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Duramax mileage


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I haven't ran a full tank without a highway trip but my 50 mile average is around 14.5-15.5 around small towns. Highway I am averaging 19.5-20. Last 3100 miles i am showing 18.3 mpg. That is with the below mods.

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I'm running at 18.9 Combined right now with 3400 miles on it. I'm sure it would be higher if I didn't remote start the truck every morning and night. I commute 26 miles each way to work and a majority of is all highway.

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28mpg on highway... 60mph tho...

 

17 on city...

 

easy on the pedal and keep on the dashboard the mpg cosumption screen

 

Yep, 57 to 65 is the sweet spot on these things. Just hard to drive like that without getting mashed on the interstate, ha!

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Awesome guys, thanks for the feedback. Sounds like there is nothing to lose from my 2014 1500 5.3 with 3.42 except the price of diesel.

I didn't look to see where you live, but around me ( suburban Chicago), I'm paying around $2.59 a gallon for Diesel at a BP gas station.

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Awesome guys, thanks for the feedback. Sounds like there is nothing to lose from my 2014 1500 5.3 with 3.42 except the price of diesel.

The duramax will not get as good of mileage as your 5.3 does, this is a fact!

 

These crazy mileage numbers of 21mpg require cruise set at 60mph in perfect conditions for hours on end, I average 14mpg, that is real mileage.

 

I also have a '14 6.0 HD Chevy that gets 12mpg average and I could not be happier with it, zero emission issues, zero problems, no worry about water in fuel, no $10,000 engine option. The price for the 2500 is the same as the 1500, I will eat the crappy mileage as best case it will take 150,000 miles to justify the duramax and that is if all goes well which it won't.

 

My next one will be gas, there WILL be a new gas motor coming soon that will use the 8-speed, that will be the one I get.

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In 66,000 miles my average for all miles is 15.629 this is stop and go, highway, and towing. Also this is hand calculated. Have some high teen's and some as low as single digit's. :jester:

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Mine will get over 14 going down the interstate at 75mph while in regen unloaded. If i set it at 60 I can consistently get over 23 unloaded. That is on the DIC which reads over 4% low because of the larger tires.

 

I think most of the people that get bad mileage on the 6.6 either short trip it or have emission system issues. My 12 LML would get 15.5 mpg highway if I was lucky, it had emission system issues and was in the shop numerous times because of it; sold the truck as GM couldn't fix it. My 15 LML gets considerably better mileage than that truck got which doesn't make sense because the engine is the same and I am running larger tires, they are about 6lbs lighter each than the ones i had on the 12 though. Only difference is no emission system issues "yet" on this one. If the EPA wouldn't have cracked down on everyone back then I would have deleted the truck and kept driving it. If I have issues with this one I know the route I will go. I had 2 different gas trucks between the diesels, a 13 6.2L and a 14 5.3L; I missed the diesel so here I am.

 

I make the same trip which is 347 miles one way every 2 weeks; been driving it for 7 years and I am good at math. With this truck I average 19.5-20 mpg on the Interstate. Below is what my other vehicles got on the same trip.

 

2007 GMC 1500 5.3 Dbl Cab, Diablew tuned, intake, exhaust lowering shackles in the back, 285/55-20 tires. 19.5-21 mpg

2010 Tundra Crew Max, 3" Level. 295/70 18 Trail Graps. 11-12.5 mpg

2011 F-150 Ecoboost, 2.5" level. 285/65 18 Trail Graps. 14-15.5 mpg

2012 LML, leveled, AFE Intake, 33x12.50 20 Toyo MT. 14.5-15.5 mpg

2013 GMC 1500 6.2, Camburg leveling kit, factory sized tires, intake, exhaust, BB Tuned. 16-17.5 mpg

2013 Mustang 5.0 GT, MT-82, Lowered on Gt500 springs, Bama Tuned, Headers, racing x pipe, ford racing exhaust, Steeda intake. 25-26.5 mpg

2014 GMC 1500 5.3L, 4.56 gears, 6" Lift, BB Tuned, 295/65 20 tires. 16-17.5 mpg

 

Towing is another story all together with 5K lbs hooked up. Only the 07 1500 and the 13 6.2 would consistently get above 10 mpg. the 14 and 12 LML would occasionally. The 15 averages around 13-14 running 65-70

 

Chances are you will not get better mileage than you do on your gas, especially in town or if you short trip the truck. It takes the diesel a good 15-20 minutes of running to get everything all warmed up. Fuel is more expensive, maintenance is higher and it costs more to get in one. If you want or need a diesel, a gas engine simply wont do. If you are ok with those reasons and have the money you will be happy with the diesel.

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