Because of the disturbance in the airflow around the Jeep while moving forward it will catch more air when facing the windshield. Same reason a ton of air comes in the sliding back glass of a pickup truck. You do not want to face it forward because it will apparently catch a lot of water and debris. At least that's what I've read here. I personally don't have a scoop at all.
What is wrong with this thread? I don't see any pictures. We love pictures. Lets see that install!
Participate in life....Keep movin'....Go there....JK'n it.........Do it! Jeep #1: Red Rock 08 JK Rubicon 4dr, 6 sp manual, Stock Mud Tires, MyGIG Upgrade, Hard Top, after sale BestTop SunRider Soft Top, Congo Cage Rack, Mopar slush mats Jeep #2 Black 08 JK Rubicon 2dr, 6 sp manual, both tops, some chrome...uggg (my wife's jeep) Jeep #3 White 92 YJ (my son's jeep) A great quote from a good friend: "All hail click clack and master jk'n." Click and clack are my idols!
chevy called it cawl induction, they even had trap door built in that opened up at wot.
there is a high pressure spot at the base of the windshield that would be even higher on a Jeep because the flat almost verticle windshield will force a large amount of air toward the bottom.
I had one, I turned it away from the windshield. It did increase airflow and helped the A/C but I took it off because I didnt care for it anymore. But snow and debris did get in there during the winter months.
I'm not too sure if facing outwards is going to increase air flow. Keep in mind you need laminar flow in order to make sure that the boundry layer is as close to the hood as possible, otherwise you won't have air mixing. Even though the boundry layer is only parts of inches thick, the lower to the hood, the better it is. The velocity profile increases as you go from laminar to turbulent.
Actually it's a rather interesting aerodynamics problem. I'm gonna try to model it and let you know what results I guess. Lets put my degree to good use