in many cases I say YES!!! I have been driving diesel trucks since '96. the first I owned was a '93 dodge single cab 2wd with 5 speed transmission. This truck was light weight at least 2000#'s less than my 2011 ford. it was also low and 2wd. it would get 20 mpg regularly, 18.5 on winter fuel and in certain situations it would get a little better mileage than that but not generally. the first gen dodges with NO emissions controls mechanical injection were known for getting the best mileage of all the trucks out there.

fast forward till now. for the local guys I drove from herriman ut to malad idaho, and back on saturday. parts of the trip were at 80 mph at least a third of it. 19 MPG!!!! yesterday afternoon drove from my house to ephraim ut, and back 20 MPG, again parts of this trip was done at 80 mph, maybe 1/4 th. a steady 70 mph would have led to even better mileage. The point I am making is this truck is matching my old '93 dodge while carrying around an extra ton of weight. with fuel at nearly $1 more than gasoline /gal. this makes me happy.

I am at 23k miles and it seems like almost a lightswitch has been flicked and the truck is really knocking out the mileage. maybe its the wore out generals the truck is still riding on thats helping me.

on edit, just remembered did the same trip with my dads early '04 dodge, the most efficient model of the third gen dodges. no catayltic convertor, no 3rd injection event. that truck got 16 I think under the same conditions. not sure if it was on winter fuel and I am not or vise versa,

 

Thats awesome man, I love how quiet they are! I took one for a test drive, have no intention of buying it, but just needed to drive it. Sooo nice!

Also test drove a 2003 Cummins not to long ago, that was supper nice too, but I'm still a Ford guy.

 

Driving a new one, with no intention of buying is almost like smoking crack. You get hooked and cant quit.

 

I agree, I want it so bad, Crew Cab F550 Long bed. But my truck works well for what I need right now and I need to save $

 

That's a pretty bold statement but technology is definitely producing some amazing things in the auto industry.

Not only are we close to matching the economy of the unrestricted diesel engines of the past, we have twice the power and you can barely hear them. No soot all over the rear end and stuck to the trailer/camper too.

Downside is the sophistication, cost, and relatively fragile components that keep it running.

Really though, times are good if you want/need a light duty diesel truck. These things treat us well.

 

I would say that my F-350 is not very efficient. I get 10 miles per gallon pulling the 5th wheel, and 13.5 miles/gal when driving around town. Ford does not want to fix the problem, because fuel mileage is not a warrented issue.

ken

 

Its all in how you drive. I've gotten 9.8 on a 900 mile trip towing a large 5ver, I just got 14.5 pulling over 10,000 lbs of hay back from Eastern Utah for a friend, Hay weighed almost as much as the 5ver, But didn't have the wind resistence. I've gotten 12-13 around town when I'm in a hurry and I've gotten 17 mpg when I drive like there is an egg under the pedal. I've gotten 23 mpg on a easy empty 70 mph cruise up to Jackson Hole.

It really depends on how I drive it, What I'm towing, head winds, winter vs summer etc. I really don't think it Fords fault that I get 9.8 mpg when I tow heavy. With 34,000 miles you can see what my true avg is below. It's 13.8 mpg over 90+ fill ups

 

We turned 10,000 miles yesterday. Of that mileage, 5,400 have been towing my 19,000 lb fifth wheel trailer. Overall, the truck is getting 11.44 mpg.
For comparison, with the 2006 F-350, at 10,000 miles, it had 40% towing miles and was only getting 10.55 mpg. So I get an extra mile per gallon even with 14% more towing miles and a heavier truck.

 

Just think if we only had 275 horsepower........

I even contacted 5star tuning to see if they could de-rate my wife's expedition 5.4L. I told him I wanted 25% less power. Make it a dog and let's see what the MPG would be. Don't need all that 5.4L power to run the kids around.

When you consider the power we have and the economy we get, there is no complaining allowed. As Tom (Crazy001) used to like to say, no matter what, it takes fuel to make power.

 

Most efficient probably not. The emissions makes these inherently inefficient for diesels. My idi pulls low 20's regularly with the inefficient indirect injection. This is recorded too. I too would like to see one of these derated probably hit 30's. The fuel systems are very very neat in these engines.

 

Love my F350,
Have 126,406 as it sits today mileage is good but as always driving habits and wind factor into mileage. I am averaging 11.7 with a dry weight 5 th wheel of 9,700lbs.

 

What do you mean " inefficient indirect injection"?

thanks ken

 

Look up the words indirect injection, you will understand how the system works.

 

I wonder what kind of mileage the Mexican spec 6.7Ls are getting?

And the MSRP for that matter.

 

Ah, but we only make that much power when it's commanded. Which happens to be at 2,800 RPMs at WOT...all other times you're making considerably less power than that. I would recommend that everyone attempt to get your hands on an OBDII gauge set that can display calculated horsepower output. If you do this you'll notice that while going down the freeway you only are making ~75-100 horsepower. That's all the engine is making because that's all that's needed. So if you were to limit it to, say...275 HP, you would see zero difference in performance or fuel economy on the highway while travelling unloaded. That's because you never approach the maximum capacity of the engine, and therefore you're only burning as much fuel as you need.

Does anyone here find it odd that those making the best fuel economy on the tuned 6.4L trucks are those who have the highest HP tune and drive the most conservatively. That's because these high HP tunes change the injection timing to improve efficiency(and power!). Real gains are only noticed when driven conservatively, as these engines with 600+ HP tunes can burn a LOT more fuel than a stock engine if pushed.

De-tuning would only change engine behavior when more power is demanded than the tune could provide. Otherwise there would likely be no difference unless other parameters were also changed. Peak power has nothing to do with fuel economy unless you are frequently running at peak power!