Well I love my 6.5's but this one I got now just doesn't have that nice whistle. I can get 10-11 psi pulling a load or hitting a hill but really miss the noise. My 97 had a beautifull sound with a muffler and 4" pipe. I replaced the crossover pipe, removed the muffler, built a TM and nothing. I was wondering if I should pay some attention to the inter cooler. Is it possible it may be plugged? The next step is to make a new intake. She's old and a bit tired, has a small puff of black when I take off and a bit more blow by than it should but runs great and has good power. Any thoughts? Its a gm-5 turbo.

 

cut off the turbo muffler and plug it. or get one of those shitty hot air intakes and then you will hear it. these turbos are just not that big of screamers

 

Smoke stacks!

the less exhaust restriction you have the more beautiful the sound will be. An open downpipes right off the turbo will let you heat the turbo spool up and down clearly. intake side restrictions are not as crucial for the sound as exhaust but will still help.