I think you would see some benifit... 1) because it would be compressed air with moisture in it, and 2) because it comes out cooler than your intake air... a better way would be to just use water injection. not sure how much benifit you'd see on a NA motor but there should be something there...

 

I know they used water injection on some or the WWII aircraft but I think it was in conjunction with some type of supercharger. If you look at the throttle quadrant on some old acft there was a gated notch for mlitary power. However you couldn't stay there long. Ancient History. I think JC Whitney used to sell some type of water injection system. (also ancient history) Might make one up with windshield washer pump and a real fine nozzle.

 

the water injection systems are used for turbo and supercharged motors.