Need advice on shock setup

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  #1  
Old 07-31-2009 | 10:07 AM
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Need advice on shock setup

I recently placed an order for a pair of front Koni sport adjustable shocks and Bilstein HD rear monotube non-adjustable shocks. The front bilstein's are on back order and I want to upgrade my shocks right now. I am aware of the difference in construction between the two as well as pressure.

My question is whether this will conflict in any way with my car. I am running stock springs and not planning on running aftermarket springs (If I do it will be Tein H-techs) and just looking to improve the stock ride quality. Also after 63k my car has been through a lot of pot holes (I'm from Chicago) and ever since I put on my 19 inch wheels the bumps in the road have had an amplified effect.

Please let me know your thoughts. Thanks
 
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Old 08-03-2009 | 03:47 AM
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Find out when the company you ordered the Koni's open's on monday and cancel the order. You need to wait for the Bilstein's to come off back order. Call them at the so cal location and ask for John, have the front part numbers handy and see if you can get a timeline.

I don't see the setup as a horrible thing on the surface. But, I have run Koni's on the car before. IMO, they might conflict because looking at the spread sheet John sent me on the HD, you might have more compression damping in the rear, then you'd want to see with Koni sports in the front.
 
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Old 08-03-2009 | 11:29 AM
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Originally Posted by Gsedan35
Find out when the company you ordered the Koni's open's on monday and cancel the order. You need to wait for the Bilstein's to come off back order. Call them at the so cal location and ask for John, have the front part numbers handy and see if you can get a timeline.

I don't see the setup as a horrible thing on the surface. But, I have run Koni's on the car before. IMO, they might conflict because looking at the spread sheet John sent me on the HD, you might have more compression damping in the rear, then you'd want to see with Koni sports in the front.
So that means setting my D-Specs at, say 1 click in the rear and 2 clicks in the front is also a big "no-no", because there will be diffferent "compression damping"? Dspecs change comp and rebound at the same time, don't they?(ie-none of these parameters are "hard coded")
 
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Old 08-03-2009 | 01:08 PM
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Well I was planning on having the front Koni's on soft-medium rebound.

I feel this is comparable to running a different set of tires on the front axle versus the rear.

They aren't designed to run with different shocks but at the same time spring rate of the front springs are less than the rear correct? The difference in compression can be compensated for with soft-medium rebound setting on the Koni's while the bilstein's are non-adjustable.
 
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Old 08-04-2009 | 04:54 PM
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Originally Posted by obender66
So that means setting my D-Specs at, say 1 click in the rear and 2 clicks in the front is also a big "no-no", because there will be diffferent "compression damping"? Dspecs change comp and rebound at the same time, don't they?(ie-none of these parameters are "hard coded")
Not a meaningfull argument. Go to tokico's web site and review the shock dyno posted. If you can read the dyno, you'll understand why.

I have dyno's for the Koni's I have owned and used with a variety of spring rates, so I know exacty how and where they meter out force. And like most all twin tube systems, they attempt to make up for having very small piston's by being excessive on rebound and light on compression. Bilstein does not tune that way, nor to they have the problem of having a small piston to work with, that is the core of the problem. You'll end up with too much rebound in the front while the Bilstein will meter out a lot of compression in the rear. That is not what's desired.

When I bring things up, I'm not just pulling things from thin air.
 
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Old 08-04-2009 | 05:00 PM
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Originally Posted by Vir2L
Well I was planning on having the front Koni's on soft-medium rebound.

I feel this is comparable to running a different set of tires on the front axle versus the rear.

They aren't designed to run with different shocks but at the same time spring rate of the front springs are less than the rear correct? The difference in compression can be compensated for with soft-medium rebound setting on the Koni's while the bilstein's are non-adjustable.
Still not a good idea. Koni's use a lot of nose force on rebound in the 0ips to 2ips (inch's per second) even at full soft. Meaning they you get a lot of rebound control in slow piston speeds. I've owned the shocks and had them dyno'd, from experience I do not recommend what your thinking about doing.

I did run front koni's with revised oem 350Z rear shocks, worked great. BUT!, that was because the revised rear shock has less rebound in the 0ips to 2ips range, but a simular compression damping profile IIRC.

Bilstein does not do it's valving like Koni does.
 
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Old 08-04-2009 | 05:02 PM
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My goal is to have a better quality ride. In Chicago I have noted the first part of the car that takes most of the impact from the poor and uneven surfaces are the front shocks. I see your point in terms of shock design.

Would you recommend a medium setting then on the Koni's if I end up running them? How many settings are on the Koni rebound adjustment? October is a long time to wait for a back ordered bilstein shock.
 
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Old 08-04-2009 | 05:20 PM
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Originally Posted by Vir2L
My goal is to have a better quality ride. In Chicago I have noted the first part of the car that takes most of the impact from the poor and uneven surfaces are the front shocks. I see your point in terms of shock design.

Would you recommend a medium setting then on the Koni's if I end up running them? How many settings are on the Koni rebound adjustment? October is a long time to wait for a back ordered bilstein shock.
Koni's are not a ride quality shock. They have too much control forces in the lower piston speed range, even at the very lowest rebound settings. And you cannot revalve them into that roll because of how the adjustor's work. I would go with Tokico HP fronts instead of the Koni's until the Bilstein's show up. But if you do install the setup with the Koni's in the front, I'd start at full soft. IIRC the front's have 2 1/8 turns of control. They do not have detents btw.

IMO, the best ride quality system is the Bilstein Pss9/10 set to full soft and never higher then 5 on the dial.
 
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Old 08-04-2009 | 06:34 PM
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I will let you know how the set up runs. Thanks for your knowledgeable input on the subject.

I did some further reading on shock absorbers and came up with an interesting point made about shocks : the compression cycle controls the motion of the vehicle's unsprung weight, while extension controls the heavier, sprung weight.

With this in mind, would you gather the Koni shocks may differ in compression from the Bilstein HD struts but their main character difference will lie in their control of sprung weight?
 
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