I am a bit comfused here.
Are we talking about relative pressure drop (in difference with ambient pressure) or partial pressure betwen gas and air?
Becouse, as l learned at chemist school, equal volume of gas in gas mix equals its partial pressure. So, if we have 50/50 gas air, we must have 50/50 pressure, meaning the pressire (vacuum) anywhere on the sistem betweet the last restriction (lets say hayfilter), air valve and engine intake manifold shuld be the same!
This is what Thiery sayd above.
Afterall, its what a membrane automixer does!
I have been thinking about puting your cycloned gas air mix to the test. I have some room in the engine compartment, and it certainly cant do no harm, l just want to be sure if its wort the effort.