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Weekend workshop: unlocking kilowatts in a late-model WRX with K&N

19 November 2019



An easy bolt-on job for anyone with only a few basic hand tools, the K&N Air Intake kit for Subaru WRX 2014–2017 is an easy way to unlock a few extra kilowatts without breaking the bank or having to permanently modify your WRX. The kit comes complete with everything required to complete the installation, including a washable, reusable High-Flow Air Filter. K&N guarantees kilowatt gain, as its dyno tests showed an increase of 6.8kW at 4800rpm, and 24.4Nm of torque at 3100rpm when installed on a 2015, 2000cc WRX.

Tools required:

  • Ratchet

  • Extension

  • 10mm socket

  • 10mm spanner

  • Phillips screwdriver

  • Flat-head screwdriver

  • 3mm Allen key

  • Measuring device

  • Scissors or blade


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Step One

Ensure that your ignition is turned off, and disconnect the negative terminal using the 10mm spanner. Remove the fresh-air intake by releasing the two clips found on the radiator support panel.

Step Two

Remove the air filter housing by loosening the two 10mm nuts located on the inner guard, and one 10mm bolt securing the housing to the chassis rail. Open the filter box and remove the front cover and filter.

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Step Three

Release the mass-airflow connector by releasing the clip located on the rear of the housing. Next, remove the intake tube by loosening the hose clamp (located just behind the headlight) and removing the 10mm nut securing it to the chassis. The unit should now come free of the turbo intake tube. Remove from the engine bay.

Step Four

Remove the mass airflow (MAF) sensor from the air filter housing by releasing the two Phillips-head screws.

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Step Five

Now install the factory MAF sensor into the K&N intake tube and secure using the provided cap screws.

Step Six

Install the K&N tube-mounting tab using the provided 10mm bolt. This bolts in the factory intake tube–mounting location.

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Step Seven

Install the K&N air filter into the K&N intake tube, securing the hose clamp. Now insert the filter assembly into the factory turbo-intake tube. Its orientation is dictated by the location of the tab that secures to the pre-installed mounted tab from Step Six. Use the provided hardware to secure to the tab.

Step Eight

Install the K&N MAF extension harness to the factory connector and then plug into the MAF meter.

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Step Nine

Install the rubber-mounted stud onto the chassis rail in the same location you removed the filter housing mount in Step Two. Simply tighten in by hand.

Step Ten

Using either scissors or a blade, cut the edge trim into three pieces: 762mm, 394mm, and 76mm. Install all three sections onto the K&N heat shield.

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Step Eleven

Install the K&N heat shield into the engine bay, and secure onto the rubber mounting stud, and the two factory filter-housing mount studs on the guard using the factory hardware.

Step Twelve

Reinstall the factory cold-air intake and secure using the two factory clips. Double check all your installed hardware and reconnect the negative battery terminal.