ScanGuageII units

[1.9SDI]

I've bought and installed my ScanGuageII – it looks great.

However, I've set my units to gallons but they are US gallons and not Imperial gallons. I know I can convert when I get home but that's not the reason I bought it. Is there any way I can get it to display Imperial gallons?

During my trip to the supermarket I averaged 80MPG! That sounds great but I know that trip averages about 57MPG (Imperial).

Any ideas?

[SentraSE-R]

IIRC, once you calibrate your unit, it's accurate for your fuel unit size, whether they're US or Imperial gallons.

[1.9SDI]

Yes, granted. But, I need to display Imperial gallons but it only offers US gallons - and I bought it from an official UK source.

I'm assuming this because of the enourmously high MPG readings I have. 80MPG on a city drive, at night, while raining, approx 10^C. Not possible in a diesel Golf, surely?

[SentraSE-R]

It shouldn't really matter what the units are called. You could record liters and call them gallons. Once you calibrate the first tank. your 320 mpg (really miles/liters) calibration would bring the next tank close to accurate for your units, since your next tank will be getting close to 320 mpg (indicated). That's why your UK Scangauge has no special Imperial gallon units to choose from. You just use gallons, and when you calibrate, your Imperial gallon size is corrected for.

[1.9SDI]

I honestly dint understand what you're saying. I want the ScanGuage to display Imperial gallons, not US gallons but you say it doesn't matter. How can that possibly be correct?

There is a big difference between the two. And it's not just a matter of terms, or why would the consumption figure change when I switch from gallons to litres? They ate two entirely separate units, just as US and Imperial gallons are two separate units.

My ScanGuage displays US gallons - how do I make it display Imperial gallons?

[PaleMelanesian]

The UK gallon is about 1.2 US gallons. You can adjust the engine size by that same factor instead of using the calibration. 1.9L * 1.2 = 2.28, or round it to 2.3L. The calibration should be pretty small from that point.

[SentraSE-R]

I shouldn't have used liters as an example, because Scangauge does have them mathematically calculated as discrete units. Since SG doesn't have Imperial gallons as an option, you can substitute US gallons. The calibration step adjusts the SG's mathematical correction of how it calculates fuel consumption from fuel injector pulse length, engine size, etc. You essentially trick it to think a 1.2 US gallon equivalent Imperial gallon is the norm. From there, it merrily reports miles/gallon accurately for the Imperial-size gallons

[PaleMelanesian]

Right. The normal way to do a calibration is the slow way - run through a tank and then adjust with the real amount when you fill up.

There are two quicker approaches.
1. adjust the engine size. bigger engine = SG thinks you're using more fuel = lower mpg reported. I like this option because it only takes 4 clicks to change the setting (2.0L, 2.1, 2.2, 2.3). It's also easy to reproduce if the unit ever resets or if you use it on another vehicle and then bring it back.

2. up until you've used 1 gallon on the tank, you can adjust the offset in the Fillup menu. Just click until it's +20%, and then DON'T hit done. Just leave it, or it will start a new tank from zero. This takes a LOT more clicking (20% in 0.1% increments = 200 clicks) and will have to be repeated if you reset or use the gauge on another car.

Whatever approach you use, I suggest recording the settings in case you need to reproduce them later. It will default back to the wrong settings if it resets.
- engine size
- fuel type
- offset
- tank size if you use the miles/gallons/distance to empty feature.