Bavaria on Boost: BMWs New 302-hp Twin-Turbo I-6 Engine

Biturbo Photos

The N54 engine packs two turbos and direct injection.  (Photo: BMW of North America)

The last non-diesel BMW turbo was one of these, a 745i Turbo. (Photo: BMW of North America)

Two, small lightweight turbines like these provide 15 percent more power and 30 percent more torque. (Photo: BMW of North America)

302-horsepower is delivered from just 3.0 liters. (Photo: BMW of North America)

Turbo lag shouldnt be a problem, like it was on this 70s 2002 Turbo. (Photo: BMW of North America)

The 3.0L Turbo makes more power and torque than the 4.0L V8 in the new Euro-spec 740i. (Photo: BMW of North America)

Geneva Show Introduction Marks BMWs Return to Turbocharging

BMW has just announced an all new, six-cylinder engine, and boy, is it ever a force to be reckoned with. Normally, the phrase “a force to be reckoned with” is paired to a big V12 with some sort of advanced fuel management mechanism, or a redline-in-the-clouds V10, which coincidentally describes two of BMWs greatest engines in modern times. This said, as fantastic as BMWs ordinary six cylinder engines are, theyre just not forces to be reckoned with - that is, unless its April Fools and were in a jolly good mood.

But April Fools is more than a month away, and with all these debuts for Geneva on the way, were more stressed out than in prank-pulling mode, so, were being serious when we say that BMWs latest six-cylinder is worthy of your attention. The new engine, codenamed N54, is a twin-turbocharged, Valvetronic-equipped inline six that produces 302-horsepower and 295 lb-ft of torque, making it the first non M-Power gasoline engine to surpass the 100 horsepower per litre mark, though forced aspiration is involved. Its also the first time in twenty-six years that BMW has strapped a turbo on a gasoline-powered car, the last of which, for your information, was the 1980 BMW 745 turbo.

The roots to BMWs latest powerplant come from the aforementioned R6, but it uses a pure alumium block instead of exotic magnesium alloy to deal with higher internal pressures. To that, BMW added two small turbochargers, each powering three cylinders at low boost in order to crank up the output. BMW chose to use two turbochargers instead of the traditional single-unit turbo in order to eliminate pesky lag. With smaller, lighter turbos on board, BMW has also managed to deliver a torque curve thats almost completely flat, also making it one of the most flexible engines that the brand has ever created. The additions of the turbochargers alone have increased horsepower by fifteen percent, while torque has been increased by 30 percent.

But thats only half the story; the other part of this motoring tale includes the addition of gasoline direct injection in place of the standard fuel injection system. Direct injection is no longer a newfound technology in North America; many vehicles now feature it, including the Pontiac Solstice GXP and any Volkswagen or Audi product bearing the FSI badge. However, whats interesting is that BMWs system utilizes the most modern piezo injectors, similar to those used in its ultra-powerful twin-turbo 535d. This allows the turbo I-6 gas engine to be more efficient and emit fewer emissions while improving power. This advancement fleshes in the rest of the power difference.

In fact, this new engine is so advanced that the only true “new” technology that it doesnt have is variable turbine geometry, which BMW is well acquainted with from building turbodiesels. VTG turbochagers are commonplace in the world of performance oil-burners, and, as a matter of fact, BMW employs them in their award-winning 3.0-liter twin-turbo diesel engine. Expect this technology, which alters the angle of the turbines blades, to arrive in the not too distant future, as Porsche has just debuted the system on their all-new 997-type 911 Turbo. 

While BMW will be holding off on announcing which models the new engine will be fitted to, its almost certain that theyre going to be dropped into the 3-Series first, in both sedan, and the yet to be revealed coupe and folding hardtop convertible, for a debut this fall. The BMW model will most likely be badged as a 335i, and will pose a direct threat to Lexus extremely quick IS 350 and the forthcoming 300 horsepower 3.2-liter FSI V6 engine that will arrive in some Audis in the not too distant future. Eventually, there is some word that BMW will mate this engine to a hybrid drivetrain to make the Ultimate Environmental Machine.