I just finished my trip the the Black Hills from Saskatchewan. And yes this will be a flat lander report, except for the Black hills.
Having done this trip many times over the 8 years in my V10 rigs, I was very interested in seeing how this new 6.7 diesel would perform.
My trailer and FJ40 are not as heavy as I thought. Under 8000lbs towing weight plus some camping gear in the bed.




The first thing I noticed was the V10 powered truck has better range. This is due to the bigger tank and the fact it gets better fuel economy. On the flat prairie, the 6.8 is superior in that regard to the new diesel 6.7. I drive at about 65mph or so and take it somewhat easy on my trucks.
When I got to S.D my average was 11.6 mpg. The V10 was always better than this by at least 1mpg.


The second thing that I noticed was the 6.7 upshifted far less. Almost never. But spinning the V10 at 3500 was no big deal anyways. I guess the 6.7 is less fussy in that regard. Really no difference here.

I really wanted to beat the V10 fuel economy so I lowered the windshield on the FJ40 for the return trip. The economy increased by .2 mpg to make the entire trip average 11.8 mpg. The V10 beats this hands down. Maybe towing a truck on a trailer isn't the 6.7's forte? Perhaps you need a far bigger load to make the difference in buying a diesel?





I have towed a 26ft travel trailer many times with the V10 trucks and they were always 8-10 mpg. I would think this truck would be about 9mpg, maybe. It may be powerful but it is thirsty.

So to sum it up, the new 6.7 towed this load without effort, but used more fuel than a V10 truck would. I guess I am wondering why I bought the 6.7 now as I was kind of hoping for an increase in economy. My 6.0 (when running) would tow this load at 16mpg all day.
I would say that if you are towing something similar with a gas truck, trading into a diesel isn't going to get you anything but more available power. Perhaps if I buy a bed camper and tow the FJ40 the diesel will make more of a difference.

 

Once you get around 8-10k miles and the engine has more time to break in, you'll see the mileage go up a bit. Most all of us here have had that happen. However, the '15s get worse mileage than the years '11-'14 from what we are hearing. Around a full mpg less.

 

I always heard good things about the V10. My '15 F-450 gets slightly less mpg than my '12 F-450 did but it takes fuel to feed 440 horsepower. It still gets about 5mpg better mileage than my '08 F-450.

 

I'd be willing to wager that you had a 6-10 mph headwind?

Almost 12 sounds about right with my experience though and I think you'd find that the weight has very little to do with it. It's drag. You're correct in that more weight will not effect the economy in average flat terrain going 65mph. It's all about the air flow. In fact, I'd also wager that your bed cap is costing you 1-2mpg.

My best towing economy is really never above 12mpg, doesn't matter what kind of trailer it is. My best solo economy has been 20mpg, a solo run driving VERY easy and keeping speed at or below 60mph, trying to stay above 40mph also.

I don't think anyone would question your opinions on the V10 and some folks, like me, don't enjoy cruising at high rpms for hours on end.

Don't forget the 6 speed transmission. It's very nice too.

 

on my '15 I saw almost a 15% increase in fuel economy once it hit 10K miles. It was like a switch flipped and the mileage shot up.

 

That would be nice since my empty truck mpg sucks.

 

The winds were light, and it was a combination of tail and head winds. The V10 turns about 1850 at highway speeds with the 4.10's and the 6.7 is about 1600 or so with the 3.55's. So its not like the V10 is turning high rpms.
Up the 7% and better grades the 6.7 is the stronger truck. But I keep it at sane speeds so either truck does the job no problem.
I like my new truck, I guess my expectations were a bit high as far as fuel economy goes.
I have used a topper on my trucks since I got my 1999 F250. I have always though my MPG was the same or perhaps even better. But I like the camper shell and I keep all my gear back there when camping.
I would like to increase the range of this truck. I am not going to an extra tank due to warranty concerns. I guess a couple of 5 gal tanks on the trailer would give me the peace of mind I am wanting.
The regen thing was a non-issue. It did one regen at about 250 miles into the trip then never did another. I would think the regen was about 4 or 500 from the last one.
From what I've read this is normal? Maybe enough heat is generated just by towing.
The exhaust brake really works well. Too well in fact. I found myself shifting it out of tow/haul and then using the exhaust brake. It really makes descending a breeze. No brake action needed at all.
And my truck towing the FJ40 is faster up a steep hill than a Passat with a kayak on top. Don't ask me how I know

 

great report, thanks..

