corvette/firebird style engine cooling
 

would an air intake system (engine cooling) like a corvette's bring less drag than leaving a small area open on the lower grill, on a dual grill car like an echo/corolla..corvettes have an area under the front of the car that sticks down into the airflow about 2-3" down and about as wide as the radiator and a curved air diverter, allowing the hood/bumper area to be completly sealed. this "air catcher" is about 12" behind the front bumper, my measurements my be off a little, as i did not want to explain to the corvette owner why i was under his car. my upper grill is already completly blocked, and my lower is partialy blocked,,tring to decide on corvette style vs. an active lower grillblock ,ideas?

Not familiar with the style. Maybe post a photo (even something from Google images)?

think of an air dam that connects to the bottom of the radiator. This forces the air into the fins.

Yup, they are called "bottom feeders" because the air is pushed up from the bottom of the car by the lower air dam. It makes a lot of sense because you get the benefit of the air dam cleaning up the bottom of the car, aerodynamically speaking, and you don't have a gigantic grill opening on the front grill of the car.

http://image.vetteweb.com/f/27151413...engine_bay.jpg

You can get an idea of whats going on there.

The opening on the front bumper seems to be for the engine only.

aero mod sticky
 

I think I put the Trans Am data in the mod data sticky here at the aero forum.It should have the number you're looking for.

Pictures of this arrangement in this past thread. A little more here.

These pictures show how cooling air is directed to the radiator.

I haven't found pictures of what special arrangements if any are made to lead
the air out of the engine bay and under the car -- something like the BMW
gently radiused ducting perhaps?