Quote:
Originally Posted by MLL67RSSS
Ok here is a little history lesson for you. Back around 1968 the GM/Chevy engineers were working on a way to get some air induction in to the engine. What they discovered was that due to something called the "skin effect" the air near the surface of the car is somewhat static. In order for it to have any effect it must stick up several inches above the surface of the car. That is why you see the pro-stock cars with the snorkel type hoods sticking way up into the air flow. They also discovered that due to the air diverting up the windshield it created a low pressure area at the base of the windshield. By placing a backward air intake there (ala "cowl induction") they were able to create an air induction system that actually worked/did something. So in 1969 the ZL2 "cowl induction" hood became available on the Camaro. Why, because it worked. Of course you have to have a seal between the hood opening and the air intake into the engine for it to work. The reason that all of those neat little scoops and stuff weren't opened was because they really wouldn't do anything/function much other that letting a bunch of rain and crap in the engine compartment.
Secondly, lets remember those functional air OUTLETS in the backs of the front fenders of the 2nd gen Trans Ams. Why were they there? Because packing a bunch of air under the hood creates lift. At high speeds it can actually create enough lift on the front end to become unstable and dangerous. Those vents were to allow any built up air OUT of the engine compartment and alleviate any high pressure front end lift. Believe it or not GM actually has wind tunnels and knows a bit about aerodynamics.
Now that mailslot being towards the front of the car MAY be less susceptible to the "skin effect" and I suppose it is possible that some air could get in there, but where is it going to go once it's there? If it has no way to get out other than out of the engine compartment and under the car you've got that front end lift thing going. But if you just can't stand the fact that that mailslot isn't open then got for it. Might be better off trying to open the BACK of the hood bulge up somehow and create a cowl induction type of intake, but with the engine air intake being at the front of the motor could be problematic.
|
Just a small correction. GM Knew about the high pressure area at the base of the windshiled for a long time before 1968.. in fact I have seen pictures of NASCAR stockcars from 1963 with a Cowl induction setup. Since they went at a much higher speed than street cars they didn't need to have the hood buldge to get the air pressure effect. they took it in at the cowl vent at the base of the windshield.
Todays cars have much less of that pressure available because of the angle of the windshield. the less upright the windshield is the less pressure is developed, it would take much higher speeds today to get the same effect as they got from the 69 Cowl induction setup. sure it would pull cooler air in, but it would not have the same ram effect..