While there are efficiencies that one might expect to be made over time (2017 vs 2011), I think it's simply a matter of more power = more fuel. Those power bumps do not come without cost.

 

I don't think that's accurate when you're talking about fuel economy. The engine doesn't make it's rated power when going down the highway at 70 MPH....it makes a fraction of that. It may only take 80-90 HP to pull this off, and you're only burning fuel to make that 80-90 HP. Put the pedal down and boost pressure comes up, injector pulse width increases, which delivers more fuel to the combustion chambers, and you get more power as a consequence of greater fuel burn.

It's a well-known thing that aftermarket high-horsepower tunes commonly get better fuel economy than tunes that retain factory power levels and delete the emissions equipment. If what you said was true, it would be impossible for a 650 HP tuned 6.7L to get better efficiency than a stock one...but they usually do.

 

My 2016 F-350 CCSB 6.7L 4x4 achieved the best fuel economy of any truck I've ever had. I would always get 17-18mpg at 70 mph and on 55 mph roads I could get mid-20's. I got 26.1mpg once over 100 miles of mostly 55mph.

The new truck...on this same route with my greatest hyper-miling effort ever...produced 20.0mpg. Does adding dual rear wheels and 18 extra inches of length drop mpg by 6?

Overall, these new trucks are supposed to be a couple of hundred pounds lighter. I'm surprised the theme seems to be less mpg...especially since during the development period, increasing fuel economy was all the rage.

 

Highway runs are in the 17.5-19 range for my '17, based mostly on speed. Keep it under 65 and 20 is pretty easy. Above 70 and MPG drops drastically.

 

Not for new Tesla customers. They have to pony up now...

And Tesla will be successful.

 

It looks like driving my typical speeds produces the expected results. Naturally, both motors will be more efficient in the 55-65 mph range. I doubt I can 'hyper-mile' (I like this term) a 6.2 to get 16.7 mpg, I'm sure I can get above 13.2.

20 sounds great in a Super Duty, but realistically I'm likely to drive the same way I have been now until I'm forced to change for whatever reason.

At the end of the day I don't think mpg is a good argument for purchasing a diesel.

tomorrow needs to get here soon to make this a moot point.

 

You're right, Tesla did start charging a tiny fee basically at the end of 2016. But I'm doubtful how successful the company will be. Their cars are glitchy, expensive, and only work as a niche vehicle. The normal people's version (Model 3) will likely still be too expensive, poor quality, and not profitable for the company. Gov incentives are going away, as they should be. It is not the taxpayer's problem to subsidize a car company.

But anyway, I'm curious as to why the 2017 trucks don't seem to do as well on mpg.

 

There could be all sort of reasons for the difference in fuel mileage. But the engine is largely the same from 2016, no? So except for the difference in power ratings, nothing's really changed, engine-wise.


Is the truck body as efficient? Probably not. Weight wise, it's a wash. The lighter body seems to be nullified by heavier frame and components, but I've never seen a 2016 model to 2017 model weight comparison. It definitely sits higher, and seems a little more "boxy" (less aerodynamic) than the previous body style. But I've never seen a Super Duty tunnel test of any year either, so who knows?


Tuned trucks generally do away with inefficiencies like emissions and torque management. Admittedly, I'm not very familiar with Ford diesels, and there's definitely a discussion to be had there. But tuned Cummins 6.7s (2013+) generally don't do much better, if any, than stock these days. In the last couple of years, fuel mileage is certainly not the attraction for tuning trucks it once was because the drastic improvement just isn't there anymore. Fellas tune these days just to get rid of the headaches of emissions. Sorry about that.

 

It is a small argument. In my experience, my diesel trucks have gotten about 5-6mpg lifetime average better than my identical gas trucks, doing identical things.

That is offset by diesel fuel being more expensive, much more costly oil changes, etc.

 

I think you could make a good argument on cost of ownership for the diesel if you keep the truck for 100,000+ miles, especially if you tow frequently. That all goes out the window with a single major repair bill, though.

 

Yup; my needs do not even come close to justifying the diesel. For me it is only a 'cool' factor, and sadly I'm not in my early 20s anymore, so this is a fun idea to talk about but not actionable.

 

That was exactly the case in my 2011. Anything above 73-74 and mpg fell off a cliff. I suspect the 2017 will be similar.

 

My experience exactly.

FWIW I also live in the FL Keys where the speed limit is 45 in many places and easily get 26 mpg. I just ran Islamorada to St Pete (300 mi) last weekend. Went 80-85 across the state on I 75, 45-50 leaving the Keys and my overall mpg for the trip was 17.5.

 

All posts referencing > 16.7 mpg are not welcome!

Come on guys.... Help me out here. These higher mpg numbers only lead to the fateful phrase "what will it take to keep me in this truck?!"

 

Yeah, but then you would slow down to see just how high you could take the MPG, and you don't want that!