BMW unveils new 'water-powered' turbo car

BMW has recently showed off a new water-injection system on its M4-based safety car for MotoGP.

The twin-turbocharged six-cylinder that powers the M4 coupes is fitted with a water injection system that sprays a cooling mist into the intake air and it will be offered in showrooms soon, the Fox News reported.

This old-school trick reduces the temperature in the cylinder, which improves combustion and allows a turbocharged engine to run at higher boost by reducing knocking and heat related stress.

In the M4, three injectors are installed in the intake plenum of the inline-six-cylinder motor, each supplying two cylinders with fine droplets of H2O. They're fed by a 5.0-liter tank installed in the rear of the car that needs to be refilled with each tank of gasoline during track use, but just once every five stops on the road.

BMW says that during less enthusiastic driving, the system can also help reduce emissions and improve fuel economy by approximately 8 percent and it will work without the water if the tank runs dry, the engine simply adjusting itself to run at a slightly less extreme tune until you top it off.

Word on the street is that the system is coming to BMW's new M4 GTS model due out in concept form in 2015.

It won't be the first production car with a water injection system. The 1962 Oldsmobile Jetfire used a water-alcohol-corrosion inhibitor mix called Turbo Rocket Fuel, and the Saab 99 Turbo S got an extra boost out of water injection, as well.