This is prolly going to be a very stupid question but I just thought I would ask. What is water injection? Or Methenol injection? Just wondering because I've seen a thread or 2 about it and just wondering exacly what it is and what it does.

 

Alkahol or water or a combination of the two is sprayed into the intake to cool the temperture of the incoming air to prevent detonation.It's usually most effective on boosted applications like a turbo or supercharger.