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Discussion Starter #1 (Edited)
clunking - swaybar related?

I'm sure someone else here has a similar setup, here's what I have on my 02 sedan (among other things, but these are the items in question):

lowered with DMS 40mm coilovers
Cusco rear sway bar
HKS Hiper catback

Now here's the deal...The swaybar makes contact with one of the hanger prongs on the catback. I wrapped a piece of washing machine hose around the prong to reduce wear at the contact/rubbing spot. The rubber has since had a rut worn into it, lumped up in the direction of the underbody.

Getting to the point, there is obviously friction between the swaybar and the exhaust hanger prong at some times. It's my theory that this friction causes the swaybar to kind of bind up at times, which I believe is causing the clunking feeling I feel from the rear. (i.e. swaybar binds up, motion of the coilovers is affected, producing a clunk).

I've had the coilovers serviced and they are in top condition. When the car is on the stock struts, there is no clunk.

I'll try removing the swaybar this weekend and see if it goes away. If it does, I either need a different swaybar, or I need to do something with the exhaust prong. So if you read all of this, is anyone with a similar setup experiencing this phenomenon? Any input would be a help.

Thanks guys.
 

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Discussion Starter #3
UPDATE

Removed my Cusco rear sway bar. Took the car for a couple laps around the block. Clunking is *drastically* reduced, but present nonetheless. Really only present on sudden changes in road height (i.e. 1/2" dropoff coming off my garage onto the asphalt)

Noise now comes only from the rear right corner, as opposed to be "spread" across the rear with swaybar on. More of a "flexing" than a clunking even, but audible from inside and outside when I push down on the rear of the car.

Ride height may be slightly higher on the rear right, I need to measure it again and lower it accordingly...could this have anything to do with it?
 

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I would take some tape to the sections that you think are making noises and keep working it until you find the culprit.
 

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I had two issues that may or may not pertain to your problems. When I installed the TBE on my car (Helix DP/Evo catback) I had some clunking issues from that area. I knew the exhaust was hitting SOMETHING but wasn't really sure what it was. I bought the Kartboy exhaust hangars and sure enough the problem went away. Fast forward a few months the woman bought me a Cusco rear swaybar (no aftermarket mounts or endlinks). I installed it and soon after experienced some clunking or popping whenever the rear suspension unloaded. I did some checking and realized that the sway bar was pinched in the rubber from the stock mounts and wasn't able to shift easily. As per instructions from this forum I bought some lithium grease and liberally greased the stock mounts around the swaybar and also where the rubber insert loads into the metal mount. VOILA! No more clunking, popping or any other obnoxious noise for that matter.

Not sure if this is the problem that you're experience, but something to think about. Once I looked around I realized that A LOT of Cusco RSB owner experienced the same noises if they didn't apply grease.


-Andy
 

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coil-overs are noisy parts. if there is no preload on the spring, the spring has free play and will clunk around between the collar and hat. check for that and make sure the coil-overs are tightened down at the strut tower.
 

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NOTimprezed said:
coil-overs are noisy parts. if there is no preload on the spring, the spring has free play and will clunk around between the collar and hat. check for that and make sure the coil-overs are tightened down at the strut tower.

Coils are notorious for producing much more horizontal flex across the whole camber set. Springs are much wider and provide a stronger base which reduces this "flex" albiet you loose you adjustability. When you go to the lowest setting ,16, you you introduce this flex to the rest of the chasis hense the "rubbing / clunking" that your hearing....especially as it relates to aftermarket exhausts.


-K
 

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Discussion Starter #11
Thanks for the input guys. I have checked and re-checked everything more times than I care to remember. Between all the info i've gathered here and at nasioc, nobody seems to have correctly identified the problem.

I'm thinking kwilson21's explanation is probably about as close as anyone is gonna get. Its interesting to note that a lot of stock STi's are having the same issue on their stock suspension and subaru hasn't been able to fix it.

I guess i'll just have to keep living with it as long as I can. Then maybe I'll go to a shock/spring setup, since there seems to be fewer annoyances that way.

If anyone comes up with a really good idea, I'd be willing to try it out, but until then I'm just gonna give it a rest :(
 
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