Quick question - and not intending to bring the thread off-topic:

Given the potential for a lack of continuity between gas pumps, and even from fill-up to fill-up, is it generally regarded as better to use the NAV mpg for mileage logs (such as here on GH)? Is the FEH's NAV or in-dash gauge considered accurate enough to be on-par with those who own ScanGauges? Is there a common practice for mileage log keeping?

Thus far I've always used hand-calculations since I thought I was being more accurate. But if that's not the case (and it sure doesn't seem to be, based on earlier comments in this thread) then maybe going with the NAV readout is at least standardizing one of several variables.

Do others use hand calculations or NAV/dash readouts? Thanks!

 

Are you saying you DON'T think that drafting on a public highway is unsafe???????

~John

 

No. I never said that. What i said in another thread is that I have done it, I don't do it all the time, but when I have done it I have seen huge mpg increases. I have never told anyone that its safe or that there is no risk, I simply said what i experienced. I leave it up to each person to make up his or her mind as to what they want to do. For example I would never think of driving even after have one beer or drink. Now there are many people who might do this all the time and never see a problem with it. Or how about the people who here in texas ride a motorcycle without a helmet? is that unsafe?? some might say yes while other say no. Again it is up to that person to make that determination. What i am saying is that if you disagree with something then by all means speak up, but do we need to start calling each other names???? If I don't share your opinion on any topic does that make me a "clown" or stupid? of course not. In retrospect I should have never even taken the time to share my experiences with the group because it seems that some of us can't be adult and have a civil conversation about a topic.

 

I personally use the NAV the most. I think its CONSISTENT.... it may no be accurate, may ACTUALLY be hi may be low, but I'll bet it reads pretty darn close to the same offset from the REAL value every time. My goal is to improve my own results, not to compete with others so I don't care if my numbers jive. I think the numbers from the pump are too inconsistent to use. The scanguage still has a thread devoted to whether it knows the gas is shut off at certain points so it might have some inaccuracy too.

Now the NAV only reads the last 2000 pts? and last few hours of driving... so you can't really compare tank to tank.. A scanguage is probably the best for that once you've got its calibration fairly close by an average over many tanks.

 

HEY!!!! clowns are good people too!!!! lets not insult them by calling them stupid!

Sorry just trying to diffuse things with a little levity!!!

 

I always thought of the instrument cluster "AVERAGE ECON" like the video poker games you see in areas where gambling is illegal: "For entertainment purposes only." Ever since I learned how to drive I've been dividing miles driven by gallons used, so that's what I'm going to keep doing.

My thought is this: so the nozzle at the gas station clicks off a little early or late. You'll even out with the next tank because it will fill more or less than the last one. It can create single tank anomalies but so can a weather pattern or a bizarre traffic trend.

Here's the weird thing... I can leave for work and the dash "AVERAGE ECON" which is basically my "TANK MPG" according to the FEH reads 41.0 MPG. At the end of my 38 mile commute my scangauge's "CURRENT TRIP" shows 39.2, but the FEH's "AVERAGE ECON" is now showing 41.4! This could be due to the limited data points in the FEH's system or the inaccuracies with data interpolation (specifically with regard to fuel cut) of the scangauge.

Bottom line is any and all of the common practices are flawed, so use whichever one you prefer!

 

Doing one tank, or even one trip, you must use the numbers from the electronics. The ScanGauge is no more accurate than the stock system, and may in fact, be slightly less accurate on the short term.

However, it is generally recognized that a ScanGauge keeps a longer running total than the stock system, that holds TWO-THOUSAND ( 2000 ) data points.
We can't actually confirm how often a Ford data point is recorded, but if it is 2,000 minutes worth of data ( it is for sure NOT 2,000 miles ) that's the most recent 33 hours of driving. In some cases, you may not finish a whole tank in 33 hours, thus you may not have an entire tank average at the end of your tank, but it will be very, very close.

If you enter ACTUAL MILES and ACTUAL GALLONS into the GreenHybrid database, your lifetime average will get more and more accurate with every fill-up. If you always use data from the electronics, it will probably be consistent, but consistently skewed one way or the other.

I say always enter ACTUAL MILES and ACTUAL GALLONS pumped, and I think 99% of drivers will agree this is best. Those same people will tend to use the electronic displays to compare individual trips.
-John

My 37.5 MPG lifetime is from actual miles and actual gallons.
All numbers in red are from a ScanGauge.

 

In my 06, I always found the SG to be very slightly more accurate at mpg than the factory NAV (which I have since removed)

I would take both readings & then figure it out mathematically & invariably the NAV would rad 1-2 mpg too high & the SG would be closer to the mathematical reading.

I kinda figured Ford did that to make people feel good........

At this point, I don't really pay much attention to my mpg. I learned how to drive it as second nature to keep it around 30+ mpg in the Summer & I really DON'T WANT to know what it's getting when it's 2º out..........

~John

 

Thanks for all the comments regarding the best way to log mileage and averages! I feel like everybody had a beneficial contribution as I'm just getting up to speed. I think I'll continue my current habit of posting actual miles divided by actual gallons in GH, but I always post the NAV "Avg MPG" reading for the tank in the notes ... maybe at the end of the summer I'll plot them on the same graph just to get some basic statistics for both like delta and standard deviation.

We now return you to your regularly scheduled thread ...

 

Great Idea Andrew.