BMW big on turbo four-bangers

BMW has revealed details of a turbocharged 2.0-liter four-cylinder gasoline engine earmarked to appear in a wide range of North American models.

This is an indirect replacement for the least powerful version of the German carmaker’s classic 3.0-liter inline six-cylinder gasoline engine.

The new direct-injection unit, code-named N20, is set to debut in the X1 xDrive28i–a reworked range-topping version of BMW’s entry-level off-roader. It makes a public premiere at the Geneva motor show in March but is not set to go on sale as part of the delayed X1 lineup in the U.S. market until early 2012.

Running a twin-scoll turbocharger together with BMW’s patented variable valve timing and variable camshaft-control systems, the new 1,997-cc unit produces a claimed 242 hp at 5,000 rpm–a significant 74 hp more than the most powerful version of BMW’s existing naturally aspirated 2.0-liter four-cylinder, along with 258 lb-ft of torque at just 1,250 rpm.

That’s 12 hp less but 29 lb-ft more than the existing X1 xDrive28i’s naturally aspirated 3.0-liter inline six-cylinder engine and sufficient enough to propel the new four-cylinder model to 62 mph in 6.1 seconds and up to a top speed of 149 mph in standard six-speed manual guise. That’s an improvement of 0.7 second and 6 mph.

Other models set to receive BMW’s blown four in 2011 include the Z4 sDrive28i and the new 528i–both earmarked to go on sale in North America in October. More models will follow, including the 1-series and the next-generation 3-series.

The last time BMW offered four-cylinder engines in U.S. models was in 1998. AutoWeek