mileage factors

[DieselBear225]

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..

[Zaairman]

You can usually squeeze another 3 gallons in the tank after it first clicks off... fill it up until you can see diesel in the neck, not just foam.

[RIVER-RAT]

When you "fill till the pump stops", you can't really get an accurate reading. Why?

When the diesel fuel flows into your tank, foam is created and when that foam hits the sensor on the nozel, the pump stops. Due to the fact that this "foam" cannot be accurately measured, it is safer and more reliable to fuel your truck until you can visually see the fuel in the "neck" of the tank, due this on several fill ups and always fill the fuel to the same level in the neck of the tank to get an accurate measurement of MPG's.

I have done this and have seen that on several occations I have put an additional 5 gallons of fuel in the tank after the foam has stopped the pump. I have also experienced 3-4 gallons in the tank after the foam has stopped the pump. Just never know how "foamy" the fuel will be at any given fuel station or time.

[DieselBear225]

that makes a lot of sense. It would explain why sometimes i think I'm getting 19 mpg and other times I'm only getting 11 mpg. I must be shorting my gallons by not filling all the way. Which would give me 19 MPG...I thought that seemed awful high MPG for a 1 ton diesel !!

Thanks !

[gemniii]

Originally Posted by DieselBear225

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..

You've been

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.

[DieselBear225]

Originally Posted by gemniii

You've been ?

Take it out for a day's drive, say 900 miles at 60mph, a couple of times.
Look at your mpg after 10K miles.

Thanks for the tip, I get what your saying.


RE: trips 4&5
Was there a difference in your load? (no load, nothing in tow)
Thin girlfriend vs fat wife? (no passengers )
A difference in in elevation? ( some hills, same route, no significant elevation from pt A to pt B )
Driving up the Rockies 11 mpg, driving down 19mpg? (no Mts. In Iowa )
A difference in temperature of fuel? (55-60 degrees trip there and back)
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.

I think 15mpg is pretty good. I would be satisfied with that.
I will probably not be taking it on 900 mile trips. I drove it from Des Moines, Iowa to Sioux City, Iowa which is about 200 miles. I was just curious what it would do for MPG at different speeds. Trip there the cruise was set at 70 and the trip back the cruise was set around 63. I figured 11mpg and then 13mpg.

Any idea what I should be expecting at 70mph, 55mph, and around town, city area ?



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[visual800]

2003 1 ton dually Im up to 18mpg 550 miles on a full tank friving bout 70 its been consistent for the past couple years. before i put S&B intake on it I was getting bout %10 miles per full tank

[DieselBear225]

Originally Posted by visual800

2003 1 ton dually Im up to 18mpg 550 miles on a full tank friving bout 70 its been consistent for the past couple years. before i put S&B intake on it I was getting bout %10 miles per full tank

? whats the %10 miles


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[Zaairman]

I think he meant 510...

[DieselBear225]

Originally Posted by Zaairman

I think he meant 510...

ahh, thanks !

wow, i'm sure there is no way I can get even close to 15 mpg doing 70 mph. with my stock setup.

I don't know anything about intakes, but I'm guessing i should do some homework on them.


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