During the process of vaporization a large amount of heat energy is absorbed, resulting in anther drop in intake charge temperature! Unfortunately, vaporized water also displaces a large volume that would have been filled with air molecules, but the lowered temperature in the combustion chamber more than makes up for this loss in volume. Indeed, the lowered temperature in the combustion chamber allows us to run higher boost pressures and, consequently, allows us to make more power!
HOW WATER INJECTION WORKS
Atomized water rather, that vaporized water is injected into the air intake system as water only boils at 212° F at sea level while temperature of the intake charge would be much lower, having already passed through the intercooler. When water is injected into the air intake system it absorbs quite a bit a heat from the intake charge. When the atomized water, together with the intake charge, enters the combustion chamber, the high temperature of the combustion chamber causes the atomized water droplets to vaporize.