Inside BMW 550i

Eight-cylinder engines 

Passion meets intelligence. The BMW eight-cylinder engines impress with high performance and spontaneous power delivery; and all this with low weight, fuel efficiency and unparalleled smooth running.

The BMW eight-cylinder engines owe the V in their name to the position of their cylinder banks, which stand at a 90° angle to each other. The arrangement and distribution of the cylinders on the two cylinder banks ensure perfect equalisation of the inertial forces and thus for unusually smooth running.

The performance of the BMW V8 engines is also unusual. Depending on the model, this is achieved through the employment of the most modern TwinPower Turbo technology or by the complex high-speed concept. In vehicles with TwinPower Turbo two equally-large turbochargers work at the same time and supply the engine with compressed air. The central arrangement of the turbos between the cylinder banks of the V8 engines allows a particularly compact design. Combined with the direct fuel injection (High Precision Injection) system, a water-cooled intercooling system and use of the most modern lightweight construction components – like the magnesium aluminium compound crank case – BMW V8 engines reach impressive levels of performance with high efficiency. Thus the 4.4-litre TwinPower Turbo V8 petrol engine in the BMW 550i delivers a full 300 kW (407 hp) and a maximum torque of 600 Nm. And all this with a consumption of 10.4 l/100 km. The V8 engine in the BMW X6M provides even more power. Here a pair of Twin Scroll turbochargers supplies the engine with air. The result is an outstanding 408 kW (555 hp), 680 Nm torque and a litre achievement of 126 hp per litre cubic capacity. The patented cylinder bank-overlapping exhaust manifold provides a particularly even exhaust supply. Thus differences in pressure, which lead to delays in the response mode, are effectively avoided. This means a high level of spontaneous power delivery.

For V8 engines, depending on the model, BMW also focuses on the sophisticated high-speed concept in addition to turbocharging with a direct fuel injection system. Taken directly from the world of motor racing, it’s used in the V8 naturally-aspirated engine and permits revolutions to a maximum of 8,300 rpm. Consistent lightweight construction and eight electronically-steered single butterfly valves characterise the V8 power unit and connect racing technology with suitability for daily use. The concept of the single butterfly valve control allows the engine to respond sensitively in the low-speed range and permits immediate reaction when high-engine performance is demanded.

 A further constructional highlight is the oiling system, which allows for longitudinal and lateral acceleration of up to 1.4g. The innovative ion current knock control monitors the firing processes at every ignition in order to detect engine knocking, spark failure and combustion misfiring. The innovative Brake Energy Regeneration with intelligent generator regulation also comes into use here and brake energy is converted to current for the on-board electrical system.

Thus the BMW M3 Coupé achieves a performance of 309 kW (420 hp) and a maximum torque of 400 Nm at 3,900 rpm. 85% of the maximum torque is demanded over a rev range of 6,500 rpm.

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