Petrol Consumption.

[dwil]

If a car uses £20 petrol doing 100 miles of daily runs to shops, work etc what would you expect the cost to be doing 100 miles straight motorway run at 70mph?

[bhg481]

I'd guess around £12-15

[Old_Geezer]

I doubt there is an easy conversion from town to motorway consumption. It depends how you drive. Check what the manufacturers claim then add say a fifth more fuel for real world consumption, would be my guess.

[dwil]

Thanks both

[Gizmonster]

A few factors to take into account are age of car; mileage of car; engine size; driving style .... prob a few more as well, but here's my take on things:

Assuming £1.15 per litre = £5.23 per gallon.
£20 = 3.83 gallons.
100 miles = approx 26 mpg.

At 70 mph, I would hope to get 40 mpg (poss more??)
40 mpg for 100 miles = 2.5 gallons used.
2.5 x £5.23 = £13.08
........ which is well within what bhg481 said :)

[mikey4444]

This question is non-sensible. It would depend on how much petrol is being used, not how much each gallon costs.

[bhg481]

Mikey - you know how much fuel is being used - it's £20 worth.
I was working on the assumption that you'd get around 50% more mpg, hence the fuel used would be about 2/3 of normal usage and cost around 2/3 of £20.

[mikey4444]

bhg....in order to answer this question, we would need to know what the MPG was for that initial £20 of petrol. I agree that what you have said is probably roughly accurate, but until we know what that MPG is, we will never have a totally accurate answer.

[naomi24]

Mikey, the OP has told you he's doing 100 miles on £20 worth of petrol and Gizmonster has estimated that to equate to approx 26 mpg. It's a sensible question.

[bhg481]

You'll never get a totally accurate answer Mikey because you don't know by how much the fuel consumption will change with the change in driving conditions. Judging by my own car I would guess the 50% better fuel consumption figure which gives a 1/3 reduction in fuel cost.
Since fuel costs around £5 a gallon he's getting around 25mpg around town, so a largish car. I guess that would become around 30-35 mpg on a run so allowed me to estimate £12-15. A small car might not have such an improvement; it might even get worse, as small cars are often designed for town use.

[mikey4444]

BHG....sorry but this is like someone saying that they are getting better fuel consumption from their new car than their old, as they can drive farther on a full tank of fuel, while not telling us what what the capacity of both fuel tanks were ! I get that told me many times.

[naomi24]

The capacity of the fuel tank is irrelevant.

[david small]

£15.34.

[bhg481]

Look at the fuel consumption figures for any new car. The actual values are irrelevant but most cars have an improvement in fuel consumption on the extra-urban cycle over the urban cycle and this is what we're estimating. dwil normally messes about in his car, doing lots of cold starts and short trips and he's planning to do a longer trip and trying to get a rough idea of how much it's going to cost.

[mikey4444]

I am sure that dwil wasn't asking for a rough estimate, but a more accurate answer.