Has anyone tested the accuracy where the gap between speeds being 10 and 20 mph (90 mph onwards 80, 90.......110?????)

Edited 20 May, 201214 yr by Binzie

I have not.

It bugs me not having 100 on there

The speedo moves half the speed. Obviously to give greater range in legal limits, and not for illegal limits.

as for accuracy, its as accurate as the rest of the range - on mine about 2% or 3% over reading, but at 110mph, you don't really want to be concentrating on speedo VS GPS. Best keep your eyes on the driving.

The accuracy will be the same for both parts, as the needle position comes from the same lookup table in the cluster EEPROM.

The accuracy will be the same for both parts, as the needle position comes from the same lookup table in the cluster EEPROM.

Do you have any experience reprogramming such EEPROMs?

Do you have any experience reprogramming such EEPROMs?

IIRC, there are 8 pairs of 16-bit integers.

The 8 speed values start at address 0220h

The 8 scale values start at address 0230h

HTH

Also...

VW released a Tech Bulletin for speedos a while back. Approx. 10% variation between actual speed and reported speed.

It can be updated to make it more accurate - but then obviously if you're running bigger wheels it could throw it out.

Has anyone tested the accuracy where the gap between speeds being 10 and 20 mph (90 mph onwards 80, 90.......110?????)

I might have! I have a RoadAngel...

100 on the speedo is 93 GPS for mine...

Officer

GPS takes no account of altitude so if you're anything other than at sea level don't assume it's absolutely accurate.

Randomly on a previous car you could change the lookup via the dealer level diagnostics package depending on the wheels fitted.

I was thinking about this on Monday at a trackday ... and wondering how fast I was actually going. Shame I didn't have a satnav running to compare at the time :(  Probably should have been concentrating on getting round the track!