Micro Image Hood Design Contest

[eTiMaGo]

Originally Posted by LtNoogie

What is the function of the vented hood?

Let the hot air out? Pull cooler air in?

I assume that we do not want to allow rainwater to pour into our engine compartment while we're parked at work.

I also assume that we don't want the hood to inhale rain and spray on the highway in a storm.

Sorry, the engineer in me says function before form. Once you meet the functional requirements, you can make it pretty.

A forward facing scoop is useful in shoving cold air to the intake. If done right, it can have a "ram-air" effect where the pressure of the incoming air actually causes some slight compression at the intake, in essence a free very light turbo. You could also duct it so that the incoming air blows behind the engine, cooling the exhaust manifold.

reverse scoops, on the other hand, are used to help extract air from the engine bay. This can have 2 purposes: keeping underhood temperatures cooler, and allowing better airflow through the engine compartment, thus reducing the car's aerodynamic drag somewhat.

So, yes, as always, there's a compromise. Have a big'ol hole in your hood and rain will come through it. Though it is my understanding that most aftermarket hoods come with a shield under the vent that can be closed to make it waterproof.