4" exhaust coupled to turbo housing question

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I am a new member of TDR and have been reading your forum since I purchased my '96 3500 dually 2 months ago. I have been reading entries in this forum to learn how to improve my mileage, and where possible, gain power. Adding 4" exhaust and low restriction air cleaner seems like a move in the right step. I popped the hood and looked at the connection from the turbo to the exhaust pipe and noticed that the exit port only looks like 3". My first thought was "What good does the 4" pipe do if there is a restriction right at the turbo? Can someone educate me on this topic? Thanks!

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'96 3500 4X4 Club Cab, Automatic, 4. 10:
'70 440 4sp RT Challenger
:'00 Harley Dyna Convertible

 

[Archive]

You an find tons of stuff on thest topics in old posts. I will be surprised if you gain mpg or power with 4" or air system. In my tsting, 4" only helps significantly with the Superturbo HX40 in engines over 350 hp at the wheels. The only true benefit I know of from the air systems would be the reduction in inlet air temp from the Psychotty. Generally reducing intake temp 1 deg. can reduce egt up to 1. 4 deg, according to Mark Chapple of TST.

Check out my article in Issue 29 of TDR for more of my opinions on power and mpg.
Joe