Water injection

In an attempt to improve performance and allow the use of lower octane gasoline, water injection was developed. The cooling of the water vapor charge suppresses detonation. A small amount of water or alcohol-water fluid is injected into the fuel-air mixture as it enters into the carburetor. Theoretically, as the water evaporates it should cool the incoming charge which then becomes denser, leading to higher volumetric efficiency. This in turn should lead to improvements in performance and economy and allow the use of lower octane fuel because cooling of the charge suppresses detonation.