The fans you mention in post #1 are about 3 inches diameter, while the louver in your link in post #39 goes up to 8 feet. Nothing about a louver that size applies to a fan so small.
The point I was making about the area of the vents vs. the area of the fan is that if the vents are smaller than the fan, you already are losing air flow before even considering any obstructions in the air path such as the components you are trying to cool. Think of it this way - if you have a 100 mm fan trying to blow air through a 10 mm hole, the hole size is going to restrict greatly the air flow. So even if the fan is rated 300 CFM, the net air flow through the hole will be much less. Generally speaking there are three things that reduce the net airflow through a system to something below the maximum rating of a fan: intake and exhaust areas, changes in direction, and obstructions. The obstructions are the things that have to be cooled, and usually you can not change them. That means that the other two are the things to manipulate to maximize flow through the system.
