[hopsami2]

I have an '03 Duramax CC dually with 50K. I put an Edge card (Attitude with Juice) on it two months ago. That gave it some serious HP at the starting line and I could break the rear duals loose. Last week I had a 4" exhaust put on front to back (straight pipe). (This rig also never had a Cat!) The first thing I noticed was the NOISE ! The second, and more important thing, was that I lost all of the bottom end I had before and couldn't break the duals loose anymore. I talked with the Edge people and the guy who installed it, and they both said that the Turbo needed a certain amount of backpressure to operate correctly. I did notice that my Boost numbers were lower at the starting line with the 4" exhaust. I went back to the exhaust installer and we decided to put a stock 4" muffler back on. I got about 1/2 the bottom end back and the PU was quieter than Stock. Before I pay to put everything back the way it was: has anybody else experienced this and what did they do about it?

 

[Strobel]

I'd try a aftermarket intake like AFE or K&N. Air in and air out.

 

[LWATSON]

My 03 did the same thing I put my stock front pipe back on and left the 4"muffler and tailpipe in place and got all of my bottom end back.

 

[hopsami2]

Thanks for the reply!! It is greatly appreciated. This PU is my Baby, the fanciest one I've had so far and it made me sick to lose the bottom end. Your reply has been the best news of this day !! Thanks again !! Will look up Scotland Neck, NC when we start full-time RV-ing in June.

Lee Desmarais

 

[LWATSON]

Good luck with your exhaust. I think the 4" front pipe decreases exhaust velocity which affects the turbo, I've never heard of a loss in torque with modifications after the front pipe.

 

[1000hp]

Increase boost by bleeding some air off from the waste gate. that'll get some back pressure back.