i have a 99 powerstroke and i am wanting to get the most power and fuel miles i can and i was told if i cut my muffler off i would gain power and fuel miles because it would let more air through and cause less black smoke which means more fuel miles, true or not true?

 

Go and get a four inch exhaust. Less restriction little more power, less egts. Maybe aliitle better mileage but not a lot. With a four inch exhaust with a muffler or no muffler the only difference is sound. In my expirence

 

Muffler or not, a good 4" turbo back will be your best bet...

Main reason to do an exhaust is to lower EGT's.

 

i got 31/5 back straight into 6inch stack but i was told that if i left the muffler on that it would cause more black smoke which means less fuel miles? was i getting miss lead?

 

i drive a 2000 powerstroke with 5 in exhaust and started off with the muffler, and just recetly took the muffler off.... i didnt notice a difference in the smoke or the millage, it is a noticable difference in sound. and for that matter, a muffler has nothing to do with why a truck smokes, so i dnt see why someone would say it gave you more black smoke

 

ok im fairly new at the diesel game so i always double check what i hear, thanks for the info!