i searched and could not find info on how to tell the difference between the s4 and s5 turbocharger i think someone may have swaped the s5 turbo into my s4 87 t2....anyone know?

 

The S4 has the twin scroll actuator & door on the manifold.
The S4 has a single port waste gate.

(nice headlights..nice bay)

 

check the manifold

 

there was just a big thread on it, answer the same question kind of, the S5 manifold doesn't have that big actuator on there for the twin scroll if IIRC?

 

ok the reason i ask is because i was haveing trouble with a leak on the turbo and i went to replace the gaskets again and i orderd the metal rings for the banjo fitting cooling lines from mazda for a 87 turbo and they were too small so i got ones for a 90 turbo and they were the right ones and also the oil drain tube is different for the s4 they share the same gaskets but the pipe must be different....i dunno but this leak is pissing me off... it looks to be coming from the bolt near the oil drain tube uderneath on the hott side...

 

oh and i do have the twin scroll manifold and the big actuator

 

I've never heard of the s4 and s5 turbo/manifold being interchanged at all.
So I'll go on a hunch and say if you have the twinscroll linkage on the turbo manifold, then its an s4 turbo/manifold.