Just coming up to 12,000 miles in my 170 TDI Elegance. Have recorded fuel consumption since new using Road Trip app on my iPhone and thought I'd share my findings.

Overall mpg to date 36 mpg

Best mpg 40.14

Worst mpg 32.31

Best and worst are tank to tank fills.

This represents a huge variety of driving from 17 mile daily commute (part motorway, part urban) to holidays fully loaded with luggage and family and four bikes on tow bar rack and everything else in between! I usually have the aircon on.

The maxi dot mpg display is ALWAYS optimistic by about 20% which I find very frustrating.

The difference between best and worst doesn't seem too bad and the mpg has definitely improved as it beds in.

This compares with my previous car (a 150 bhp 1.9 CDTI Zafira) which averaged 34 mpg over the 10,000 miles that I used the app. Also my Caterham which has averaged 33.4 mpg over the 4,000 miles I've used the app.

I would love to know what other 170 TDI owners are getting and if anyone else finds the maxi dot display just as inaccurate? Just for reference my Zafira trip computer used to agree with the app mpg to within 1mpg typically so it must be possible to make an accurate trip computer!

Anyone know if it's possible to get the maxi dot recalibrated?

I have a 170 CR Elegance on order and I have to say I hope it does more than 36mpg.

That's not good for a modern diesel, even with part time 4x4.

You can see mine below!

Use power through gears and for spirited driving but tend to stick to 70ish on D/C's and M'ways.

These figures over 7.7k from brim to brim filling using premium fuel - I ignore the Maxidot readings.

That's about 3-4mpg down on my previous 170PD Golf

Rockhopper has had a VCDS adjustment to his Maxidot, which I think now gives pretty accurate figures?

Your biggest killer is your daily commute, which isn't going to get the engine up to full temp for long enough.

Mine has averaged 41.70mpg over 5012 miles (true measure not maxidot). The Maxidot reads about 45mpg average for a 42mpg true calculation. As mentioned in my other posts elsewhere there is some evidence of a fairly sudden improvement - as indicated on maxidot - but which needs verifying over a series of true calculations. This appeared to happen when I put on my winter tyres/steel wheels, but I find that hard to believe as the reason if indeed there is a true improvement.

I do a fair amount of short journeys (well the car does with SHMBO shopping trips) of 3 miles to 8 miles duration about 4 times a week on country roads. Weekly trips into town of 16 miles return. The occasional run of 80 miles return on A roads - every 2 weeks and a holiday run of about 500 miles return about twice a year.

I drive to speed limits but I would not say my driving was of a spirited fashion.

I use premium fuel most of the time.

I get 35mpg when I drive above 85mph for a prolonged period or when there is a bad head wind and I have roof box on too. I managed 30mpg with the caravan on. Motorway sitting at 70 mph I get 48+ great.

Anyone know if it's possible to get the maxi dot recalibrated?

Recalibration is a simple job if you know anyone with a VCDS.

I have manage to get mine accurate to within less than 2%

My maxidot shows a long term average of 49mpg, but overreads by about 12%, so 43-44 brim to brim. Best I have seen was 68mpg in a slow convoy on a single track road over about 20 miles.

Andy

Why should vehicle owners pay to rectify something (Maxidot) that should be accurate?? Surely this is the responsibility of the dealer or manufacturer.

GeoffL

Why should vehicle owners pay to rectify something (Maxidot) that should be accurate?? Surely this is the responsibility of the dealer or manufacturer.

GeoffL

Why should it be accurate? If it was a statutory fitting then I would agree, but it is just an "added extra".

Mine seems to be just under 10% over, and I can live with that. Others seem to be a bit more.

My remapped CR140 is now in reality a CR170-180 and averages 36.4mpg. It is automatic (DSG) and it is driven around South London all the time.

