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Impreza swap FAQ’s

bANSHEE'S

If you are looking for my Impreza swap wire merge guide, its here

Turbo motor swap!

Turn your Impreza into a real street fighter! Theres tons of choices ranging from a budget minded USDM EJ205, to JDM EJ207’s, to build motors that can have stroker bottom ends and ported/cammed heads. In relation to OEM options, EJ20s are the better option, engine harmonics are smoother, more RPM range and wider power band, and they dont blow up. EJ25s make more torque off boost and are nicer to lug around town, but thats where i feel the advantages stop. Oil pumps fail frequently, higher cylinder pressures will break ring lands, cam solenoids fail and buying used usually means youre buying someones neglected problem. If budget allows, i recommend buying a new shortblock and putting a good useable set of heads on, then pick a turbo and match it with an 08+ topmount and upgraded EBCS.

STI 6MT six speed trans swap!

With great power comes great responsibility, so if you plan on going past the 300hp range or track use, definitely look into a 6MT setup. USDM 04-07 6MTs are getting quite hard to find in driveable shape, i recommend having them rebuilt if your unsure of its history. V7-V9 JDM trans are always a treat, prices are coming down and RPMs are going up. 80mph sits you around 3800rpm but the ratios match an EJ20 quite nicely. 08+ USDM 6MTs dont have speed sensors so they require a module to read from GPS or ABS sensors to run the speedo, these transmissions are dropping into the sub-$2000 range

Drivetrain, suspension and brake upgrades!

If your bumping the power, and bumping the rev limiter, youre gonna have to get that down to the ground and eventually stop it. R180 rear diffs are not required for a 6MT swap, you CAN find 3.90 and 3.54 R160 diffs around. Doing an R180 requires a moderate investment, you’ll need R180 axles which require R180 STI hubs, which then require custom rotors in some situations. Further, you can convert to 5×114 which requires a front strut and axles from a 05-07 STI. Suspension upgrades are definitely what i recommend as a entryway into modifying your car, bigger bars, lower ride height, proper geometry correction and an aggressive alignment wakes the platform up. Brake cables seem to be a controversial topic, both the GC and GD cables are the same length under the car, the bridge cable thats under the console is different. You can use GC cables on STI hubs, and STI cables on GC hubs etc. Forester cables are longer and those will give you fitment problems.

The harness!

This is the largest investment of your time and money that will go into the swap, cutting corners in here can lead to lots of problems down the road, ive seen people sell cars because of poorly soldered wires causing engine signal issues that affected drivability. Firstly, crimp dont solder, end of story. When i do harnesses i also add in a handful of things that make expansion easier in the future like reusing 12V/Gr wires that are cut in the merge process, and repurposing them for DCCD controllers, plug ins for gauges/accessories in the car, even things like replacing the fuel pump or audio wiring with new heavier gauge wire to support upgraded components, even adding wire for a set of fog lights or underbody neons. A little future proofing will save you time and money when you’re fiddling with it down the road. Keep in mind, when merging say a 93 L harness, you are twisting/pulling 20+ year old wire/connectors, things WILL break so expect to hunt down pins/connectors and get comfortable with the tools associated with them.