Our test car was 52 percent biased over its nose, which is no bad result given that a 3.0-litre straight six engine with two turbochargers resides there.
Ah, the engine. The capacity has dropped by a full litre over that of its 2007 predecessor, yet power is up from 414bhp to 425bhp, while torque rises from 295lb ft to a fairly whopping 406lb ft. If you add the Competition Pack the M4 gains an additional 19bhp while its torque remains the same. The newest addition to the range is the M4 CS, which gets a peak 453bhp driven through its rear wheels, while heading the range is the limited edition GTS which produces a monstrous 493bhp.
It is developed from 1850rpm and is available until 5500rpm, rather than at the 3900rpm of the V8. The red line has decreased from 8500rpm to 7600rpm in the process, but all of the headline figures are more compelling than they were before. The fitment of two turbochargers has increased the natural lethargy of the M4’s six-cylinder engine, so BMW has gone to great lengths to mitigate the lag.
The most effective way to do so is to minimise rotating masses and therefore inertia, which is why there are two small turbos rather than one big one. They’re both single-scroll units. Twin-scroll turbos split exhaust gases from the cylinders until they reach the turbine, but you can’t really do that between an uneven number of cylinders.
Ancillaries that might in past times have been driven off the engine — such as the power steering, obviously, and the pump that drives coolant to the turbo bearings when the car is stationary, less obviously — are here electrically driven to further reduce the load on the engine.
Farther down the line, the driveshaft is constructed from carbonfibre, which makes it 40 percent lighter than that of its predecessor, while half-shafts are hollow and therefore spin more easily than on the previous-gen M3.
Elsewhere, other changes deemed worthy of BMW’s M division include a carbonfibre roof and output shaft, aluminium suspension components, an ‘active’ differential (in the form of an electronically controlled mechanical limited-slip differential) and an aluminium bonnet and wings.