Due to the sports design of the M5 and Z8 higher cornering speeds are possible and thus also increased transverse acceleration of up to 1.2 g (1.2 times the earth's acceleration). Due to these high transverse acceleration levels the engine oil would be forced into areas of the engine facing the outside of a curve and would collect there particularly in the valve cover and oil pan area.
For this reason, a special oil system with a triple oil pump is fitted on the S62.
The main oil pump serves the purpose of generating the necessary engine oil pressure and thus engine lubrication. Depending on the current driving status, two auxiliary oil pumps convey the oil from the collection areas to the intake of the main oil pump. Each auxiliary oil pump features two intake lines that lead into the right-hand and left-hand sections of the oil pan. Special changeover valves open the corresponding intake line as required. One-sided oil intake cuts in as from a transverse acceleration of about 0.9 g. The signal is transferred via the CAN-bus from the dynamic stability control DSC to the DME control unit which then activates the corresponding changeover valves.
When driving straight ahead or when the transverse acceleration limit is not reached, both auxiliary pumps convey oil via the intake lines to the intake area of the main oil pump.
When the transverse acceleration limit is exceeded (approx. 0.9 g) while cornering, the corresponding changeover valve switches such that the auxiliary pumps convey oil from the valve cover and oil pan area facing the outside of the curve to the main pump..