I know these get old....but I was doing some comparisons for a trip out west possibly in December and since I hadn't had a chance to run very far I thought it was a good time to do so.

Route was I70 from Frederick, MD to Rocky Gap State Park and back along I68.

This route although not as impressive as say I70 through the rockies (of which I have driven many times) still presents a good run where every gets a real good workout. Route along I68 is full of 6% grades for about 13 miles.

Biggest hill is called Sliding hill. In my 6.4 I could round the top at 55 mph in 3rd gear at 3K rpms and close to 40 lbs of boost.

With the 6.7 I topped the hill at 62 mph and about 22 lbs of boost. Don't have my torque app up and running yet. Still in 3rd gear and 3K rpms.

All of route running on I 68 up and down the hills I netted 7.5 with the dually. In my 6.4 I would get on the average 5.5 through this stretch.

So a 2 mpg gain in the mountains!

Whole trip was not any better at just 8.2 mpgs overall. About the same but I believe once you get on the flats it would be closer to 10. So that would also be a slight improvement.

So I am fairly confident to plan for 8 mpgs in fuel useage and cost calulations.

Another area of concern as many have had in the past is the tow/haul and engine braking of the 6.7. It sucks, plain and simple. Let me explain.

Tow/haul and the braking effect do work but I honestly think because of the turbo capabilities it does no produce the braking effect required on the downhills. This one area the 6.4 was much better at. I don't think it is so much of a tranny issue with the additional gear (6th) as it is with the turbo.

Using the manual mode and forgetting about the tow/haul seems to be the way to go so you can control your descents.

So I did get a couple of pics as well.

 

I traveled much of the same route this time last year when I went out to Cincinnati to pick up a new toy hauler. Coming home the new trailer was just over 13,000 lbs and I was pulling all the grades at 64-65 mph in 4th gear. Despite what the magazine tests tell us, the 6.7 likes to play in the mountains!

Back in July, I took the camper up to Canandaigua, NY near Rochester and the route up there involves quite a few nice mountain climbs. This time with a load of fresh water and the trailer loaded for camping (probably somewhere around 14,500 lbs) I was limited to 60-62 mph most of the time still in 4th gear and a few times 3rd gear. I had also just installed new 295/60/20 Nitto Terra Grapplers which have stolen some thunder from the 6.7.

I never had the chance to do the same with the 6.4, but I guarantee you the 6.0 would have been on its knees at somewhere around 55 mph at best even with a 75 hp tow tune! As far as exhaust braking goes, the 6.0 was far superior with aftermarket programming. The 6.7 turbo could do the same job, but with the mass of the dual compressor, I don't think it would last long doing it. I'm glad to hear that Ford ditched that turbo in favor of a larger conventional VGT style turbo!

 

Yeah, I knew the reviews were not that good on the engine braking but I expected a little better than that.

It is ok, know what it is you can make accommodations.

 

Looks like Ford is doing something about engine braking on the '15 models. I copied this from the Ford press release.

"A further benefit of the larger turbo is improved engine exhaust braking, manually controlled by a push-button switch on the dashboard. Extra braking power helps reduce wear and tear on wheel brakes and requires less manual brake application from the driver, especially on downhill grades."

 

I still have all of my banks stuff, 6 gun, IQ and the speedbrake. Wish I could just slap it on this one and use it. Mostly the IQ and speedbrake.

 

As a point of reference, I have a 4x2 model truck and scale out about 500 lb. less than you are (right at 23k total, maybe a little over). On mostly flat (I-65 from Montgomery, AL to Mobile, AL, then I-10 to Hammond, LA) interstate running 65 mph, I averaged 10.3 mpg (hand calculated).

 

I don't get tired of these types of threads no matter which truck you had before. They always point out the good and bad of each year model. I like the write up myself. Now, I just can't wait to pull with mine!

 

I have yet to weigh the truck empty but I'd imagine we are about the same Monty.

So we burned a little diesel..hey what else to do a gov furlough!

 

Great writeup.
It's nice to read an honest and experienced opinion on the engine brake.

I do spend a lot of time in manual mode, especially when towing.
I feel it gives a bit more control but I was hooked on manual since I spent so much time there waiting on Ford to create a transmission fix.
Even in auto I'll lock out a gear or two if I don't want it going there...because it will try.

 

Nice rig and nice write up.

I live in South East Texas and it's pretty flat so I'm not critical on the engine brake, although it does feel more aggressive than my 6.0 psd.

 

Yep, when I weighed mine on the way home from Myrtle Beach last year with the 6.4 and family, the total rig was just shy of 26k.
And I agree...too bad we just can't get rid of the EPA radicals...

 

Coming from a 2004 6.0, I also noticed that the engine breaking function seems weaker on the 6.7. While towing my 5ver, hills that I could coast down on the 6.0 (6-7% grade) need to have the brake applied periodically to keep the speed in check on the 6.7.

I find the manual +/- buttons awkward to operate, can't see them while seated normally, rather not take my eyes off the road on mountain curves to deal with them. Would have been nice to locate these somewhere else more visible.

 

I have all the gears displayed on the right hand side of the screen. So whether in manual or drive they are displayed with the current gear highlighted.

seems to work well with me on the hwy. In town though it would be a pita.

 

Nice write up senix. Thanks for sharing your thoughts.