trying to figure out from what year rx7 this check valve came from. it has N201 imprinted on it.

 

It looks like the thing that connects to the main cat and opens up the aux ports on an S4 n/a.

 

that is a split air tube..it is on an S4 N/A.(well my s4's had them)..it goes from the back of the engine(passenger side,roughly,it attaches onto the firewall with a bolt),and it Runs down to a Flange that is on the side of the catalytic converter,,.the Purpose of it is to Get air to the Cat..also there is a little Nub coming off it..a hose goes on it,and it Runs to the Auxiliary Ports(5th and 6th ports)..the Back pressure in the Exhaust helps to open them up around 3500-4200 RPM(depending on Tune,etc.)

 

thanks for the help guys however, i know exactly what this part is and how it works. what im really trying to figure out is what year and model RX-7 did this part come from?????

 

S4s. so... 86-88, all models.

 

thank you!!! just curious, how did you determine this. what are the key points that make them different?

 

I do not think its a split air pipe from 86-88 but 89-92 because it does not have the tee for the aux port hose.