I was unsure of where to post this request for help or advice. I have recently replaced the front/rear sways(Eibach), springs(350Z H-Techs) and exhaust (JIC y-pipe and Fuji). When I hit large bumps, especially on highway creases that make car kind of jump, I am getting a rattle noise in the rear that sounds like it is coming from the passenger rear quarter area under the car. My mechanic and I have gone over everything twice and from the outside can not see anything. The sways are tight, the springs are seated and the exhaust feels solid. It does not sound like a metallic sound, but more of a thunking noise, if that makes sense. I have checked the spare and the jacking tools and everything seems fine. I have an 05 coupe. Anyone else encounter anything like this? Anyone have any ideas so we can possibly pinpoint problem. Any help or advice is greatly appreciated.

Thank you.

 

Anyone have any ideas? Anything?

 

Yeah i am getting the same rattle sound coming from rear passenger side too.
I brought it to the dealer, and checked if that sound caused by rear axle (like
many members here suggested). After one hour, the technician came out
and said because i have after market sway(hotchkis) and shocks(d-spec)
so the car moving(weigh transfer?) more than the car designed. He suggested
to put all the stock back?, so now i am driving with rattle too
Mike

 

I can almost guarantee it is the exhaust hitting the rear swaybar. I have the same thing with my stillen sways and stillen exhaust. I have heard that only the Hotchkis sways have sufficient rear clearance for aftermarket exhausts.

Also, all of the aftermarket exhausts tend to sag a bit over time because the clamps are not as efficient at keeping the pieces together as the stock set up. I think once I get my clutch installed next Saturday I am going to have my exhaust tightened up and then just tacked to keep it from sagging.

 

Thank you for the advice. I will have my mechanic look into the situation with the exhaust. Maybe we can tighten it up so it does not move. I really appreaciate the help.