This swap is fairly straight forward to get it to start and run by just putting the USDM intake manifold from the Legacy GT or Outback XT onto the JDM engine. You could stop here and just tune for the new engine. To get the exhaust side AVCS working, it is a bit more of a challenge.
The USDM ECU does not have the capability to control the exhaust side AVCS so the JDM ECU needs to be utilized. This is not as simple as the earlier 02-05 WRXs running JDM ECUs that are plug and play (more about that here) because the Legacy models are immobilized. Below are the steps.
First Step 2005-2006 Models - Swap to USDM Manifold and Harness
Swap over the USDM manifold and harness onto JDM engine so engine will plug in and run.
Second Step 2005-2006 Models - Confirm Cam Position Sensor Type
Make sure the exhaust side AVCS camshaft position sensors use a 2 wire sensor.
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3 wire camshaft position sensor on the exhaust side AVCS - Will not work because the ECU that goes with this engine is not compatible with the 2005 - 2006 Models.
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2 wire camshaft position sensor on the exhaust side - The immobilizer chip needs to be copied over to the JDM ECU so it will start and run.
Last Step (2005-2006) - AVCS Wiring from iWire
Once the camshaft and immobilizer chip have been taken care of, we can build an AVCS harness from the ECU to the sensors and solenoids on the engine with a connector in between for easy service to get the AVCS working. If you would like this custom AVCS kit, please get in touch with Us.
First Step 2007-2009 Models - Swap to USDM Manifold and Harness
Swap the USDM manifold and harness onto the JDM engine so the engine plugs in and runs.
Second Step (2007-2009 Models) - Confirm Cam Position Sensor Type
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2-wire cam position sensors on the exhaust-side AVCS will not work because the ECU that goes with that model of engine does not plug into the 2007-2009 harness.
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3-wire cam position sensors on the exhaust side AVCS - Plug in the JDM ECU, get the immobilizer matched up, and run the car on the JDM ECU.
Last Step (2007-2009) Models
WARNING - The issue we have noted with these models is that the USDM platform has more features than the JDM models for systems like the VDC and SI Drive. If you put in the JDM ECU you may lose some features even though it will run the dual AVCS. As a result, we do not make an exhaust AVCS wiring kit for this application.
If you decide to add the AVCS wiring, you can use these connectors.
- https://iwireusa.com/products/active-valve-control-avcs-solenoid-plug-a?_pos=1&_sid=546d98f5a&_ss=r&variant=40734099767449
- https://iwireusa.com/products/camshaft-position-sensor-plug-b?_pos=1&_sid=59ee0600f&_ss=r&variant=40734139777177
Learn more about the pros and cons of the EJ20X and EJ20Y platforms here:
