aftermarket suspension = noise?

azn370z

I have bc br too. The rear passanger makes a clunk sound when going over bumps. The driver side makes noise too but it has to be a big bump. From what I've read coilovers can make noise because it's mostly metal to metal contact. Some people with coilovers have noise and some don't, some people are bothered by the noise and some aren't.

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2010 k23
H&R sport springs / Spc rear camber arms / SSR SP1 / Berk cbe / Varis cf lip / Nismo S-Tune side skirts

jmlenz

Man tell me about it! I have the Megan coilovers and am experiencing the same noises from the rear. Over large bumps, dividers, etc the rear will make a loud 'clunk' or 'boom' on impact. Sometimes loud enough to startle passengers lol...they always ask WTH was that? I thought I could ignore it but it is just pissing me off now. Oddly it ONLY comes from the rear. I have fiddled with the springs/perches and even had them taking out and reinspected to be sure everything is installed correctly...it is. What the hell causes this?

Also, how do you adjust preload on the rear springs? The instructions dont mention anything about this and this was never brought up by the installer. My only thoughts are that the rubber isolator (on top of rear spring perch) is not thick or robust enough to dampen these noises. Did you notice how big the OEM rear spring isolator is?

azn370z

For the rears what you need to do is remove the stock strut and spring
Take the spring seat collars and set them at the same level not tightening them yet
Put the springs on, put the tires back on and bring the car to the floor
See if the height of the car is the desired height, if not then raise it back up doing the prev steps
(be sure to keep the height about 1/4" higher than what you want as you still need to set preload)
Once you have achieved the height you want, raise the car back up, take out the springs and spring seats
tighten the collars on the spring seat and reinstall (if you try to tighten them while on the car there is a possibility you can strip them)
You should have a bolt that goes through the factory lower arm and bolts to our spring seat, at this point tighten that too
Take your spare jack and place under the hub raise the hub so that the spring sits snug but not compressed

Now install the strut, tightening the top only
Measure the distance from the center of the hub to the fender
Raise jack 1/4" creating the preload on the spring
Scroll the lower mount of the strut up so that its level with its mounting bolt, slide the bolt through it and tighten
At this point you should have the spring preloaded 1/4" and the ride height at your desired level.

__________________
2010 k23
H&R sport springs / Spc rear camber arms / SSR SP1 / Berk cbe / Varis cf lip / Nismo S-Tune side skirts

jmlenz

Thanks for the tips...im pretty sure the installer did not take these steps and hence set no preload. This might be why the springs are loose and there is noise coming from back there. I will PM you with further questions when I get around to reinstalling these for the 3rd time haha.

azn370z

You should first try jacking up the car so the wheels are off the ground then grab the spring and shake it, if it moves then you need to preload them. If it doesn't move then your preload should be fine.

__________________
2010 k23
H&R sport springs / Spc rear camber arms / SSR SP1 / Berk cbe / Varis cf lip / Nismo S-Tune side skirts

jmlenz

I think that may be the problem. When I jack the rear of the Z up i can reach in their and rattle the hell out of the springs. If I remember I think even the installer said this was normal on this suspension design...guess that is BS then huh. So even when the rear tires are completely off the ground (jacked up by rear diff) the springs should be solid in there with no rattle or movement?