February 19, 2014

2006 Ford F250 6.0 4x4 four door

Well, the latest fuel mileage figures are in and the average city/highway (60% city / 10 % interstate / 30% country, no load) mixture is 20.6 mpg.

Another 400 plus mile trip on interstate resulted in 23.2 mpg.
verified via manual calculation by filling tank all the way to the point one could see the fuel level.

NOTE: For interstate: I reset the computer after getting up to speed on the interstate and drove almost 5 hours straight early morning hours - no traffic. The only non-interstate mileage occurred when getting off interstate and driving to gas station. The mileage was 24.1 just after coasting off interstate to exit to go to gas station but dropped to 23.2 during the 3 miles driving to the gas station (and I went through a mini bank).


Basically a stock truck except:

(1) new head gaskets although OEM;
(2) heads have been milled 12/1000 and 14/1000 with no valve work;
(2) shorter push rods;
(3) EGR Delete;
(4) 4" exhaust all the way back, no cad;
(5) stock turbo
(6) custom tune

Mileage is a little better than before the motor work.

I believe milling the heads 12/1000 and 14/1000 may have actually improved mileage. I suspect the combustion chamber now creates a more efficient burn, some how, perhaps by favorably changing the stoichiometry of the fuel air mixture. Or it could be the 4" exhaust or perhaps the custom tune (or all of the above).

Point is, one can get 24 mpg out of these trucks with no load driving down I95 to Florida from NC.

 

Typo: Title should read 23.2 not 20.6.

20.6 is the city mileage.

 

Milling the heads has no effect on the combustion chamber, it is in the piston. The heads are flat on the bottom.

 

True, but the enclosed chamber/cylinder volume has to have decreased as the valves are now 12/1000 or 14/1000 closer than before.

Small change in volume, for sure, but still a change.

One thing for sure, milling the heads does not appear to be a bad thing at the moment with regard to mpg.

 

Enlighten me why you suggest the newer shorter pushrod makes a difference because the valve travel is the same.

 

I respectfully decline to discuss any issue with you. I never know when my comments will be considered trolling.

 

If the machine shop truly did their job correctly, they should have set valve recession within specs so there would be no change in compression. If I took a diesel head to have milled and the shop didn't suggest recession change or at least check it, I'd turn around and walk out.

 

No recession done (so I am told, I was not there, was not charged for recession). The machine shop has done numerous 6.0 heads and does measure to verify they are still in spec. All I know.

We did use shorter push rods (new OEM push rods) but such simply takes some preload off.

 

This thread is about the gas mileage that my 6.0 provided on my latest trip and the possible mods that help such mileage.

Please do not troll on my threads.

 

Maybe your getting better fuel mileage because your not burning coolant.

 

Yes. If the engine was burning coolant before the engine repairs such would certainly affect fuel mileage.

But I do not believe the coolant was getting into the cylinders. I believe the compression of the air fuel in the cylinders was pressurizing the coolant and causing it to puke.

So good point, better compression from new OEM head gaskets probably affected the stoichiometry of the fuel air mixture far more than milling the heads.

 

Me? A TROLL???

 

Being the heads are completely flat with no chambers I think its pretty save to say thats not it.

 

I simply asked a question since you are so adamant.

 

Such is true on paper, but in the real world, heads are not perfectly flat. In fact, my heads were 12/1000 and 14/1000 from being flat.

But you could be correct.