Why different mixtures of methanol

[tomcat]

Just wondering what the advantages of adding h2o to the methanol is for cooling , I have a supercharged engine with a wipple on it at 8psi , currently using a crude h2o injection system before the blower to try and help cool the intake charge.
I have been planning to convert to a methanol; injection system but are worried about the effect on the blower casing and rotors , and was also wondering what the advantages of mixing with h2o are - does it stabilize the methanol , make it less corrosive or less likely to evapoate and turn into a gouey mess ????