[sambeeb]

My small turbo ramps rapidly up to a 20psi peak at 3200rpm or thereabouts and then boost trails down to about 12psi at max airflow. With boost pressurized I guess it would be possible to modulate water flow against injector duty cycle provided I used a nozzle that could provide enough water at peak air/ fuel flow, but at 12psi. At the boost/torque peak it then wouldn't matter that there was excess boost as the flow would be modulated by the solenoid? But since the fogging nozzle has an air and water signal (both exposed to boost pressure) it stands to reason that I'd need to modulate the flow of water and air to the nozzle equally. Do they make dual circuit/quad port solenoids so that a common solenoid could be used for both signals. I think without controlling the air and water to the nozzle simultaneously the behavior of the nozzle would get a bit unpredictable yeah?

As it is the system I suggested will spray the most water at max boost/ cylinder pressures where my car is normally seen to be pulling bits of timing and then would be under flowing at higher rpm. I guess this would be good for inlet temps at the critical knock point, but would not give the wet compression ' bigger turbo' benefit later in the rev range as I wouldn't be spraying enough water. Yeah I see where you are coming from as what you suggested would produce that benefit too, not just cooling.