I've heard that 23 highway in a 4x4 is easily attainable with exhaust and the right tune. Is this right? Can it go higher?

 

sounds about right

 

yeah it is, the guy in last years diesel power challenge hit 23 or 24 im almost positive. alot has to do with your drivin style too.

 

That's impressive. I guess a guy would have to stay at 60 to make it happen though....

 

in either diesel power mag or diesel world i cant remember which one, but they got a 12v cummins to get like 28 mpg. now mind you they duct taped the every hole on the truck, blocked off the radiator to make it run hotter, folded in the mirrors and didnt run ac. they did other things to but you get the idea

 

I would think that 24 is pushing it. 20-21 seems more realistic but on the internet there is no telling what someone will post.

I just topped my truck of with 24.7 gallons of ulsd and had 257 miles on the trip =10.40 mpg not hot rodding, in fact almost all highway.

 

i heard tommy got 27.2 mpg with his LMM for the diesel power mpg test

 

Yeah it was on a trailer, and not running. I am sorry call me a cynic but there is no way someone is getting that kind of MPG.

 

he had his dpf removed and his race 530hp tune, the speed ranged around 55-65

 

I don't think I've heard of many autos getting over 23MPG manuals do a little better. I can get 21MPG with 85% Hwy driving in town and think I was getting the same on the open road at 75MPH. I'd say your doing ok at 20MPG or better some never see over 18. This is only true with the pre-PDF trucks.