so I've searched and looked at engine diagrams but I'm still not sure, are there intake ports in both the center housing and the secondary housing? so each rotor has a port on either side of it? if so, are there any differences between the two ports? thanks guys

 

primary ports is biggar! wait. i dont know crap about first gen. i think its the same as 2nd though. front and rear ports are bigger and the 2 middle ports share the intermediate iron so they are smaller.

 

Yes, each rotor has a primary and secondary port, coming in from each side. The smaller barrels on the carb supply the primaries, (center) ports, the larger ones supply the secondary, (end ) ones. The size of the ports vary, not only from engine model to model, i.e.,12A/13B, FI/carb, but also from year to year.

 

alright i understand this much mself ... but how does the 6 port work? Please forgive me I'm a newb

 

The 5th and 6th ports are a 2nd set of secondary ports, found on all 13B NAs fom 84 on. The S3/4's opened around 3600-3800 rpm, by backpressure from the exhaust, S5s were electricly controlled. The ports are opened by a sleeve that rotates, exposing an opening in it.

By limiting the amount port cross section at low rpms, the engines developed more lowend torque. While we got the SE engine, the rest of the world got a 6-port 12A. Those posrts had butterflys.