Hi all, I have a 2002 WRX Wagon with a MY02 B4 liberty engine that has been modified from twin turbo to single turbo. Im planning on having it tuned, but am assuming that there may be differences to a wrx engine. Would it be likely that the ECU is from a B4 or a WRX? Also the compression on the B4 is different to the WRX, so Im wondering why the previous owner decided to go with the B4 engine instead of a WRX, do you think its because they are a cheaper engine, or is the compression ratio better? I think other than the compression the ej20 is the same?
You will achieve higher hp with the higher compression ratio. But a .5:1 gain is not much but it will make a difference. I would guess that it is a B4 ECU, just reprogrammed for a single turbo set-up. All parameters on the ECU can be changed to make it believe and run like a single acting turbo'd engine.
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