I am frequently amused by owners who are apparently sufficiently interested in their fuel consumption to post on here about it, sometimes at great length, but never seem to be suffciently interested to ever actually measure it!

I certainly wouldn't rely on my dashboard computer.  This indicates that on most of my journeys the fuel consumption is apparently 50mpg or very close to it.  But measuring the actual consumption, by simply noting the mileage and the fuel put in at each fill-up, shows that the real fuel consumption is very different - around 42mpg.

For the record, my overall fuel consumption over nearly 2,700 miles averages out at 41.8mpg.  However a more useful statistic than any "average" are the 25-percentile figures of 41.3 and 42.9mpg.  In other words, a quarter of the time it does worse than 41.3 mpg and a quarter of the time it does better than 42.9 mpg, so that most of the time the consumption is between 41 and 43mpg.

I find this the clearest and simplest way of indicating what both the fuel consuption normally is, and the extent to which it can and does vary.

As for miles-per-tankful nonsense (what is "a tankful"?), my fill-ups have variously been at 428/280/281/420/275/357/345 miles.  Simply because if I am passing an exceptionally cheap filling station and am less than half-full (or sometimes less than  three-quarters full) I take advantage of it.  That saves far more money than fussing about differences of 0,01mpg in fuel economy!  
   




  

I use fuelly. Plots it all down for me for very little effort.

Not sure I care about getting the MPG up, but it's an interesting stat all the same.

Never really compared what the car 'thinks' it's doing, will have a nose next time.

Sometimes play the how many MPG can I get on the journey today game, but always get giddy coming off roundabouts which drops me a few MPG each time - but it's fun!

My computer reads lower than I ever get. I love to talk about how economical my car is, I enjoy it. However, average MPG doesn't interest me. I care about long journeys, nothing else. Town driving is a necessity and I see no point in measuring it. It's low and awful, like most cars.

If you fill up when you're half a tank down, how does lugging that extra 20Kg of fuel around, compared with letting it get right down low, affect you mpg?

All I know is when I stick £70 in I can get around 460 miles before its pretty empty.

That's on the journey from Brum to Carlisle and back with a bit of running around in between.

Not sure what that is in MPG on a 06 2.0TFSI, but I'm happy paying that price for the journey to take 2 adults and 2 kids with luggage.

Maxidot says about 40mpg but I've never worked it out.

Edited 22 April, 201412 yr by vrs777

Do you have any figures for how much the weight of fuel (as distinct from the weight of the driver, passengers, spare wheel and the car itself) affects the fuel consumption?  Or the difference between a fat driver or a thin one?

No, me niether.  But it is very unlikely indeed to be anywhere near the 5% or more difference between cheap filling stations and expensive ones.  And remember, we're only talking about the weight of 1/4 of a tankful at the most - the difference between the average contents if you only fill up when empty as distinct from filling up when half-empty.  

... Town driving is a necessity and I see no point in measuring it. It's low and awful, like most cars.

.

Oddly enough, my car is far more economical round town than on the open road.  Speed seems to be the principal factor, more than driving in traffic.  And this is worth knowing, since I have a choice of cars to use for different types of journey.

But that is according to my dashboard computer, so imay be complete nonsense.  I was shocked how useless and inaccurate the computer on my Octavia was when I actually cheacked my real fuel consumption.

The excellent little ScanGauge which I have fitted to my Mazda MX-5 is far more accurate.

 

Edited 22 April, 201412 yr by Stuarted

I anally retentively "brimmed" der Galaxy and noted fuel bought over a few thou miles of mixed driving.

Calculating my mpg per fill, and also ongoing cumulative average.

And comparing these figures to the Trip1 and Trip2 figs.

And checked milometer/distance against Motorway marker posts.

(But I did not actually check the accuracy of the filling station pump.)

Regardless, within about 2.5% (optimistic.

So I then simply trusted the trip computer, and deducted a 1/4 of 10% from the read out.

13 years later, repeated the exercise with the Octavia.

An optimistic error of about 2.7%

Yawn.

Trust the technology.

Edited 22 April, 201412 yr by dieseldogg

 

... Trust the technology.

.

Why?  Dashboard computer says most trips = approx 50mpg.  Measurement of actual fuel used shows real fuel consumption = 42mpg.

 

Trust the technology.

 

I wouldn't.

 

I own 2 Skodas and both have/had significant errors in the dash fuel consumption readout. My octavia over read by nearly 10% (I've now corrected this with VCDS) and my Fabia under reads by about 6.5%. A friend had a MK5 Golf that was out by more than my Octavia before he corrected it.

 

By all means use the MPG readout to modify driving style to the benefit of economy, but don't trust it!     

Mine's got 52k on the clock now and the Maxidot tells me that its getting better fuel economy now - this is also born out by the miles to a tankful increasing (i.e. completely full to when the fuel light comes on) - so this is all good. More importantly (IMHO), it still puts a smile on my face when I drive it!!!!!!! Ah, the simple pleasures................

Mine's got 52k on the clock now and the Maxidot tells me that its getting better fuel economy now - this is also born out by the miles to a tankful increasing (i.e. completely full to when the fuel light comes on) - so this is all good. More importantly (IMHO), it still puts a smile on my face when I drive it!!!!!!! Ah, the simple pleasures................