I think the difference is with the big sail tow loads. at least for me.


my flat front car hauler at 7,000 loaded tows at 11.5 or so (dually),
With my gas suburban same 3.73 gearing over same roads with same load 6.8 at same speed.

towing my 13k FW gets just under 10.

 

Really? That makes me feel better.
Anybody else have any mpg figure for towing a vehicle around?

 

My V10 gets 10 MPG empty flat road. Towing a Travel Trailer it goes does to 7-8. My setup has more drag then yours. What are the MPG empty?

Could the trailer breaks been dragging. Its a new setup, so did you setup the break controller for new truck? Our you getting 11.6 empty?? If so see your dealer look for a dragging break caliber.

On the diesel side
In San Diego driving I get 16(traffic all the time), Once I get out of the city traffic it goes to 18-19. Towing it depends but from 9 to 12.

 

I rarely get over 12 towing anything, I think a jet ski would even drop it below 16 on the highway.

So, I do think you're on the mark and I do hope you like the truck. I realize the v10 can cruise in overdrive for the most part, especially with a average load like you had.

Don't get me wrong, I don't know why but I don't like it when someone is less than impressed with this diesel. I enjoy it so much I want everyone to experience the joy too. That's all, I hope it grows on you.

I am not sure and probably am not doing any good for mpg but I really like using the manual shift when towing. Any trailer or weight, I can get around with plenty of power and keep the rpms below 2500 at all times so I'm trying to gain as much mpg as I can. Hardly ever full throttle and I don't wind it out, I wish it helped but I'm not sure. Maybe you can play with it for a while and see.

 

I've only towed once with my 6.7 since I bought it a month ago. I can, however, compare it to a V10 with a 4.10 and a 6.0 with a 4.10 since I have owned both. My V10 was the best gas engine I have ever owned. I towed my previous 5th wheel with the V10 and the 6.0. The V10 got about 8-9mpg. The 6.0 would push 12mpg with the same trailer same set up. I never pulled the current 5th wheel with the V10 but I put tens of thousands of miles on it with the 6.0. From home to KC, the 6.0 had to shift down on every hill and over pass and would stay shy of 10mpg. On the same route, the 6.7 will run at any speed, I prefer 65, on cruise control and it only shifted down twice in 450 miles. I averaged 11mpg. If I was pulling something smaller and lighter, I would prefer a V10. However, since Ford took it away from us in the pickups, the only option is the 6.7. Even when the 6.7 does shift down with 14k on the hitch, it is much quieter and smoother than any truck I have driven. The comfort of that 6.7 pulling a load that heavy is hard to believe until you do it. And compared to a 6.0, the 6.7 is so quiet its as if the motor isn't even there.

 

That sums it all up. The 6.0 doesn't hold a candle to the new 6.7. Not even close. And the 6.8 is no longer offered in F350 or F250 trucks. The 6.7 is the only real choice if you have to pull anything.
And you are right in that you just set the cruise and go. The truck hardly ever shifted down and just motors over most hills with incredible ease. Can't really tell your towing another truck on a trailer.

 

My 6.0 did beat my 6.7 in one aspect and that is mpg's empty. In that one area it isn't even a competition. All other aspects it's the 6.7 hands down.

 

I towed my 43 ft 5th wheel ( at least 15k ) from CO to AZ through the mountains and average was 11.6 MPG ( 2012 6.7 with 3.73 ) empty I-10 in AZ running 70 ish is 17 MPG
of course the same RV this past Feb going from Wisconsin to Colorado I ave 6.9 only thing I can credit that bad fuel mileage is maybe winterized Diesel ??