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Duramax Fuel Mileage


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I just bought a brand new "06" duramax 2500HD Crew Cab 4x4 w/ the new 360hp and 650ft/lbs

 

I justed put it to the test last week with about 1500 miles on it and I was towing about 6500lbs and my onboard fuel millege gauge said that my average economy was ONLY 10.2 miles per gallon. On the 1000 mile round trip of which half of that was just running un-loaded needless to say it wasn't what I was looking for.

 

 

I was wondering what others were getting on their Duramax especially on the "06" model?

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I was seeing about 14 for a mix of country road and highway driving with my '05 Sierra HD. That dropped to about 10 while towing an enclosed 24" car hauler. A few months ago I upgraded to the Westers tuning. Regular mileage went up to 16-17 and all highway mileage is 22-23 while doing between 68-72 MPH. All of these numbers are hand calculated. The displayed mileage will be off with aftermarket tuning.

 

I haven't gone on any road trips while towing with the new tuning yet.

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I was wondering what others were getting on their Duramax especially on the "06" model?

 

 

 

 

Mine is an 03 so might not be comparable, but here are the numbers from our recent 8.600-mile trek through the SW pulling 12,500# 5th wheel. Towing driving was mostly on 4-lanes, in a mix of terrain (flat plains to moderate mountains in CO, NM, and AZ). Unloaded driving was on all kinds of roads (gravel backroad sightseeing, small amount of city driving, and some 4-lane cruising also).

 

Loaded miles: 3,715

Fuel consumed: 321 gallons

Loaded MPG: 11.57mpg

 

Unloaded miles: 4,885

Fuel consumed: 252 gallons

Unloaded MPG: 19.38mpg

 

All these are "hand figured", as the DIC is at best a good guess.

 

On my truck, the "sweet spot" for mileage is around 1900RPM, and I generally try to stay near that speed. I've noticed that the mileage drops quickly above 70mph.

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Hi guys, about your Duramax economy. We have 3 Duramax 3500 4x4, all of them have a Diablo Sprot computer programer in them . The best mileage we get , unloaded doing 120km/hr through the mountains in BC, is 32mpg. When were loaded pullling a 12,000lb trailer through the same mountains we get 20mpg. The only other mods weve done is an Airraid intake system. Hope this helps :mad:

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Mileage should increase with more miles. Our diesels didn't do very well until at least 10,000 miles were on them.

As for towing, I can get better mileage towing a 6500 lb gooseneck than towing my 3500 lb enclosed trailer. Even with the gooseneck loaded down, it is rather close to the enclosed trailer. Wind drag seems to be harder on mileage than weight.

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I have 76K on mine. I just did a mileage check on the last fill up. I went 320 miles on 22 gallons. This is mixed driving, mostly county roads and towing a heavy load 75 of those miles. This is about 15 mpg average on the last tank.

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I have a 2006 Duramax/Allison Crew LBZ CC/SB. The first few tanks of fuel were low but, after the second tank, my mileage took a real spike (which happened at the same time that I had the glow-plug reflash).

 

Now, I'm getting a solid 16-17mpg in city driving and 19-20mpg on the freeway. I'm still waaaay under 5K miles on the odometer and my friends tell me that I will not get good mileage until around 10K miles.

 

My truck is absolutely bone-stock and it will stay that way. I'm a happy guy.

 

Steve

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I have a 2002 GMC 3500 Duramax dually with the quad cab and Allison transmission. I tow a 34' 15K lb 5th wheel and get about 10-11 mpg towing and about 14-15 mpg empty around town and on the road. The truck has 59k miles. Does this mileage seem reasonable?

Also, can anyone shed some light on the fuel injection system troubles that seem to have plaqued the early year Duramax's?

 

Thanks

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  • 1 month later...

Hey Folks....Newbie here

 

I thought I might find a discussion about this on this website!

 

I was talking to a guy the other day about his '05 D/Max, and asked him about his milege.....he claimed that towing his 5th wheel thru NM, AZ,CA and into Nevada he could get up to 15MPG......and he is towing a Toy Hauler at about 12,000lbs!...I called B.S. right away, telling him that I had just taken a trip to Denver and back and talked with other owners, and they all seemed to be getting the same as I was at anywhere from 9.5 to 12, dependent on the hills.....

 

His claim is, he has a Technician that turned his fuel pressure up and got immediate results.....

 

Anyone else hear of this, or have experience ???

 

Thanks

 

Mike :cheers:

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My 06 LBZ will do around 11-15 towing my Fifth wheel camper, depending on terrain and speed. Ive seen as good as 22 on flat highways staying 65mph or less when empty. If I can drive like a normal human Ill get around 15 in town. I was pretty pleased right from the start, I got 18( hand calculated) driving it unloaded the first day I owned it.

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