils ...thus not affecting suspension travel...

perryinva

I don't see how. There is only so much plus and minus travel that can be allowed in the shock part of the strut before you hit bump stops or bottom the shock. Even PSS9/10s really only have a limited adjustable range. You CAN physically push it beyond those numbers, but then you are shorting travel in one direction or the other. The official, allowed by Bilstein, not to be exceeded, in italics, underlined, in quotation marks, is 20mm in the front and ONLY 5mm in the rear, and that value has to be within the measured range on the strut body itself. They cannot and will not guarantee a specific desired height. Only state that the heighest is approximately 30mm below stock. The threads are physically there to raise it above or lower it below the allowed range, but they are not supported by the shock itself. They may be height adjustable, but really just barely, and then, really enough to corner balance, with some small height adjustment available. The 5mm rear range is what really shocked me. I did a ton of homework before buying mine, and I NEVER caught that until recently while going over the install instructions from Bilstein for the 20th time! I wonder how many of the issues that people have had with PSS9s are adjusting them out of their correct operating range.

ArneeA

PSS9/PSS10's height adjustment is not independent of shock travel, so YES, you will lose shock travel if you set the PSS9 to max lowest. Unlike JIC, KW, H&R, and of course Moton, Ohlins...where the height adjustment is independent of shock travel so you can set the car to the lowest setting and still have a good range of shock travel.

This is one reason why I've been craving going with a "better" coilover system. KW or JIC maybe?

Doug Donsbach

That seems physically impossible.

Unless you meant to say that those shocks maintain their dampening characteristics over a wider range of motion than some other brands, which is a completely different thing from the height adjustment being independent of the travel available at the shock.

himself

Yes, and it can be substantial. Info from a post I made on 6speed:

When you put on the PSS9, you will drop the ride height about an inch from stock already. I seem to recall that this is due to the parts themselves as well as droop (explained shortly). Then you have about ~20mm of adjustment in the front, and ~10mm in the back (check the spec from Bilstein for your car, but it's close to 20/10). But, this needs to be taken in context:

For our cars, the PSS9 shock has about 85mm of total travel available. Of this, about 50mm is free travel before it reaches the internal bumpstops. The bumpstops can then can compress about 50mm, giving you a total MAX of about 100mm of shock travel [a little less than 4"]. Why 85mm if the numbers calculate out to 100mm? Well, in use, the internal bumpstop stiffness becomes REALLY high - effectively becoming a solid mount - at around 35mm of compression. So you have an effective operating range of about 85mm, or about 3.35". Well, what does all this mean?

With the car resting on the ground, the shock will compress simply do to the weight of the car, i.e., droop. It could be 10mm, but might be as high as 30mm [or so] based on your car weight.

So, if you only have 85mm for shock travel, and 30mm is taken up with droop, you get about 20mm of free travel, and 35 of bumpstop travel. 55mm = ~2" of shock travel before you have "no shock" left. On some heavier cars (like the GT2, the weight of the car causes about 50mm of droop, meaning you are ALREADY on the bumpstops! YIKES!] What about simply getting heavier springs so the car doesn't droop? Well, you would have to revalve your shocks to accomodate the springs. It CAN be done though.

Another issue you face with the PSS9 system is that adjusting the ride height [any lower] also reduces the PSS9 shock travel distance [as well as preloading the springs]. Using the above example, say you use all of your 20mm adjustment range for the PSS9. Well, you would further reduce your 55mm of shock travel to 35mm (about 1.4"). On virtually any thing but the smoothest roads, 1.4" is not enough shock travel. You WILL feel it, and NOT like it. If you have less droop, you can lower the ride more, but you won't know you've gone too far until you hit that big bump that really jolts the car.

The good news is, there IS a happy lowered place where you can get optimal suspension travel without compressing to the bumpstops, but you will need to figure that out based on your car weight and track/road conditions. I had mine lowered about 15mm, but then had to raise them back up 10mm to get it off the bumpstops when at the track.

If you get the car all situated and aligned, and THEN realize you are riding the bumpstops, you can raise it up just a bit without really needing to realign it. I forget the amount, but 10mmF/5mmR should be fine. This will simply take out some negative camber and shouldn't screw up the hangling.

I hope this mess is factually accurate and helps, lol.

-td

Doug Donsbach

Not only do you have "no shock", you also have "no spring".

Well, except for the tire sidewall.

perryinva

On the other types, which I know nothing about, I can see where, for a price, it is possible to design a strut such that raising or lowering the spring perch would also raise/lower the bottom mounting of the strut itself. Lower the spring and shock together, car gets lower, same travel, within limits of the suspension geometry.

Doug Donsbach

You're right, and after a quick look it seems that some of the systems out there seem to do just that (JIC, for example).

I stand corrected.

maci911

ok now i am confused ...and broadened my search to pss9,row030 and jic
this why....my current hieght 25.5 all around,but ride is harch on some roads....which i am trying to eliminate.i am shooting for lexus ride at 26 to 26.5inch height...............

pss9 at full height will lower car 1inch from 26.5 to 25.5=$2100
row will lower 26.5 to 26 or 25.75=$1100
jic ...has an adjustable lower sleeve that allows shock lowering without affecting susp travel=$2800

himself

If you think your ride is harsh on some roads with stock (or close to stock) suspension, I do not recommend upgrading to a sport suspension (ROW M030, PSSX, JIC, or anything else). All of these sacrifice comfort for performance - which will result in an even harsher ride. Of course, this assumes your current suspension is operating correctly. You need to move away from "sport" suspensions to get a more comfortable ride.

-td [edited]

maci911

h&r springs and sways and bilstein hd ....

himself

What spring rates? Sway bars don't really affect ride harshness.

[edit] FWIW, I run 300(F) and 550(R) springs with my PSS9. I had 170/260 with my ROW M030.

The only issue I had was when my car was too low and hitting the PSS9 bumpstops. Otherwise (for me) this spring/suspension setup is completely streetable. [PSS9 run 2 from full stiff]

-td