[keithmac]

I inject 75% methanol, I got this mix by trial and error through logging knock at higher boost settings. If your car is octane limited and this is the main cause of knock then running methanol is a good way to fortify the fuel. I inject nearly as much water/methanol by volume as I do fuel on full boost, just water at these quantities would bog the engine badly.

It all depends what your engine and setup wants, and you have to work from there.

My cars a JDM so requires a higher grade fuel than is normally available in the UK, add on top of this more boost and more timing and
the need for higher qantities of methanol arises.