Might be fitting an STI ecu into a 93WRX. I'm not sure what my the ecu is from though, I think it might be an STi II.

Does anyone know which ones wont work?

cheers

 

I know a 6K, 7K and Z4 will fit and be fine.

 

Wouldnt have thought that the STi ecu is the best option for your car (doesnt it have different injectors to the early wrx's??) so id go for a 95/96 wrx ecu and up your power that way (just my opinion BTW).
Tony

 

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If your STi ECU has four "sockets" on it then it is either an early (STi I or II) or very late (STi VII) ECU. Odds are it would be a version I or II. In this case the injectors are the same grey top 380cc units, so no issue there. The piston crowns on the STi II were different to the WRX, and also there is the possibility that the ECU came out of a Wagon which would have been 8.5:1 compression not the usual 8:1. All of these could affect both the required fuelling and the tolerable ignition advance.

I would suggest that it could be fitted and tested, BUT this should really be done at a rolling road where it will be possible to monitor the engine closely for both appearnce AFR and the onset of detonation. Load the engine up lightly at first to make sure it's clean and not running so lean it will melt a piston, then load it up more heavily etc etc until the load is greater than you could possibly generate on the road. If then it is still clean, I'de suggest that it will, in all likelihood, be OK for the road, but it's no guarantee and still no substitute for a) a know monitor, b) an AFR monitor or c) a properly matched and/or mapped ECU.

Cheers,

Pat.