Does this give an accurate average or is it just for show?Depends what you mean by “accurate” and why you want that accuracy. If you’re keen on measuring your mpg with decimal places, then it’s not that accurate and you need to do something else. But if you just want to ensure you’re driving as efficiently as possible (which is actually why it’s there), and be able to take action if your mpg starts dropping off, then it’s plenty accurate enough.
You want accurate MPG? Use (for example) this: https://www.spritmonitor.de/en/Spritmonitor is just a calculation tool, the accuracy of the results depends on the accuracy of the data you enter. Sources of error can be the accuracy of measuring the fuel added (eg brimming the filler pipe in exactly the same way every time), and that the odometer reading can be a few % out.
Easy:
Use Spritmonitor.de on the road with your Android- or Apple-smartphone and the Spritmonitor.de app! Enter new fuelings right at the gas station.
Sure, but if you run the calculation over several fill-ups then the vagaries will be ironed out and the overall average will be very close to real consumption. Certainly accurate for comparison purposes.You want accurate MPG? Use (for example) this: https://www.spritmonitor.de/en/Spritmonitor is just a calculation tool, the accuracy of the results depends on the accuracy of the data you enter. Sources of error can be the accuracy of measuring the fuel added (eg brimming the filler pipe in exactly the same way every time), and that the odometer reading can be a few % out.
Easy:
Use Spritmonitor.de on the road with your Android- or Apple-smartphone and the Spritmonitor.de app! Enter new fuelings right at the gas station.
Sure, but if you run the calculation over several fill-ups then the vagaries will be ironed out and the overall average will be very close to real consumption.
Certainly accurate for comparison purposes.But so is the car's computer read-out!
Just a ballpark figure would do.. :)Over 46000 miles in my Mk3 with trip B left running throughout, I have found the display to be about 9% optimistic showing 56.8 mpg while the true figure based on fuel bought is around 52. I expect the Mk 4 computer will be similar.
Not if you are comparing between 2 different makes of cars.Sure, but if you run the calculation over several fill-ups then the vagaries will be ironed out and the overall average will be very close to real consumption.
Only if the errors are broadly above and below a mean value over repeated fill-ups. If they are biased to one side of the mean (eg if the odometer error is due to tyre wear) then you'll get a biased result.Certainly accurate for comparison purposes.But so is the car's computer read-out!
Just a ballpark figure would do.. :)Over 46000 miles in my Mk3 with trip B left running throughout, I have found the display to be about 9% optimistic showing 56.8 mpg while the true figure based on fuel bought is around 52. I expect the Mk 4 computer will be similar.
Sure, but if you run the calculation over several fill-ups then the vagaries will be ironed out and the overall average will be very close to real consumption. Certainly accurate for comparison purposes.You want accurate MPG? Use (for example) this: https://www.spritmonitor.de/en/Spritmonitor is just a calculation tool, the accuracy of the results depends on the accuracy of the data you enter. Sources of error can be the accuracy of measuring the fuel added (eg brimming the filler pipe in exactly the same way every time), and that the odometer reading can be a few % out.
Easy:
Use Spritmonitor.de on the road with your Android- or Apple-smartphone and the Spritmonitor.de app! Enter new fuelings right at the gas station.
Why is there a consistent variation?It must be designed that way. I think the measurement of fuel consumed is based on regular sampling and it’s clearly in the maker’s interests to err on the side of flattering the consumption, making us all feel better. I don’t suppose there are any regulations specifying accuracy as it is not a safety issue.
Why is there a consistent variation?It must be designed that way. I think the measurement of fuel consumed is based on regular sampling and it’s clearly in the maker’s interests to err on the side of flattering the consumption, making us all feel better. I don’t suppose there are any regulations specifying accuracy as it is not a safety issue.
Not at all, I used to do that when I commuted at 11k miles a year but now that I only do about 2k miles a year I don't bother.
No one can check accuracy of MPG indicator when using sprittmonitor without knowlege of accuracy of fuel pump on gas station.
They can sometime lie, for example - you car low fuel lamp lit, you enter gas station and get 40l of fuel in tank that can "hold" 40l (wait moment i have at last 5l in tank, how i can get 40l ?) , tank actualy can hold more fuel but filling it fully wery dangerus to do, this wil kill charcoal canister at last.
next time in same situation you enter another gas station our another fuel pump on same gas station and get only 35l.
Some gas station can fraud some ammount of fuel when driver filling tank to full, but when filling fixed ammount of fuel up to 10l you will get exactly wat you pay for.
Some have badly ajusted stopper on pump (so it can stop filling tank sonner or later)
The weights and measures legislation in your country must be particularly lax.
