BMW recently demonstrated water injection on a small hatchback, but its first planned production use of the feature will be on quite a different type of car.
At the 2015 Pebble Beach Concours d'Elegance, the carmaker unveiled the M4 GTS concept--a hardcore version of its current M4 sports coupe.
A production version of the M4 GTS will arrive in 2016--and that all-out performance coupe will feature water injection.
Designed for use with turbocharged engines, water-injection systems have the potential to improve both fuel efficiency and performance.
BMW's system sprays a fine mist into both the intake manifold and cylinders of the M4 GTS' 3.0-liter inline-six, cooling the pressurized mix of air and fuel before ignition.
In the M4 GTS, BMW expects a "noticeable" improvement in power over the standard M4's 425 horsepower.
BMW M4 GTS concept, 2015 Pebble Beach Concours d'Elegance
BMW did not discuss improvements in fuel economy, but it has said that water injection can boost the numbers in that area as well.
Water injection should also lessen instances of early detonation--known as engine knock--and reduce stress on internal components.
The feature should also allow engines to run higher compression ratios, while still using lower-octane fuel.
This provides another potential avenue for improving fuel economy--without requiring consumers to pay for premium gasoline.
BMW first demonstrated water injection on its M4 MotoGP Safety Car.
But it also installed a system in a 1 Series compact hatchback, which shares the same rear-wheel drive platform as the 2 Series coupe and convertible. Unlike those models, it isn't sold in the U.S.
BMW 1-Series Hatchback prototype with direct water injection
BMW claimed water injection could reduce the fuel consumption of the car's 1.5-liter three-cylinder engine by up to 8 percent.
That prototype 1 Series used water collected from the air-conditioning system--eliminating the need to replenish the water-injection system separately.
BMW did not specify whether the system in the M4 GTS employs a similar method, though.
The M4 GTS is expected to enter production next year as a limited-edition model, and it will be sold in the U.S.
It's entirely possible that BMW will adapt water injection for additional vehicles, including more efficiency-focused applications.
We're just curious as to whether the air-conditioning condensate will continue to suffice for the water supply, or whether we'll be adding distilled water to our Ultimate Driving Machines.