Duramax Fuel Mileage

[TSchwantes]

My brother-in-law claims that he can get 30mpg with his truck on highway trips. Is this even remotely possible? His truck is a 2004, without mods (I think). It seems to me that he couldn't get 30 going empty 50mph downhill with a tailwind (he's still pushing 7000# around and has all the aerodynamics of a brick wall).

 

[JoelMartin]

Pigs might fly.

 

[DCreed]

is that on the display? tell him to document miles/gallons.

 

[TSchwantes]

He claims it's calculated... I just think maybe math is not his specialty!:-laf

 

[Grizzly]

My brother-in-law claims that he can get 30mpg with his truck on highway trips. Is this even remotely possible? His truck is a 2004, without mods (I think). It seems to me that he couldn't get 30 going empty 50mph downhill with a tailwind (he's still pushing 7000# around and has all the aerodynamics of a brick wall).

The best way to improve your fuel mileage is to lie about it. That's what my brother-in-law does, who has an 08, 6. 4 powerjoke. He gets 21 mpg, empty at 75 mph on the interstate.

 

[JHerr]

30-mpg with a Duramax? Not likely. I agree with Grizzly.



The most efficient full-sized diesel pickups I ever encountered were 12-valve, 2wd Dodges. 12-valves could better 25 mpg if driven properly. The best I ever got was 25. 8-mpg with my '94 4wd. My '98. 5 24v 4wd got just shy of 25-mpg on one tank. Both of those times, I purposely drove for maximum mpg. I routinely get 21-22 mpg in normal driving, using the pen & paper method.

 

[Flinty]

Does it have a LLY or LB7? The LB7's got better mileage but no where near what a 12v Cummins will. My friend has a LLY that's mod'd with edge programmer, exhaust, intake and he rarely sees more than 17mpg, more like 14. That's when it's not overheating! However I will say in a straight level line that thing makes tracks. Thirty is pretty hard to believe.

 

[MDTyree]

Not likely, A friend of mine has a 05 duramax with 30,000 miles on it and he said he only gets 15 to 15. 5. He said the truck display says 16 to 16. 5 unloaded and on the highway.

 

[maxburk]

Somebody is adding fuel to that boys tank.

 

[TSchwantes]

Yeah, I thought that was a little high! I don't know what the motor is, but I think it's a 2004 truck. I do have to say I am impressed with the towing mileage that my Dad gets with his truck though. I hand calculated about 13. 5 for his 2007 Duramax (before all the new emissions BS) for a trip towing his 11,500# fifth wheel! I had my 8000# TT behind my 2003 Cummins on the same trip and I only got 11. 5 mpg (which is about normal for me towing)! Could all this difference be just the aerodynamics of the 2 trailers?

 

[Larry Willard]

The best way to improve your fuel mileage is to lie about it. That's what my brother-in-law does, who has an 08, 6. 4 powerjoke. He gets 21 mpg, empty at 75 mph on the interstate.



My brother in law also has an '08, but gets much better than that! My other brother in law used to get 25 towing his travel trailer with a 7. 3!!

 

[robertyoke]

propane injection perhaps? I know a guy that would say he gets 25+ w/pane and not consider the cost of the extra fuel.



I can get better mileage than that with my 03 truck... ..... just tow it with my 04:-laf

-robert

 

[steved]

One of the guys I work with has an 05 Dmax... he is really disappointed with the mileage... 15mpg is the best he gets...



The drilling crew I'm working with has one, they claim pretty good with the dual OD Ally... but nowhere near 30mpg!



steved

 

[TFucili]

More like 30 KILOMETERS per gallon:-{}Gimme a break.

 

[FATCAT]

Does your brother-in-law have that "Tornado" thing in his intake? And/or does he have that secret magnet that goes around the fuel line?



Maybe thats how he does it!:-laf

 

[TSchwantes]

I think he has the tornado thing, magnets, acetone, and a special voodoo doll!!:-laf

 

[JTruelove]

There are two things men lie about... fuel mileage and sex