Hey All, I'm new and just did my intro.
To the point, For a month I'm a new owner of a 2002 F350 w/7.3L.. I have no reason to believe it's been tuned. Stock size wheels/tires. I've been figuring mpg and messing with speeds on long trips to see how it changes. I figure it by filling until it stops on its own every time and dividing miles driven by gallons filled.
1st Trip was a 225 mile on Interstate w/ cruise set at 70mph....AVG was 11mpg.temp was really cold @ zero..
2nd Trip was a 153 mile on Interstate return from above (same road)
w/cruise set at 63mph...AVG was 13.9mpg..temp was single digits.
3rd Trip was a 217 mile, all local town/city/hwy driving...AVG was 11.4mpg...usual February weather in Iowa. cold..
4th Trip was a 186 mile, 2 lane hwy...w/cruise set at 55mph...AVG was 19mpg
5th Trip was a 186 mile, 2 lane return home on same road w/cruise set at 55mph...AVG was 11.9mpg.
6th Trip was 382 mile, 2 lane w/ speeds around 60mph...AVG was 19mpg..
Any insight on why such a difference on trip 4 and 5 ? I took the same route on the same day and got really different numbers..
messing with speeds on long trips
Take it out for a day's drive, say 900 miles at 60mph, a couple of times.
Look at your mpg after 10K miles.
RE: trips 4&5
Was there a difference in your load? Thin girlfriend vs fat wife?
A difference in in elevation? Driving up the Rockies 11 mpg, driving down 19mpg?
A difference in temperature of fuel? Fuel expands as it warms, if you absolutely top off a tank (that was empty) so the neck is about to drip with fuel from a cold storage tank it will overflow when it warms if not used.
My 2002 F350 Duallie 4x4 has gotten 15.74 over the last 2,000 miles, mostly above 65mph thru the Appalachians on I81. Half of it towing a minivan w/ the bed loaded.
'88 Ford 7.3 E350 Customized Maxivan
'09 VW JSW TDI (up to 47MPG highway)
'02 F350 DRW 4x4, 7.3 PSD, CC
tractors-'07 Kubota B7610
'95 Kubota M4700