What do these air flaps do?, And how important are they? Options

[JeffBowlsby]

I bet most 914s don’t have these flaps anymore. These hinged flaps in the diagram are called ‘engine fan flaps’ or ‘non-return flaps’ in the parts manual. They close off the supply air duct path from the engine fan to the heat exchangers when the engine is off by gravity. They open up with the force of supply air to the heat exchangers when the engine is spinning, to circulate air through the HEs into the cabin, as assisted by the electric blower fan in the engine bay.

So the only thing I can figure is that after the car is hot and the engine is shut off, the flaps close to prevent hot air from entering the supply air fan plenum…but I can’t figure out why that’s important.

Any ideas?

[SLITS]

QUOTE (North Bay 914 @ Dec 15 2005, 03:13 PM)

I added the double blower to my car, with aircraft quality hoses (from Aircraft Spruce), top and underneath, the little doors are still in place, as are the correct gaskets for the elbows...stainless exchangers. The heat in my car is crazy. Its like sitting next to a fireplace...actually burning your shoes. Defrost works great, even in the rain. Even clears up a stuffy nose. Its like desert heat. ZERO humidity!

And the assumption is your HEs are not swiss cheese either.