If I believe my computer I get 22 mpg. BUT, since I hand calc every tank I know that I am REALLY only getting 18 mpg.

When you add a "tune" it screws with the computer and you will read MUCH higher. But, it is not "real" mileage, just make believe....

Happy now?

On Edit. I believed this silly nonsense of the Cummins getting out of this world mileage when I switched brands of diesel trucks. Reality is about the same mileage. And I drive like grandma 24/7 and obey the speed limit, making me the slowest person on the road. Plus I live in Texas where it never gets cold. So I should have the best possible recipe for super mileage. Haven't seen it yet..

 

install smaller tires, don't cal the speedo so the speedo reads faster and watch the overhead. 28 is not going to happen.

 

It's simply not enough to say you can get, or can you get "X" mpg. It's about fuel used over a distance, not just some instantaneous number. The longer the averaging goes on the more accurate the mileage numbers are or the more you can really say what your mileage is.

For instance when idling in the driveway you are getting zero mileage. Coasting down a hill you could be getting almost infinite mileage because the injection may have completely stopped. Steady state at 60 MPH on level ground with no wind might yield 25 MPG, but just then you have to pass someone or climb a grade or something else.

It's the avearge over many miles that counts, and it's the only thing that counts.

It's pretty silly to reset the computer readout on the fly and then report the mileage after a few seconds. Try getting that mileage during an entire trip or through an entire tank. It's not gonna happen. Then try planning your fuel peurchases by the best mileage you can trick the truck into getting and see how far off you are.

Just keep track of fuel used over a period of typical driving. Make sure your odometer is accurate. Average it out and there you are. Real world mileage you can count on. Long trips on secondary roads will get better mileage. City will be worse. Towing will be worse. Very high speed driving will be worse. Slowing down really helps to increase it. Idling long periods will reduce it. Extra big tires (wide and aggresssive tread) will reduce it. 12 valve trucks better, 6.7s worse, '04s somewhere in the middle.

My all around average is a little over 18. Approximately 50% high speed highway (75 MPH), 20% city, 30% secondary roads through the mountains with speeds of 50-60 MPH. All of these miles might be empty or with up to a thousand pounds in the back. That's real world, averaged over thousands of miles but it can be down to 16 or up to 21 on occasion on certain trips. The shorter the trip the more it varies. Maybe 10 on a trip to the store and back, maybe 22 coming home from the mountains empty.

John

 

Apparently you can according to this guy

 

People will say anything to sell a vehicle.. Also seat 6 comfortably, wonder, maybe a midget riding center hump up front?

 

on one of the snowmobiling sites someone posted spy pics of an 08 big durango. it was suppose to be in the same class as the suburban. had a detuned cummins. it was supposed to get 28 mpg. but it was not a 350 hp and 650 tq engine.

 

Well guys, I get 17.7mpg overall. I don't drive crazy. I do get improved mileage on the freeway, 22-25 mpg but the city driving kills the average for me.
I'm not also going to look like a dork doing 60 in 80mph traffic trying to dave a gallon of fuel.

 

I did a little test today just for giggles. With a tailwind, SMARTY level 7 at 40mph in 6th gear I got 31.1mpg, 45mph = 30.4mpg and 50mph = 28.7mpg.

I know it's worthless data but it was fun seeing it on the Guess-O-Meter......

MikeyB

 

My 04 overhead computer is telling me 27mpg highway. 60mph , 3.73, stock everything. Truck has 243,000 synthectic trans and dif fluids. I need to take a trip to get a hand calculation average. I've only had the truck 2 months. Might do an air filter mod. Any suggestions? I'm getting greedy for mileage.

 

I know a diesel guru who has an 03. He got 29 MPG going down hill from Amarillo TX to Denton TX. He had a tail wind and drove 55 MPH. Best I've seen from mine is 24 MPG. These are both hand calculated.

 

[QUOTE=mopardamo;2038114]Hello,

No need to make truck changes. Get er up to OD speed and then back down. On relatively flat terrain I can get better than 28mpg. Big problem. I do not want to die. Doing 45 to 50 on the highway is stupid in my o

Hand calculated or overhead? I agree, going 45-50 on interstate is dangerous and possibly get you ran over.

 

i have had my overhead say 30mpg before. at 58mpg. with my x2 set on the MPGtune. I KNOW that it isn't really getting that i calculated it out once before and it was around 26 27 mpg. this was with a 6" lift and 285 70 BFG"s. and a 4" straight pipe with a stack. with my big tires i have on now i get about 19 or 20. And this is driveing sensable. not like a granpa and not like a A$$hole.

this was with a empty truck. not towing anything

 

Simple!
Move to Canada!
30 MPG no problem here!
But our gallon has about 4 1/2 of your quarts!

 

My 06 has used 3815.12 gallons over 58723 miles. Thats 15.39 MPG average, I might give someone up to 18mpg average but more than that you need to take the truck off the trailer

 

To the original post....No, you cannot get 28MPG.
I can get 20.1 with max tire pressure and driving so carefully it puts my mom to sleep.

18 is about average for me. But I can kill that real fast with a couple of dips into the skinny pedal.