Speedo vs Nanocom

[RoundaWhile]

My problem is that Nanocom "road speed" varies significantly from my speedo. At 100k on the speedo, nanocom reads around 107, 110 speedo 118 nano.


I have noticed consistently that at standard speed limits I am always slightly faster than normal traffic.


What should I believe, nano or speedo?


I am going to get hold of a GPS to see what it says is my speed, but in the meantime has anyone come across this issue before?


Cheers


Tony

[TheTree]

Hi

A decent GPS will provide a reference speed, not sure how the nano works it out, but I use a GPS to check the speedo in any car I own.

Steve

[OffTrack]

There was a tyre correction factor on the speedo that is set away from 1.0 (to 1.08 from memory) for some bizarre reason.

If you set the coefficient back to 1.0 it will read as per the speedo.

http://www.nanocom-diagnostics.com/downloads/1086334467.pdf

cheers
Paul

[Xtreme]

Yes, my Nanocom indicates a higher road speed than the speedo but GPS indicates about 5% less than speedo.

Anyway, now that I have learnt that there is a "tyre correction factor" that can be adjusted (thanks Paul), I'll go and make the necessary adjustments.

[PhilipA]

Just to be clear, can you change the speedo tyre correction factor or just the Nanocom tyre correction factor.

I have bigger tyres and my speedo is about 3-5% slow and ODO 5% out.
Regards Philip A

[OffTrack]

It's purely an adjustment to the road speed the Nanocom displays. There is no effect whatsoever on any of the vehicle systems.

cheers
Paul

[RoundaWhile]

There was a tyre correction factor on the speedo that is set away from 1.0 (to 1.08 from memory) for some bizarre reason.

If you set the coefficient back to 1.0 it will read as per the speedo.

http://www.nanocom-diagnostics.com/downloads/1086334467.pdf

cheers
Paul


Thanks muchly Paul, I will follow that up on the weekend!

[benji]

The nanocom uses the speed signal that the abs ecu makes.
So any difference between the nanocom speed and the speedo will be in the workings of the speedo.
LR may have fiddled with the speedo calibration though to sit different size tires. P38 vs Defender for instance.

[OffTrack]

The nanocom uses the speed signal that the abs ecu makes.
So any difference between the nanocom speed and the speedo will be in the workings of the speedo.
LR may have fiddled with the speedo calibration though to sit different size tires. P38 vs Defender for instance.


On the D2 the SLABS outputs a 8000 pulse per mile signal which is used by speedo and ECM. The fact that is "per mile" indicates that compensation for tyre size is done in the SLABS unit.

Defender, P38, and D2 all use the same core WABCO Type D ABS system, so I'd expect that the speed signal in all three is compensated for the standard tyre size for the platform.

cheers
Paul