I know those that buy SD's shouldn't buy them if they are worried about mileage, however I would love to see your results. I am on the verge of getting a magnetic Lariat. I ssoooo excited. Thanks guys!

 

16-18 depending on conditions. Only have 200 miles on the engine so far.

 

Have about 900 mile on her at 13.3 according to the truck. Mostly city driving

 

my salesman told me 21 hwy. I should've known that was sales talk.

 

First 1,500 miles, I was around 13-15. After that though, it went up to 16-19.

 

At risk of being called a liar again, my friend has a 2015 6.7 and back in August we got an actual 21 mpg on a 400 mile fishing trip with full camping gear and an 18' boat in tow. These engines get better as time goes by and everything gets fully seated and the computers learn their mission. A light foot helps tremendously however, there is a lot of weight to get rolling and some of us have pretty heavy right feet

 

It was up hill both ways too eh??? Out of all my 6.7's, my '11 was the best on fuel, had the least frequent and shortest regens too. Ended up with some pretty sweet mpg numbers. My '15, it was never stock, no idea how good it could of been.

 

I'm getting 15.4 on highway with some hills. This is manual calculation, computer is telling me about 1 mpg better. Middle 14's around town. I have the e-locker 3.55 rear end. Running all highway from CT to OH on Sunday. I will report back mileage on this trip.

 

With my 2011 dealer said break her in gently and good fuel mileage should show up around 7000 miles

it was a concern when I first bought it but is did come up
in fuel mileage.

one thing that helps you to speed things along I found.
espicially after towing.
Remember like a kid the truck is always learning
your habits.
So a reset on fuel gadge.
i always reset going down hill & never too heavy of a foot.
goes a long way.
Helps reset from heavy trailer pulls quickly.

 

2900 miles 40% HWY, 40% CITY, 20% towing 7000 lbs 15.4 MPG

-Dave

 

2200 miles and I've averaged 18.3 MPG 75% highway.

 

That was the 4 miles I walked to school, in a snowstorm every day so the horse didn't have to stand out in the cold.

 

Reseting your computer will not increase mpg. The fuel pump still knows

Plus I got 40mpg going 15 miles down hill in neutral.

 

Do you guys up north use US gallons or Imperial (British) gallons? I know when I was in England for a while a few years ago, that the Brits buy all of their fuel in liters (as you do in Canada) but whenever you ask an Englishman about fuel economy, they stubbornly recite imperial MPG figures.


US gallon = 3.785 Liters
Imperial gallon = 4.546 liters

Using these figures, 21 imperial MPG is equivalent to 17.5 Murican MPG.

 

I have to chuckle a little every time I see these "what should I expect for mileage" threads.


While the weight of a vehicle does matter when it comes to overall mileage, it's pretty negligible compared to the speed that the vehicle is driven due to wind resistance. For example, at 50 mph it takes 8 times more hp to drive that same vehicle at 100 mph. That's why it takes between 600-700 hp for a sedan to break 200 mph. Below are some words for a study that was conducted.




According to studies backed by the department of energy, the average car will be at its advertised MPG at 55 mph. But as the speed increases:

- 3% less efficient at 60 mph
- 8% less efficient at 65 mph
- 17% less efficient at 70 mph
- 23% less efficient at 75 mph
- 28% less efficient at 80 mph


The SD is a slightly aerodynamic brick (a good looking one I might add) and mileage will vary depending on whether it is 2wd or a 4x4, mirrors extended or not, etc. No two people drive the same speed and one guys 65 mph is far different than the guy cruising down I-15 in Utah at 85 mph. Let's not forget city vs. hwy, tire size and gearing, headwinds or not, and the frontal area of anything being towed. I'd bet I could 25 mpg out of SD, so long as I was happy driving it at 45 mph.


I think it's safe to say you'll get anywhere between 9 and 21 mpg depending on how you drive it and cross section of the configured vehicle.


Adam