jasons

Water injection,

it injects as a fine mist at around 165psi through a really fine nozzle, so it atomises into the air intake.
On compression it turns to steam and cools the exhaust gas temperatures by a couple of hundred degrees, thus allowing safer running of higher boost levels.

The methanol mix is for its high octane rating (a bit like race fuel), so simply adds more torque and in turn power.

Water injection is nothing new, they used it in WW2 air craft.

Also steam cleans the inside of the engine!

but it is not good to inject before either the turbo or intercooler.