Originally Posted by Hobbymanbill

Dan believe it or not the temp difference between underhood and out side can help if you can get it in unrestricted. Look at naturally aspirated Pro Stock drag cars, They utilise the low pressure area at the base of the windshield to pull in cooler air and actually add something like 2% HP. Remember though, they are not running ANY AIR FILTER, And they make something like 1,400HP. Also their air scoops are designed in the wind tunnel to help pull air in and aid the carbs ability to use all the available air. No matter how you try to get cooler air into our engine, you can't have a measureable affect.