2003 6.0 whistle

[03machstock]

Hey guys, new to the forum here. Reason i am posting is we just took the cat out of my buddys 03 6 liter and the whistle is not there. Started it up with nothing on but the down pipe and it was loud, but not that hiss from the turbo that comes on a couple seconds after starting it up that you hear on the straight pipe ones. My question is is that due to a stock down pipe having a resonator or was there some turbo rebuild that could have been done before he got the truck to make it like that? Im guessing it would just take getting a new down pipe to solve the problem or is there any simple cutting out of the resonator?
Thanks,
Dan

[dhanna6powerstroke]

You say you took the cat out? You are talking about the one closest to the front of the exhaust correct?

[03machstock]

Correct, i removed the cat.

[SickStroke6.0]

It could be the stock downpipe, but another thing is, was the truck warm or cold when you were trying to find the whistle?

Mine doesn't whistle much at all at normal idle when cold, just the hiss.

[NEWT92]

Sounds like the turbo was replaced at some time with a newer style one. (05-07)

[03machstock]

Thats what im talking about is it doesnt have the hiss at idle. Truck was decently warm when we started it with nothing on but the downpipe.