[Excaliber]

Higher octane fuel is less prone to 'self ignite' or detonation. I would have to assume the water/alky injection also impacts the potential for self ignition in a positive way. Therefore, it would be like an 'octane' boosting effect without actually raising the octane level of the fuel.

By the way, I wish I had dime for everytime someone has told me that high octane fuel makes more horse power or is somehow 'stronger' than regular fuel. It is simply more 'refined' you might say, in that it RESISTS self ignition, in other words it's HARDER to light this fuel than regular fuel, that about covers it.