Under the 3.0si’s immense hood is BMW’s familiar N52 inline-six, of 2996cc displacement, variable intake valve lift, and variable intake and exhaust valve timing. This is from the same engine family as that found in the 3-series sedan, with its novel magnesium-and-aluminum hybrid block casting. The engine makes incredibly smooth power through a slick-shifting six-speed manual or a six-speed automatic. We expected our 3080-pound Z4 coupe’s broad torque band and shorter final-drive ratio to equal quick acceleration, but our 3.0si manual ran to 60 mph in 5.5 seconds and hit the quarter-mile in 14.0 seconds at 101 mph, no quicker than a 3.0si roadster.
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