I was told it's S4 turbo. Is that right? Shouldn't a turbo have open water jackets?

There's no knock sensor hole on housings. It may look like there are square openings under the lower ports on the outer irons, but that's just a print from the gasket that has square holes. The big round hole under the center ports is blocked off and pretty much flush with the engine. Exhaust ports have the diffusers and two small round holes under them.

 

Looks like S5 NA from the exhaust side. A pic of the driver side of the housings would make it easier to determine. And yes, if it was turbo housings those holes above the exhaust manifold would be open and the diffusers would not be in the exhaust ports.

I can also see that the oil injector holes have been plugged. Are you planning on premixing?

 

It's a 6-port engine, so that rules out turbo right away. The gasket marks you mentioned are where an S4 NA would have port air passageways, and an S5 would have a single rectangular port on the center iron for this function. Yours has a big round port instead, so maybe this is a GSL-SE engine?

Pictures of S4 & S5 LIMs / port design here: http://homepage.mac.com/carldavis/intake/mod.html

 

The center iron has a freeze plug below the intake, ironicly this freeze plug blocks exhaust. i had a customers car last summer that blew that plug out and had a bad exhaust leak, her car was an S4 n/a.

My 13b-GSL-SE.
Nope not GSL.
My vote is for S4 N/A, the most common rotary engine.

 

NOT series four non turbo. The front and rear side housings would have had the rectangular holes below the intake there.

The intermediate housing looks like a series four non turbo in that it has the "freeze plug" covering up the internal passage that is related to the EGR. IF your intermediate housing has a EGR in the top of the housing...........then it is probably series four non turbo intermediate housing.

The exhaust gasket looks wrong in that it has no hole for the EGR feed, that half inch size hole that is usually below the rear exhaust port.

NOthing turbo about the whole thing imho

 

so S5 rear iron, N/a housings(can't be sure of s4 or s5), S4 N/a middle, S5 N/A front iron.

Which really makes sence if your building a performance motor and you dont want have any exhaust ports blocked by a gasket.

 

^ Yes, that seems to be it: a mix of S4 and S5 NA parts.

 

Alright, thanks for the info, guys.

Sounds like quite a sandwich. Judging by the lack of knock sensor holes in the housings I'm gonna assume the housings are S4 N/A.

And yes, I know the exhaust gasket doesn't have EGR holes, but I don't have EGR, so I think it should be fine.