This blog post reviews our recommendations for a turbo Subaru engine swap based on the non-turbo chassis type. If you have a turbo car, you are looking to swap; we generally recommend replacing the long block and leaving the rest of the car intact. More about turbo to turbo or NA to NA swaps here - My Engine Blew Up, What Should I Replace It With?
_______________________________________________________
A question we get asked often is, “What engine do you recommend for my swap/upgrade?”. And our response is always, “What chassis are you putting the engine into?” Not all cars are created equal, so the chassis type has a lot of effect on what engines can be swapped into the car. Below we have categorized different chassis types with our recommendation for the best engine swap.
Some definitions:
Group 1: Non-Turbo, Non-CANbus, Cable Throttle Chassis:
Cars:
93-04 Impreza
98-04 Forester
95-04 Legacy
96-04 Outback
02-06 Baja
This chassis group has the most options for an engine swap because you can stick with cable throttle or upgrade to a drive-by-wire platform.
The engines we recommend for this group include the following:
JDM 2.0 Engines like the EJ205 or EJ207 (not the EJ20X/Y (learn more here)), USDM 02-05 WRX. Another set of good options would be DBW 2.5 liter models like USDM 06-07 WRX, USDM 04-07 STi, or USDM 04-08 Forester XT. If emissions are a concern in your area, you'll want to stick with a US engine for your swap.
Check out this blog with our full write-up on “easy” engine swaps for these chassis.
Special case for USDM 2002-2005 WRX chassis. The JDM 02-05 WRX and STi models are simple plug-and-play options. More about these here. The USDM 04-07 STi, USDM 06-07 WRX, and USDM 04-08 FXT are great options but require a harness merge to run the upgraded 32-bit ECU and drive by wire.
Group 2: Non-Turbo, Non-CANbus, Drive by Wire Chassis:
Cars:
04-08 Forester
05-07 Impreza
For this group of chassis, we recommend sticking with a DBW engine. You could swap in a cable throttle engine, but you’ll lose some features (more about that here), and it will not pass emissions if you do this.
The engines we recommend for this group include the following:
USDM 04-07 STsimilar-year8 Forester XT, or USDM 06-07 WRX. Most DBW JDM motors need to either be converted to cable throttle (JDM Forester) or their ECUs are CANbus equipped, making them difficult to swap (JDM EJ20X/Y), so we don't really recommend them for any non-turbo to turbo application.
Group 3: Non-Turbo, CANbus Equipped, Drive by Wire Chassis:
Cars:
08+ Impreza
09+ Forester
Regarding CANbus-equipped chassis, it is challenging to swap in a new engine. There are just too many inputs/outputs on the CAN line that the car is generally unhappy when installing a new engine/ECU. For these cars, we recommend finding a similar year turbo donor car (for example, a 2010 WRX for a 2010 Impreza or a 2012 Forester XT for a 2012 Forester) and putting all of the wiring and engine components from the donor car into the NA chassis. This would include rear harness, ABS pump, dash, HVAC, etc. Every component from the turbo car must be put into the NA chassis to work correctly. Since you basically need an entire car for this to work, we generally recommend just purchasing a turbo car and adding some mods to that. However, some chassis have sentimental value, so we understand why keeping them alive may be more appealing than buying a new one. Please click here for more about the CANbus complexities.
Swapping the long block and keeping the wiring and ECU intact is the other option to keep a chassis alive. More about this option here - My Engine Blew Up, What Should I Replace It With?
Non-EJ Engine Choices:
Some may have noticed that we do not recommend any FA engines (2015+ WRX or 2014+ Forester) or any of the 6-cylinder engines (EG33, EZ30, or EZ36). We do not generally suggest these engines for the average DIY project because of the difficulty and expense of swapping them. We've written in-depth blog posts about both engine types so you can learn more about the pros and cons to see if it's a good engine for your project.
FA Engines: https://www.iwireservices.com/post/fa20-engine-swap
6 Cylinder Engines: https://www.iwireservices.com/post/2018/11/27/6-cylinder-subaru-swap
Some more information about 6 Cylinder projects:
6 Cylinder vs. STi Comparison: https://www.iwireservices.com/post/subaru-engine-comparison-6-cylinder-vs-sti
iWire H6RS Build Specs: https://www.iwireservices.com/post/iwireh6rs-build-specs
Comments (12)
Hi Marcos, We would not recommend swapping your impreza since it is Immobilized and CANbus equipped. You would need a turbo parts car and you would have to put every component into your impreza in order to do the swap. Since you need a full parts car you may as well buy a turbo car you like and mod that one. More about that here – https://iwireusa.com/blogs/iwire-university/canbus-part-2-can-bus-and-your-subaru-swap
Hi Jamie, Check out this blog post with more details about replacement engines – https://iwireusa.com/blogs/iwire-university/my-subaru-engine-blew-up-what-should-i-replace-it-with
Hi I have a 2009 Impreza outback sport with a dialing transmission right now. I’ve been wanting to do a wrx upgrade but I don’t know where to start. Can I go with an ej20x or should I stick with an ej25? I couldn’t find out if the ej20 fits on the sport or not. It’s an 1k cheaper so that’s why I liked it. Also replacing the clutch while I’m doing the transmission. Any tips or guidance will be much appreciated. I won’t be doing the swap just FYI luckily there is a Subaru shop here that mostly only deals with non na suby stuff.
I have a 2002 Legacy GT Limited with a blown 2.5 liter engine. Can a 2004 Forester 2.5 be swaped in its place ?? Having a heck of a time finding a replacement.
Hi Alex, Most JDM motors will not pass emission since you’d want to use the JDM ECU with it. If you need to pass emissions we’d recommend a replacement US engine that is compatible with your car. More info about that here – https://iwireusa.com/blogs/iwire-university/my-subaru-engine-blew-up-what-should-i-replace-it-with
I have a 2005 92x aero. Drive by cable. Coil on plug usdm ej20 turbo. Im literally Looking for a jdm replacement that will also pass emissions in NY. Car needs to be done By next week . Should I get avcs engine or non avcs? Can I transfer the ignition system ? Which is the better choice? Thanks in advance. -Alex
Hi Kevin, The engine will technically fit but because your chassis is CANBus equipped it would be an incredibly difficult swap from an electrical perspective. Here’s a blog post with more about CANBus swaps – https://iwireusa.com/blogs/iwire-university/canbus-part-2-can-bus-and-your-subaru-swap
Hi Kristy, we’d recommend going with an engine where it’s easier to find parts. You don’t have to scrap the project but you are correct that finding components for that engine will be tricky moving forward. If you have more questions, please send us an email to info@iwireusa.com
I have a 2016 subaru legacy premium I want to put the new 2.4 turbo charged cvt in it. Will it fit
I have a 96 brighton 2 door coupe, as we speak I have a 98 forester jdm dohc with the transmission sitting in it now. Unfortunately it has been sitting for years because subaru only made it for 2 years for that motor so it is VERY difficult to have a ecu just talk and get it t crank. Thats what i get when trying to get it to swap and go. SO for over 4 years it has collected dust. it was replacing the 1.8 motor to the 2,5 non turbo jdm. best to trash the project and go sti swap?