Gas mileage

[superman072000]

I have a 2004 6.0L gas 2500HD. As such I have the worst gas mileage I have ever seen. I love the truck and the power that comes with it. But i am looking to upgrade a few things. First I have already ordered a cold air intake which should be here any day. Next i would like to configure the exhaust so that it is workign with the intake. My stock is 3" dual inlet and 3.5" outlet. The only muffler that i have found that has the same setup is the 50 series FM. Is there anything else? I also want the deep resonate sound of the FM. I was originally looking for the 40 series, but not offered in the dual 3"/3.5out. Also next on the list would be a throttle body spacer. Any comments or recommendations for fuel economy/HP.

[Ductape]

I would contact Allen Nelson and tell him you want your truck tuned for economy. That's going to do more for you than intake or exhaust.

I don't think I've seen any evidence that TB spacers work on this generation of engine.

 

Mike

[redvett]

The big dual exhaust has taken all the back pressure away the engine needs for bottom end torque & mileage. Ditch the big exhaust system and get a tune.