[curcercanty]

Everyone talks about mpg, it's used as standard in many countries and in car handbooks.

However, is there one standard in the use of mpg in terms of gallon size, or am I just to assume that a user manual for a US car is going to use US gallons, while a user manual for a British car is going to use imperial gallons?

So would I be right to assume my Stang was using American mpg's on the display, while the C63 shows British mpg?

[emexiagog]

Everyone talks about mpg, it's used as standard in many countries and in car handbooks.

However, is there one standard in the use of mpg in terms of gallon size, or am I just to assume that a user manual for a US car is going to use US gallons, while a user manual for a British car is going to use imperial gallons?

So would I be right to assume my Stang was using American mpg's on the display, while the C63 shows British mpg?

That's a fantastic question. I would imagine if your car was directly imported from the states then it would be a US gallon, but if it sold to you at say a dealer it may be different. I'm probably wrong though :X

[mpxricyNimb]

I suspect that if you're being sold the car through official channels in your country, then it would be whatever gallon you use. Fuel economy ratings are typically regulated by a government agency for accuracy, standardization, etc.

[zdoppiklonikaa]

If it's sold at a UK dealer or went through an SVA then it should show UK gallons. A direct import left hooker would still show US gallons.

I very much doubt it makes much difference in a car like yours though. There is only half a litre difference in the gallon size. Probably about 2.5mpg difference.

[Pateeffelty]

next time you fill up do the maths... see what it says on the computer then you can work out if its used US or UK gallons in its calculations.

[BonjGopu]

next time you fill up do the maths... see what it says on the computer then you can work out if its used US or UK gallons in its calculations.

I do not believe that would have the desirable outcome. Mainly because driving conditions change the actual mpg too much to offer a fair comparison.

[LClan439]

mpg and mph noobs

[Pa33anger]

On some cars you can change the units.

[JakilSong]

We use L/100km here in Australia to measure fuel economy. My 1992 2.0L Mazda 626 get's an average of 7.0L/100km (still holding excellent fuel economy after almost 20 years).

I think that equates to about 33.6mpg. Best my car has ever got was 6L/100km doing 110km/h on the freeway for about 8 hours straight which is considerably better then the cars best fuel rating (which is 6.9L/100km highway driving @ 60km/h)

[Pateeffelty]

I do not believe that would have the desirable outcome. Mainly because driving conditions change the actual mpg too much to offer a fair comparison.

eh?

fill up and note litres used... drive... see what MPG the car computer gives out and then compare that to what you work out using the two different values of gallon.

there is only one variable here and thats the size of the gallon... petrol in and miles driven are constant.

[daguy]

Everyone talks about mpg, it's used as standard in many countries and in car handbooks.

However, is there one standard in the use of mpg in terms of gallon size, or am I just to assume that a user manual for a US car is going to use US gallons, while a user manual for a British car is going to use imperial gallons?

So would I be right to assume my Stang was using American mpg's on the display, while the C63 shows British mpg?

Call the dealer. [yes]

[BonjGopu]

eh?

fill up and note litres used... drive... see what MPG the car computer gives out and then compare that to what you work out using the two different values of gallon.

there is only one variable here and thats the size of the gallon... petrol in and miles driven are constant.

I should have worded it better. Computers in a car are not precision measuring devices. I note my fill ups in aCars (Android app) and it's calculated MPG is not the same as my car's mpg used.

2nd, you can not guarantee that you put in the exact amount of fuel as what was used. Variables like temperature, sensitivity of the pump shutoff, angle of vehicle (might not be on level ground) can affect where the "full" point of the tank is. If you watch Mythbusters, this is why they go by weight instead of volume.

[daguy]

I should have worded it better. Computers in a car are not precision measuring devices. I note my fill ups in aCars (Android app) and it's calculated MPG is not the same at my car's mpg used.

2nd, you can not guarantee that you put in the exact amount of fuel as what was used. Variables like temperature, sensitivity of the pump shutoff, angle of vehicle (might not be on level ground) can affect where the "full" point of the tank is. If you watch Mythbusters, this is why they go by weight instead of volume.

Do you even know the difference between US en UK gallons?

If a tank holds X amount... you drive it till your re-fuel light goes on, or untill some area you marked as refill.

You get gas at same station ( because tank stations may alter their stop time, indiicating full tank) and driive again.

Note what you've got in and what's driven. You find out easely what the difference is, but a call to a dealer be best, easiest and fastest way.

Or do you want to see Real World Date?

[daguy]

I should have worded it better. Computers in a car are not precision measuring devices. I note my fill ups in aCars (Android app) and it's calculated MPG is not the same as my car's mpg used.

2nd, you can not guarantee that you put in the exact amount of fuel as what was used. Variables like temperature, sensitivity of the pump shutoff, angle of vehicle (might not be on level ground) can affect where the "full" point of the tank is. If you watch Mythbusters, this is why they go by weight instead of volume.

Anddroid app cant see your car's condition either and they way you drive...

