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Old 07-25-2008, 12:21 PM   #4 (permalink)
EcoModding Lurker
Join Date: Jul 2008
Location: California
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Originally Posted by aerohead View Post
The convention has been to keep the inlet tract opening ahead of the radiator bulkhead to take advantage of the high static pressure which can be harvested at this forward stagnation point.
Sure, on an unmodified car that makes sense. However, once the grill blocks go in, is that position necessarily still optimal, assuming it is still possible. On my Protege5 the engine intake is through a space under the leading edge of the hood. It's hard to describe this, but it is sort of on the upslope of the front end of the car. If the upper grill was blocked aerodynamically the intake would still be possible but probably the air pressure there would be greatly reduced by better flow over the front. For our Subaru Legacy the engine air intake is 1/4 of the upper grill (which is split into 4 parts by a sort of "+" shaped member). There at least one could block 3 of the 4 quarters and I think the engine intake would be little affected as the ram effect at speed would be unchanged. If the entire upper grill was blocked the intake would have to move, else it would be literally sealed off, at which point the question becomes, where to move it to. In this regard, brucey avoided the whole issue by blocking the lower intake:

Originally Posted by aerohead View Post
The air mass moving "through" the engine itself, would be of such low volume, as compared to that flowing through the cooling sytem,as to render it" invisible" and of no consequence to the cooling system airflow.
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