Power & Efficiency for Your Car's Engine: Water Injection

What is It? How Does it Work? a De-Geeked Explanation

WATER INJECTION 101

Water injection is old technology. Dating back as early as the 1930s, World War II fighter planes such as the stealthy De Haviland Mosquito used water injection to increase engine power immensely.

Water injection works by introducing water vapor in with pre-combustion air before this air goes into the engine. Upon combustion, the water vapor turns to steam and delivers more power than if it were not there. When the burnt exhaust gases and steam have finished delivering the power to your engine, the steam assists in removing useless heat from your engine.

Water injection also lowers the engine's overall operating temperature. Reducing temperature this way reduces stress to the engine. Water injection also concentrates the force of combustion to the exhaust gases themselves - thus producing a more efficient burn.

Several other benefits of using water injection are:

- It cools the engine intake air temperature, thus providing an overall more dense charge of air going into your engine. This increase in air mass allows for an increase in power and efficiency.

- After combustion, the water vapor turns to steam. This steam cleans your exhaust gas sensor, yielding a more accurate on-board computer reading from this gizmo. Theoretically, this increased accuracy can help your car run more efficiently.

- The exhaust steam derived from water injection also cleans your exhaust valves. Engine exhaust valves invariably have a build-up of carbon attached to them, which could significantly degrade your engine's performance. By steam cleaning the exhaust valves, you can regain lost power and efficiency. Likewise it steams out the rest of your exhaust system, including the catalytic converter.

ALCOHOL IN THE WATER HELPS, TOO

Over the years folks have found that by mixing methanol alcohol (denatured) or isopropyl alcohol ("rubbing" alcohol) with the injection water, the water mist evaporates more fully. By doing this, the overall water injection concept works even better.