I got 20.5 mpg this past week in my 2003 6.0 diesel 4x4 crewcab cruising at 70-80 mph on an interstate for 508 miles on one tank. This is my first road trip after installing MBRP Cool Duals and AFE stage 1 intake kit. I was also running a superchips programmer, set on high performance instead of economy.

Has anyone achieved higher milage on their 6.0??? If so, what mods did you install to get the higher mileage???

Thanks,
Lee

 

Lee, I have an 06 F-250 with all of those mods (AFE Stage 2, Superchips Flashpaq, 4" Magnaflow turbo back) and the best I've done is 15.5 mpg but I have 325/60/18's and have not yet emptied a tank on all highway miles yet. Mine is also a crewcab 4x4.
What formula are you using to figure your mpg's? I'm zeroing out after filling up then running it down to the next fill up and getting the gallons filled and dividing the miles on the trip meter by the gallons filled. Not sure if that is the most accurate way to figure it but......

Scott

 

Only way to accurately figure fuel mileage is to fill until you see LIQUID fuel in the filler neck. Then run down to however low you go and then fuel up to the same point as the last time. This is the ONLY way to accurately figure fuel mileage on your truck. The reason is that diesel foams so much in the tank you never know how many gallons are in the tank until you can see the liquid in the neck. My truck kicks the pump off and then I can usually put another 5-7 gallons more in. Thats how much space that foam takes up.

 

I just fill the tank until I can see the liquid level and divide the miles travelled by the fuel used. The filler neck holds so much fuel that I filled the tank until I could see the level, then drove 107 miles, turned off the ignition, then later started the truck, and that computer thought that I had filled the tank and recalculated my range to be another 514 miles!!! Theoretically I could get 621 miles on that one fill-up.

That MPG readout on the trip computer is not so accurate. It seems to be highly influenced by the ongoing fuel usage instead of averaging for the whole tank full. I can coast a long way prior to exiting the freeway and gain 0.1 to 0.2 mpg, which cannot be accurate for the whole tank.

If you are running 315's, you will need to correct your mpg for your tire size (unless you adjusted your speedometer to be correct). Your truck is travelling farther for each tire rotation than your speedo/ODO thinks it is travelling. Example: You may have driven 475 miles while your odometer measured only 450.

Cheers,
Lee

 

my Flashpaq has tire adjustment settings so it should be close to accurate. That is why I went with it over the xcalibrator. I know the x allows for more HP but not tire size adjustments for the 06.
I will try filling it up more at the next fill up until I actually see the fuel. I havn't done that yet.


Scott

 

It is a running average from the last time it was reset. Try this .... get up to speed 60-65 or so, take your foot off the accelerator, reset the computer. Bet you get a reading of 99.9MPG until you step on the accelerator again. On the other hand, when you are stopped and the engine idling, reset it, and your MPG will be zero or very close.