If memory from reading posts serve me correctly, the aux(5&6) intake ports are opened and closed by solenoids. Although Mazda used a pressure switch in the exhaust system to activate these, there is occasional talk about doing it completely electronicaly. fc3s.org has a write up on using an RPM switch to activate an electric air pump, thus fooling the pressure switch. It seems to me that the same RPM switch could be wired, either directly or through a relay) to the aux port solenoids, resulting in fully electronic aux port activation. This would keep low RPM power, while allowing us to upgrade to very high flow exhaust systems with out loosing high RPM power. What problems do you see with this idea?

 

No, they are pneumatically controlled, not electrical solenoids, by either exhaust back pressure or factory smog pump (depending in series).

And the write up on FC3S.org is to use a pump to pneumatically open them instead of using either the exhaust back pressure or factory smog pump.

 

Darn. Cross-wired neurons. I guess that idea's a bust. Oh well. I should probably be spending my time moding the car so port actuation becomes an issue before I worry about any way.