BMW'd already revealed details on its new, twin-scroll turbo four when it took the sheet of a car using it for motive power. It's the Z4 sDrive28i, revealed in a sunny shade of National School Bus Chrome earlier today in NYC.

The roadster — jammed into a corner during a press conference dominated by the company's electric-vehicle strategies — will be the first BMW in the US to receive the direct-injection, 2.0-liter TwinPower four-cylinder. (The TwinPower name refers to its combination of direct injection and Valvetronic intake control — not because of some unicorny combination of supercharger and turbo, like Volkswagen's Twin Power.) The result is 240 horsepower and 260 lb-ft of torque — which seems low until you consider it's more than the naturally aspirated inline six it replaces. Max power arrives at 5,000 rpm, 1,500 rpm less than in the six. There's also 30 percent more torque, peaking at 1,250 rpm, which is also 1,500 rpm earlier than the six.

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We'll know more on weights and measures later this week — including power-to-weight, which might even be better than the previous 3.0-liter Z4 3.0i. Combined with BMW's 8-speed automatic, the four is also 20% more efficient than the naturally aspirated six.