[dsdbkranz]

I have a 2008 F-450 4X4 Lariot with 4.33 gears and pulled a 40 ft toy hauler full profile height. Trailer weight for this trip was around 14,000 lbs. Truck was very impressive and pulled the trailer really well I think. I'm sure there are a lot of people that I can compare apples to apples and rate how my truck did.

1. Highway was mostly flat with 10mph head winds.
2. Travel distance was about 150 miles.
3. Truck speed was set at 57mph cruise control
4. Truck boost gauge was mostly at 18 pounds.
5. Truck MPG reading was 9.4

So the question is would this be about right for this truck or should it have done better on MPG and should the boost be that high? I have nothing to compare against. Thanks

 

[SmokeyWren]

Did your tranny stay in overdrive, or did it downshift for every little bump in the road? On my much-older PowerStroke, when towing I had to maintain about 62 MPH to maximize fuel mileage. At slower speeds the tranny would downshift for minor grades such as an interstate overpass, and MPG went to the dogs when the tranny downshifted. But at 62 MPH (1,800 RPM in my case) I was high enough on the HP curve that the tranny didn't downshift except for major grades.

But with your more-powerful engine, 4.30 rear end, and the tow-haul mode, you shouldn't have that downshifting problem, and I would expect more than 10 MPG with your load and speed.

However, MPG with a PowerStroke engine is based a lot on the luck of the draw. I was unlucky. I got around 15 unloaded and 12 towing, whereas others with a rig identical to mine got 18 or more unloaded and 15 or more towing 8,000 to 10,000 pounds.

The computer gives you an "about" MPG number. To get the real number, you must fill the fuel tank through the foam until you have liquid diesel at the cap, zero the trip meter, drive at least 300 miles, then fill up to the cap again. Compute your real MPG and it probably won't be the same as what the computer told you.

 

[dsdbkranz]

The truck mostly stayed in overdrive with one time down shifting on an overpass, I was towing about 62 MPH and my MPG was around 8.4 so by slowing down to 57 it improved to 9.4 MPG. I will do what you suggested next time I pull and calculate my own MPG. Unloaded and traviling at 65 I get 15.4 MPG, I still wonder if the boost was high or was that about right. What kind of truck do you drive now?

 

[SmokeyWren]

What kind of truck do you drive now?

We're too old and beat up to RV now, so I sold the 5th wheel RV trailer and no longer need a diesel towing machine. So I sold the '99.5 PowerStroke. I need a pickup, but only enough to tow a 7,000 pound cargo trailer for 300 miles twice a year. I should have kept the PowerStroke, but it was 12 years old and I assumed a newer small pickup such as a Toyota Tacoma would do the job I needed. But only very special Tacomas with the V6 engine and factory HD towing pkg will tow 7,000 pounds, and the rare used ones cost almost as much as a new one.

I was about ready to order a new F-150 EcoBoost when my brother died. He left his handicapped widow a truck she couldn't get into or out of. And he was upside down on the lien against the truck, so she couldn't sell it for what she owed on it. So to help out Li'L Sis, I paid off the truck and kept it. It's a "true blue" 2003 F-150 Lariat SuperCrew with 4.6L engine and 99,000 miles. Not my dream machine, but it's a nice old pickup, and with the addition of a new OEM heavy-duty tranny cooler it tows my 7,000 pound cargo trailer just fine.

I still wonder if the boost was high or was that about right.

I don't know about your '08. It has different turbo setup than my old 7.3L. On mine, I would see 18 PSI only when downshifted out of overdrive and climbing a steep mountain grade at 60 MPH. Normal boost when cruising at 62 MPH on the plains and grossing 16k would be 8 to 10 PSI.