Mileage with 2500HD and Duramax

daletomlinson · August 11, 2005

I am thinking of trading my 1500 ext cab with 5.3 for a 2500HD ext cab with Duramax diesel. What kind of mileage can I expect solo on the road and also towing 12,000# fifth wheel trailer?

dtomlinson

willieboy · August 12, 2005

Solo: 19-22

Pulling: 12-14

BlackSilver · August 12, 2005

I am thinking of trading my 1500 ext cab with 5.3 for a 2500HD ext cab with Duramax diesel. What kind of mileage can I expect solo on the road and also towing 12,000# fifth wheel trailer?

<{POST_SNAPBACK}>

I have a 2003 2500HD extended cab, 2WD, with Duramax/Allison, and tow a 5th wheel which weighs about 12,500 loaded "ready to roll".

My empty mileage (on the highway) is in the 22MPG range.

My towing mileage is 11 to 12.

Diesel engine fuel economy is quite sensitive to speed --- they have a definite "sweet spot" where performance and fuel economy seem to "come together". On the Duramax that seems to be at about 1950RPMs which works out to just under 65MPH. If I drive that speed I get my best performance/mileage. If I run just a bit faster, say 70MPH, the MPG starts to head for the toilet.

whitesnake01 · August 12, 2005

My experience is the same as BlackSilver's. In my case the tow mileage is a bit better since I have a lighter (8300) and more aerodynamic travel trailer. During a recent trip to FL I saw a mileage of about 13.5. Regular solo driving: 18-21 depending on where we drive.

daletomlinson · August 12, 2005

BlackSilver,

Is yours a shortbox or longbox? How much problem to tow a fifthwheel with a shortbox?

BlackSilver · August 13, 2005

BlackSilver,
Is yours a shortbox or longbox? How much problem to tow a fifthwheel with a shortbox?

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Mine is a short box, and I've had zero problems towing. I do have a sliding hitch installed, but have never been in any situation which required me to extend the slide out of the "towing" position.

Most (all except the very heaviest) 5th wheel campers are now built with an extended pin box which gives proper clearance for any reasonable maneuvering.

Having said that, the slider is still probably a good idea, because **someday** I'm sure I'll get cranked around in a tight turn and on uneven ground or some such embarrassment and will be glad for the sliding hitch. It's a manual one, and only cost about $100 more than a fixed one.

Daubs · August 14, 2005

Nice to see the Duramax's getting high teens and even 20's highway.

My big block / Allison / 3.73 combo is getting 10.5 around town and as high as 15 MPG highway. I've installed Volant and Westers. Thought I would chime in from the gasser side of things so you all could compare.

Love the big block. It's a runner. I really can't complain about MPG. My Dad has a 76 K-20 HD 4x4 with 350 and 4 speed manual and got...are you ready for this...SIX miles per gallon! City / Highway, uphill / downhill, wind at back / wind in face...you name it, 6.

I can't complain one bit about my MPG. I knew this going in and have been very pleased with my engine / transmission choice (makes it easier when my 6.0 buddies are getting 11-12 around town and 14 highway)

dewfpo · August 14, 2005

Nice to see the Duramax's getting high teens and even 20's highway.

My big block / Allison / 3.73 combo is getting 10.5 around town and as high as 15 MPG highway. I've installed Volant and Westers.

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DAUBS,

Are you still getting 14 & 15 on the highway?

As sson as I'm flush with some cash I want to get a CAI and Westers.

DEWFPO

Daubs · August 14, 2005

DEWFPO: Yea, I'm averaging between 13-15 highway. Remember when I say "highway MPG" that's filling up in town, driving highway and keeping it under 65 MPH, then filling up right when got to destination.

What's a CAI?

dewfpo · August 14, 2005

CAI = Cold Air Induction/Intake

DEWFPO

Timberwolf · August 16, 2005

Getting 16.5 city and 21 hwy with my Duramax empty. Haven't pulled with it yet.

75woody · August 18, 2005

15 mpg if I'm lucky ! City or Highway. Bone stock 03 2500HD CC. I'm pissed. Somethings gotta be wrong.

bluenote · August 18, 2005

19½-22½ Highway (depending on speed)

16-18 City/Mixed driving

10-12½ Towing 5er weighing between 11K and 12K(again, depending on speed)

dannyukonxl · August 20, 2005

DEWFPO: Yea, I'm averaging between 13-15 highway. Remember when I say "highway MPG" that's filling up in town, driving highway and keeping it under 65 MPH, then filling up right when got to destination.

What's a CAI?

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im averaging about 14.5 at 78 mph and not easy on the gas, then when i dropped under 65 i saw it go up to 16 but i couldnt stand it, thats according to the dic so take it as is.... as soon as i get off the freeway it drops like a brick, but towing my boat like a madman i got 9

i know this is a dmax post and i drove a friends and it got 21 mpg, i was almost sold but the mileage when towing isnt that bad either, just the price of diesel kind of ran away