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      06-30-2020, 08:18 PM   #1
maupineda
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Drives: E86 Z4MC
Join Date: Jul 2012
Location: Detroit, MI

iTrader: (3)

E86 H&R Coilovers Knock -- FIXED!!!

I am super happy as I finally was able to fix a little knocking noise I had in the front suspension of my Z4MC. This noise has been there since I bought the car, and I actually changed the coils it had to H&R thinking it could be the coils and camber plates setup I had, as solid mounts inevitably result in higher NVH.

Well, I was disappointed to find that the new coils would do the same

After searching online I found that some times the problem is with the springs as the coils can slap one another, so I found that some companies like TEIN and EIBACH do coils spring sleeves and so I decided to give it a go.

I just installed those on the fronts and OMG, the noise is completely gone and it just saved me from throwing more money at this issue as I was thinking that my control arms and bushings may be wrong since everything else is new!

I kid you not, the ride now has a pliant ride over pavement joints that before were very harsh and abrupt and would create a knock, now is completely silent and feels more compliant.

When looking at the OE spring is evident why they are silent, all coils are of a different diameter, so even when the coil compresses fully the coils never touch, the lowering spring of H&R coilovers, on the other hand, have the same diameter for the top 3 coils, then reduce gradually to meet the adjustable perch. These 3 coils are almost at max compression with the vehicle on the ground so any small suspension travel make them contact and when the move is quick and sudden they slap creating the knock

Below the images of what sleeves I used and how they look installed, I used one sleeve per spring which is enough as covering the middle of the 3 top coils give cushion to the progressive part of the spring.

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Sorry for the poor light, but you can see the sleeve in the next two photos

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I bought 4 of these sleeves as sometimes my rear does it too so this weekend I will put them on as I need to take the wheels off and maybe even lose the shock to squeeze the sleeve on. the front went in, in seconds. It took me more time identifying where to start putting the sleeve to cover the right contact areas.

Last edited by maupineda; 07-01-2020 at 09:22 AM..