I just had my resonated testpipes installed...When I rev up and the rev comes back down I hear a whistle/wheeze/rattle type of sound coming from under my car. I first thought it was exhaust rasp but the sound is produced under the car around where the TPs are. Is this normal or is there something wrong with the install...

 

probably got a leak, jack it up and tighten them up, make sure the gaskets are good

 

i had the same problem on my '06...had strups put on...that rattle bothered me so much..along with the smell...i took them off

 

I went back and the shop is saying that it is normal for the 350z ...apparently all of the ones they have worked on does this. Its more of a off pitch whistle/rasp on only when the rev comes down at a neutral reving. If it was a leak wouldnt I hear it when im driving?

 

i have the same thing with my exhaust and cats set up. when its cold i really hear it but when the cars warms up for a while it goes away and it only happens in low rpm range. i was told it was normal too but who know still sounds great other than that

 

Mine does that too with my test pipes or any aftermarket exhaust. Can you record what yours sounds like?

 

ill get a sound clip asap...its kinda annoying

 

video of the TP on stock exhaust/piping...All the video captured is the rasp because its not able to record bass/deep sounds..lame..Sounds pretty good with stock exhaust other then a small amount of rasp

http://youtube.com/watch?v=NtLYQmArLE8
http://youtube.com/watch?v=jWsaWjZW1PE

 

Check For Clearances If You Removed The Test Pipe Bracket Your Exhoust Is Able To Move More And Will Sag. It Could Hit Your Cross Support.

 

that sound i got from the backpressure going throught he test pipe

 

does it sound like a loose washer when the car rev down about 2k rpm? cause mine does that.

 

Yup...I made a poll thread about it.