Great idea, but why not just put a small nozzle of just water injection (no meth, ok maybe a little meth like 10%)
You can make a cheap rudementory system that runs from a 4psi hobs, gets DI water from the washer tank, all going to a relatively small nozzle.
This way there is no fire risk due to water not being flammable, neither is 10% meth.
Small nozzle means there is no risk of hydrolock.
And since it's only being used for cooling there no need for an expensive controller.