Does anyone know how accurate the "average fuel consumption" reading on the MAXI DOT display is in real life?

The reason for the question is that I've just upgraded my Yeti from a 140hp 2013 manual diesel to a 150hp 2017 manual diesel. The old Yeti always indicated an average fuel consumption of 52 mpg. The new Yeti which I collected yesterday is indicating 43 mpg and hardly changed on a 50 mile drive home. A difference of 9 mpg is quite a lot between the two vehicles which are fairly similar.

The early car had a defeat device to cheat the emissions and the later Euro 6 has not, that makes a difference.

The only way to get a true fuel consumption is working it out from brim to brim tank fills as the Maxidot MPG figure is usually very optimistic.

It is possible to use something like VCDS to put an adjustment into the Maxidot MPG figure to get it nearer to true.

Edited 3 December, 20196 yr by Urrell

I record actual and computer mpg, and on average the computer is showing 7% better than my brim to brim calculations..ie maxidot reads about 3.5mpg on the optimistic side.

7% is the average error in average MPG the Maxidot reports on my current Yeti, although i has been as high as 11% and as low as 4%.  On my previous Yeti (140 4x4 manual) the average error was 10%, with the worst being 16% and the best 2%.  (Cue a discussion about accuracy vs precision.)

 

I typically put about 40 litres in at each fill up, so those kinds of variance can't solely be down to small errors in my MPG calculations arising from differences in what a given pump thinks is "full".

Thanks for your replies.

My first worry was that there might be a fault with the new (to me) 150 Yeti but it sounds as though it could be just down to different errors in the Maxidot reading.

I shall keep a eye on it.

 

As Urrell said, if you want to know what your MPG really is, you need to do your own brim-to-brim calculations (which means no "£x worth" fills - you have to top it off each time).  Given the variation in error of the average reported by Maxidot, IMO it's not even much use for comparative purposes e.g. a weekend away mostly involving long trips on relatively clear roads vs a week of urban/suburban driving.

Based on maxidot only (I don't want to know the truth!) My 2017 150ps DSG shows 55mpg at best on the motorway , just me in the car. Urban, it averages 42.5 mpg. That is an average over 2000 miles, including one 180mile a road drive, the rest local commuting.

Fiction does not help you know how many Pounds and Pence are needed to get places at different times.

Knowing actually how many miles to the litre you can go on different journeys is what matter, and it is a long time since fuel in the UK was priced or sold in Gallons.

Huh? I have no need at all to know how many "pounds and pence" are needed to "get to places" . I just fill up the car when it gets low like everyone else.

 

Litres/ gallons - what are you on about ? The op was asking about maxidot MPG. Miles per gallon.

 

I was posting to give a helpful comparison . How are you helping ?

I was hoping the OP or even you could actually say how far you can actually drive for say maybe 45 litres of fuel used.

45.5 litres and going 450 miles for that is simple to understand, or getting further and still around 10 gallons is good, less miles not so good.

Edited 4 December, 20196 yr by Roottootemoot

Ok a great mix of journeys with a DTUK box fitted, brim to brim 45ish mpg using premium diesel using ordinary about 40mpg, so, try to use premium as it gives more mpg at a lower cost/mile, although its not easy to find here in finistere!

I must add here, I am not a bean counter, the car is a tool to be used!!

Edited 4 December, 20196 yr by Frenchtone