As you can tell from the title, I need to know how to tell the difference between s4 and s5 for a Jspec automatic engine. I bought it from a good friend but de didn't know whether or not it's series 4 or 5. All i know is that it's from Japan, and it's automatic (especially so because there were no US auto TIIs). Any help in identifying my engine would be much appreciated! Anyone that just wants to talk mess can read my sig!

 

same difference with the S4 and S5 turbo engines, only with the additionall J-spec difference from the USDM engines.

 

yeah but even that seems to be widely under debate, i've heard a bunch of conflicting things. so please be more specific

 

s4 is mechanical OMP the s5 is electric OMP (bigger and has wires to it) dead giveaway

 

hard to convert without using harness and ECU

 

OMP--> are you talking about the Oil Metering Pump?