M3 E90 Clubsport harness

The aim of this project is to transform an original 'road' M3 into a car used as a 'Trackday' for the racetrack. So here's the BMW M3 from Carrosserie Alpina in Romanel-sur-Morges, on which I had the privilege of carrying out the electrical work.

To begin with, the passenger compartment needs to be dismantled. Start with the seats, steering wheel, centre console, dashboard, carpets, roof lining, door trim, etc.

Unlike other manufacturers and models, the majority of the wires are connected in a single cabin harness. So there are no interconnections that allow the wiring harness to be removed 'end to end' from the vehicle.

Once the passenger compartment has been completely dismantled, the main wiring harness can be removed from the vehicle.

The scotch tape that surrounds the wires must be completely removed. Then it's time to work on the electrical diagrams to optimise and remove some of the wires so that only the necessary elements remain (lighting, ventilation, meter, etc.).

In the meantime, the vehicle has been returned from the body shop, where a complete roll bar has been welded and a full coat of paint applied; the inside of the body has also been repainted.

In order to make it as 'uncluttered' as possible, the wiring harness has been modified so that it only runs along one side of the vehicle. The necessary wires from the original harness running along the left-hand side have been modified to run along the right-hand side. The same modification has also been made to the fuel pump module (EKP): this, which is normally located on the passenger side, level with the rear seats, has been moved to the centre console.

With the hardware modification complete, it's time for the software part (programming/coding). The aim being to be able to communicate with the vehicle (particularly in the event of a breakdown), a minimum number of ECUs have been kept, so several sensors and various contactors have been deactivated by coding to prevent them from malfunctioning.

The following ECUs are still present in this vehicle:

The S65 engine ECU (MSS60), DSC (M3DSC), junction box (JBBE), fuel pump module (EKP), air conditioning/ventilation module (IHK), key module (CAS) and lighting module (FRM).

Credit :

Alpina bodywork : http://www.carrosserie-alpina.ch/