I'm currently rebuilding a 1987 RX7 FC3S Turbo II (Euro model).
As the old center iron needs to be replaced, i searched for a new one. As i found out, the center irons for 87 Turbos are sold out.

I searched in the forum for similar questions but did not find a suitable thread.

So, can someone tell the differences between the S4 Turbo II and S5 Turbo II center irons? I found some old threads for the NA engines but not for the turbos.
As the S5 ones are still available can i replace my old one with it?

Part numbers are:
for S4: N332-10-D00B
for S5: N370-10-D00C

 

here are the options.
N332-10-D00B is NLA, like you say. its the US and i guess EU spec.
the JDM S4 is available, N318-10-D00C, not sure what the difference would be. the JDM cars didn't have EGR, but the EGR passages aren't in the center iron? it is the cheapest one, by a LOT

the S5 part is also available, N370-10-D00C. the big difference with these is that the port openings are FD spec, which are smaller. port runners are a little different also.

 

Not sure what the difference is on a S4 or S5 T2 center iron, I've always identified them by the flanged oil fill tube, one is taller than the other one. I have a both of those for sale if you need one

 

I have made some pics of the old center irons. I need some irons with EGR ports / channels.

Exhaust gas flow from housing throug center iron into intake.



Port for EGR

 

that is for the air injection, not the EGR

 

It's certainly for the EGR, as well as air injection. This is part of what the ACV is switching between.

 

What is the point of this port? I see it's for the EGR and air injection but why is it routing through the housings?

 

the air pump air goes through the round port in the intake manifold, into that square hole, down the housing and into the exhaust ports. Mazda calls it Port Air

this is the FC picture, which i guess is like a schematic view


the FD picture shows the passage better, but the ACV is kind of all over, lol


i don't know about the EGR passage, except that the JDM S4's don't have it, and US cars do