Does anybody know the Internal Diameter of the exhaust sleeve labelled here in mm? Is it different between engine generations? (13B-RE, 20B-REW, 13B-REW etc..)

 

it does vary, so you'll have to measure it. at the end where it meets the manifold the FC is about 48mm, but its not actually quite round. it then tapers way down to meet the exhaust port in the rotor housing trochoid

 

Don’t really have access to any rotor housings at all but assuming that by FC you mean the S4/5 Turbo, that’s the perfect rotor housing that I wanted the figure for. Thank you so much! (Even if it’s not the turbo an estimate of ~50mm still helps a ton.)

 

the FC has an outlet around 48mm (again its not perfectly round), and the manifold is 50mm, so there is a step there. it may help with anti reversion.
one of the reasons headers aren't thought to work very well on NA FC's is because the RB headers are 43mm, and the exhaust port is 48, so there is a step the wrong way.... the older engines have smaller sleeves

 

can somebody measure and post the dimension for the FD housing?
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