Probably a topic beat to death but curious. Day 2 on my new 03 6.8l limited and looks like I am pulling 13.1 mpg on my 20 mile (40 round trip) daily commute. Decidedly more city than Highway with many stops and lights along the route. Have not had a chance to see what she will do on the highway. I purposely drove ultra conservative with a lot of rolling to lights, "egg under foot" driving and very happy with the results. Yes this is via "lyometer" but still good results I think. Thinking pure Highway could be North of 16mpg at 55mph or so and a very light foot? V10 and tranny appear to be functioning flawlessly and super smooth too!

 

You really need to hand calculate, 16 mpg is possible but that would be some real granny driving with a v10. Might as well install a flower on your antenna

 

I try to keep my rpms under 2k unless I really need to get on it for some reason. I usually see 19mpg around town and 22mpg on the highway trips.

 

Same here on the rpms - great mileage gotta love hose diesels..

 

Gotta fill that tank to hand calculate - twice, lol. Just using the meter for comparison - meter we at 11 mpg from previous owner plus some moving it Round the lot I assume. Will actually end up averaging lose to that I assume - especially when my wife gets behind the wheel... Lol

 

I've had 3 V10 Excursion's and they all got virtually the same with my Tune on them. Stock i was able to pull 10 MPG consistently in town(mixed driving) but with the tune i'm running that drops to about 8.8 ish.

8-10 MPG city/mixed

11-14.5 MPG highway

V10 4x4 3.73 gearing.

You can see my last 34,000 miles or so by clicking the link below...

 

I don't know if any of you noticed but if I fill my tank (50gal) completely full and then fill it again when it is about half way, I get roughly 18mpg. If I wait until the tank is on E and then fill up, it is usually around 19mpg.

This means that I am getting 2mpg more on the second half of my tank, then on the first half. I have tested this on several fillups and it is consistently the same. This possibly is true only for diesels with large tanks. Diesel weighs roughly 8lbs per gallon. It goes to show you how much weight plays a factor in mpg.

Has anyone else tried this, did you get similar results?

 

On my old work commute I was pulling down 12.5 mpg mostly hwy with a few stop lights. just recently on a 100% hwy trip I knocked down 15.5 mpg. it was raining pretty hard so speed was held to 55. normally I get 14.5 at 70 on the hwy! that is by the overhead. I`ve hand calculated before and it is always within .2 mpg. so my gauge is very accurate.

 

Took a 1000 mile trip with 8 in the cab and towing our TT. Averaged 9 but about 300 was without the trailer and got 14 at 75mph hand calculated

 

On a recent camping trip that I took with my wife, a toddler, an infant, and two elementary-school age children, plus being cubed out and pretty heavy in the back (my wife doesn't understand "camp light") I got almost 25 MPG when I filled up once I got home.

6.0 diesel, 4x4, 5-speed automatic, stock tune, stock everything.

 

'04 4X4 6.0PSD and I have only filled up twice so far. Both tanks have been mostly around town and occassional towing of 5k lbs.

1st tank average was 12.1 - hand calculated
2nd tank average was 12.8 - hand calculated
Current tank so far is 14.0 - computer readout which has been accurate on the last 2 tanks

 

Mixed driving according to gauge...

'00 V10 = ~ 11mpg

'01 7.3L = ~ 16.5mpg

Calculating is always less however, mpg would always be higher that what you hand calculate because that is the total fuel consumed over a given number of miles and not the actual mpg. The actual mpg is closest to what the gauge reads as it can calculate fuel used during those inconsistent times, like idling, that you can't calculate.

I don't get why everyone calls it a lieometer when it can calculate much more often and with a greater degree of certainty than that of a person. Not to mention, the gauge is a running total over time, not just one fill up. It's a MPG gauge, not a TOTAL fuel consumption gauge which is what you are "hand" calculating. Your hand calculated number will always be less than the gauge but that doesn't translate into your numbers being an accurate mpg rating.

 

Unless you reset your MPG gauge at every fill up, which many of us probably do.

People are, literally, hand calculating miles per gallon. They divide the miles driven by the gallons refilled into the tank. That's exactly what miles per gallon is, and it's better and more accurate, on average, to hand calculate, rather than relying on the computer to do it for you. The computer takes averages at each reading, and small variances at each reading can add up to large differences over the 600-800 miles that many of us drive between fill ups.

That being said, the only way to be 100% accurate is to fill up at exactly the same flow rate from exactly the same pump and at exactly the same fuel temperature and outside air temperature to guarantee that your fuel is at exactly the same density and that the pump shuts off at exactly the same point, but hand calculation is more accurate than a MPG meter for miles per gallon over time, where a meter is more accurate for instantaneous readings.

 

The gauge reads "AVG miles/gallon" and I'm not sure many understand what that means. I realize many people believe the world works the same for everyone but there are some of us that leave our trucks to idle for long periods of time. Do you have any idea what that does to your hand calculations? If I start my truck in the morning and it never shuts off during the day and I only drive about 150 miles total, what do you suppose the mpg would be by hand calculation? Would it be real?

 

The gauge also still sits there and takes reading during idle for commuters, as well. I've seen what happens on the MPG gauge when I reset it after I fill up and have to wait at a red light or stop sign. The numbers go down, and often rapidly if I've only managed to drive a couple of miles before coming to a stop. So, then, would you calculate out all fuel consumed idling during rush hour stop-and-go driving? No, absolutely not. How about time spent idling at a red light? Or at the drive thru at Dairy Queen?

I realize that this probably sounds like I'm engaging in reductio ad absurdum here, but for most people that spend the bulk of their time commuting in their cars and/or buzzing around doing errands, hand calculations are better on average than the MPG gauge on just about any car.