Instrument cluster US->EU conversion

[strokemycocktus]

I have changed the gauge faces in my US E92 M3 for the km/h version. The speedometer is scaled differently, in the US version the 320 km/h equivalent is in the same place as 330 in the EU model. Given that, changing just the gauge faces resulted in some misreading. I have seen on an originally EU car that at 140 km/h on 6th the rev counter shows about 3600 rpm, while mine shows exactly 3500 (due to wrong speedo calibration for the EU gauge face). I went to two independent coders, the first one claims to have changed all units he found to km/h (no effect on speedometer reading), the second says that he has coded the instrument cluster entirely for the EU version (still the speedo shows as if it were for the mph gauge face).
The first dude says the whole CIC unit has to be coded for EU for the gauges to work properly, the second says the gauge cluster unit needs to be replaced with a EU version. I have also read somewhere that the whole car needs to be coded for EU version, so that when connected it shows EU, not US, and then the speedo will work fine. I have no idea who should I listen to and how this issue should be addressed.
I would like to note that the cruise control notification on the small center display shows the set speed in mph, and the speed warning in idrive is also displayed in mph. Everything else is shown in metric units: mileage, service info, etc is in km.
I would like to be able to run EU speedometer and have correct readings, as well as the cruise control and speed warning to be in km/h. Is anybody able to help? I don't have any experience with coding, and I am not really planning on doing everything myself, just wanted to know which solution to go with (vehicle coding/cluster replacement/ CIC coding).

Or maybe there is no problem and the reading is fine? The reading I base on (140 km/h at ~3600 rpm) is from a pre-LCI, mine is LCI. Maybe LCI cars read a bit differently?
Also, I have a digital speed display in my instrument screen (the lower one) - when I scroll through gas mileage, oil level, etc, I have a digital speed showing something like "v= xxx km/h). This speed is always lower tha what is shown on the speedo, and even lower than GPS reading. It does also does not read 140 km/h at 3600 rpm as I guess it should. What is it and why do I have it?

[Dtype]

Cic doesn't need coding. Just some nettodat coding on kombi.

[strokemycocktus]

Thanks for the info. Do you happen to know what apart from the speed units should be changed?
I have also found something like this:
KOMBI - BC_DIGITAL_V_KORREKTUR - nicht_aktiv - nicht_aktiv=True car speed in digital speedometer (removes the standard circa +5mph safety feature for radars)
KOMBI - BC_V_KORREKTUR - nicht_aktiv - nicht_aktiv=True car speed on analogue meter and HUD (removes the standard circa +5mph safety feature for radars

Maybe somebody has coded these functions and this is the reason for the speed differences?

EDIT:
I have checked the speeds:
speed indication on speedometer - cruise control speed notification - digital display speed (v=xxx)
120 km/h - 74mph=118km/h - 118 km/h
140 km/h - 84mph=134km/h - 134 km/h
148 km/h - 88mph=141km/h - 141 km/h

Seems the cruise control readings are the same as on the display. This would more or less correspond to the scaling differences on the speedometer (the biggest difference in scale is after 120 km/h).

[jdamore]

Originally Posted by seevin

Thanks for the info. Do you happen to know what apart from the speed units should be changed?
I have also found something like this:
KOMBI - BC_DIGITAL_V_KORREKTUR - nicht_aktiv - nicht_aktiv=True car speed in digital speedometer (removes the standard circa +5mph safety feature for radars)
KOMBI - BC_V_KORREKTUR - nicht_aktiv - nicht_aktiv=True car speed on analogue meter and HUD (removes the standard circa +5mph safety feature for radars

Maybe somebody has coded these functions and this is the reason for the speed differences?

EDIT:
I have checked the speeds:
speed indication on speedometer - cruise control speed notification - digital display speed (v=xxx)
120 km/h - 74mph=118km/h - 118 km/h
140 km/h - 84mph=134km/h - 134 km/h
148 km/h - 88mph=141km/h - 141 km/h

Seems the cruise control readings are the same as on the display. This would more or less correspond to the scaling differences on the speedometer (the biggest difference in scale is after 120 km/h).

The first parameter you mention will remove the correction to the digital display only. This is a percentage of correction (ie: not set at "+5mph"). So the faster you are going, the larger the delta between your digital and analog read outs.

The second parameter is to remove the correction on the analog gauge only. This does not work for our cars and you will not see a difference whether it is active or not.

Im not much help otherwise but im curious, is the low end (20km/h) the same? Have you matched up to gps speed?

[strokemycocktus]

I haven't tried to match it with GPS at low speed, only at 140 and it shows around 132 then. I am comparing the two gauge faces - mph and km/h version and the biggest difference shows up after 120 km/h, because there is the biggest step in these gauge faces.
I am a producer of gauge faces so I am able to have a deep look into all the details when I have everything drawn in vector graphics. The scale up to 120 km/h is almost the same, and then the two dots showing 130 and 140 are moved to the right on the mph speedo more than on the original km/h one. In other words, 120 km/h on the mph gauge face corresponds to around 121-122 km/h on the original speedo, and 140 corrseponds to 146.

Given that the analog speed correction is not functional in our cars, I am certain that the speedometer needs coding or calibration (at this point not sure if either is possible), or I just need to put in a porperly rescaled mph to km/h speedo and just be done with it. This is a solution, however it's not perfect, as the speedo ends at 320 km/h which is not what OEM gauges look like.