MPG!! Why not litres per 100 Miles??!!

[grober]

There is a fundamental difference MPG is a distance that can be travelled by a fixed volume of fuel ----- litres per 100kilometers is the volume of fuel used to travel a fixed distance. Different variables for fixed constants. In these days of instantaneous fuel consumption readouts, fantasy land manufacturer fuel consumption figures , and high cost of fuel I reckon most people measure their fuel consumption by (a) the cost to fill the tank and (b) how often they have to fill it --- you notice neither distance travelled or fuel volume used are employed in this calculation.

 

[markjay]

Incidentally.... fuel should be sold - and consumption calculation - based on mass, not volume.

Fuel expands with temperatures - and its volumes increases. Or, on other words, for the same fuel volume you will get more fuel mass on a cold day than on a hot day.

The energy you get from fuel depends on it caloric value, which in turn depends on it mass. On a cold day your fiver paid for fuel will buy more energy (and more miles) than it would on a hot day.

If you are tight - fill-up at 4am, and don't brim it, to allow space for the fuel to expand later on when it gets warmer...

 

[boxbrownie]

Incidentally.... fuel should be sold - and consumption calculation - based on mass, not volume.

Fuel expands with temperatures - and its volumes increases. Or, on other words, for the same fuel volume you will get more fuel mass on a cold day than on a hot day.

The energy you get from fuel depends on it caloric value, which in turn depends on it mass. On a cold day your fiver paid for fuel will buy more energy (and more miles) than it would on a hot day.

If you are tight - fill-up at 4am, and don't brim it, to allow space for the fuel to expand later on when it gets warmer...

Apparently not, fuel is normally (almost universally) stored underground where the the temperature is pretty much consistent all year around.

So whenever you fill up you will get the same amount, but your correct about the cold fuel/hot day.......or were a few years a go, now manufacturers test for that very eventuality (after a few incidents in the US) and there is "expansion" room in the tank capacity, of course that will not rule out the odd idiot who stands there for 30 minutes filling up to the neck when the pump and fill system have warned him so many times by auto cutting, they just keep squeezing it in

 

[Dieselman]

Then even bigger descrepancy is why describe MPG at all when the type of fuel is so diverse eg petrol is now far far far cheaper than diesel - this wasnt a factor when MPG was invented but now its huuuuuuuuuge factor thats completely ignored in this calculation


"Price per mile" is also intuative information language that anybody could use/adopt very quickly whether they are 17 with the brains of a toad or 65 with 40 years of "mpg" drummed in

So "Price per mile" is optimum calculation to compare like with like, absolute running cost and *intuative* information that anyone will understand

2/Deisel is x times more expensive than petrol

I know Renault 12ts has already covered this, but I would be really interested in your opinion on what is a huuuuuuge discrepancy in the cost of petrol and diesel.

Price per mile is great for keeping track of how much a particular car costs in fuel, but useless as a comparison because there is a variable part...the price per unit of fuel, for the same fuel.

 

[boxbrownie]

I know Renault 12ts has already covered this, but I would be really interested in your opinion on what is a huuuuuuge discrepancy in the cost of petrol and diesel.

Price per mile is great for keeping track of how much a particular car costs in fuel, but useless as a comparison because there is a variable part...the price per unit of fuel, for the same fuel.

Not only that, what happens with the in car fuel computer if it reads cost per mile, every time you fill up you would have to input the fuel cost per litre.

 

[markjay]

Apparently not, fuel is normally (almost universally) stored underground where the the temperature is pretty much consistent all year around.

So whenever you fill up you will get the same amount, but your correct about the cold fuel/hot day.......or were a few years a go, now manufacturers test for that very eventuality (after a few incidents in the US) and there is "expansion" room in the tank capacity, of course that will not rule out the odd idiot who stands there for 30 minutes filling up to the neck when the pump and fill system have warned him so many times by auto cutting, they just keep squeezing it in

While you may have a point that if fuel is stored underground at constant temperature it will cost the same filling-up on a cold ot hot day.... the mpg you get from the fuel once in your tank will still vary according to ambient temperature. That is miles per gallon-in-your-tank, not miles per gallon-at-the-pump.

