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      02-08-2019, 03:32 PM   #1
taranfx
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Z4 KW v3 compression/rebound settings?

Just installed KW v3 on Z4 35is with 19" Michelin PS4S. and H&R swaybar at stiff setting.
With factory settings of everything in the middle, ride was extremely harsh for daily driving and my gf refused to sit in the car :P

I changed it to:
Front: compression: 4 from softest, rebound 5 from softest
Rear: compression: 5 from softest, rebound 5 from softest

Ride is much better now but it still has some hardness vs comfort mode of stock adaptive suspension. Still going to play with it for couple of days to figure out happy medium

What are your experiences? What settings are you using with or without swaybars, with 19" or 18", with stif sidewall tire like PS4S?
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      02-23-2019, 01:40 PM   #2
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I had the KW recommended setting for quite a while, over a year I would say. It felt great but did sag slightly over time.

I ended up raising the car all around, but slightly higher in the rear, and went one step stiffer for all around which helped with response and high speed handling.

Overall very happy.
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      08-28-2019, 05:46 PM   #3
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Quote:
Originally Posted by jts1981 View Post
I had the KW recommended setting for quite a while, over a year I would say. It felt great but did sag slightly over time.

I ended up raising the car all around, but slightly higher in the rear, and went one step stiffer for all around which helped with response and high speed handling.

Overall very happy.
Thanks for your input. Do you've swaybars too? If yes, how was the comfort and handling before/after?
I'm thinking of getting rid of swaybars, they just feel overkill with KWv3 especially when going over bumps, the whole body moves resulting in creaks and noises when one wheel goes over a bump and not the other. WDYT?
Also, what damping/rebound are you running?
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      09-17-2019, 05:05 AM   #4
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Or you can modify the HR front sway bar to become adjustable like I did. It has a noticeable impact on how comfortable the ride is imho. The OEM sway bar is really really comfortable in comparison though, and easier to swap as a first step.

Anyway you bought adjustable dampers. Use them! Try and adjust them some more and see how you feel! In the end only your own feeling will matter - so trust it. Remember soft is fast as long as you can handle the weight transfer.
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      09-26-2019, 06:05 PM   #5
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Quote:
Originally Posted by Asbjorn View Post
Or you can modify the HR front sway bar to become adjustable like I did. It has a noticeable impact on how comfortable the ride is imho. The OEM sway bar is really really comfortable in comparison though, and easier to swap as a first step.

Anyway you bought adjustable dampers. Use them! Try and adjust them some more and see how you feel! In the end only your own feeling will matter - so trust it. Remember soft is fast as long as you can handle the weight transfer.
Thanks for the tip.
Can you share your bump/rebound settings along with Swaybar settings? and what tires are you running and what PSI?
Also, I cant find adjustable swaybar. Which one do you've? What adjustable swaylinks are you using, I have none.
Sorry for so many questions
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Last edited by taranfx; 09-26-2019 at 06:12 PM..
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      10-01-2019, 05:17 PM   #6
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Ok, finally took time to play around with my V3 settings.
My problem was that it was a bit too bouncy. Especially the front is what makes it uncomfortable and even bit wierd. I could understand being a bit bouncy on ruff city streets but it even felt bouncy on a highway. Once i was going 150km/h and that front bounce made the car steer badly over ruffer spots. it felt like front would bounce, lose some traction and then land. Had to correct it with steering inputs. Really wierd behavior.

So what i did:

Left all the rebound settings stock: 9 clicks from stiffest both front and rear.
(turn all the way to + side and from there 9 clicks towards -)

Now bump/ compression:
Front compression: 7 clicks from stiffest ( stock is 5 clicks)

Made front absorb ruffer stuff a lot better and just ride over them. Not judder or bounce anymore. Steering maybe is a bit more numb than before but its fine.

Rear compression: 4 clicks from stiffest ( stock is 6 clicks)

This makes rear a bit stiffer but not uncomfortable. Rear feels more planted and communicative. It actually did not make the ride more uncomfortable.

Why I tried these settings? Googled around a bit on other Bmw forums and found this thread on e46 M3 KW V3 settings. Last post is where the important information is located!

Link:http://www.m3forum.net/m3forum/archi...BOAl9cWu568HMM

Did a 2 hour long midnight testdrive and it felt alot better than before.
Also going to mention that my ride height is set 5mm higher in the rear than in the front. Before fitting V3 my stock ride height had the same difference.

