Is there a published ratio for outlet air?
RV4, 0320, inlet area 52.5 square inches. Outlet at back of cowl 30 square inches.
Anybody?
Still getting higher than hoped for CHTs. Have to come back to 25 squared in climb to keep them below 400. Engine only has 14 hours on it so still breaking in. Was considering enlarging the exit area slightly to see if that would help.
Given typical engine baffling, the cowl exit is the system throttle. So yes, more exit area will allow more mass flow.
That said, there are many factors which can contribute to high CHT. You may want to look at some of them before cutting the cowl.