I was hoping that by directing the cold air into the engine, you would gain more than you lose by having the air-con operating.

The exhausted hot air would need to be expelled.

From your response, and the fact that the car manufacturers do not do this, I was kinda expecting your response.

Its just that I cool my home PC with an air-con unit, venting the hot air outside. The effect on my PC means I can really overclock it, but my electricity bill is higher.