i have an 01 gmc 2500 4x4 with a 6.0. first question is what kind of mods will improve mpg without hurting my wallet? second thing is when i take off it sounds like a jet is lifting off (the fan) does everyones 6.0 do this or is there something wrong?

 

anyone else have lift off in your 6.0 truck?

 

its probably your clutch fan being engaged, that year they were still running off the motor

 

+1 probably the clutch.
as far as MPG mods, my personal experience is that the best things for mileage were the cold air intake, electric fans (also eliminate your takeoff feature), good tune, and exhaust. plus they will all make the truck more fun to drive.

 

I have basically the same truck but a chevy, just did the nelson tune and havent run a tank of gas out of it yet to check mileage but it appears to be doing better. Power wise obvious increase, also seems to run alot smoother and with less effort. The turck is running 315/75/16s

 

In order to get rid of the fan noise and also increase your milage, you should replace your stock clutch fan with the 05+ e-fans. They cost about $250 + $100 for a harness, and you'll get better mpg, more power, and less noise.

 

if you go with the oem e fans u have to get the bigger 05 radiator, due to the fact the fans/fan shrouds are bigger, but u can always go with aftermarket fans that work just as well, http://nelsonperformance.com

has the fan harness

 

Since he has an HD he already has the 34" radiator, perfect candidate for 05 e-fans .