[mtbendo]

Originally Posted by Huey130

The pump starts sucking. Water flows through the grate. It does so at the entire surface area of the grate. The pipe continues to pump water into the pool.

That's an airbox. It's always full of air. The engine sucks the air out all the way across the filter. The tube from the fender well ensures the airbox is always full.

Keep in mind that while the entire filter maybe flowing air, the air velocity at all points of the filter may not be the same, especially at higher flows. Flow will take the path of least resistance. Even in a smooth pipe, the air/fluid velocity along the walls in less than the velocity in the middle of the pipe due to surface fiction.

How's that for an engineering geek response? M.E. btw.