In this blog post we talk about twin turbo engines for you swap. This engine swap has some challenges so for those looking for a simpler solution take a look here for “easy” Subaru swaps.
Subaru made 4 types of twin turbo engines. 2 from phase 1 (engine codes EJ20H and EJ20R) and 2 from phase 2 (engine codes EJ206 and EJ208). Since this is a difficult swap there are a few things to consider before digging into the project.
The secondary turbo on the engine will hit the steering column in a LHD car so the twin turbo engine will not fit in a LHD car without a lot of modification. It was designed for a RHD model in mind so for those who really want to do this swap it would be best to start with a RHD chassis.
We’ve seen a few thousand swaps and we only know of one person (doesn't mean there aren't more) who has successfully been able to modify the steering column to get the twin turbo to fit properly in a LHD chassis. (We don't know what modifications they made as we never saw the car in person).
Parts: For those really set on doing this swap, they must have ALL of the wiring components. This includes the harness, ECU, and solenoid box a.k.a. Black Box of Death. We are not able to source these parts and without them the engine will not run properly.
(Big Black Box of Death)
Another thing to consider is the fact that many people who purchase the Twin Turbo Legacy models from the factory end up converting it to a single turbo engine because it's more efficient. If the end result is better with a single turbo then we figure it's probably best to just start with a single turbo platform.
What if the engine is already purchased?
Assuming a phase 2 platform, then the simplest route (other than changing engines all together) is to swap over a USDM 2.0 WRX intake manifold and harness as well as associated parts to a USDM 2.0 WRX and we'll wire it to match for a pretty good setup with a tuneable ECU. There is nothing wrong with the twin turbo longblock so this method updates the parts to something that will fit in a LHD car.
iWire’s Opinion: Despite the lure of the inexpensive price tag, we suggest staying away from these engines. The mechanical and wiring aspects make it a difficult swap. For those with exceptional fabrication skills maybe it's worth it, but if you are looking for a reliable daily driver we recommend a single turbo engine instead.
That being said, if you want to move forward with the twin turbo swap, we are happy to wire it up for you just make sure you have all of the required parts.