scangauge fuel tank size accuracy

[PaleMelanesian]

The tank size has no bearing at all on the mpg readings. It only affects the "Miles to Empty" and "Gallons to Empty" readouts. I pretty much ignore it.

Engine size and fillup offset are what you should worry about.

[MetroMPG]

Carlos' point is also key: realize the ScanGauge reads in US gallons.

You can effectively change the MPG readings to display imperial gallons using the fuel offset if you want to.

[alexander.foti]

Originally Posted by PaleMelanesian

The tank size has no bearing at all on the mpg readings. It only affects the "Miles to Empty" and "Gallons to Empty" readouts. I pretty much ignore it.

Engine size and fillup offset are what you should worry about.

Sorry for not responding for soo long, I have been very busy.

I appreciate all the responses.

My question is that if you say fillup offset affects the accuracy then the tank size does also technically as when im filling up I input the offset im inputting it against 10 gallon tank size rather than 10.6 gallons....

[alexander.foti]

Originally Posted by MetroMPG

Carlos' point is also key: realize the ScanGauge reads in US gallons.

You can effectively change the MPG readings to display imperial gallons using the fuel offset if you want to.

I have read that if I tell i have a 10 gallon tank (uk gallons) and then input the first fuel adjustment in UK gallons then all other values will be in UK values.

Im not too bothered if the fillup adjustment factor only affect the miles to emtpy becuase I can ignore this knowing my avg and instant mpg values are accurate.

[cfg83]

alexander.foti -

Originally Posted by alexander.foti

I have read that if I tell i have a 10 gallon tank (uk gallons) and then input the first fuel adjustment in UK gallons then all other values will be in UK values.

Im not too bothered if the fillup adjustment factor only affect the miles to emtpy becuase I can ignore this knowing my avg and instant mpg values are accurate.

I am actually bad when it comes to this. I never "calibrated" my old SG-I beyond engine size. The engine size is critical. Double the engine size and you will see your reported MPG drop like a rock.

In my fuel log I use my odometer (after GPS correction factor) and (US) gallons measured at the pump. This puts me at the mercy of gas pump innacuracies, but you can't have everything, so I can live with that. I use the same pump when available, but not at the expense of my or another's convenience.

Because I don't have a calibration factor, my instant and average MPG may be off. However, I consider them to be valid *relative* barometers, and I am fine with that.

CarloSW2

[gone-ot]

...just curious. How many times does one have to "tweek" the GALLONS-used offset ("calibration") before things 'settle-in'?

...once, twice, three times, ...continuously????

[Lazarus]

Originally Posted by Old Tele man

...just curious. How many times does one have to "tweek" the GALLONS-used offset ("calibration") before things 'settle-in'?

...once, twice, three times, ...continuously????

With mine it was 2 times but I was careful to fill at the same pump and run it till the low fuel light came on before refill. From that point on it was pretty rock solid. Once in a while it would be different but I would wait and see if the next tank after that was also different before I made any tweek assuming it could be pump or fill error.

[gone-ot]

...I asked the question because I'm now on my first tank 'after' doing the initial calibration, and (obviously) there's a BIG difference between the previous (pre-calibration) AVG and MPG numbers and what I'm seeing now.

...and, I, too, waited until the "empty" light came on, figuring that the larger the GALS-value, the more likely to be correct (ie: "percentage" of the whole). But, since the "correction" value was only 0.X while the actual gallons pumped were 0.XXX, it's also apparent there's a big discrepancy in accuracies. In my case, I had to 'round' 9.868 actual gallons up to 9.9 'adjust' gallons (+13.7% per SGII).

...again, just a curiousity question.

[Lazarus]

Originally Posted by Old Tele man

...I asked the question because I'm now on my first tank 'after' doing the initial calibration, and (obviously) there's a BIG difference between the previous (pre-calibration) AVG and MPG numbers and what I'm seeing now.

...and, I, too, waited until the "empty" light came on, figuring that the larger the GALS-value, the more likely to be correct (ie: "percentage" of the whole). But, since the "correction" value was only 0.X while the actual gallons pumped were 0.XXX, it's also apparent there's a big discrepancy in accuracies. In my case, I had to 'round' 9.868 actual gallons up to 9.9 'adjust' gallons (+13.7% per SGII).

...again, just a curiousity question.

Here's a link to a post about the off set. It looks like they can be all over the map from 2- 15%. So the 13.7% does not seem to out of line.

[gone-ot]

...I somehow missed finding that page when I fumbled around looking for information; I appreciate the direct link...Thanks!