how many mpg?

VoucherMan

Best reply so far on the MPG issue from custardy on the duplicate thread (IMO)

pompeyrich

sebdangerfield wrote: »

But he doesn't. And he didn't. He's done it the proper way, work out how much fuel it used to do x amount of miles. Not, as you make out, estimate how much fuel the tank holds then use that to work out the MPG, wholly inaccurate. He said;



He hasn't used the light as a point of reference, he's just filled it up when the light's come on. i.e from an almost empty tank, then filled it up some more for a long journey and added the amount of fuel put into the vehicle together, there's no guessing when the light comes on involved. That bit where he said he did a refuel mid way for a long journey should prove that. He put in a total of 65 litres, that's the point of reference. The light's got nothing to do with it.

Sorry to be petty but the OP stated "My car doesn't have a button that tells you the mpg when you are driving so I have filled it up from when the red light came on and checked the mileage when the light came on again." This says to me that they are using the light, the 2nd time, to determine that the tank is at the same level it was before they filled up, this may or may not be accurate. OK probably good enough for a ball park figure but not a guarantee.

sebdangerfield

How do you account for the fact the op said he filled up the car for a second time in between the fuel lights comming on?

I had to do a refuel mid-count due to a long journey but the figures I have are:

hence, he won't be able to estimate fuel used on when the light came on as he filled it again in between. He said 65 liters did 450 miles. I think it's a bit rude of you to simply assume the op's guessed this figure from a figure he came up with by working out when lights come on and tank size when there are calibrated pumps at stations that can tell you how much fuel you've put in. Simply, don't assume the op's too unintelligent to work out how much fuel he filled his car with!

cyclonebri1

The only really accurate way;

Brim it, note mileage

Use it

Brim it again when needed

Use it again.

Ad infinitum

But the last time you brim it note the mileage.

Take note of all the fuel used after the 1st brim untill the last brim.

Do the calc based on distance driven and fuel consumed and Bobs your doodah assuming the fuel rate hasn't tripled in the meantime



Alternatively just give in to the oil barrons, the government, whatever compound it maybe, pay up and get on with the rest of your life :T:T

pompeyrich

sebdangerfield wrote: »

How do you account for the fact the op said he filled up the car for a second time in between the fuel lights comming on?



hence, he won't be able to estimate fuel used on when the light came on as he filled it again in between. He said 65 liters did 450 miles. I think it's a bit rude of you to simply assume the op's guessed this figure from a figure he came up with by working out when lights come on and tank size when there are calibrated pumps at stations that can tell you how much fuel you've put in. Simply, don't assume the op's too unintelligent to work out how much fuel he filled his car with!

I'm simply pointing out that the low fuel light is NOT a calibrated device and it might have come on earlier or later than it did the 1st time and is therefore not an accurate method of determining how much of the 65 litres of fuel was used.

At no point did I question the ops intelligence and cant understand why you think I did.

Fairwinds

sebdangerfield wrote: »

How do you account for the fact the op said he filled up the car for a second time in between the fuel lights comming on?



hence, he won't be able to estimate fuel used on when the light came on as he filled it again in between. He said 65 liters did 450 miles. I think it's a bit rude of you to simply assume the op's guessed this figure from a figure he came up with by working out when lights come on and tank size when there are calibrated pumps at stations that can tell you how much fuel you've put in. Simply, don't assume the op's too unintelligent to work out how much fuel he filled his car with!

Must agree with pompeyrich on this one as you DO need a point of reference, otherwise you don't know how much fuel you have used. Using the red light is an attempt to determine that the tank contains the same amount on each occasion.

They can fill up in between as many times as they like, but they need to know how much fuel they have used over that period - which they don't if the tank contains a different amount on the final occasion

sebdangerfield

pompeyrich wrote: »

I'm simply pointing out that the low fuel light is NOT a calibrated device and it might have come on earlier or later than it did the 1st time and is therefore not an accurate method of determining how much of the 65 litres of fuel was used.

At no point did I question the ops intelligence and cant understand why you think I did.

Its not about determining how much of the 65 liters were used! He used all of them, the point is, the pump tells us how much fuel we've put in the car! Filling to the brim is the point of reference.

sebdangerfield

GordonD wrote: »

Must agree with pompeyrich on this one as you DO need a point of reference, otherwise you don't know how much fuel you have used. Using the red light is an attempt to determine that the tank contains the same amount on each occasion.

They can fill up in between as many times as they like, but they need to know how much fuel they have used over that period - which they don't if the tank contains a different amount on the final occasion

And if you read back through the posts you'll see that I also say you DO need a point of reference. If we don't have a point of reference, we don't have a sum to do in the first place do we? I think we can all agree we need a point of reference but thatks anyway! The way to determin the tank contains the same on each occasion is to brim it. It's the only accurate way to determin that the tank's got the same amount of fuel in it. It's simple maths that in this context people seem to totally fail to grasp! The fuel light just doesn't come into it.

pompeyrich

sebdangerfield wrote: »

And if you read back through the posts you'll see that I also say you DO need a point of reference. If we don't have a point of reference, we don't have a sum to do in the first place do we? I think we can all agree we need a point of reference but thatks anyway! The way to determin the tank contains the same on each occasion is to brim it. It's the only accurate way to determin that the tank's got the same amount of fuel in it. It's simple maths that in this context people seem to totally fail to grasp! The fuel light just doesn't come into it.

This is hard work, its you that hasn't grasped it, I agree that full to full is the easiest, most accurate way to calculate consumption. The op had used their fuel light coming on as their indicator that the fuel level was back to where it was 65 litres previously. You keep on that the fuel light doesnt come into it when it clearly does in the ops case, as that is their start/finish point.

ali-t

sebdangerfield wrote: »

But he doesn't. And he didn't. He's done it the proper way, work out how much fuel it used to do x amount of miles.

Oi sebdangerfield, he's a she!