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What is your opinion on letting the air cleaner stick out of the hood?

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I currently have a hood scoop on my s30 because my air cleaner sticks up above the hood line. What do you think of just leaving a small hole in the hood for the base of the air cleaner and then just putting the air cleaner on after I close the hood? Do you think this is doable or are there any concerns?

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Hoods can be replaced. If the aesthetics of cutting a hole disappoint, it's not too great a trouble to start over afresh. It's not like tubbing the rear or cutting the roof to make a convertible....


One should be careful about extrapolating aero results for overall car aerodynamics, to the flow through an air filter. The middle of a typical hood is a region of local separation, so air flow into the hole would be poor. However, the air filter acts like a local low-pressure region - because, well, air is flowing into the engine. It would of course be better to source airflow into the air filter from near the hood/windshield juncture, but a hole in the middle of the hood is NOT necessarily awful.


Proper air-scoop design is difficult. So I suggest cutting a hole for Version 1.0, and then worrying about an air-scoop in Version 2.0. Also note that an air filter sticking out of a hole in the hood would at least partially alleviate issues of high underhood temperatures reducing intake mixture density. There are ways to solve this in a "clean" installation with no hood cutting, but which approach is simpler?


After much tinkering, my home-built fiberglass hood has a hole in it, for a 14" round air filter case (Chevy big block V8). It is not suitable for the rain, but in dry conditions it is very convenient. I can tinker with the carb without having to remove the hood.

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