Thinking about swapping my sways for stock as I can't seem to find a comfortable balance of settings that play nice with the Bilsteins.

Currently at med rear and full soft front and they still seem to be at odds with the rest of the suspension. I'm thinking the Bilsteins were designed with the stock sways in mind so going to switch back to those unless anyone here has any other ideas to try?

I want more street ride comfort, so willing to sacrifice some roll stiffness to get it. Anyone else with Bilsteins and aftermarket sways that can chime in?

parts/settings:
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Bilstein PSS9 coilovers (Monotube construction, adjustable dampeners)
Special Note: Mild spring rates, but Bilstein says the dampeners are performance valved
370/240-420 (rear progressive) F +18% R +23% (at peak rear spring rate)
Transfers +5% roll stiffness to rear
Piston Size: 46mm
Damper adjustability: 9-way adjustable
Set to 9 (soft) front and 5 (med) rear

Hotchkis v2 Adjustable sways (w/adjustable end links):
Front - Hole 2 = 1845 lbs/in (48% Stiffer than stock)
Back - Hole 1 = 520 lbs/in (80% Stiffer than stock)

Michelin PS2 Tires:
265/35-18F, 275/35-18R
(included since they are a functional part of the suspension)

 

The softest settings on the Hotchkis sways are supposed to be the same as the OEM sway bars.

 

I just double checked and they are as follows for v2:

Bar Rates:
350Z & 03- 05 G35 Front
Hole 1 = 1525 lbs/in (22% Stiffer than stock)
Hole 2 = 1845 lbs/in (48% Stiffer than stock)
Hole 3 = 2270 lbs/in (82% Stiffer than stock)
Hole 4 = 2855 lbs/in (129% Stiffer than stock)

Rear
Hole 1 = 520 lbs/in (80% Stiffer than stock)
Hole 2 = 655 lbs/in (125% Stiffer than stock)
Hole 3 = 840 lbs/in (185% Stiffer than stock)

After reading some more online about possible negatives with stiffer sways I think they might be the problem, although I can't recall anyone on this site ever mentioning any downside when talking sways:

 

I stand corrected. There's a definite tradeoff on ride quality and handling capability.

 

"they still seem to be at odds with the rest of the suspension"

Need more detailed info, what exactly is going on behavioral?

What year is your Z? If it's a 2004, do you know if you have the revised suspension or not?

I've been on the Pss9 with aftermarekt sways so i have something to say on the issue, but I need more info on what's going on. I will so though that rear damper settings could be a issue, 5 up from full soft was my limit and it was a downward curve to even that point from full soft.

 

^ hey man! You helped me out a lot when I was in buy mode. Thanks for chiming in here. I have the 2004.5 with the revised suspension. But I'm pretty sure the only bit revised was the rear spring (427 vs 342).

Basically my sore points were pretty well articulated in that article:

I don't lift a wheel but do experience some unsettling of the chassis...enough to make me lose confidence and back off the gas to regain chassis composure. Kind of reminds me of how my 96 Cobra with the solid rear axle felt (another reason I'm thinking sways too stiff).

"Skatey" is how I would describe it at speeds above 15mph unless the roads are really smooth. <15mph rides great, lol.

I was getting some bounciness on concrete seams at freeway speeds but was able to dial some of that out by increasing rear damper stiffness vs. front, I suspect for the same reason Nissan stiffened the rear spring in 04.5+ models?

 

The bigger the anti-roll bar the less independent an independent suspension becomes. "Skatey" is good way to describe anti-roll bars that re too big.

 

UPDATE: Based on the more is better principle, I adjusted the rear dampers to full stiff. This entirely restored my confidence in the car eliminating the skatey feeling. I can tell they are stiffer but because their is less bounciness I'd say ride quality is actually improved...you don't get that sea-sick feeling anymore waiting for the car to stop moving up and down. I'm truly in love with my Bilsteins now.

I had never tried this before due to the reviews and shock dynos posted by Gsedan35. All I can say is perhaps my dampers are valved differently or the adjusters aren't as aggressive in their steps?

