Originally Posted by DanP
Thanks Frank. Very simple and concise explanation for what could have been a lot of bumbling in the dark. So, does that mean those little vents at the back of the box would be more of an intake vent rather than an outlet? Or would the vent system from the hood be able to easily handle that kind of airflow?
My google-ing tells me that 500cfm is a bit of a tight squeeze through two 3 inch tubes without some sort of pressurized system. Especially since the surface area at the intake in the hood is even smaller than the cross sectional area in the tubes.
Sorry if I have gone way off topic from my original post. Im just curious about the air flow direction and source now.
The air coming in at the front and exiting the rear are there so the bilge is ventilated, with the added benefit of providing air for combustion inside of the engine. If the vents weren't there, the concentration of combustible vapors in the bilge would cause major problems in the event of any kind of spark, assuming the fuel:air ratio reaches the danger zone.
The direction of air flow doesn't really matter but if the enclosure is too close to the engine and there's no vent on the cover, heat won't be allowed to escape through convection. You also don't want to have hot surfaces too close to combustible materials.