I also agree with the OP, and my fuel consumption on maxidot is also pretty spot on, for short term and for long term readings (comparing with Fuelly). Others may or may not be so accurate but that can only be validated by the owner but I suspect the variation will be fairly consistent.

My additional comments are that other car technology can be less accurate namely the Fuel Gauge, but also the Speedometer and Odometer.

A fuel indicator showing a nominal 50 litre tank needs refilling at 43 litres or less is nearly 25% inaccurate and in that situation I would rely on the maxidot to estimate actual remaining fuel if unable or inconvenient to fill up at that point.

The Speedo and Odo on my Octavia 3 have respective 8% and 0.5% relative inaccuracy (measured against GPS), but I have had 10% and 7% on another vehicle (Hyundai).

Again the errors were consistent and once you know what they are you compensate for them when driving.

I read a road-test of the new Bentley which said that Speedo was 6% out so price is not necessarily a factor. In some respects we have not advanced far from the old Smith's instrumentation of my youth, reliability yes, accuracy no.

I read a road-test of the new Bentley which said that Speedo was 6% out so price is not necessarily a factor. .

 Another VAG motor!

Regarding tank capacity: 55L sounds about right (http://www.briskoda.net/forums/topic/333957-fuel-tank-capacity-on-my-16-tdi-be-estate/?p=4027771)

I rest my case.   :cocktail:

The Speedo and Odo on my Octavia 3 have respective 8% and 0.5% relative inaccuracy (measured against GPS), but I have had 10% and 7% on another vehicle (Hyundai).

Again the errors were consistent and once you know what they are you compensate for them when driving.

I read a road-test of the new Bentley which said that Speedo was 6% out so price is not necessarily a factor. In some respects we have not advanced far from the old Smith's instrumentation of my youth, reliability yes, accuracy no.

 

Speed errors (compared with GPS) is normal.

In all countries there are rules about the accuracy of the speedo reading.

In the UK, the speedo will read higher than the real speed by ~5% but as you say the odo should be very accurate.

The offset is configurable by country

Secondly, GPS is not so accurate in Europe due to the limited number of satelites.

 

My fuel gauge also seem very regular but again the linearisation of the fuel gauge is configurable (likely depending on the markets they are sold in).

I usual achieve around 800km for a tank and this nicely matches with the major tick marks on the fuel gauge for 100km per marker.

Speed errors (compared with GPS) is normal.

In all countries there are rules about the accuracy of the speedo reading.

In the UK, the speedo will read higher than the real speed by ~5% but as you say the odo should be very accurate.

The offset is configurable by country

Secondly, GPS is not so accurate in Europe due to the limited number of satelites.

 

My fuel gauge also seem very regular but again the linearisation of the fuel gauge is configurable (likely depending on the markets they are sold in).

I usual achieve around 800km for a tank and this nicely matches with the major tick marks on the fuel gauge for 100km per marker.

GPS was not available when I lived in the UK but then the authorities were a lot more casual about speed limits and fuel was cheap (those were the days).

I did not think that Europe was necessarily less well served by satellites, don't forget they are there for military purposes and the next battlefield was always going to be cold war Europe. My understanding was that standard domestic GPSs did not have the necessary algorithms to be truly accurate, but they are good enough for our verification purposes especially if the comparison distance was say 20km or so and not just 1 km.

I agree with both your points about speedo variations being normal and relative to whatever country's legal requirements. No country allows it to under read (eg 100kph on display and >100kph actual). I am just saying that the system of measuring the rotation of a wheel, which varies with wear and pressure is archaic and needlessly inaccurate.

Similarly with fuel gauges, some are accurate and many are not. I think every car I have owned or driven in had different idiosyncratic fuel gauges

Unfortunately I cannot find the contribution that had a link to a Ford engineer saying that they deliberately configured fuel gauges to show improved consumption over the first indicated half tank. Perhaps that is not allowed in Switzerland, too illogical, and quite right too.

Edited 25 November, 201411 yr by Gerrycan