Quick and simple question. Are the front and rear aluminum rotors housings essentially exactly the same? I am planning on buy one from someone and am being asked if I want the front one or the rear one.... didn't think there was a difference.

 

for most of the 13b's there IS a difference because the egr port is only on one of the rotor housings so those still using the emissions egr it would matter BUT the s5 rx7 nonturbo which you have it doesn't matter.

look at the exhaust gaskets on www.mazdatrix.com to see what i mean

so for YOU it doesn't matter.

for anyone else who doesnt drive a 89-91 non turbo it DOES matter (if they stil use the egr)

 

its actually not the egr, but the air pump ports. the air pump air goes thru the center housing, and into the rotor housings, so if you swap the housings it blocks off the port.



good news is that the passage is literally just a hole, and you can drill out the other side, if you need to.



if you put it backwards it will never pass smog