Engine compartment airflow

[roadyj]

I was wondering if anyone has any thoughts on improving airflow around the engine (front mounted)? I was thinking of making a radiator shroud between the engine and radiator. The shroud would begin at the bottom of the radiator as far forward as possible. The top of the shroud would be as far back as possible creating as much angle as possible. This shroud would contain all of the airflow leaving the radiator. All others sources of airflow could then hopefully be blocked from entering the engine compartment. The shroud would direct the airflow into a wide duct, which could be as simple as light flashing attached across the entire underside of the hood. The duct could then vent across the entire width of the hood between it and the windshield. If the underside of the compartment was belly panned and the compartment itself was sealed off the only air coming in would have to move through the shroud and duct.

It seems that unless you suffer a really big weight penalty it could help the economy of the vehicle by directing the airflow and missing a lot of flat vertical surfaces on the engine and in the engine compartment.

My other thought is that the engine and under hood components must receive some benefit in cooling from the air flowing around them normally. So their could be unforeseen problems in doing this.

Or could the whole thing be a waste of time because after the air passes the radiator it becomes "dead" and you would not suffer anymore aerodynamic penalty afterwards?

Any thoughts?