High speed, low weight.
The fact remains that more power alone - that is higher torque - is not sufficient to be a winner. And so the BMW M3 outperforms competitors focusing on the torque concept alone, wherever those models require a massively reinforced and, accordingly, heavy drivetrain to convey their extremely high level of torque, since this extra weight and mass must first be accelerated and propelled to a higher speed. The high engine speed concept, on the other hand, enables the engineer to opt for a much lighter drivetrain and choose a far shorter transmission ratio.
The other side of the coin is that the M high-speed engine concept is extremely demanding in technological terms: While the former straight-six was still limited electronically to maximum engine speed of 8,000 rpm, the new eight-cylinder exceeds this mark by far, revving all the way to 8,300 rpm. This is indeed the fastest-revving V8 power unit in the world built in numbers going beyond a small model series.
Given this kind of power and such unique technology, the engine of the new BMW M3 shifts the limits of technology in series engine production to a much higher level than before - quite simply because the higher the speed of an engine, the closer you come to the highest limit physically achievable. At a speed of 8,000 rpm, each of the eight pistons covers a distance of 20 metres or almost 66 feet per second - piston speed found until recently only in the exclusive world of motorsport. The conventional wisdom so far was indeed that this kind of speed and the loads exerted on the materials in the process were simply too much for series construction.
Targets in the design and construction process: compact, stiff, light.
In developing BMW's new eight-cylinder power unit, the engineers and other specialists sought to reduce all moving masses to an absolute minimum, focusing above all on the crank and valve drive in their search to ensure minimum rotating and moving masses. Precisely this is why they decided to combine two rows of four cylinders at a V angle of 90 and an off-centre arrangement of 17 millimetres or 0.67 to make the entire power unit extremely compact and efficient.
The decision to choose a 90 angle was taken on account of the efficient compensation of mass forces provided by this geometry, serving to minimise vibrations and maximise motoring comfort. By and large, therefore, this specific geometry offers the optimum solution to the conflict of interests resulting from maximum smoothness free of vibrations, on the one hand, and maximum stiffness of all relevant components, on the other.
Engine block from BMW's Formula 1 foundry.
The engine block featured on the new BMW M3 comes from BMW's light-alloy foundry in Landshut near Munich, which also builds the engine block for BMW's Formula 1 racing cars. The cylinder crankcase is made at the foundry in a low-pressure die-casting process from an over-eutectic aluminium-silicon alloy, with at least 17 per cent silicon. The cylinder liners, in turn, are formed by exposing the hard silicon crystals, the iron-coated pistons running directly in these uncoated honed cylinder bores and thus not requiring any additional lining. Cylinder stroke is 75.2 millimetres or 2.96, cylinder bore 92 millimetres or 3.62", adding up to provide overall capacity of 3,999 cc. ...next page >>