 

[scumbag]

C or F anyone

 

[Dieselman]

C please Bob.

 

[boxbrownie]

While you may have a point that if fuel is stored underground at constant temperature it will cost the same filling-up on a cold ot hot day.... the mpg you get from the fuel once in your tank will still vary according to ambient temperature. That is miles per gallon-in-your-tank, not miles per gallon-at-the-pump.

I do, your correct.

 

[boxbrownie]

C or F anyone

I'll have a K please Bob.....

 

[scumbag]

I'll have a K please Bob.....

0 it is then.

 

[Palfrem]

I prefer Furlongs per quart

 

[Troon]

Fuel consumption is best measured in picoacres.

It’s volume divided by distance, which is an area. 40 mpg is about 17 picoacres.

That’s the cross-sectional area of a “wire of fuel” that the vehicle is conceptually eating as it goes along.

Surprisingly, 17 picoacres is only 0.07mm².

 

[219]

Figures are usually quoted in mpg and in litres per 100 kilometre so you have a choice, and this really defeats your argument. Im pretty ocd with figures like mpg, but generally use miles per litre and convert. However some people make remarks like they use 20 pounds worth of fuel a week,

I generally use around £20 worth a day , before I go anywhere more than just to work and back .

It seems hardly worth having a car if you are going to do less since you could just as easily walk , train or cycle the few miles a day that would be involved .

 

[219]

I don't think an average of 5p per litre cheaper could by any stretch be described as "far far far cheaper than diesel". Diesel is about 3% more expensive...but diesel mpg (or litres/100km) tends to provide in excess of 20% better consumption.

The difference has closed over the last few months since I last bought , or looked at the price of , Diesel .

Petrol seems to have remained at around £1.27/litre , while Diesel has dropped from around £1.39 to around £1.35 locally , with a few places asking as high as £1.46 ! Prices courtesy of Petrol Prices Pro app on my iPhone for a 5 mile radius around my current location in Hamilton . I generally check the app whenever I need petrol and go to the cheapest place nearby .

 

[geraldrobins]

I generally use around £20 worth a day , before I go anywhere more than just to work and back .

It seems hardly worth having a car if you are going to do less since you could just as easily walk , train or cycle the few miles a day that would be involved .

It was just a for instance of how some people refer to their costs. Would you prefer it if I said £50 per week. £100????
£20 would take me over 180 miles but a bit far to walk.

 

[Dieselman]

I generally use around £20 worth a day , before I go anywhere more than just to work and back .

It seems hardly worth having a car if you are going to do less since you could just as easily walk , train or cycle the few miles a day that would be involved .

3.35 gallons at say, 30mpg in a petrol. Do you really drive 100 miles per day going to work?
That's 25,000 miles per year commuting...and you still opt for a petrol car...

 

[renault12ts]

The difference has closed over the last few months since I last bought , or looked at the price of , Diesel .

Petrol seems to have remained at around £1.27/litre , while Diesel has dropped from around £1.39 to around £1.35 locally , with a few places asking as high as £1.46 ! Prices courtesy of Petrol Prices Pro app on my iPhone for a 5 mile radius around my current location in Hamilton . I generally check the app whenever I need petrol and go to the cheapest place nearby .

Today, in Belfast, the difference is about 3p a litre.

 

[Dieselman]

4p/l here.

 

[flango]

3.35 gallons at say, 30mpg in a petrol. Do you really drive 100 miles per day going to work? That's 25,000 miles per year commuting...and you still opt for a petrol car...

I'm going back to a V8 for my daily driver and cover 20,000 a year, that's from my Volvo who's long term 3 year average is 52 mpg Life's too short

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