[jdeas]

I am currently building a vertical induction FI (Bendix). The plans call for both a heated air door at the front of the air intake and an emergency air door mounted to the bottom of the filter box.
I fly behind an O-360 where this makes sense to me but are they both needed for an FI system?
What additional risk would I be taking if I just installed the 'emergency' unfiltered air door on a FI system?

 

[flyinga]

I never heard of heated air for a FI engine. With no venturi ice is most likely to form on the filter. I'd go with the alternate air door only.

 

[flion]

That's correct. Leave the heated air flapper off. If you use Van's alternate air kit, make a reinforcing ring to sandwich the fiberglass bowl with the inlet ring. Just riveting the ring to the bowl will see the rivets pulling through in short order.