Puppaduck - Sweet mate, I won't grill ya!
Wind chill is do with the affect of cold air over skin... liquid water on the skin evaporates drawing heat from your skin making you cold, airflow just makes this affect worse.
Water sprayed onto intercoolers have the same affect, but you need liquid water.
confak - Air/Air Intercoolers cannot cool below ambient.
Assuming that the pressurized air leaving the turbo is held at a constant temperature, say 70oC. Say ambient is 25oC. As the temperature of the pressurized air flows through the intercooler its temperature drops, as the temperature drops the driving force for heat transfer (the temperature DT or the difference in ambient temperature and the air in the intercooler) starts to decrease. Assuming that the intercooler was infinitely large at some point the temperatures would be almost the same.
However in real life the Intercooler has a set area, defined by its geometry. So the exit temperature out of the intercooler can only decrease to a temperature above ambient.
I pose a question. If the air does go below ambient, then where is the heat from the pressurized air going? If there is nothing around the intercooler that is below ambient, then there is no temperature drving force, therefore it cannot go below ambient temperature.
However add a water sprayer or dry ice then everything changes!
I personally like the idea of an air/water intercooler, An intercooler the size of the one in a stock GTS-T can be made to be more effective than an air/air intercooler twice maybe three times its size! Its all to do with the heat transfer coefficients!