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grathke
06-23-2017, 09:02 AM
Pardon me if this has been covered somewhere. First off I'm just starting my trek with the 818s. I've signed up for the build class, starting to see what donor parts I need, etc..

My question is, what engines can we use. I see so many different Subarus like WRX, Impreza, Impreza Outback, WRX. And yet there is also the Legacy, Forester, Outback. Are these also valid, at least for the engine. Is it simple as using an engine from 02 - 07 regardless of the car model. What would be really great if the designation such as EJ20, EJ25, etc were noted. For my needs I could use a naturally aspirated engine. How to know EXACTLY which engine to get. I'm looking at Sunshine State JDM and they have a ton of engines, just need to figure out which one.

Thanks
Glenn

fastzrex
06-23-2017, 09:54 AM
First, if you haven't already, read the sticky in this engine forum. It will prime you to the differences.

Most Subaru engines from 2002 through 2007 would be suitable, both NA (naturally aspirated) and turbo. The most important considerations are 1) Get the ECU (and if a 2006-07, the immobilizer module and keys) for this particular engine and 2) engine wiring harness for the engine you are buying. While you may be able to use other harnesses not actually made for your install, for you it would be best to get the correct ones to start with; will save a tremendous amount of time and money.

phil1734
06-23-2017, 12:15 PM
Any EJ motor and 5MT should work.

The only thing to watch out for is the switch to a CAN bus engine harness, which depending on exact model and trim occurred sometime between 06 and 08. All Impreza derivatives switched in '08, I believe Legacys may have switched earlier. Not sure about Foresters.

I believe if you may also need the instrument cluster for some later builds with the immobilizer unit (it's an odometer thing.)

Wikipedia has a pretty good breakdown of all the differences between engines. https://en.wikipedia.org/wiki/Subaru_EJ_engine
The sections on the EJ20 and EJ25 will be most prevalent as that's what Imprezas had from '02 to '07.

grathke
06-23-2017, 03:25 PM
Thanks for the replies. Tons to read up on and learn.