Duramax Milage, What Are You Getting?

[hotjava66]

I have had a couple Duramaxes, my current one is an 05 SRW Crew Cab. I have had it a few months but havent really done any road trips, gets around 15-16 daily driving. So today I went to get my boat, 3hrs each way, drove around 78 empty there, got 15.5mpg. On the way home loaded 72mph, havent fueled up yet but looks like around 10-11mpg. This is bad compared to my last 2 Duramaxes, I could always pull 18-20 empty and 12-14 loaded (MPG) on the highway. Any ideas, what does everyone else get? Should I be checking for a problem? BTW this is running a Bullydog programmer in Haul/Economy tune, which I have used on the last 2 trucks as well. Power seems fine, just doesnt get the economy im used to. I dont know much history, I picked it up as a repo so it prob. wasnt kept up great but seems ok. Anyone got any ideas or is that normal mileage and I just had 2 really good ones before?

[fund razor]

Mine is a couple of months new to me. 2006 DRW CC LB.

I am getting 16.5 highway, empty.
According to the DIC anyway. I may haul today. I am interested to see what I get. I am expecting 11-12. No tunes.

I find that it really drops off above 70.

[JupiterSunsation]

There will be a huge discrepancy here between guys that can do math and the DIC readouts. The DIC is overly optimistic and the correct way to figure it out is to fill it, reset trip odometer, drive it until it is empty and then divide the miles driven by the gallons used. 300 miles on 25 gallons is 12 miles per gallon.....

That being said on my bone stock 03 with 152,000 miles I get 12-13 regularly in 90% city pulling a light trailer and plenty of idling with a/c on. Truck has a decent amount of tools/junk onboard at all times. Best I ever got was 17 driving home from the dealer empty of everything but the dealership paperwork!

[BUIZILLA]

there's no such thing as *haul/economy*

it's one or the other..

mine would get 15-16 in town and 19.5ish at 78 bobtail

the Diablo plug in set at +65hp picked up 2 mpg all around

[Hilltop Kyle]

I have the same truck in an '04. I get 16-17 around town empty and 18-19 Hwy running similar speeds. These are hand calculated numbers. The DIC has me getting 22-23 hwy (I wish!). I've replaced the intake, exhaust, and have an Edge Programmer. Unless towing I always run the Edge on the #3 Drive setting (+75hp).

[hotjava66]

my numbers are all hard/hand calculated. the tune im running is the tow tune, 1st stage lowest program. checked my tow mpg and it was 10.5, boat/trailer/full fuel probably 9000lbs. im a little disappointed, my 03 did quite a bit better, but i did have an upgraded intake and exhaust, and was a standard cab. i know if you keep under 2000rpms you can do a lot better but i just cant drive that slow.

[Tyler83]

Kinda a little off topic here but I got a 06 2500 crew cab from what I understand they have 25-26 gallon tanks but I have never been able to get more than 21 gallons in it, and that is filling it to the neck after running with the low fuel light on for awhile.

[hotjava66]

Kinda a little off topic here but I got a 06 2500 crew cab from what I understand they have 25-26 gallon tanks but I have never been able to get more than 21 gallons in it, and that is filling it to the neck after running with the low fuel light on for awhile.

mine never takes more than 22 and thats if I run it on empty for a while

[JupiterSunsation]

Kinda a little off topic here but I got a 06 2500 crew cab from what I understand they have 25-26 gallon tanks but I have never been able to get more than 21 gallons in it, and that is filling it to the neck after running with the low fuel light on for awhile.

My 03 crew cab got 25.6 gallons added today........26 gallon tank is what my truck has. The long bed trucks have 31 gallon tanks which would be nice!

[Tyler83]

My 03 crew cab got 25.6 gallons added today........26 gallon tank is what my truck has. The long bed trucks have 31 gallon tanks which would be nice!

Yea it sure would be!

[endeavor1]

08 D-Smack, PPE hot plus 2 ET running on + 140hp.
Empty in town -15
Empty on highway 16.5
Loaded wth the Black Thunder - 10

Also, I haul ass everywhere, 80-90 on the highway loaded or not so take that into acct.

[sweet addiction]

Damn, I need to get me one of those. I have to pay the tax man $$$ this month so I may get one for Christmas this year. My truck gets like 12 or so with the boat in tow, 17ish on the highway 18 if I am easy but I drive like endeavor does so my mileage is crap.

08 D-Smack, PPE hot plus 2 ET running on + 140hp.
Empty in town -15
Empty on highway 16.5
Loaded wth the Black Thunder - 10

Also, I haul ass everywhere, 80-90 on the highway loaded or not so take that into acct.

[jwurl]

I have a 05 GMC with a Banks 6 gun tuner,exhaust,and intake. I average 16 in town. 18.5 on the highway running 70mph and 14 on the highway towing a 9K lb boat. Jeff Wurl

[fund razor]

There will be a huge discrepancy here between guys that can do math and the DIC readouts. The DIC is overly optimistic and the correct way to figure it out is to fill it, reset trip odometer, drive it until it is empty and then divide the miles driven by the gallons used. 300 miles on 25 gallons is 12 miles per gallon.....

That being said on my bone stock 03 with 152,000 miles I get 12-13 regularly in 90% city pulling a light trailer and plenty of idling with a/c on. Truck has a decent amount of tools/junk onboard at all times. Best I ever got was 17 driving home from the dealer empty of everything but the dealership paperwork!

Nice way to put it.

[fund razor]

My 03 crew cab got 25.6 gallons added today........26 gallon tank is what my truck has. The long bed trucks have 31 gallon tanks which would be nice!

The 34 gallon that many of us have is nice, also.

On topic: did tow yesterday. Got 12 on the DIC going 65 hwy. (for what that's worth) Didn't have the variables on hand to do the math, although I can do the math.

[hotjava66]

The 34 gallon that many of us have is nice, also.

On topic: did tow yesterday. Got 12 on the DIC going 65 hwy. (for what that's worth) Didn't have the variables on hand to do the math, although I can do the math.

I really miss my bigger fuel tank, having to fill up every 300 miles is a pain, my old Duramax with the big tank I could sometimes make close to 600 miles

[JupiterSunsation]

The 34 gallon that many of us have is nice, also.

On topic: did tow yesterday. Got 12 on the DIC going 65 hwy. (for what that's worth) Didn't have the variables on hand to do the math, although I can do the math.

Fund

I just laugh when guys either post or tell you at a gas station their diesel gets 22-24 MPG.......then the BS begins, like ran 85 all the way up I95 from FL to GA, pulled my 30 ft camper like it wasn't even back there and had 4,000 lbs of gear in the bed.......

The trucks are more efficient than their gas equivalents but everything has its limits!

[endeavor1]

Fund

I just laugh when guys either post or tell you at a gas station their diesel gets 22-24 MPG.......then the BS begins, like ran 85 all the way up I95 from FL to GA, pulled my 30 ft camper like it wasn't even back there and had 4,000 lbs of gear in the bed.......

The trucks are more efficient than their gas equivalents but everything has its limits!

+1

[OldSchool]

I drive 62 miles each day and about 40 of then are highway miles. the rest are through the city. I get 16.5 MPG's with my 2005 lly Duramax 2500. It never changes. About 19-20 on the highway trips. That's running 70-75.

[hotjava66]

I drive 62 miles each day and about 40 of then are highway miles. the rest are through the city. I get 16.5 MPG's with my 2005 lly Duramax 2500. It never changes. About 19-20 on the highway trips. That's running 70-75.

thas whats bugging me, the 15 empty on highway, my other ones were closer to 18-19.