I am finally getting decent mileage out of my 05 Duramax. I have a crew cab 2500HD with a camper shell. Started out by adding a Predator right off the bat. I don't have an around town MPG, since I just drive it on road trips. First trip was to Arizona and back from Missouri, got between 14-16 MPG per tank. After 10,000 miles it was getting between 17 and 18. These miles were loaded but no trailer.

Added a K and N filter, boosted the mileage around .5 MPG as best as I can tell.

Added a Pro-Flo 4" exhaust and got an increase of 2-2.5 MPG on the first trip. Drove to Atlantic City and back and averaged just over 20 MPG. Best tank was 20.89 MPG all interstate running 65 with the exception of 20 miles of detour.

Also the black cloud of smoke I would get each time after the Predator was added is now just a puff of grey.

I am pretty pleased at this point. All mileage was hand calculated using odometer, which was within .2 of GPS on each tank. The on board computer was off from 5-7 MPG from my computations.

If anyone can think of something that will help me get even better mileage, please let me know.

LBhttp://www.dieselplace.com/forum/images/smilies/smile.gif

you mean MPG right? ;)

Yes

Get an Accord Hybrid like mine, it gets 35mpg at 70mph. Thats one way to get better mileage!

hhm the wifes saturn get 40 on the interstate. Its no hybrid

Wife's VW TDI .... 45+ mpg 70 mph ... :)

Buffertech,
I see you have the 4" Flo-pro exhaust. Impressive gains in MPG with it. How do you like it overall? What is sound level like compared to stock? Is there any resonance in the cab? Never heard of this system before, but a shop in the area is selling them now at a reasonable price.
Thanks..............Dunk

You can improve the diesel mileage by adding propane or just making sure you have a good tailwind.

I made a trip yesterday, freeway only, 70 MPH (corrected for 285s) (65 on the spedo), a few small hills but mostly fairly flat.
21.6 MPG calculated, after calculating propane usage.
Propane is giving me about 2.5 MPG net increase in fuel economy under these conditions.

If I increase speed 12 MPH to 82 MPH my mileage drops almost 4 MPG. :eek:

These engines really do have a sweet spot. Get out of it and it will cost you...

Buffertech,
I see you have the 4" Flo-pro exhaust. Impressive gains in MPG with it. How do you like it overall? What is sound level like compared to stock? Is there any resonance in the cab? Never heard of this system before, but a shop in the area is selling them now at a reasonable price.
Thanks..............Dunk

Love it. Just a bit louder than the stock unit, but sounds better. You don't notice any difference in the cab.

LB

Those are great mpg #'s, but none of those cars are as roomy, near as nice, or have 255hp and cut 0-60's in the mid to low 6's as well as the ability to walk away from most sports cars on the freeway from a roll. All cars will be hybrid soon, I say bring it on!

My point wasn't that my car was the ultimate mileage maker, thats the prius or the insight, my point was if mileage is the real driving force behind the purchase then you shouldn't have got a big heavy diesel truck. Buy something else to commute with and use the truck for fun or towing and don't sweat the mileage.