Fuel cost per mile.

[john.wigley]

Originally Posted by J liddy

My Diesel 940 is only returning 30 mpg on average daily driving local.how does this calculate my driving costs ?comments most welcomed!

I'm not sure that I fully understand the point of your question, 'J liddy'.

For what it is worth, my own approach is to break my motoring costs down into four categories; viz: Fixed (Tax, Insurance, MOT), Servicing, Repairs and replacements (Tyres, Battery, etc.) as well as Fuel of course.

By recording these on a spreadsheet, I can analyse and plot the results as required. I look for trends, which can indicate potential problems, rather than absolutes, which are useful mainly as a snapshot in time, for example, a holiday trip.

Interestingly (for me, at least) there seems to be a Pareto effect at work in my figures. When I was working, fuel costs amounted to 80% of my total motoring expenditure; now, they represent only 20%. Not all motoring costs vary with mileage but are now amortised over a much lower mileage. This, in turn, leads to a much higher cost per mile travelled. I won't frighten you with the actual figures, but it would probably be cheaper for me to take a taxi everywhere!

Regards, John.

[john.wigley]

Then there is the cost of depreciation, or, if one is lucky or bought wisely, appreciation, of course. This is probably of more interest to owners of more expensive cars than a £500 V70, but the way I treat this is to take the purchase price, subtract the sale price, giving the cost of ownership. Divide this figure by the period owned or the miles covered to give the depreciation per year or cost per mile respectively. Remember, this could be a negative figure if you are selling at a profit.

This is not the total cost of ownership, of course. One must add in lost interest on the capital employed, or, if one has taken on a loan, factor in the interest charged. In this way, it is possible to arrive at a total cost per mile at the point of sale by adding this cost to the cost of operation calculated above.

Remember that your car is still costing you money even when it is standing idle on your drive - a lot of people overlook that!

You may think that I am mad - that's fine - but I do derive a strange fascination in accurately calculating the true cost of my motoring.

Regards, John.

[J liddy]

Thanks for all your thoughts .I'm
thinking my 1995 940 tic auto is still good value .its not worth a lot .but road tax will be £325 in April. Insurance is about £250 .I can still do a lot of maintenance myself except cambelt . .ie brakes .oil changes. Fuel line. If and when they fail . I swopped radiator 10 years ago .changed vacum pump and cold start device and.wheel bearings lots of little jobs

[Chris1Roll]

Since I have no trip counter button and the fuel guage is intermittent I have to write down the Odometer reading each fill up so I don't forget to fil up every ~200-250 miles.
I got a little black notebook for that so I decided I might as well also work out and write down the mpg every fill up too

The lowest I've seen is 18.9, just once when just driving in town.
Highest just over 29 last weekend on the Rustival trip, mix of M5 and free flowing roads.
Average is probably about 24.

B200E Auto, only running Super/E5, almost exclusively from the same shell garage every time on the way to town.


Rustival trip was pretty much bang on 250 miles, and the fill up cost £63.25 = 25p/mile.

IF (Big if) your fuel is the same cost/litre, then you are getting about 14-15mpg, and I'd be thinking that needed looking into.

[Offgrid]

Once again, there is a lot of useful info in the replies, and I'm grateful to you guys for expanding my knowledge of Volvo redblocks.

Particular thanks to Forrest for his (probably) apposite reply. I've noticed that the hot idle has increased from 850rpm to around 1300rpm, so there may be a sensor giving a false reading that is not confirmed by the temperature gauge.

John Wigley - You must be psychic, as I decided to keep a log of my petrol purchases against mileage about an hour befor I read your post.

I think I paid about 152 pence for E5, and I got double Nectar points with it. The car seems to prefer E5 over E10, so once again I am resisting UK government recommendations. I'd prefer the land to be used to farm healthy beef, rather than creating fake petrol to the detriment of the environment.

I'm checking the fuel consumption from full tank to full tank. I forgot to reset the odometer last time, so I will have to start a log after the next refill.

Have I got the only 740 with a working odometer? Cinders needs a new gear wheel to divulge her secrets.

[baggy798]

Originally Posted by J liddy

My Diesel 940 is only returning 30 mpg on average daily driving local.how does this calculate my driving costs ?comments most welcomed!

That's about 23p per mile. A modern small city car like a Toyota Aygo will be around 14-17p per mile.