Need a new exhaust turbo-back on my 01` HO-6spd. 3.54 ratio Van-Aken box otherwise stock.
Used for modest towing/8,000lbs and driving empty.
Does the exhaust diameter used effect mileage?
Seen where it can effect other brands of diesels.

 

Not really, just helps lower egt's and changes sound of truck.

 

I have 4" from the turbo back in stainless. When I dropped the CAT and went to 6" stacks I noticed a little improvement, went from 17 to 22 mpg on the highway.

 

I had 3" straight pipe on my 12valve, & added / had it made into duals, & after a few days noticed it breathed alot better, had better throttle response & more torque (opened up the restriction a bit). Was it a miracle cure? No, but it definitely made a difference

 

That seems pretty awesome...wish mine netted me a 5 mpg improvement!!!

 

don't go any bigger than a 4"... you will loose back pressure and horsepower...

a 4" exhaust can support up to over 500hp.. so unless you're going to be adding a ton of performance parts the 4" would be plenty

 

I installed a 4"ss turbo back ,Did not notice a thing other then it sounds a lot nicer. (strait piped)

this is on my 01 HO 6sp

 

How do you lose horsepower by lowering backpressure?

 

I think he meant VELOCITY.

 

Maybe. Pittsburg Diesel Power claims if you can keep the EGT up farther down the pipe you will gain power as well. Thinking of trying on the daycab.

 

I have not ever lost MPG from the larger exhaust.. Had 4" with stock turbo, Went to 5" (with 5"-51" Donaldson muff) when I changed to Silver 62 and kept the 5"(straight from Turbo to tailpipe) when I changed to to stock/S475 compounds.. Only time I lose MPG is when I am pushing o the long peddle more than trying to go light on that same peddle.

 

The less pressure you have on the outlet side of the turbo, the better off you are.

 

I have a 2001 6 speed also, and was wondering the same things. When pulling my trailer I usually run EGT's between 900 & 1100 degrees pre-turbo right now with an EZ box and everthing else stock. I was wondering how much a 4 inch exhaust would help bring down the EGT. I also would like to know what system I can put on that won't be too loud or have a drone when pulling my trailer.

 

My 98.5 Cummins powered Ram has 112.000 miles on it and the stock exhaust system went south. Installed a 4" Bully Dog stainless turbo back exhaust last week. Really like the sound, and so far have increased my milage from 19 MPG Highway to 22 MPG highway. Wish I had done this years ago.

 

the best thing you can do to these trucks is make them breathe easier. you will never regret it.