Even Audi's boardcomp is misstaken, seen on topgear. It was 0 milage left and he drove on and on... It always makes sure you aint driving last drup, ALWAYS have fuel in tank left, even saying it is empty.

It's pretty logical.. because there is always a chance you are somewhere, sometime, with low fuel indicator on a piece of road with no gasstations around. Plus that it is better not to suck in all de concentrated 'dirt' gatherd in your last bit of fuel.

[BonjGopu]

Do you even know the difference between US en UK gallons?

If a tank holds X amount... you drive it till your re-fuel light goes on, or untill some area you marked as refill.

You get gas at same station ( because tank stations may alter their stop time, indiicating full tank) and driive again.

Note what you've got in and what's driven. You find out easely what the difference is, but a call to a dealer be best, easiest and fastest way.

Or do you want to see Real World Date?

Seriously? You are going back to that?

You lost almost all credibility with me when you accused me of blindly following a forum that had actual laboratory testing data when your source had nothing more then people's comments/opinions.

And all I am saying is you can not guarantee that you will replace the same amount of fuel consumed, nor can you guaranteeing the computer is 100% accurate. Those two factors alone are enough to throw off any calculations you could make.

Anddroid app cant see your car's condition either and they way you drive...

Never said it did. Like I said, the MPG it calculates is never the same as the MPG on my car's computer. But I use it for a lot more then just mpg caculations.

[daguy]

I dont know whats wrong with you either, I am just happy you are FAR away from me.. yet so fing close.

[Munccoughe]

Seriously? You are going back to that?

You lost almost all credibility with me when you accused me of blindly following a forum that had actual laboratory testing data when you source had nothing more then people's comments/opinions.

And all I am saying is you can not guarantee that you will replace the same amount of fuel consumed, nor can you guaranteeing the computer is 100% accurate. Those two factors alone are enough to throw off any calculations you could make.



Never said it did. Like I said, the MPG it calculates is never the same as the MPG on my car's computer. But I use it for a lot more then just mpg caculations.

Doesn't need to be precise - UK galon is 25% more than the US gallon - or the US gallon is 20% less than the UK gallon - should be well outside your margin of error, especially if note is made over several fills.
Fill up until pump stops, set distance trip meter, reset computer display - drive until about 1/4 full, find service station, check computer MPG reading, top up fuel until pump stops, note fuel used in imperial gallons (or litres and convert), note new trip distance covered, work out mpg from fuel and trip, compare to display.
If they are close, display is probably imperial, if not, correct for US gallons and check, if now close, it's in US gallons.

Can't see what the problem is, TBH, unless people are just looking for something to [female dog] about - wait, this is FM, of course it's just an excuse for abuse, silly me...

[BonjGopu]

Doesn't need to be precise - UK galon is 25% more than the US gallon - or the US gallon is 20% less than the UK gallon - should be well outside your margin of error, especially if note is made over several fills.
Fill up until pump stops, set distance trip meter, reset computer display - drive until about 1/4 full, find service station, check computer MPG reading, top up fuel until pump stops, note fuel used in imperial gallons (or litres and convert), note new trip distance covered, work out mpg from fuel and trip, compare to display.
If they are close, display is probably imperial, if not, correct for US gallons and check, if now close, it's in US gallons.

Can't see what the problem is, TBH, unless people are just looking for something to [female dog] about - wait, this is FM, of course it's just an excuse for abuse, silly me...

Well, I did some quick math.

I figured the margin of error is about 10% at most. If your mpg is more then 10% off, then the margin of error will overlap and it could very well be either standard.

For example, if your car says 30mpg and you calculate 33mpg, then there's an equal chance of going either way.

I'm not going to tell you if it's an acceptable margin of error or not, that will stay in the realm of opinion.

[Munccoughe]

So you can't read a trip meter and/or read a petrol pump fuel meter and/or do a simple arithmetic problem without a 10% margin of error?
You should be able to get it within 1%, easily, allowing for slightly different fills, and o.1% isn't out of the question.

[BonjGopu]

So you can't read a trip meter and/or read a petrol pump fuel meter and/or do a simple arithmetic problem without a 10% margin of error?
You should be able to get it within 1%, easily, allowing for slightly different fills, and o.1% isn't out of the question.

Edit: I decided I'm not going to argue with you since you feel the need to spout unrealistic crap. 1%? Really? Let's do the math.

At 30mpg, 1% difference would be .3miles. at 10gallons, that's 3 miles difference for the entire trip. I'll use 1 US gallon, which has 128 fluid ounces. That comes to about 4.3ounces per mile. Now to be within 1% between the car's computer and what is filled at the pump, you would have to be pretty much within 13fluid ounces. That's a scratch over the size of a can of coke.

So you are telling me, in conditions you can not see (unless you mounted a camera in your fuel tank) and assuming the computer is 100% accurate. With unknown temperature conditions, levelness of the car, shutoff point of the pump, and of course, who doesn't round up to the nearest whole dollar/euro/whatever you use, you can guarantee your tank is filled to within 1/10th of a gallon. And .1% you would have to be within a few ounces to achieve that.

No sir. That's a load of BS.