Injecting water into a rich a/f mixture is not a good idea

There are few variables in the equation. Where is the IAT sensor in the inlet track. Will you be injecting before it so it is wetted? If so, you will just need to lean the fuel maps for whatever mixture you are sparying to bring the AFR's back to a reasonable level. If you have a rough idea of the heat compensation curve for your car(how much timing it pulls at what temp thresholds) you will get an idea of what can be gained even without changing the timing maps.

If practice, the right amount of methanol sprayed in the inlet track will provide substantial cooling. This is the type of application where I really like using methanol, as it will flash off and cool better. Straight water will not cool (according to the sensor ) as well as methanol. Each application is always a bit different so it will take a testing to find what works for you.

[stevebez]

Originally Posted by Howerton Engineering

Where is the IAT sensor in the inlet track. Will you be injecting before it so it is wetted? If so, you will just need to lean the fuel maps for whatever mixture you are sparying to bring the AFR's back to a reasonable level.

Can you elborate on this a bit ... why would a wet bulb read lead to more rich conditions? all else equal. The IAT and MAP are a few inches from the I/C exit. The intercooler is a long narrow water/air type.

Either jet location option will result in a wet bulb read.

Some people spray after the sensor to avoid "tricking" the ECU. I see it as a tool, that when used right works well without tuning of the ECU. Some cars like the STI, run on a MAF with built in IAT before the turbo so in that case, no cooling effect is transmitted to the ECU.

May comment was to say that is you use methanol to cool the IAT sensor, more so than water will, that methanol is fuel and if the car is already at an optimum AFR the methanol will move the motor to a richer mixture.