[jmhud31]

hey everybody, first timer here. I just recently installed a MBRP race catback exhaust on my car and a Mishimoto catted downpipe and i’ve been experiencing a strange noise as of lately. when i turn the car on and once it warms up a little bit it develops a “fluttering” noise under the car by the downpipe that sounds like a baseball card going through a bicycle wheel. If i’m sitting in park and rev it up a little bit the sound goes away but then comes back once it’s sitting idle again, but if i actually put the car in drive and begin driving lightly on the throttle i can hear the noise and it sounds awful. I’m at my wits end with this issue and i don’t know what to do about it

 

[EQ 7-2521]

First guess would be exhaust leak. Start inspecting by the turbo and work back. You might need a mirror in some areas. If the system has been on for some time you'll see black soot evidence at any leak. If you didn't seat the donut by the turbo or tighten it down enough, you would hear it.

 

[magneto]

I have the MBRP race catback and had to disconnect the mic in the rear headliner to stop the ANC system from over compensating for the extra cabin noise and causing some uneasant sounds and vibration from the speakers.

 

[HeightsLife]

if its not an exhaust leak, maybe it's actual contact. my exhaust developed a rattle weeks after i did it. the trouble spot was in the axle-back section where the hangers are. each pipe passes under/thru an upside down 'U' and it's gets kinda tight.

 

[jmhud31]

First guess would be exhaust leak. Start inspecting by the turbo and work back. You might need a mirror in some areas. If the system has been on for some time you'll see black soot evidence at any leak. If you didn't seat the donut by the turbo or tighten it down enough, you would hear it.

that was my first guess as well, i’m taking it to an exhaust shop tomorrow. the noise is coming from under the car though i’d say more closely to where the downpipe and catback connect, could that donut not being sealed tightly cause the noise to come from this spot?