Staight Fuel = RED
Water Only = BLUE
Water/Meth = GREEN
y axis = Maximum Break Mean Effective Pressure (essentially torque)
x axis = Air/Fuel Ratio. (water/fuel ratio was constant at 60%)
Several things to note:
0. To convert Fuel/Air ratio to Air/Fuel ratio invert value.
1. As you can see, water and methanol make the best mixture, but this is partly due to the high blending octane of Methanol.
2. At leaner Air/Fuel ratios water can generate huge amounts more power when compared to just fuel. At leaner A/F ratios alcohol only adds to this a little.
3. Water Only in this case peaks at around 12:1 A/F ratio. Beyond that drowns the engine.
4. Meth/Water 70/30 peaks at around 11:1 A/F ratio. In fact, it produces around 60% more torque (and it's reasonable to assume that it would produce that much more horsepower) than just straight fuel. Indeed around 40% more than just water injection.
5. It's estimated that an engine which normally requires 100 octane at MBT, could be run on 80 octane with water/meth injection. Roughly 10 of those octane points are from the high blending octane of Methanol, but the other ten are from the combination of cooling, and retarded Peak Pressure Position.
6. I would say that very similar curves should appear even on an intercooled engine, as long as the water is completely vaporized before the combustion cycle begins. Even a poor water injection setup should accomplish that.
Adrian~