So a person on ebay is selling some 86 13b rotors saying they are from a 6 port engine I thought all 86 87 88 engines are 4 port? So I asked him about this.

This is the response I got from this person.

Dear baker1184,

the 6 port is all na 13b engine from 85 to 91 the 4 port engines are turbo engines maybe you should check into rx7 history

- silverfdturbo6port

 

All NA's are 6 port but only use the extra 2 ports (auxilary ports) above 3500 rpms, all turbos are 4 port..doesn't matter on what year s4 or s5. So yeah hes right.. again read on the 7..search..read..repeat

 

I have a 74 repu engine in my bug and it is an NA 4 port.

Thanks for the info.

 

yes i believe it starts at 85 and older are 4 port n/a they were latter upgraded to 6 ports n/a. the 86+ turbo motors retain the 4 ports.

u asked if the 86,87,88 motors were all 4 ports even n/a and no thats wrong

 

Thanks for the great info I have some reading to do.

 

You're still not getting good info, though. 70-85, all carbed rotaries were 4-ports. For 84 and 85, the GSL-SE was an injectied 6-port, very similar to the S4 motor, but with the coolant seal grooves in the housings like the rest of the carbed motors. All NA FCs were 6-ports with the coolant seal grooves in the irons, while the turbos got 4-port irons.