DSG or Manual?

[WelshGas]

Since the speedo overreads by approx 4% is it safe to assume that the distance is also approx 4% out?
Resulting in 4% worse fuel figures also?

Not quit that simple. Speedo varies by upto 10%. Will also vary depending on tyre circumference/wear. So it could be 4% today, and tomorrow?

 

[B J G]

Not quit that simple. Speedo varies by upto 10%. Will also vary depending on tyre circumference/wear. So it could be 4% today, and tomorrow?

Appreciate all that but if speedo out is it safe to assume odometer/mileage also out?
I assume that it is meaning fuel consumption is worse than whatever method is used if reference is made to the vehicle distance recording.

 

[WelshGas]

Appreciate all that but if speedo out is it safe to assume odometer/mileage also out?
I assume that it is meaning fuel consumption is worse than whatever method is used if reference is made to the vehicle distance recording.

Quit possible. I suppose the answer is technically beyond the average owner/motorist.

 

[B J G]

Quit possible. I suppose the answer is technically beyond the average owner/motorist.

Guess that it would be necessary to know what VW software calculates as it wouldn't be safe to assume that overreading speed calculation would apply to the distance.

Recall a rather difficult method of counting lamp posts on a motorway (were 100yds apart then but may have gone metric) over a mile and checking against odometer reading. Same principal for speed using time. Never even bothered to try it.

 

[2into1]

All of the (recent) above is an interesting diversion but a bit out of bounds. It seems Tom has also had a mpg hit to his DSG van after a service and reprogramming. As well as changing character as described earlier, I saw a hit to my mpg too, although only about 5 mpg. It seems to be edging back now but I have changed to winter tyres so comparisons are less valid.

 

[Eber123]

Good afternoon ,

After I got the software upgrade on the Tiguan (EA189 engine) I was convinced the consumption was 0.5 to 1 l per 100 km more than before. But again this is based on the on board computer.

Would it save to assume that all Californias have the same software? Meaning even it is not accurate for comparison sake it would prove that I use more diesel per 100 km than my neighbour?

Regards,
Eberhard

 

[2into1]

I think the computer figure is useful for comparison against your own history, but like many here I rely on the brimming method, if possible using the same pump at the fuel station.
The computer in my old 2010 Cali was very accurate The one in my 17 Ocean is about 4mpg optimistic.....so I'm not sure comparisons with other vans would be valid.

 

[Amarillo]

All of the (recent) above is an interesting diversion but a bit out of bounds. It seems Tom has also had a mpg hit to his DSG van after a service and reprogramming. As well as changing character as described earlier, I saw a hit to my mpg too, although only about 5 mpg. It seems to be edging back now but I have changed to winter tyres so comparisons are less valid.

I’ll wait judgement on an mpg hit following software upgrade and new wheels and tyres until a few more refuels. Since the refuel before I did a lot of city driving including a 22 mile / 4hr 30min tour of London’s Christmas lights with the boys.

However, I do feel that the DSG is holding lower gears for longer since the software upgrade.


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[Amarillo]

Guess that it would be necessary to know what VW software calculates as it wouldn't be safe to assume that overreading speed calculation would apply to the distance.

Recall a rather difficult method of counting lamp posts on a motorway (were 100yds apart then but may have gone metric) over a mile and checking against odometer reading. Same principal for speed using time. Never even bothered to try it.

It would not be difficult for even a basic computer to constantly calculate tyre circumference from wheel revolutions and GPS distance measurements and so give extremely accurate speed and distance measurements. I think that a similar method is used for altitude measurements on many Sat Navs: they use extremely sensitive barometric measurements, compare them with the less accurate GPS altitude measurements to work out the air pressure resulting in a highly sensitive altimeter calibrated to current atmospheric conditions.

I calibrate my bicycle computer by measuring ten front wheel revolutions dividing by ten and entering the revolution circumference in mm. I reckon on a speed and distance accuracy of +/- 0.5% until the tyre wears or I lose or gain weight.


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