.

So - what is your fuel consumption? 

Edited 22 April, 201412 yr by Stuarted

MPG don't bother me, I do less tan 3K a year, I run my Petrol Vrs only on Shell V power and have great pleasure trying to get the MPG into the low teens or even single figures. ( with engine up to temperature )

MPG don't bother me, I do less tan 3K a year, I run my Petrol Vrs only on Shell V power and havre great pleasure trying to get the MPG into the low teens or even single figures. ( with engine up to temperature )

.

Fair enough!  Can't argue with that - it's a consistent and logical philosophy.

The  people who intrigue me however are the ones who discuss and take all the trouble to post about their fuel consumption on a forum like this, but couldn't be bothered ever to actually measure it!  Dur ...

 

Edited 22 April, 201412 yr by Stuarted

The sceptical side of me (the dominant one!) believes the on board computers are purposely set to read high by the manufacturers to con the lazy into thinking they are getting better mpg figures than they actually are. There's a significant number of motorists that don't even look to see what they are paying for their fuel in the first place, so can't see them taking the trouble to see if their car is having them on or not.

anyway mine told me I got 58.2mpg when I went to Milton Keynes and back last week. Hmm mm mm..........zzzzzz zzzzz

if you got a vrs with an oil burner in it and sit glued to the mpg read out you got the wrong car.

I hear the greenline is quite good on juice.

Me? I like hot summers and cold winters. I do my bit by running thirstyish petrols, safe in the knowledge they are nicer to drive and may help me get a better tan in the UK during the summer months :-)

I always seem to trust the posters that say their diesel is doing 35-45mpg and can't get near the uber high average 50+ lot. I think it is simply because of the self human trait of trying to justify why, that make people over hype things. People buy a diesel to save money no ifs no buts. The fact that on the board currently I am still seeing DPF faults on CR's etc which if the cost is factored in would mean another 10k of driving to make up makes me confused with some owners.

You see the real evidence on car magazines etc with there fuel returns etc. An example is the supposedly super efficient BMW engines even they are getting around the 40mpg mark in daily use............but they don't have to hype their mpg......just report the reality.

Don't get me wrong, I recently sat on the A1 in a 1.6 diesel Kia Ceed at 70mph on cruise at 4am with just the odd lorry and got 62mpg ! But by eck if some of you are driving like that in a diesel.......life will be over before you realise it :(

if you got a vrs with an oil burner in it and sit glued to the mpg read out you got the wrong car.

I hear the greenline is quite good on juice.

Me? I like hot summers and cold winters. I do my bit by running thirstyish petrols, safe in the knowledge they are nicer to drive and may help me get a better tan in the UK during the summer months :-)

Thanks for the advice, but I'll stick with what I've got. I only looked at the readout when I got back home and switched the Amundsen satnav off which made me laugh as I'd been making progress throughout my journey and don't as you suggest sit glued to the read out.

Enjoy your tsi and lighten up a bit!

It was an attempt at a bit of light hearted humor hence the :-) in relation to the general theme of this thread.

My post was not aimed at you, otherwise I would have quoted your post as is the norm...

Don't you just love the written word!

Edited 22 April, 201412 yr by fairlight5

Not me I only got O level english! I'm as bad at it as my maxidot is at calculating an accurate mpg figure.....

Not me I only got O level english! I'm as bad at it as my maxidot is at calculating an accurate mpg figure.....

:-)

I don't check mine, just keep tipping the juice in and try not to take any notice of the £ display.

We've also got a 1.7 puma. Thankfully it doesn't have a read out. But I do know 220 miles from £50 ain't great :-)

The Mrs can do better though!

I dare not work out my pence per mile costs on our cars. Tyres and fuel alone make for grim reading without taking into account servicing and fixed running costs :-(

Over more than 10,000 miles my average fuel consumption has been 43.75mpg.  Yes, I do record every fuel purchase.  The Maxidot shows 46.0 so is just over 5% optimistic and this inaccuracy has been consistent since I bought the car.

 

My last car, a 2005 Honda Civic Type-S 2-litre, showed  34.9 whilst the calculated was 32.8 so the read-out was 6½% high.  That was checked over a total of more than 70K miles.

 

I consider any fuel consumption figures that are not calculated over, at least, 2,000 miles or 4 tank fulls as unreliable. 

I screw my receipts up, throw them away and try to forget about them as fast as possible :-)

If it makes any difference and you MPG Luddites want to worry about fuel, I burn on average about 19,907 gallons of fuel two to three times a week !

And I couldn't care less because she ain't a diesel

Many readers of this thread have stated that they don't care much (or at all) about their fuel consumption.  I don't have a problem with that at all!  I don't care about football or TV "reality" shows or The Environment.  Everyone has a different range of hobbies, interest and obsessions.

But there are some readers who are very interested in fuel consumption and a few are even willing to use quite unneccessarily high octane fuel in their cars in an attempt to improve it.  And they then spend a lot of time discussing it at great length on forums like this.  Yet ... in many cases, for some wierd reason, they seem to be unwilling or unable ever to actually measure the fuel consumption of the cars they are so keen to talk about!   

Edited 23 April, 201412 yr by Stuarted