I am new to this rotary discussion, and I am looking for some help
with fuel system design for a Mazda 13B NA in a Sportsman 2+2. The
kit is designed for a Lycoming IO-390X, and has small, header tanks
mounted behind the " rear door posts". For a Subaru installation in
this airframe, an alternate 5 gal header tank in the baggage area is
required to "cool the fuel".
I would prefer not to plumb a return fuel line to the wing tanks....
is there another solution to the header tank? Does it really cool the
fuel? Is there another way to cool the fuel (air to fuel heat
exchanger?), or is the real problem air-bubbles in the fuel?

TIA,

Thomas Lowell


Doc is building just what you are looking for. A no fuel return
line system. The real problem with a return line is it heats the
fuel. This becomes a real problem when you get low on fuel.
You could experience vapor lock. Yes a heat exchanger would
cool the return fuel.