A few weeks ago I installed Nismo Exhaust, Meagan Racing Test Pipes, and a Lower Plenum off a REV-UP engine...everything was good until this weekend. Now, my car sounds like shat under 3K RPM @ which point it begins to sound normal. At first I thought it was an exhaust leak(as my y-pipe is slightly damaged), it has that famous "flutter" sound. But today, after getting my car back from the body shop, it seemed a bit worse, I popped the hood and I can still here a flutter, louder under the hood, with a hint of a tap...not like the JWT cement truck "tap and grind", I climbed under the car... nothing from the y-pipe...
SO my questions are...
-If it is an exhaust leak, why would it "go away" over 3K??? (Perhaps it is still there, just not audible...hhhmmm)
-If it's louder under the hood than under the car, does that mean it could be around the header or top of the test pipe?
-Is it perhaps not related to the exhaust, but in fact some sort of A/F problem in low RPM from the TP/plenum?

I'm going to put it on a lift at work tomorrow and check it out, but I figured I'd post up here first, just in case this rings a bell with anyone.

Thanks,
Mike

 

Here we go..... leaks, flutters, taps. The start of "maybe I should get a Z06
afterall." j/k! Make sure the seller gives you some free lift time. Hope you find the problem.

 

LOL Mike! Anything is an excuse to get the Z06

I did find the problem, my test pipe cracked at the O2 mount, they are less than a month old, so I am going to make some calls and throw the HFC's back on for the time.