02 Feb 06
When moving off, the power is split 50/50 between the front and rear axles, changing to a fully front-axle bias once under way. Only when the car senses slippage at the back wheels, or when it thinks you're really pressing on, does it pump power back to the rear axle. It also uses a variety of sensors - including yaw, steering wheel position, lateral G and engine speed - to judge your driving characteristics. It has three preset modes of operation: normal, sport and stability, the latter for when driving on snow or ice. However, the driver has no way of choosing the mode, the car doing it all.
In practice, the MPS takes a while to get used to your driving style - and, as a driver, it takes time to accustom yourself to the 4WD system and begin to trust it. Say, for example, you have a tightish corner coming up: your initial response would be to slow down nice and early before the corner, only bringing the power on smoothly once the road opens up, thus keeping the car nicely balanced and safe through the corner. However, if you try that in the MPS things go a little odd...
Because the car has sensed that you've slowed down, it shifts all the power to the front wheels, thinking you're just cruising along. This means that once you hit the gas on the exit of the corner you plough forward with oodles of understeer - which bizarrely, the standard DSC traction control system chooses to ignore. So, in order to avoid becoming too familiar with roadside shrubbery, you have to change your driving style.
