BMW M4 2015 MotoGP Safety Car-08

BMW will once again provide the safety car for MotoGP, and like last season, the 2015 MotoGP Safety Car will be the RM750k BMW M4 Coupe. But unlike last year’s white M4 safety car, the black 2015 edition doesn’t just feature every item in the BMW M Performance Parts catalogue, we get a preview of some new tech as well.

The M Division has equipped the M4’s 431 hp inline-six with a water injection system. Water injection makes it possible to raise the upper performance limits, which have otherwise been restricted thermally.

Power and torque aside, the water injection system also improves efficiency with benefits in full-load consumption and exhaust emissions. Benefits at both ends of the scale, can’t argue with it!

BMW M4 2015 MotoGP Safety Car-13

The system makes use of the water’s physical effect during the vaporisation process to extract the energy required from the environmental medium. Water is injected into the intake module’s collector as a fine spray, significantly cooling the exhaust air during vaporisation. This lowers the discharge temperature in the combustion chamber and thus reduces the tendency for knocking, allowing the turbo engine to have higher charging pressure and an earlier ignition point.

Lower process temperatures also reduce the formation of hazardous substances, in particular nitrogen oxide (NOX). Water injection consequently “dramatically improves the effectiveness of the engine,” BMW says. Also, improved performance can be achieved without increasing the heat applied to performance-related components, meaning that reliability is not affected.

In this M4, BMW has opted for a layout with three injection valves in the plenum chamber, each supplying two cylinders. Located in the boot is a water tank with a gross volume of about five litres, which houses the water pump, sensors and valves, all controlled by the engine electronics.

In practice, the pump feeds the water to the injectors at a pressure of ten bar, whereby the appropriate volume is supplied depending on load, engine speed and temperature.

On track, the water tank has to be replenished whenever the car refuels. During more normal operation, the intervals between water refills are considerably longer, roughly once every five refuelling stops. To ensure the system is as suitable as possible for daily use, it does not require any additional maintenance, BMW says.

Not just a fun project for the engineers, water injection will be going into a production M car soon. Munich says that following extensive testing via the MotoGP series, the system “will also be employed in a BMW M production model in the near future.”