When I drive it enthusiastically it will give me low 30's. When towing a caravan it gives me about 25mpg at 60mph. On a long run at 60mph on the motorway it can get up to about 48-50mpg. Driving for hours a day around South London doesn't do the overall consumption much good, at an average speed of 12-13mph.

PS it did not leave the factory like this but Ben at Shark Performance remapped it for me to get me up to the CR170 figures or above.

Gizmo68 recallibrated my maxidot as it was out by 10% when he coded my tow bar electrics.

Why should vehicle owners pay to rectify something (Maxidot) that should be accurate?? Surely this is the responsibility of the dealer or manufacturer.

GeoffL

Surely the Maxidot readings are a direct correlation to distance measured by the car? Distance measured informs the speedometer of what speed to show. As we all know that is set with a safety margin on all cars so that if you see an indicated 70 you are in fact doing slightly less. Following from that your Maxidot will surely always be out by the same amount as that safety margin? Hence it is totally accurate but only within the confines of the speed safety margin. That is my view on things anyway.

Hence it is totally accurate but only within the confines of the speed safety margin. That is my view on things anyway.

That argument will apply to the maxidot speed and distance readings on maxidot but the fuel flow measurement sensor which is part of the equation for the maxidot mpg readings may not be subject to the same accuracy and hence mpg readings via maxidot may not be so accurate.

That argument will apply to the maxidot speed and distance readings on maxidot but the fuel flow measurement sensor which is part of the equation for the maxidot mpg readings may not be subject to the same accuracy and hence mpg readings via maxidot may not be so accurate.

Fair enough, but there is an M in mpg which relates to distance (miles) and this is then used by the car to calculate speed. Surely it does not have two registers? One for real distance and/or speed and one for displayed distance/speed? It has only one register and that then has a margin of error to it that might explain some of the Maxidot inaccuracy in terms of displayed MPG readings.

As an aside this also explains why some people report better mpg on their smaller diameter winter tyres. (Conveniently ignoring that cold air also reduces fuel consumption) So the cold air AND the distance changes due to smaller tyres both make consumption appear better on the Maxidot in winter.

The way i look at is that the maxi-dot is a guide to the MPG you are getting. If you want a true figure use brim to brim calculations an mileage coverage, and fuel added.

Yes; but... So many people rely on mileage covered by using the odometer/trip meter. Which may or may not be correct, as Johann says above.

The way i look at is that the maxi-dot is a guide to the MPG you are getting. If you want a true figure use brim to brim calculations an mileage coverage, and fuel added.

+1

It does not bother me by how much it might be out or the absolute terms of what it says. If it says 15mpg I'm in trouble. If it says 70mpg I'm happy. When it does not say either and says 41mpg (as it normally does on long distance trips) I know all is well. Job done.

Think I will stay at home and not go anywhere!

Yes; but... So many people rely on mileage covered by using the odometer/trip meter. Which may or may not be correct, as Johann says above.

C & U Regs state that the speedo, which drives the odometer, can be up to 10% over, but nothing under. Therefore it is impossible to make it 100% accurate, because of variations in tyre sizes, from both useage and manufacturers variations.

I find my MFD fuel consumption is about 5% high, and the speedo and odo about the same, and to be honest I'm really not that bothered. I do keep a spreadsheet of brim to brim consumption which I think is more accurate.

I have 170 CR engine in Yeti and here is my mileage - it is in litres per 100 kilometers and you can translate it to Mpg.

Photos are from yesterday and I have average temperature here in Croatia (Dalmatia) for last 10 days about 15 Celsius.

I found also that Board Computer in Yeti was to optimistic, so I calibrate it by VCDS and is showing very accurate now (adjusted to show 6% more than originaly).

I reset memory 2 on BC last time when I refuel car, than I drive 904 kilometers and refuel full tank again - with 52 litres.

Calculation will give 5.7 litres/100 km and BC shows now 5.6/100 km which I believe is accurate enough.

Driving was in the city and local roads with no highway (when I driving on highway consumption increases up to 9 l/100 km).