The supercar attempts to stay true to Formula 1 powertrains, yet achieves a leading thermal efficiency of over 40 percent.

Mercedes-AMG has finally revealed the Project ONE, billed as the closest street-legal vehicle to a Formula 1 race car.

Developed via close collaboration with the Mercedes-AMG Petronas F1 team, the Project ONE is equipped with a hybrid powertrain combining the benefits of a turbocharged internal-combustion engine and four electric motors.

One electric motor has been integrated into a hybrid turbocharger, running at up to 100,000 rpm even at low engine revs when there is little exhaust flow. Throttle response is consequently better than a naturally aspirated V8, while surplus energy from exhaust flow can be used to charge the onboard battery.

Another electric motor is linked directly to the 1.6-liter V6 engine via a spur gear, providing 161 horsepower or operating as another generator. Two additional 161-horsepower motors drive the front axle, each operating at up to 50,000 rpm and helping recover 80 percent of braking energy.

The gasoline engine and electric motors together produce 1,000 horsepower. Incredibly, overall thermal efficiency is over 40 percent -- on par with the latest Toyota Prius and far higher than average non-hybrid cars.

The mid-placement V6 benefits from pneumatic valve springs to help reach 11,000 rpm. The redline is still a few thousand rpm short of a true F1 engine, though Mercedes claims the reduction was necessary for higher longevity and tuning for commercially available gasoline.

AMG Performance 4Matic+ torque vectoring and a Speedshift eight-speed transmission can launch the Project ONE to 112 mph in under six seconds, with a top speed of 217 mph or higher. Alternatively, the car can quietly sneak around for 16 miles on electricity alone.

"Motorsport is not an end in itself for us. Faced with intense competition, we develop technologies from which our production vehicles also subsequently benefit," says Daimler chairman Dieter Zetsche.

The company only plans to build a few hundred units, each expected to sell for more than $2 million.

Photos by Ronan Glon.