Sometimes our police checking gas stations, but gas station operators have now advanced tech to fraud only if someone fill full tank or more then 10l, if someone want to check accuracy of fuel pump at gas station uses special measurement 10l canister with temperature correction marks, so when someone filling only 10 liters program that used to fraud fuel not adding readings to pump meter.The weights and measures legislation in your country must be particularly lax.
...or maybe non-existent?
It is of course also possible that Roman has no idea that something like weights and measures legislation exists in his country...???
Sometimes our police checking gas stations, but gas station operators have now advanced tech to fraud only if someone fill full tank or more then 10l, if someone want to check accuracy of fuel pump at gas station uses special measurement 10l canister with temperature correction marks, so when someone filling only 10 liters program that used to fraud fuel not adding readings to pump meter.
And any complain about fuel tank capacity not working because they sais tank can hold more than specified......
The error on the fibometer seems to be quite closely related to the speedometer over read. Both over reading about 4/5%.I think the distance travelled part of the fuel consumption calculation is based on the odometer reading, not the speedometer. Speedometers read high to eliminate the legal defence of “But my speedo reading was only 70 your worship”!
Is the false calculation of petrol consumption perhaps based on a false reading of speed?
Remind me, why does the speedometer over read?
If the mpg reported by the fibometer was an unbiased best estimate based on measurements of fuel into engine and distance travelled then some people would see high mpgs, others low mpgs and many close to correct. However, no one has ever reported the fibometer reporting an mpg lower than the fuel into tank calculation so there must be built-in bias.Why is there a consistent variation?It must be designed that way. I think the measurement of fuel consumed is based on regular sampling and it’s clearly in the maker’s interests to err on the side of flattering the consumption, making us all feel better. I don’t suppose there are any regulations specifying accuracy as it is not a safety issue.
The error on the fibometer seems to be quite closely related to the speedometer over read. Both over reading about 4/5%.
Is the false calculation of petrol consumption perhaps based on a false reading of speed?
Remind me, why does the speedometer over read?
However, no one has ever reported the fibometer reporting an mpg lower than the fuel into tank calculation so there must be built-in bias.With my Mk1 I have experienced some regular incidences where the calculated mpg is higher than the "Fibometer". About 10-12% of the time, but always with exceptionally good mpg figures (60 mpg+).
And don't forget - manufactures mpg are lies - they aren't done in the real world.
And don't forget - manufactures mpg are lies - they aren't done in the real world.
That’s a bit harsh. Manufacturer’s figures are measured under precisely specified and controlled conditions in an attempt to ensure the figures are comparable across marques. The whole point of the mandated testing is to eliminate the kinds of factors you mention as much as possible to give consumers an objective comparison across brands and models. Of course they don’t represent real world consumption because of all those factors (to which one could add things like ambient temperature, hills, wind strength and direction etc, etc), but that doesn’t make them “lies”.
OK ColinB- maybe a bit harsh - but don't forget how there are several manufacturers that are being taken to court etc for "falsifying" test results to "improve" result - that his lying in my books.Again, a bit harsh and possibly incorrect. There has been plenty of publicity about falsifying emissions testing results (for example: https://en.wikipedia.org/wiki/Volkswagen_emissions_scandal), but I don't recall hearing anything about anyone falsifying the economy figures.
I do find the WLTP figures a lot more real world than the old NEDC figures. I think the combined figure for my car is 46.3 on WLTP and I get around 42 mpg but, to be fair, my usage isn't really balanced with the majority of my journeys being 3 to 5 miles.The WLTP is divided into 4 different sub-parts, each one with a different maximum speed:
EVs do have a problem with over promising and under delivering on a truly epic scale. Here WLTP seems some way from reality. The Honda E is a sub 100 miles car and yet, I think, the WLTP figure is about 135 - it's hard to imagine how perfect the conditions would have to be for a Honda E to attain that.WLTP for EVs suffers even more than with ICEs when power is needed for functions other than moving the vehicle. Heating / aircon is the biggest drain but lights / wipers etc all need power. EVs used on slow journeys will be using bigger proportion of the battery power for these other functions. An hour's worth of heating (for example) needs the same amount of electricity whether driving 10 miles or 50 miles.
Based on this and a bit of online research it now seems that EV's are totally unsuitable for longer journeys. If you can only fast charge once on a journey then the useable range is dramatically reduced.
Has this been hidden by EV makers or is this information only just being understood by the industry?
( Li-Ion actually like to be kept about 50% charged for longest life ).
( Li-Ion actually like to be kept about 50% charged for longest life ).
It's usually between 50% and 80%.