I did an economy run today to see what MPG my car can achieve. Just over 100 miles (Devon to Wiltshire), cruising at 70 MPH (slight traffic delay around Bristol) and I averaged 60.3MPG.
Now I usually average about 45mpg in day to day driving but I normally cruise at 80/85. Of course the 45 mpg average includes ALL driving. Cruising at 80/85, I'd get 50 ish mpg but that doesn't include cold starts, town driving, A roads, etc, hence the overall 45 mpg average.
Going back to the original question though, I don't know why I care. I have a fuel card that includes private mileage so why do I still want to max out economy from time to time?
PS - Car is a 520d Touring Auto. Total average mpg is worked brim to brim, the 100 miles was from trip computer HOWEVER over the past 3,000 miles I have used the hidden menu to apply a correction factor to the computer mpg reading. The computer reading is now always +/- 0.5 mpg from true brim to brim calculations.
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I've a trip computer in my Nissan, which I always reset at each tank fill. I also still do a manual check of miles and fuel consumed, indicating an error +/-10% in the trip computer.
I recently hired a Corsa in Spain and was surprised I couldn't match the fuel economy indicated on the trip computer achieved with cruise control over manual control.
I think they call it OCD.
SWMBO reckons all men are somewhere on the autism spectrum.
Perhaps Pat could offer her observations?
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I'm sure SWMBO is right, after all we always are.
Pat
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When I was financing my own high mileage vehicles I wasn't the least bit interested in the mpg calculation. Far more so though in the ppm ( pence per mile ) costs which of course included fuel but in addition took into account all other running costs such as maintenance, tyres, insurance, depreciation etc etc.
For example, if you do 40,000 miles ayear and the fuel costs you 15p a mile ( less VAT of course on the business miles ) you've spent a gross £6000 on fuel. However, you've probably also bought 6 tyres, ( £600- £900 ) knocked at least £3000, quite possibly more off the value of the vehicle, a few hundred quid on insurance and maybe 3 services. Then there's tax discs, repairs if required, financing the purchase or lease of the vehicle...
I used to reckon fuel was about half the overall real cost of running the car.
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Humps point is fair, having said that i'm very impressed with the fuel economy from a900ss's BMW, astonishing how frugal such a big car can be, albeit as some hefty initial cost.
Its too easy to get carried away with fuel figures alone though, how many times have we tried here to dissuade someone from spending several thousand pounds to change to an otherwise equivalent car that offers 10mpg better economy...according to the figures which few can match...they might well have to cover 50k+ to get the cost to change back and if used then its yet another gamble, one turbo/pump/injector problem puts them back 20k miles in cost terms let alone the headaches.
I was interested to see MADF's recent test drive of the Yaris Hybrid...he made little or no mention of fuel consumption figures, paying more attention to things that some car buyers amazingly never even consider before signing, servicing and tyre costs, and wrote more about the cars driveability, one of the most sensible vehicle appraisals i've ever seen.
The important thing is to get a vehicle that does what you want, is nice to drive, reliable and durable with fair running and all other costs, not get too carried away with fuel figures alone.
Economy runs can be fun though, sometimes when in the right frame of mind i will do the same with lorries, its always satisfying to wipe the floor with the figures produced by a computer controlled automated manaul box by overriding it and driving the vehicle with best progress in the right gear at every moment.
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>>Economy runs can be fun though
Getting an extra 10-15mpg by sitting 30 yards behind an HGV at an indicated 60mph is great.
The extra stonechips are the price you pay :-)
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Even on the occasions when I really couldn't afford to waste money I never could justify wasting time by driving slowly either. Wasn't making money while driving. My view was to choose a car which was economical enough for the purpose without having to think about driving it too carefully.
A guy I know, who also needs to use his car a lot, has an oldish BMW 7 series petrol but drives it everywhere at no more than 60mph. Go figure that one, I can't...
:-)
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Humph, I totally agree.
I normally drive at 80/85 and go with the flow. 45mpg is fine. 60mpg is ridiculous, admittedly that was just motorway at a constant speed.
I have a fuel card so I benefit from no financial savings.
I think an earlier poster is correct, I just have an OCD. Still, I know what it can do now so back to normal for me.
PS - this is the link to the actual trip computer run.
flic.kr/p/deS4BP
Last edited by: a900ss on Sat 29 Sep 12 at 11:48
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>> I normally drive at 80/85 ...........
Whatever misdemeanor will you be telling us you habitually commit next? At least when I was caught doing 37 mph I hung my head in shame.
Last edited by: L'escargot on Sat 29 Sep 12 at 14:28
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>> >> I normally drive at 80/85 ...........
>>
>> Whatever misdemeanor will you be telling us you habitually commit next? At least when I
>> was caught doing 37 mph I hung my head in shame.
>>
At no point in the thread do I state I am breaking the law. You have made the jump from 80/85 to 80/85 mph.....
;-)
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>> At no point in the thread do I state I am breaking the law. You
>> have made the jump from 80/85 to 80/85 mph.....
I should have realised it was either feet per second or kilometres per hour.
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I thought I'd seen this thread elsewhere. :-)
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>> Its too easy to get carried away with fuel figures alone though, how many times
>> have we tried here to dissuade someone from spending several thousand pounds to change to
>>
>> The important thing is to get a vehicle that does what you want, is nice
>> to drive, reliable and durable with fair running and all other costs, not get too
>> carried away with fuel figures alone.
>>
>
There is a simple equation:
Car life is approx 100,000 miles : 10 years at 10k miles pa.
Assume 40 mpg - range 30 to 50: So fuel used: 3,333 to 2,500 gallons.
At say £6.25 /gallon £20,830 to to £15,625.
Assume capital cost is £15,000 to £30,000 Depreciation over years 1-3 = 50% or £7,500 to £15,000
The depreciation charge over the first three years is equal to exceeds the fuel bill over half the car life.
So fuel costs are not the main factor in running costs of a new car.
Of course if you keep a new car for 20 years the above is irrelevant.. but the percentage of owners who do so must be very low. probably less than 1%..
And if you buy a banger for £1,000, and do 10,000 miles a year, they are very relevant..
Most cost analysis of motoring is written by people whose understanding of simple sums is zilch or those with an axe to grind...
The Americans have it right...
NEW YORK (CNNMoney.com) -- By keeping your car for 15 years, or 225,000 miles of driving, you could save nearly $31,000, according to Consumer Reports magazine. That's compared to the cost of buying an identical model every five years, which is roughly the rate at which most car owners trade in their vehicles
money.cnn.com/2007/08/30/autos/cr_drive_200k/index.htm
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I never give a monkey's about the fuel economy. My time is more important to me than whatever the savings would be on driving more slowly.
I do use the diesel car in our family, if a longer journey is needed, so i'm not totally blase about the costs, but once i'm up and running I often use a fair degree of the performance of the car (when safe to do so).
When it gets low on fuel, I fill it up. That's it. I have no idea on what it costs per litre.
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Wise words WP, wise words.
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Same principle on using a toll road.
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Toll roads?, ah no can't agree with that.
Fairly charged and signed yes thats fine you pays your money and makes your choice, but when car drivers are charged half the rate of a 44 tonner, and as for signing, er shall we say misleading, no thanks only when absolutely necessary.
Unless i'm on ex's like..;)
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BMW - Why do I do these economy runs? - bathtub tom
