My MY95UK block is on it's way to the great Subaru graveyard in the sky because the big end is about to go

I have been offered a few short blocks to replace it with including WRX, UK & even a MY97STI block which I would be very interested in if the answer to the following question is yes .

My question really is...can you run an STI or WRX short block on a standard MY95 ECU? It has a scooby ECU mapped to run at 15.5psi on it. Would this need re-mapping or would it be a straight swap?

Thanks for any help.

MAFFA

 

Yes, plus you will have the added bonus of the forged STi pistons.
However, it must be phase one sti (ie. ver 1-4)

Rob

 

MY97 is a phase 2 isn't it? Thats when they facelifted it. How come that matters on just the block...are some of the fixings different or something?

Oh well David from API is calling me back in a mo so i'm sure he'll put me straight on a few things as when it comes to engines & internals etc...etc... i'm useless

MAFFA

 

Just done a bit of research and a MY97 is a Version IV which is a bonus

The engine might have uprated internals as well, which would be a bonus . API are gonna check it this week & give me a full diagnostic on it inc. any work that needs doing

If it's good then it might be time for an uprated ECU to get the full potential

One thing i've just thought of. A MY95UK has 380 injectors if i'm not mistaken. Would presumably just be putting these into the STI engine initially? Uprate the ECU & then I can go for the 440,s i've got lying around or poss even bigger?

MAFFA

 

MY97 is most likely a Version 3, identical short engine to the ver 4 so no diff there.

You can basically say that the sti short engine will make absolutely no difference, almost as if you were replacing it with a UK engine as far as bolting your stuff back on goes. Likewise with uprated internals, it doesnt mean you have to change anything just that you have the added security/peace of mind plus the added strength for future mods.

Phase 2 is slightly different compression ratio IIRC, this can be overcome with thicker head gaskets but i believe the piston castings match the phase two heads..

Rob

 

You're an absolute star. Cheers for the advice fella