Turbo Four for BMW Z4

BMW is seriously considering launching its new turbocharged four-cylinder engine in the Z4 sports car, Motor Trend has learned, even after M Division chief Ludwig Willisch said before retiring last summer that the engine was designed for a 1 Series M.

Why the Z4 before the 1? Product cadence. BMW won't have an all-new 1 Series until calendar 2012, the 2013 model year in North America. The turbo four is being readied, and BMW isn't in the habit of launching an all-new engine in an all-new car at the same time. BMW is basing its turbo four on the 2.0-liter gas direct-injection four, rated 170 horsepower and 155 pound-feet in normally aspirated form.

The 1 Series M will reportedly weigh less than 2900 pounds and, to be a proper M car, the new engine must make more than 300 horsepower, Willisch told MT earlier this year ("Trend," June 2009). The name we're hearing for it, by the way, is 1M, to avoid confusion with the iconic BMW M1 supercar.

So the Z4 turbo four will be an M too, right? Hold on: Willisch was adamant that there would be no M version of the new Z4, which has been repositioned slightly to compete more directly with the Mercedes-Benz SLK. He said that just as BMW was revealing its X5 M and X6 M and just before he retired.

Willisch's replacement, former Mini chief Kay Segler, has been silent on the Z4 M issue. He confirmed M's plan for a turbo four and said the next M3 would switch back to a six-cylinder engine. The Z4 turbo four may be called a Z4 M or simply, a Z4 with M Power. The turbo four is said to be so much lighter than the twin-turbo six that its weight may overcome the 10-percent power deficit.