I'm about to build a fan shroud for my inline- powered '40 Chev coupe. The core is roughly 17 x 22, I'm using a 16" electric fan. I've seen commercially made fan shrouds with multiple round openings covered by rubber flaps. Makes sense- at low speed the flaps are pulled shut by the fan, forcing it to draw through the core, but at highway speed the flaps blow open, allowing the greater volume of air to exit the shroud through the holes. Has anyone made a setup like this? What did you use for the rubber flaps? On a different but related note, due to space restraints I can only make the shroud about 1" deep. Does this put the fan too close to the rad core inside the shroud? Will it be able to pull air through the areas of the shroud not directly in front of the fan, or will the shallow shroud be too restrictive?
Well, I would think some shroud is better than no shroud, as the fan certainly can't pull anything through the radiator outside the fan cir***ference without a shroud. But, I share your concern about being so close to the rad. Perhaps a 'ring' around the fan opening in the shroud would help to pull from inside the shroud as opposed to around it's edges. As for the flap material, many vehicles have 'cabin vents' in the body, usually around the trunk, either in the well behind the rear wheels, or at the rear trunk panel behind the bumper or, in some cases, in the door pillars, and they have rubber flaps that may be adaptable for your purposes. A trip to the salvage yard should turn up something useful. Ray
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