10.9 is getting old.

[Butch Cassidy]

Yes,

The 6.4 is quieter than the old 7.3, however the 7.3 will always get better mpg than the 6.4.

The 6.4 has alot of emissions controls, that the old 7.3 doesn't have. While your have a quieter, more clean burning engine - it comes w/ an expense - more fuel used.

In todays' soaring diesel prices, the 6.4 makes you say "OUCH" more at the pump

Butch cassidy

 

[TampaDieselFX4]

I think mileage is very finiky and hit or miss. I can see up to 24mpg's in my 6.0. A/c is a killer, along with speed. Did you have your PCM reflashed to the most current update? I'd give the truck a 101 point inspection... dragging brakes, tire pressure, oil, etc. I know the mechanical cooling fan on the ford is a bigger fuel eater too. Especially when it's engaged. Stuipd Q, but is the truck warming up? I had a car that got 10mpg's and it was b/c of the Thermostat that broke open!!! Warm is good.

 

[F350DRW1]

I think mileage is very finiky and hit or miss. I can see up to 24mpg's in my 6.0. A/c is a killer, along with speed. Did you have your PCM reflashed to the most current update? I'd give the truck a 101 point inspection... dragging brakes, tire pressure, oil, etc. I know the mechanical cooling fan on the ford is a bigger fuel eater too. Especially when it's engaged. Stuipd Q, but is the truck warming up? I had a car that got 10mpg's and it was b/c of the Thermostat that broke open!!! Warm is good.

A/C is good for about 10% reduction in mpg from what I've calculated. 65+mph is good for at least another 5-10%. Keeping the a/c off, speed at 55-59, tires hard, little idling, and I got almost 20% more out of the last 8 tanks of fuel. I'm seeing 18 out of an automatic 4x4 C/C 4.10 dually with the 6.0. Its tedious at times, but it can be done. Supercab w/3.73's should be alot better.

 

[desert50eagle]

A/C is good for about 10% reduction in mpg from what I've calculated. 65+mph is good for at least another 5-10%. Keeping the a/c off, speed at 55-59, tires hard, little idling, and I got almost 20% more out of the last 8 tanks of fuel. I'm seeing 18 out of an automatic 4x4 C/C 4.10 dually with the 6.0. Its tedious at times, but it can be done.
Supercab w/3.73's should be alot better.

Cruise at 59ish... no a/c...Mine is into the 20s easily.
Thank FOMOCO for the supercab w/ 3.73s

 

[yukondiesel]

Just took a short (220) mile trip.
Windows and moon-roof open wide for first 100 or so; A/C blasting for the rest. Averaged about 72-74 MPH and got 15.5 MPG including a REGEN about 1/3 of the way through the trip. I only have 800 miles on the truck, so I hope it keeps getting better...joe

OBTW: 08 6.4L; F-350; crewcab; short bed; 3:73 gears; 20 inch Ford wheels w/goodyears

 

[centexkr]

got about 15,000 on the 08 here. lately mileage has
gone down for some reason. Its been reflashed
and check out at the dealer. But on road and city
combo now is about 11 to 12mpg. Have reset the
meter several times but hasnt shown any improvement.
If hand calculate the mileage has been lower ?

 

[yukondiesel]

That last mileage was calculated for that that trip ONLY. The average on the meter (never been reset) is now at 13.2 (up from 12.3 at start of trip). I can give you my EXCEL spreadsheet if you have the software and want to use my formulas...

 

[F350DRW1]

The big thing calculating mileage is to fill to the same spot every time. I fill to seam on filler neck at bottom of cap threads. Otherwise you can easily be off a few gallons or more. I know this is old news, but I get a kick out of the guys who stop filling when the nozzle clicks off and then try to figure miles. Without a reference point, its not accurate.

 

[yukondiesel]

The big thing calculating mileage is to fill to the same spot every time. I fill to seam on filler neck at bottom of cap threads. Otherwise you can easily be off a few gallons or more. I know this is old news, but I get a kick out of the guys who stop filling when the nozzle clicks off and then try to figure miles. Without a reference point, its not accurate.

WHAT HE SAID!!!

 

[muddobber]

Well, I finally did it. Got the Spartan box and 5 inch exhaust system. Don't know excatly yet what to expect, but will put the truck through its paces soon. Did get 19 mph on the way home, that never happened before. By the way, when my DPF came off we noticed alot of black soot out the exhaust end back to the tip on the tail pipe. The guy helping me suggested my DPF chamber was not working corectly. Any one think they may have the same situation? I don't know what a DPF costs, worthless to me, but I bet they are not cheap.