How much open area does a 911 decklid need?
 

I have an idea for a deck lid for my car and was wondering what the minimum open area (square inches) for engine intake/fan intake is. I have a 3.2 carrera engine with 46mm PMOs, non AC.

I would have thought that the original decklid designed by the Porsche engineers would be a good starting point as a minimum. In the case of your 911 the more the better would apply. Equally important to getting the cold air in is getting rid of the warm air. You often see people that has drilled holes in the rear bumper for this purpose. If you were to have a GT2 style decklid with scoops you get more air. Its a "how long is a piece of string" question really.

LJ.......when I started to make aftermarket grilles...i measured/ calculated the open area of the stock grille...to ensure that my design met or exceeded that baseline....somewhere in this thread is my post of the open area calc........

http://forums.pelicanparts.com/porsche-911-technical-forum/602269-do-you-like-my-new-grille.html

regards,
al..

Thanks Al, I found your numbers in the thread you linked.