Looking back on McLaren's->ke284 background with high-displacement engines for both race->ke148 and road cars, it's hard to believe the Brits have built an electric motor from scratch. We are talking, of course, about the unit used by the P1->ke4608 hybrid->ke147 supercar, which is identical to the power source motivating the entire Formula E grid. The motor generates up to 225 horsepower in a Formula E->ke4660, as opposed to the 176 ponies delivered in the P1, but that's just one of its outstanding properties.

Making the power unit that much more special is its size. This thing is downright tiny. It's smaller than the transmission it mates to and weighs only 57.3 pounds, making it the smallest and the most power-dense electric motor ever built. The small size and low weight aren't at all surprising. These specifications are what make it perfect for the P1, a supercar->ke177 that needed a compact and light electric motor to go with its lightweight nature. And this compactness is exactly what made it suitable for Formula E where a low curb weight is essential to performance.

"We couldn't find a motor in the marketplace that was good enough and small enough for what we wanted to achieve," says Peter van Manen, vice president of McLaren Applied Technologies. Hard to believe McLaren built its first engine -- the 3.8-liter V-8 M838T -- for road applications only five years ago. Hit the play button to learn more about the company's first production electric motor.

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