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EDC Satellite Control Unit with Damper: Notes

The VDC dampers on the rear suspension are either steel-spring or air-spring versions depending on the optional equipment fitted.

Fig 1: Identifying EDC Satellite Control Module And VDC Damper
G06925033Courtesy of BMW OF NORTH AMERICA, INC.
INDEX REFERENCE CHART

Index Explanation
1 VDC damper with steel spring
2 VDC damper with air spring
3 Front EDC satellite control module
4 Rear EDC satellite control module
5 EDC data-map valve for compression control
6 EDC data-map valve for extension control
7 EDC data-map valve for extension control
8 EDC data-map valve for compression control
Fig 2: Identifying EDC Satellite Control Unit And Damper Tube
G06925034Courtesy of BMW OF NORTH AMERICA, INC.
INDEX REFERENCE CHART

Index Explanation
1 Damper tube
2 EDC satellite control unit
3 EDC data-map valve for extension and compression control
A FE = Extension force
B FC = Compression force
C VE = Extension velocity
D VC = Compression velocity
E Extension and compression characteristic data map

Difference between a VDC (1) and a VDC (2) damper:

A VDC (1) damper with only one EDC data map valve uses combined extension/compression adjustment which has to be cycled extremely rapidly.

With this type of control, the damper adjustment is based on wheel frequency.

The wheel frequency is the frequency at which the wheel oscillates along the z-axis.

Fig 3: VDC Damper Fluid Flow Diagram With EDC Data-Map Valves
G06925035Courtesy of BMW OF NORTH AMERICA, INC.
INDEX REFERENCE CHART

Index Explanation
A Extension progression
B Compression progression
1 Damper tube
2 EDC data-map valve for extension
3 EDC satellite control unit
4 EDC data-map valve for compression

A VDC (2) damper with two EDC data-map valves uses independent extension/compression adjustment which does not demand such a high cycling rate.

With this type of control, the damper adjustment can be based on body frequency.

The body frequency is the frequency at which the body oscillates along the z-axis.

Fig 4: EDC Satellite Control Unit Fluid Flow Diagram During Extension
G06925036Courtesy of BMW OF NORTH AMERICA, INC.
INDEX REFERENCE CHART

Index Explanation
1 EDC data-map valve for compression
2 EDC data-map valve for extension
3 Force/direction of piston rod movement
4 Fluid medium
5 Data-map control
A FE = Extension force
B FC = Compression force
C VE = Extension velocity
D VC = Compression velocity
E Extension data map
F Compression data map

The two EDC data-map valves firstly enable independent extension control and, therefore, data-map compatible design, and secondly independent compression control and, therefore, data-map compatible design.

Fig 5: EDC Satellite Control Unit Fluid Flow Diagram During Compression
G06925037Courtesy of BMW OF NORTH AMERICA, INC.