Here's the part I referenced, said more precisely -
" . . . . .When done properly, very little of the
water methanol mist injected into the inlet of the compressor survives the process. Thereby, discharging a much cooler air charge with a relativity high humidity with very little or no water methanol droplets present.
When injecting water, we can quickly over saturate the air charge and have an excess of fluid discharging the compressor. Water has a much higher latent heat of vaporization, nearly double that of methanol, and does not flash (instantly evaporate) like that of methanol or other alcohols when injected into a hot air stream. Therefore, a smaller nozzle must be used when spraying pure water.
A better choice for pre-compressor injection is a greater concentration of methanol vs. water or pure methanol. Methanol instantly flashes (evaporating) as soon as it enters into a hot compressor and meets the heat within it. By using an alcohol, this dramatically reduces the amount of actual fluid exiting the compressor due to it‘s fast evaporation. Additionally, methanol offers much greater cooling effect then water. Furthermore, methanol is also less dense then water thereby having a softer impact on the impeller. The specific gravity of pure methanol is .792 @ 68° F compared to water which is 1.00 @ 64° F.
One major concern associated with pre-compressor injection is erosion of the impeller. This is only likely to occur when injecting solid stream of water at the impeller of a turbocharger or using an excessively large nozzle .. . . . .."