My own speculation is based on a couple things 1) What the automotive world learned in the 70s, and 2) The current status of 49 state motorcycles vs. California models (motorcycles are not required to be tested for emissions, similar to diesels).

1) Cars today polute MUCH less than they did in the 70s, they're much more fuel efficient and more powerful, but at the expense of being harder to diagnose problems and more costly to fix.

2) There is now no real power difference between California motorcycles than 49 state models. In fact, some of the California models are actually more appealing because they get better fuel mileage than the 49 state models. I suspect most manufacturers will soon manufacture all their bikes to California standards.

I predict the changes the consumer notices on diesel motors will be very subtle. There will be some hic-ups as the technology moves forward, and there may be some increase in service cost and parts cost, and some affects on fuel mileage. The bottom line is the engineering capacity for internal combustion engines is far enough beyond where we were in the 70s that you can basically ignore what happened back in the bad old days. I believe the trucks will get better and better as time goes on.

 

My observation as far as mileage goes is VERY subjective at this point. First of all . . .

1) I only have 126 miles on the clock (flew to NY right after taking delivery last week) and the dealer filled the tank. Who knows when they stopped pumping.

2) My overhead was reading 9.8mpg after about 90 miles which freaked me out. I reset yesterday and now it's closer to 12 with a lot of stop and go. Still not stellar, but better than 9.8 - and I'm driving it like there's an egg under my foot.

3) I'm already just below the 3/4 mark on the gauge with 126mi. I don't know yet how linear the fuel gauge is, but a simple extrapolation to 500mi for the 34gal tank would yield 14.7mpg. That's making BIG assumptions. The next tank will be totally under my control and I will hand-calc, so there will be no questions.

Oh, I nearly forgot to mention. My 00 PSD (7.3) averaged 17-18 in the same driving conditions that this truck is reporting 12.1. I will wait until I have more accurate numbers and until break-in happens, but my initial reaction is disappointment.

Neil

 

Neil
I believe your ford was 2wd(K&N,Hypertech PPIII) and broken in.I was in the same boat as you (A little disapointed with with mileage) My overhead computer is approx. 1.3 mpg off and the total miles till empty isn't even close to what I'm actually getting. The best thing to do, go on a nice long ride 500 miles or so at 75-80 mph and try not to look at your trip computer. After 3800 miles on mine I'm at 17-18 mpg @70-75 and she's still not even close to being broken in. The best thing to do is not baby it.


Good luck
Odie

 

Neil, give it time. Mine was the exact same...

First tank 12.25 (driving like grandpa)
Second tank 14.22 (driving like dad)
Third tank 14.11 (driving like grandpa again)
Fourth tank 15.25 (multiple WOT's, showing off the power to friends)

It's going up, albeit slowly, wierd how the harder I drive it, the better mileage it gets!

Initially I was really disappointed with the economy, and still am not thrilled in the least, but seeing my numbers come up some is giving me a little hope.

I'm anxious to see what happens after I hook up my boat and drag it around for a while... I've been told it will get even better after that.

 

BTW, my mileage is all hand/calc... I don't have the stinkin' computer!

 

I hand calculated my mileage on this past weekend's trip to Maine and back. Based on the trip computer, my average speed each way as about 60 mph, however, much of the trip was 70+. With 2000 miles on the clock, my mpg was 13.5 - 14. Trip computer was pretty close to this.

This same route, under the same conditions in my PSD netted me over 20 mpg. Now, again, my PSD was a single-rear-wheel, a little lighter, and a 6 speed, so it's not quite apples to oranges.

Still getting about 12 on my daily driving that my PSD got around 15. So, we'll see.

 

Talked to a guy who works at a truck accessory place. He said he had a 600 and pulled a load of firewood and got 6mpg with a 4x4 drw qc. I can't believe these numbers..... but then again I don't like my unloaded numbers either. (13 mpg)

 

Some additional information.
I called Cummins and they said that they had had reports of better MPG and some that were worse. This guy seemed to know what he was talking about and even pulled up HP and torque curves. He said that at this point they did not have enought feedback to consider it a problem.

I recently test drove 2 CTD trucks, both 4x4 with 3:73, one with a 600. When I pulled out of the dealership the first mile was down grade. With the old engine the computer calculated from high to low, at time I was upto 30-35 MPG, once I hit some lights and made the trip back it settled in at 14 MPG. The new 600 started a 0 and went up, the highest that it ever went was 19, on return it was 10MPG. I know that most everyone calculates by hand, but this was just an observation.

 

While mine is the "little" 555, I agree with y'all that not being afraid to let'r buck is important. Mileage really has increased over time and I run it hard. I think keeping the Cummins exercised with clean filters is key. After say 20 K of city/interstate driving, I'd consider 17 to 18 mpg still pretty good. My two 7.3s' were in the 14s'.

 

Jonesboro,

In terms of '07 "new" fuel, since it's been in use in Europe, engines tuned to take advantage of it have considerably more power and much higher fuel mileage. How would 350 hp and 24 mpg do?

 

Neil

MY dealer probably only filled mine to the first click. After that tank was empty and I filled it, I got 130 miles and the needle was just getting to the F mark. Just took a 360 mile round trip and when I got back I was just slightly over 1/2 of a tank. That tank yielded me 602 miles and took 32.4 gallons giving me almost 18.6 MPG (hand calculated)

You will definetly get more mileage out of the first 1/2 than you will out of the second.

 

It seems the Autos especially with 4.10s are the most suspect to the marginal fuel economy.

 

Towing with an auto with 3.73's really bites, the truck wants to gear hunt all the time. I'm fine with my average of 14 MPG on the highway and 12.5 in the city with the 4.10's. I now have 23K on my motor and it seems to get getting better as it gets warmer due to fuel changes and keeping my foot out of it.

 

Mine is an early build date, (12\03 on engine data plate) and with only 1100 miles after owning for a month, mileage is not so bad.
The first two tanks by hand calculated out to about 14.5 with 50% city-highway. I Just did a trip on Interstate 5 over the past weekend and trip computer often would climb to 17 - 17.5 at 65 mph. Not to bad so far, I hope I can count on it getting better as I get more miles on it.

My travel trailer is 24 ft and about 6000# loaded. I hope to try it out soon. Cummins shouldn't break a sweat right?.

BTW, the truck I got rid of was a 95 Ford F150 Ext cab 4X4. I was lucky to get 16 mpg, 14 was the rule. With the same trailer mpg was about 6-7 (ouch).

I am not worried, fuel prices will drop (hopefully by Elk Season).