These swaps are our specialty and are very simple to complete. Some engines are easier to swap, but from a wiring perspective, we can tackle these easily. We recommend doing this swap over a CANbus-equipped swap for those on a budget.
Non-CANbus Engine into a CANbus Car
These swaps depend on the model of the car. One option is to gut the wiring harness, turn it into a race car, and effectively eliminate the CANbus system. The other way to do it is to use a standalone ECU like Haltech that can communicate with the Subaru CANbus system up to 2014 and run the new engine. This will keep the CAN system happy on the car side and allow for more options on types of engines to run.
CANbus Engine into a Non-CANbus Car
For this type of swap, a standalone ECU can be utilized, or, depending on the engine model, the CANbus ECU can be replaced with a non-CANbus equivalent. An example would be a 2010 WRX engine that could run on a 2007 WRX ECU. Click here for an excellent resource for this.
Another option is something called a CANbus emulator. This module would go onto the CAN line and recreate the ID's the ECU needs from the missing modules. We have some prototype CANbus emulators working in a 15 WRX swapped 99 OBS (picture at top) and a few other cars, including an 08 STi powered 02 WRX and a 3.6 6 cylinder in a 98 RS. However, we're still working out some issues, so we'll keep everyone posted on developments.
The other piece to consider when doing these swaps is the immobilizer system since the gauge cluster is part of the immobilizer circuit on CANbus-equipped cars. We can wire the cluster up for this, but the fitment could be better, and there are a lot of features you won't be able to use because the rest of the CANbus features of the original car need to communicate with the cluster. This is also something we plan to address with the CANbus emulator.
Keep up with progress on the OGRSTi, our GC swap with a 2018 STi engine on YouTube.
CANbus Engine into a CANbus Car
Currently, these swaps are purely on a case-by-case basis because other than using a standalone ECU and treating the engine much like a non-CANbus engine in a CANbus car (see section above), there really isn't a good option. The only viable option to run an OEM ECU at this point is to transfer the entire turbo car over (ideally a similar model year like an 08 WRX donor into an 08 Impreza non-turbo or 2006 Legacy GT into a 2006 Legacy non-turbo) in parts and modify the harness where it meets the original non-turbo chassis. We currently do not recommend this swap as a byproduct of these issues.
Note - We no longer build harnesses for standalone ECUs, but plenty of companies do.
Mighty Car Mods did a Swap Between a Levorg and an STi. They did it the way we recommend, so please check it out below.
CANbus Auto to Manual Swap
The automatic transmission system, in general, is pretty complex due to the number of components that intertwine to get the car to shift at the correct time. The complexity is increased on the CANbus platforms to the point where it may be more complicated to change the automatic transmission system than to do an engine swap. As a byproduct, our recommendation is the same as the above scenario: find a similar version of your car in manual form and swap everything over. From a practical standpoint, purchasing the vehicle in the form you desire may be more cost and time effective.
2009 to 2013 Forester XT Auto to Manual
We understand this is a common scenario because a manual from Subaru did not exist for this group of cars. Unfortunately, we do not have a solution to this problem. We have seen people take a WRX in parts since they are similar (but not the same) as a Forester and swap everything over, as noted before. The problem we see is there are differences between the chassis features of a WRX and Forester, like the rear hatch that would have to be addressed one way or another and may not work, so it would depend on how much someone cared about certain features to work if they were to go down this path.