My friend scored a freshly rebuilt/ported s5 engine at the junkyard and we were wondering what the rotor housings came from. We compared them to our other s5 engine and the housings are different, especially the exhaust ports (HUGE).

Heres a shot of the exhaust ports:



Heres a shot of the exhaust side:


Top View and side view:



Anyone know what these housings came off of?

 

95% postive they're series 4 NA. Series 5 didn't have the HIROSHIMA written on the top of them (infact they had nothing written up there)

 

why would someone put a s4 engine in an s5?

 

S4 housings on an s5 engine wouldnt be that much of an issue if both housing were the same, but it looks like those two housings are different. Are the sparkplugs in different places? BTW dont S4 housings have a little metal piece in the exhaust port?

 

double post

 

Those are both s4 housings (the square nameplate on top) and though the outside casting may vary a little in different places, it doesnt change anything inside. THe exhaust ports are so big because there is NO EXHAUST SLEEVE present. In theory this will be loud as hell, and have some poorer output; on an NA you dont need that much exhaust flow anyway, plus, if you note, the inlet on your exhaust manifold/header is not nearly the size of those exhaust port outlets, so that's a big source if disturbance there.

 

Is it some kind of hybrid – like s4 housings with Cosmo irons?

 

cosmo irons? lmfao. these are regular, plain old, s5 6 port irons. Note the lack of an egr valve in the center housing (s5 na) and the 6 port front and rear irons.

 

Soooooooo...if thats a series five center housing (it is), then don't expect the emissions to work for flip. I'm guessing that there is no way on this green earth for the Port Air to get to the exaust ports. Could be wrong. But then again, who cares about emissions until the time comes once a year.

EDIT: Which gives me thought. Take a look at the exaust ports and see if there is a hole just inside back of the rear rotor housing and just inside the front of the front rotor housing. Or see if there is a pluged hole there on each rotor housing.