I've seen people put crazy #'s on mpg, I'm not saying that you can't get good MPG, but most times it's a single event. Like say your heading east from Col. To Kc. The wind is almost always out of the west so you have a 20-40% drop in wind friction. And say your empty w/tailgate down, full of fuel and don't stop to pee. The trip I'm describing was 1 of mine about a year ago when diesel was +$4 per gal. When I got to Kc it took 16 & a 1/2 gal to fill'er up. That works out to about 31mpg. Since this was my business truck I kept milage records from Jan 1 to Dec 31. The truck normaly averaged 21. This was a 93 GMC 6.5 TD 1/2 ton auto O/D w/3.42 gears that I drove 80mph on the interstate.

On the other hand in a similar circumstance I got 22mpg in a 1ton dually crew cab 92' f350 7.3 IDI non-turbo and averaged 11mpg for the year.

I guess it's just a case of where you are and what your driving.

 

Well said Joe Dad

 

Since I have changed jobs I am driving the state routes at 55-60 vs highway at 70-75 and I now get about 17-17.5. I am messing with the settings on the comp to try for best mileage and so far 4X4 with the tap turned off works the best. 5X5 with no tap lost 2MPG!!!

 

Never have gotten better them 21-22 on the HWY, but I normally go the speed limit +5. If I do 19 or better I'm happy with ahead wind 17 at best. I have since straight piped, tuned, and gotten larger MT tires, so who knows now. It looks so far like it maybe worse.

 

I know diesel power magazine did an mpg test a while back and the winning truck was a regular cab newer duramax with EFI live tuning and a couple other mods and it got 30 mpg.

 

If you have a link for an article, could you post it in here?

I've been trying to hunt down a test like that for a Duramax, but all I could find were the 7.3L and 99 Cummins tests, and I've been eager to see what someone could do with a Duramax. EFI live on a 2wd regular cab I imagine could get 30 easy considering early Duramaxes can get 23mpg bone stock. It seems like 30mpg is the magic number.

 

hah i get bout 16.5 roughly and i floor it all the time, just love the noise

 

16-17 everyday driving and 20 or 21 highway

 

There is definitely something wrong, I have almost the same setup and I am getting around 18 on the highway, I am a little lower and that may have something to do with it...