It's still a bit harsh over rough roads so I'm still going to try switching back to stock sways for a more GT setup.

 

Any suspension can be made to work by not letting it work.

 

Is that comment in reference to my setting the rear dampers to full stiff or on the aftermarket sways?

 

Your original post had the shock settings at:

And now you're at:

And based on those two extremes you've determined that its time to switch to softer anti-roll? Maybe use the Goldilocks principle and try a setting in between these two extremes before writing another check...?

 

Awfully hard to wager a guess without knowing

tire pressure
wheel offset
alignment specs
rideheight

 

Agreed. Alignment was my first thought, actually. Many members report major chassis instability at moderate speeds when the alignment is known to be off. It was surprising to me to find out that even fairly small alignment misconfiguration can have such a dramatic effect.

I do not have PSS9s but I do have PSS10s with aftermarket swaybars. Based on what Gsedan35 has been posting regarding the shock dynos and my own experimentation, PSS10s seem to be valved slightly differently than the 9s so I am not sure how useful my feedback is but I can tell you, based on my experiments, that going full stiff does not yield better comfort and performance results with 10s, and it is likely that 9s are similar in that regard. At F5, R5, my ride is uber smooth. It seems like a perfect compromise between comfort and performance. It just rolls over all imperfections on the road with no drama. Amazingly civilized. I ended up settling with F7, R6. This seems to yield best traction around corners with reasonable tradeoff in ride comfort. Love this setting. I tried going stiffer but I found that the rebound control was getting brutal as I approached 10 and I noticed moderate onset of oversteer which yielded less traction through the corner. Stiffer was not better and I am usually the first one to sacrifice comfort for extra traction. This just wasn't happening.

One more question, how old are your coilovers? Is it possible that you're trying to mask a problem with the shocks by adjusting your damping to such an extreme level? Perhaps they are getting tired and the valving just isn't working as it should anymore?

 

Typo...my settings at the time of the first post are in bold (medium R soft F). I have also tried soft and medium all around but neither helped with the skate. I posted yesterday what is currently working for me best because I'm curious if others have found the same. It would make sense since the porpoising of the 2003 MY was fixed with a stiffer rear spring/damper.

 

Tire pressure
I've tested in the 30-35psi range and did notice some improved ride quality and stability in the lower range

wheel offset
18x9.5+22 all around

alignment specs
Degrees | Left | Right
Caster | 8.5 | 9.1
F Camber | -1.4 | -1
F Toe | .05 | .05
R Camber | -2.1 | -2
R Toe | .09 | .06
Thrust Angle | 0.0

rideheight
Measured to top of fender arch:
25"F, 26.375"R (rear lowered to max. acceptable adjustment range by Bilstein)

 

I did purchase them used but had the sense to send them to Bilstein first for evaluation before installing. I was told they checked out within spec but here are the dyno printouts. There are no included acceptable ranges so didn't really know what to make of them.

 

your camber is off significantly in the front and I have a hard time believing that they exactly 0'd out your front toe by making it perfectly even. I suppose anything is possible, it's just not common if the camber is also off.

IIRC you also bought your coilovers used, so there may be an issue there, really impossible to say. Then you get into bushing integrity, roll center, etc. I can't pretend to know what your car feels like, or what you are trying to get it to feel like (or what your expectations are) on your intended roads, so I think your best bet is to have a qualified suspension tech give everything a once over

 

Thanks Adam, I posted shock dynos if that helps. Bushings should be good still. Car has <19k miles on it but I guess they might have missed a bad bushing when they were installing the suspension.

Oh and thanks Ziggyrama. It may just be my old butt tolerances changing as well. These were a huge improvement over the hotchkis springs and stock shocks I had in prior...just trying to take it that next step further.

 

At what adjustment settings were these shock dynos done? I cannot tell from reading the sheet.

 

Full soft and full stiff. I'm assuming the ones marked "CLOSED" are set to full stiff and "OPEN" is full soft.