If i change my settings further i will post an update. Maybe will play around with rebound a bit. Cant get my hand to the rear wheelwell to adjust rear rebound without jacking up the car. Thats one reason why i did not try to play around with rebound this time.
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Last edited by KennyP; 10-01-2019 at 05:40 PM..
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      10-01-2019, 06:17 PM   #7
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Quote:
Influence of low speed compression adjustment

Compression adjustment has significant influence on handling and driving behaviour.
General rules are:
A harder compression adjustment on the front axle makes car more precise and more aggressive, whreas a softer adjustment favours more forgiving steering behaviour.
Harder compression asjustment on the rear makes the car more stable on fast direction changes and helps if it has too much tendency to oversteer. On the other hand, softer rear compression makes the rear looser and might improve the handling if the car was too tight or had too much understeer before.
However, too much compression might cause uncomfortable and loud tyre role and/or cost grip.
From KW V3 setup manual.
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      10-24-2019, 07:57 AM   #8
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Quote:
Originally Posted by taranfx View Post
Thanks for the tip.
Can you share your bump/rebound settings along with Swaybar settings? and what tires are you running and what PSI?
Also, I cant find adjustable swaybar. Which one do you've? What adjustable swaylinks are you using, I have none.
Sorry for so many questions
Attached is a picture of my customized HR sway bar.

I run different tires for different purposes. See here.
Attached Images
 
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      10-27-2019, 02:48 AM   #9
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Thats one impressive build thread you got on ***********. Very informative.
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      01-29-2020, 01:27 PM   #10
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Update: my z4 is now comfortable and nice handling at same time.
Multiple things that were wrong:
- removed front h&r sway and switched to stock
- set rear sway bar to middle stiff
- raised rear to half finger gap
- most importantly I was twisting bump wrong way on the right side of the car. Crazy I know
- set it to factory recommended setting. Will go stiffer eventually
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      02-01-2020, 06:45 AM   #11
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Quote:
Originally Posted by taranfx View Post
Update: my z4 is now comfortable and nice handling at same time.
Multiple things that were wrong:
- removed front h&r sway and switched to stock
- set rear sway bar to middle stiff
- raised rear to half finger gap
- most importantly I was twisting bump wrong way on the right side of the car. Crazy I know
- set it to factory recommended setting. Will go stiffer eventually
Curious how you feel about this setup in a few days. I also once tried going back to stock front sway bar while keeping the rear HR. I was amazed by the amount of body roll I got. Yes it is much more comfortable, but man... it feels like the rear sway bar has almost no say over body roll compared to the front sway bar. I was particularly unsatisfied with how the car would transfer weight coming back from slight oversteer on corner exit. So I went back to HR all around to get the directness back. Keep in mind though that I still run koni fsd dampers.

That being said, the KW engineer I once spoke to says he prefers to go stiffer on the dampers and softer on the sway bars and springs.
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      02-03-2020, 11:11 PM   #12
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Quote:
Originally Posted by Asbjorn View Post
That being said, the KW engineer I once spoke to says he prefers to go stiffer on the dampers and softer on the sway bars and springs.
i thought it should go the opposite (softer damper but stiffer sway bars), did he say why?
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      02-03-2020, 11:37 PM   #13
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Quote:
Originally Posted by engine killer View Post
i thought it should go the opposite (softer damper but stiffer sway bars), did he say why?
The wording he used was that they typically select the softest spring that can support the car at the ride height selected and then adjust everything from there with the motorsport dampers.

I am just guessing here, but I assume you need that in order for the frequency variable dampening to work at its best. Then you can optimize for grip on both curbs and smooth surfaces.

I understood it like this: If the springs are doing all the work, you don't leave anything for the dampers to do. And the dampers offer more dimensions of adjustment.

But I could be wrong...
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      02-06-2020, 04:45 PM   #14
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Quote:
Originally Posted by engine killer View Post
i thought it should go the opposite (softer damper but stiffer sway bars), did he say why?
Swaybars link suspension together and interfere or limit your dampers job. Forces are transmitted from one wheel to the opposite. This makes a car jarring and uncomfortable on rougher roads. Get really stiff swaybars and you can have inside wheel lift off the ground. Having softer links between opposite suspension towers allows each corner to work independently on damping without interference. In theory its more precise. In the end its always a tradeoff with suspension.
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Last edited by KennyP; 02-07-2020 at 05:38 AM..
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      02-07-2020, 05:27 AM   #15
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Quote:
Originally Posted by KennyP View Post
Swaybars link suspension together and interfere or limit your dampers job. Forces are transmitted from one wheel to the opposite. This makes a car jarring and uncomfortable on rougher roads. Get really stiff swaybars and you can have inside wheel lift off the ground. Having softer links between opposite suspension towers allows each corner to work independently on damping without inteference. In theory its more precise. In the end its always a tradeoff with suspension.
got your point, thanks
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