2015 WRX Tuned Up!


Richard brought us his 2015 WRX wanting a couple of simple, but engine transforming mods.

Simple Recipe – Stage 4 package

The recipe Richard has used to get his new generation FA20DIT engine performing, is much the same as we’ve used on the older EJ-powered vehicles. To feed more air into the engine, a Mishimoto cold air intake was fitted before we got a hold of the car. This bumped up the ‘before’ dyno power reading that can be seen bellow. To free up the exhaust that restricts flow of the gasses exiting the engine, we proceeded to fit an X-Force turbo-back system, including a high-flow catalytic convertor.

The icing on the cake for this package is the PBMS Tune Package. This is where we run the car up on the dyno, making custom adjustments to the tune in the factory ECU. We are able to reprogram this to optimise power, torque and drivability to suit the engine’s new-found flow. A small increase in the boost level has also make a big improvement down low, giving more response and a much stronger pull!


So what exactly is in a Stage 4 Package?

  1. High flow downpipe/front pipe (with or without catalytic convertor)
  2. High flow cat-back exhaust system
  3. Cold air intake system
  4. PBMS Tune Package.

Tell me the results already?!

Okay, we’re getting to that. Like we’ve seen on earlier generation Subaru’s, this package gives great gains in performance, whilst maintaining drivability and economy (if you can control yourself, we typically even see gains here). On a pre-tune run, the car spun up a very respectable 178kw at the wheels. This is above what we would normally see, thanks to the cold air intake already fitted. Once the exhaust was fitted, we got to work on the dyno, optimising the tune. The result was a solid gain across the board, with peak power increasing 24% to 220kw. Additionally, we were able to smooth out in the mid range, maintaining a 25% gain in this area.

Based on previous results, we’d expect this WRX would have made 160-165kw at the wheels in completely factory form. We estimate that it would this stage 4 package has unleashed 37% more power than it originally had!

Richard is over the moon with the performance, mentioning the exhaust is sounds great. It’s added a nice tone, but isn’t too loud and doesn’t drone. Tuned FA20DIT


About the author, Julius

Julius provides technical support and expertise to Possum Bourne Motorsport. He's been involved with the industry since 2009 and has stamped his mark as an industry leader.

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