Fuel consumption

Have I got this right I have a citreon berlingo multispace,

Milage at last fill up 32525
at previous - 31882
Milage 643

Liters filled 36.79
devide by 4.5 = 8.17 galls

643 miles devied 8.17galls =78.70 mile per gall

 

Your litres to UK gallons measure is a little bit out. There are 4.546 litres in a gallon.

So, 36.79 / 4.546 = 8.09 gallons.

643 / 8.09 = 79.48 mpg. So actually slightly better than you thought.

However, and this is a big however. There can be quite a difference between fill-ups, as different pumps cut out at different back pressures (ie some think your tank is full when it isn't), and of course you wont have run it dry, so lets say you had 3 gallons left at the previous fill up, but only a gallon left at the last fill up, then that's going to make quite a difference.

Add to that the fact that engines behave differently in different weather conditions, different road surface conditions, different vehicle load, different tyre pressures, and of course different routes and driving styles. So, your mpg figure is impressive as a ball park figure, but if you want to calculate the actual average mpg for your driving style and your vehicle, you need to work it out over several fill ups.

If you want to track it effectively without having to do the sums, have a look at fuelly.
https://www.fuelly.com/

No matter what the actually final figure though, I can tell you it is impressive, and I'm quite jealous, as I get an average of a whopping 23mpg out of dear old Gothilda.

 

I still cant belive the figure even after doing the sums three times and still getting the same answer I will keep a check on the next fill ups to see what happens , Have checked out fuelly .com

 

The only way to prove it is to BRIM fill it, so you can actually see the top of the fuel in the filler, or what C1 said back pressure on filling, and different pumps etc occurs

Jack McH

 

I always fill up with £50 each time at 3/4 empty so all the time the price stays it will be 36.79 ltrs until the next price hyke that is . so I was only calulating on the fuel I had actually put in the tank , should I run the tank almost empty then refill to get a true reading

 

Is this result similar to previous or have you never worked it out before. I run a Berlingo van and round the houses regularly get 54mpg and on a long run about 65mpg. Your figures if correct will give me something to aim for.

 

This is the first time I have worked this out thats why I posted as I was surprised I will keep a note and work out after a few more fillups . I as i said i always fill up at around the 3/4 empty mark and always put in exactly £50.00 and zero the mile counter although I havent really taken note of the milage when zeroed its always around the 600 mark

 

Another thing to bear in mind is that odometers are notoriously inaccurate. You might be doing less miles (or indeed more) than you think. To check the accuracy of your mileage readings, you could use a satnav. I don't know about nowadays, but certainly a few years back french motors were known for the innacuracy of their instruments. I once had a renault motor, and one day I was driving through a village, doing 30mph according to my speedo, when my gut said I was going faster than that, so I eased off the throttle a bit, and then the speedo needle jumped instantly to 50mph. I've know a few people with french motors where the instruments decided to take a break from reading anything at all.

If you're getting significantly higher mpg than you expect, it might be worth using a combo of satnav for accurate mileage, and fuelly for accurate fuel use tracking etc, but also check your tyres are not over inflated. If the car has been in the tyre shop recently, you might find they're pumped up to about 50psi. Half the time they just stick the compressor on them and don't bother to check the pressure before giving you it back. Over inflated tyres will give you a significant saving in fuel, but will give you brown underwear if you have to slam on at high speed.

 

They say that to calculate fuel consumption figures you should fill up at exactly the same pump the second time - so if the car is on a slight slope etc. that the level in the tank will be compensating the same both times.

Make sure the pump nozzle is inserted all the way in, and fill up until the pump cuts out. Don't "top it off", just stop when it cuts out. The idea is that the exact same pump, next time, should cut out at the same point of "tank fullness" as last time.

Then record the mileage between the two fill-ups. If you need to fill up elsewhere in between the two "same pump fill-ups" that's fine, just add the litres purchases to the "total fuel used", but the mileage travelled should only be recorded when you next fill up at the original pump.

Then you have the issue of whether your odometers is accurate, as C1 said ...

Google will calculate it for you (if that helps ) as follows:

(32525 miles - 31882 miles) / 36.79 litres in miles per imperial gallon =

 

Quick question: is £25 a week on petrol for an 05 Scenic bad or average?

 

Depends on how many miles you drive?

Only alternative is that you move closer to your work isn't it? But maybe I'm missing the point? ...

... I am a cheat as I work from home so my commute is both zero cost and, to me more importantly, zero time

 

About 60 miles a week on average.

 

So £25 for 60 miles? Sounds a lot to me??

Average Petrol price currently 130.01p (136.15p for Diesel) so £25 would be 19 litres or 4.25 gallons.
http://www.petrolprices.com/

60 miles on 4.25 gallons is 14 mpg ... perhaps you are driving most of the way in bumper-to-bumper rush hour traffic?

 

Aye pretty much bumper to bumper, 8.4 miles to work and back. The dash says about 33mpg but I've never believed it.

 

That sounds like the culprit then. Bummer :(

I only believe mine as a "comparative" tool to see if one trip, or one driving style, is better than another.

Don't suppose you can go to work at a less congested time? My wife leaves at Sparrow, gets to work in half the time it would take at rush-hour, and has done most of a day's work by the time that the World is at their desks. Dunno whether that would enable you to knock off early instead? You'd be in the garden tinkering / enjoying it by mid afternoon

As for me, working from home, I try to knock off at 5pm, or earlier, this time of the year and am out in the garden until 8pm so I get 3 hours work a day done - which would, otherwise, be my commuting time I reckon ...