Strange Case of the Vibrations
 

I'm not sure if this is the right forum for this question, but if it's not I'm sure the Mods will over it to the appropriate area :driving:

Anyway, lately the Z has developed an odd vibration that manifests itself most strongly coming off acceleration or on uneven roads. On cruise control it's barely noticeable, it's not really noticeable going over speed bumps or grates or anything likely to jolt the exhaust...which is where my initial speculation about the origin might be stemming from.

However I've checked my exhaust. There is nothing touching any part of the under carriage at all, and all bolts seem to be tight. I've had a friend, a fellow forum member take a second look and do a ride-along with me...and the only thing that we could find was the left exhaust tip was slightly loose...for the record, it's an AAM GTR Titanium tip that is only slightly bigger than my AAM 2.5 Dual Exhaust...but it fits. We tightened it again and the vibration is still there.

If anything, it seems to be getting stronger and more noticeable over time, and I'm starting to get pretty concerned.

Has anybody ever had anything like this before, or heard of it?

What does the vibration sound like (is it metal on metal etc.)? Where do you feel the vibration ( do you feel it in the steering wheel or your butt...)?

I don't feel it so much as hear it. Maybe Dragonbreath can add some insight when he sees this...but it sounds like it's coming from the rear.

You can hear it occasionally when cruising over uneven roads, but it's very strong, very loud when coming off an acceleration.

It sounds very much like metal on metal, to my ears. A while back I had a piece of the rear strut connecting with my exhaust core, and it sounds like that...only that problem has been fixed, and there's ample space now between. We checked it with wiggle, and it would take an aggressive wiggle to make them even come close to connecting.

I also had an issue once right after the car was lowered where I had scraped the cuved cross-section right around the mid-pipe area of the exhaust...banged it upward and that was connecting to the exhaust, causing a audible vibration...but that piece was replaced a very long time ago, and that was the first place I checked.

It's spotless; no dents or dings, certainly no connecting between it and the exhaust.

do you have spacers or changed wheels recently? if so, retorque them as it could be the cause of the vibrations.