Just finished short trip with new truck....

All I can say is: wow.

The new truck is a 2015 F350 6.7L Lariat 2WD DRW 3.73 Supercab automatic. The old truck was a 1999 F350 7.3L Lariat 2WD DRW 3.73 Supercab automatic. In other words identical as they can be but for year. Same camper.

There were the expected improvements in creature comforts, the seats are more comfortable, climate control is nice, much quieter so you can hear the better stereo.

The main difference though is in the drivetrain which are worlds and decades apart:

860 ft lbs vs. 500
440 HP vs. 230
6 speed vs. 4
tow/haul mode vs. OD lockout
exhaust brake vs. not

Those are the specs. Driving it, there is a huge difference in power, all the time, any RPM, any situation. And a huge difference in transmission gear selection. Combined, it is a night and day difference in driving experience.

I drove to the coast and up CA 1 a bit, mostly used the tow/haul mode because it kept the revs up a bit more and downshifted sooner, this was useful on corners as much as grades, keeping the engine in the right range to accelerate out of the corner. It will aggressively downshift if you are on the brakes on a downslope. That would have been disconcerting with the 7.3L which made quite a fuss above around 2300 RPM, but the 6.7L revs freely and without fuss or much noise to 3500.

One section of side road over to Limatour spit has a short section marked with a warning sign. "17 percent grade". On my '99 this required 2nd gear with a heavy application of brakes till the bottom (was there with it 2 years ago). On the '15, I touched the brakes once momentarily and the combined downshift and exhaust brake easily slowed the rig, I ended up adding a little throttle to maintain speed to the bottom, no brakes required.

With the '99 I was about 300 lbs over GVWR (though under the GAWR at both ends). Though the '15 weighs more empty, I am about 1400 lbs under the GVWR loaded for a trip with the camper. The ride is a little better loaded than the '99, maybe a little worse unloaded.

These trucks cost a LOT of money and the smog controls are spectacularly complicated - but as long as it is working, it works really, really well.

Truck Campers

Kayteg1
Explorer II
Apr 11, 2016
The HP playing is generations old.
I remember that older Cats were (for example) rated
250 HP for commercial trucks
300 HP for RV use
350 HP for fire trucks.
All the same engine, just predictable different usage.
ticki2
Explorer
Apr 11, 2016
I agree . It is probably more to protect the truck in fleet life where you have many drivers and often very low gears .
HMS_Beagle
Explorer
Apr 11, 2016
On the Ford, different PCM tuning is used to lower peak output. Prior to '15, the chassis cab also had a different turbocharger than the pickup, but in '15 on they put the chassis cab version in all of them. Unless you are the kind of driver that drives flat footed, I doubt you would know the difference. I have come no where close to needing full throttle yet.
ticki2
Explorer
Apr 11, 2016
hedgehopper wrote:
ticki2 wrote:
I find it interesting that for heavy duty use they reduce the torque and HP ratings quite a bit , as in f550 . I would think that hauling a heavy camper qualifies for heavy duty use . It may not be an advantage to have all that zip with the 440HP , although a lot of fun .
I'm confused: What do you mean by "they reduce the torque and HP ratings"?

Look up the torque and HP ratings for an f350 and then look at the f550 , same 6.7L
rider997
Explorer
Apr 11, 2016
hedgehopper wrote:
ticki2 wrote:
I find it interesting that for heavy duty use they reduce the torque and HP ratings quite a bit , as in f550 . I would think that hauling a heavy camper qualifies for heavy duty use . It may not be an advantage to have all that zip with the 440HP , although a lot of fun .
I'm confused: What do you mean by "they reduce the torque and HP ratings"?

I don't know about Ford, but GM oftentimes rates the chassis cab drivetrain's engine at a lower RPM than the same engine in a pickup application. The tuning and peak HP/tq are actually the same, but the chassis cab is rated at (for instance) 2,200RPM (which is below the HP peak), and the pickup at 2,800 RPM.
hedgehopper
Explorer
Apr 11, 2016
ticki2 wrote:
I find it interesting that for heavy duty use they reduce the torque and HP ratings quite a bit , as in f550 . I would think that hauling a heavy camper qualifies for heavy duty use . It may not be an advantage to have all that zip with the 440HP , although a lot of fun .
I'm confused: What do you mean by "they reduce the torque and HP ratings"?
Farmerjon
Explorer
Apr 11, 2016
We also went from a 7.3 to the 6.7 and our experience is the same as HMS Beagle and others others. WOW do I love it.
We still have our 2000 7.3 and I still very much enjoyy hauling with it but it is not in the same league for power and comfort.
We just made a 600 mile round trip to Illonoise with out the camper but with the 2 horse trailer We hit some horrible winds . It knocked our mpg down to 13, which we stil thought was pretty good. It didn't slow us down. IT was no problem maintaining our speed against the wind and up any and all hill. They are very nice and capable trucks.
jimh406
Explorer III
Apr 11, 2016
Congrats, the new rig looks good!
HMS_Beagle
Explorer
Apr 11, 2016
It's a little early to claim mileage figures, but so far:

A trip of about 180 miles on the freeway I take frequently shows about 20 mpg empty (about the same as the '99 7.3L) unless there is a regen cycle in the middle of it, which knocks it to 18.5. That's on the meter, when calculated by hand both '99 and '15 seem to be about 1 mpg optimistic.

This is the first trip taken with the camper, the road over to the coast is 50 mph secondary highway with some traffic and stops, was just kissing 15 and then a regen happened, knocking it to 11.7. From there is slowly climbed back up, even though the coast road is hard on mileage. Got home at 13.7 on the meter but haven't filled it up yet. In the '99 I would get 14-15 indicated on that same trip.

But for the regens, it seems to be about the same as the '99. The regens seem to take 1 - 1.5 off the average. In a couple of months I will be driving to Lake Tahoe every couple of weeks, all freeway but from sea level over 7200 ft Donner Pass. I've done that maybe 50 times with the '99, it will be an interesting comparison. There are 13 grades on I80 which required the '99 to downshift to 3rd. I don't think they are going to be much of a problem in the '15!

Ford derates the chassis cab versions figuring that you are far more likely in those, to make continuous use of the power. My use is typical of this 1T pickup, camper and occasional towing or bed load. There is no reasonable (or legal) way I could use the 440 hp continuously. The engine has impressive complexity in sensors and powertrain control computers, and will not let you hurt it - if anything gets too hot or whatever, it derates itself. All the modern common rail diesels are that way I think. You can 'chip' them and wreck them very quickly, but that is a different thing. You could call the HP and torque ratings specsmanship, and it is, but the real useable power is still very impressive.

So far this truck is quieter, more comfortable, more powerful, and about the same mileage. The main downside of buying one is poverty. Also the smog controls are extensive and very expensive to repair I am told. Usually I don't buy the extended warrantee, but I think I may for this one.
ticki2
Explorer
Apr 11, 2016
First let me say congrats on a sweet looking rig .

I find it interesting that for heavy duty use they reduce the torque and HP ratings quite a bit , as in f550 . I would think that hauling a heavy camper qualifies for heavy duty use . It may not be an advantage to have all that zip with the 440HP , although a lot of fun .