An aluminum / magnesium engine block exclusive to BMW, hollow camshafts, plastic camshaft cover, improved combustion chambers, a further evolved Double VANOS(*), higher fuel injection pressure, all-new engine electronics, an electric coolant pump, a variable-volume oil pump and an oil / coolant heat exchanger are the other weight-saving features and improvements of the new engine.

(*) VANOS = VAriable NOckenwellen Steuerung = variable camshaft control, or variable valve timing



BMW's other approach to modern 6-cylinder power

It is the most powerful engine within BMW's wide range of inline-six driving machines that does not wear an "M" badge. This brand-new engine, designated N54, develops a maximum output of 300hp in U.S. specifications from 3.0 liters displacement and generates peak torque of 300 lb-ft for powerful acceleration in any situation. And it achieves these results using technology that might surprise students of BMW history: turbocharging. 

Although it is standard equipment on BMW's highly acclaimed diesel engines, BMW has not used turbocharging with a road-going gasoline powerplant since the 1980's. Until now, the BMW 745i Sedan, which debuted in 1981, and the iconic BMW 2002 Turbo, introduced at the 1973 Frankfurt auto show, were the only two standard production, gasoline-powered BMWs to employ the technology. 

While the technology works as advertised, BMW engineers were not satisfied with the most often-cited downside to turbocharging; the frustrating lag between when the driver presses the accelerator pedal and when the turbocharger develops sufficient rotation to increase power. This lag is at its worst at low engine speeds. Other drawbacks included relatively high fuel consumption and available materials did not always fare well under the high-heat, high-rpm operation of the turbocharger, which gets its energy from hot, flowing exhaust gases and typically spins up to 5-figure rpm's. For these and other reasons, BMW put turbocharged gasoline engines on the shelf for more than 20 years.

Two recent developments caused BMW to reconsider turbocharging: a trend among many luxury-performance carmakers to achieve power gains by building engines of ever-increasing displacement and technology transfer from turbocharged diesel engine development to their gasoline-fired counterparts.

Accordingly, BMW recently articulated its new approach to developing high-performance engines as part of its EfficientDynamics initiative. Beginning with the N52 normally aspirated engine and the N54 turbocharged unit, BMW will achieve its performance goals with smaller, lighter, more efficient and cleaner-running engines. 

The all-new N54 features twin, relatively small turbochargers to boost performance significantly, but, at the same time, minimize the response lag. Thanks to their lower inertia, two small turbochargers build up pressure much faster than a single, large turbocharger, thus eliminating even the slightest lag. 

The front turbocharger feeds cylinders 1-3; the rear unit delivers super-compressed air to cylinders 4-6.

A further advantage of turbocharging is that this is the most weight-efficient method to boost engine power and performance. The N54 turbocharged inline 6 weighs approximately 150 lbs. less than an equally powerful eight-cylinder engine displacing 4.0 liters. This lower weight means a significant advantage not only in fuel economy, but also in balancing the car's weight distribution.

To enhance efficiency to an even higher level, the turbochargers are made of a particularly heat-resistant material which makes them immune to high exhaust gas temperatures in the interest of a fuel-efficient combustion process particularly under full load. 

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