Today I went stage two with a cobb catless downpipe and I've
got a pretty strange sound. The most accurate description I can
think of is that it sounds like the turbo is sputtering(it sounds similar
to compressor surge except this is while it's spooling up between 0
and 5 psi). Once it gets past this, I hear it no more. I currently have
no heat shield, but I really don't think that has anything to do with
it, however it may make it seem louder. Please anyone tell me that
this is normal or how to fix it. It's about to drive me crazy and it
must be fixed. PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!!! Thanks.

 

waste gate flutter possibly?

 

Going from a stock exhaust to catless DP and or full TBE you'll start hearing some sounds from the turbo. If your getting full boost it's probably not a leak.

 

Sounds like wastegate flutter. Mine does it sometimes too, at part throttle under load(going up a small hill or something) .

I don't think it's a big deal.