Originally Posted by ace996
Do you think the string collapsed on the mesh as a result of the air, that was passing over the hood at a high speed/pressure, because it was just "blown-over"...or does the vent actually enjoy a high-enough pressure from air passing over the vent that it becomes a legitimate intake source?
Or that the motor actually needs the vent as a source of air and creates a vacuum in the box?
The string was flapping in the breeze up to and beyond 100MPH - there was clearly a strong blast OUT of the opening. Until I went full throttle I was convinced the opening was an outlet not an inlet. At wide-open throttle the string would suck down onto the grill on the opening and stay there. It didn't seem to matter how fast I was going, at least up to about 120MPH. I watched it do this all day.
My conclusion is that at full throttle the opening provides extra air for the engine, and at part throttle it keeps cool air coming in and warm air blowing out to prevent heat soak. You could put a flap on it, but then on a hot day in traffic it would cut power because the intake air would be super hot.