Mid-engine, four-wheel-drive layout

In automotive design, an M4, or Mid-engine, Four-wheel-drive layout places the internal combustion engine in the middle of the vehicle, between both axles and drives all four road wheels.

The motive output is then sent down a shaft to a differential in the centre of the car, which in the case of an M4 layout, distributes power to both front and rear axles.

[2] Because the engine is not in the front, the car can be designed with a minimum amount of frontal area perpendicular to the wind, greatly increasing aerodynamic efficiency.

Having a front engine layout with a rear wheel drive powertrain almost evens out the weight distributed in order to optimize performance and handling.

Four-wheel-drive systems tend to be quite heavy and some of the engine's power can be lost through the various differentials in the car, in addition to the frictional losses of the powertrain.