How much Water/Methanol?
To prevent detonation, the ratio of Water/Methanol to gasoline is roughly 1 to 5 in gasoline applications- 1 to 4 in diesel. In practice, you give it as much water / methanol as it takes to eliminate detonation without quenching combustion. The amount depends on the onset RPM of injection, the octane of the gasoline, fuel/air ratio, cylinder head type, even the weather conditions. Your engine is actually pretty tolerant of extra water vapor, you will know it’s too much when the engine misses and loses power.
