2018 Subaru WRX STi Broken Piston Ringlands

The Problem: Broken Piston Ringlands

Chris’s STi was full bolt-on with E85 when he brought it in to SL Autoworks. He had every aftermarket modification except an upgraded turbo.

The car was brought in to SL Autoworks because it was misfiring, and consuming oil. When an engine is misfiring, it can’t properly combust the correct amount of fuel and air, which can lead to bigger issues!

STi broken piston ring
Broken piston ring

This is a very common problem with the Subaru EJ257 engine. Since the introduction of the WRX STi in 2004 with the 2.5 liter engine, the piston ringlands have been known to break, which is exactly what happened. It’s sometimes difficult for the owner to diagnose a broken piston because the exhaust doesn’t always emit blue smoke as one might expect. Due to ringland failure, the engine will consume a large amount of oil in a short amount of time which can result in bearing failure. SLA prevented this from happening to Chris’s car because we caught it in time.

Pro Tip: For these engines, keep an eye on your oil level. If it shows signs of excess oil consumption,  bring your Subaru into a trusted shop before any major damage occurs.

The Solution

Our customer Chris decided to do a full engine build plus larger turbo and fuel system since the engine already needed to be repaired or replaced.

We recommended:

  • JE pistons
  • BC I-Beam connecting rods
  • BC 280 Cams
  • GSC Beehive valve springs
  • Outfront Motorsports Closed Deck Conversion (An insert of roughly 1/2 inch is pressed into the top of the deck in the block. This helps prevents the sleeves from cracking under high cylinder pressure.)
  • 1/2 inch head studs
  • King main and rod bearings
  • JDM 12 mm oil pump
  • Forced Performance Black turbo
  • ETS 4 inch FMIC kit
  • Killer B header
  • Radium double pump fuel hanger
  • Injector Dynamics 1700 injectors

We expect to achieve roughly 600 wheel horsepower once fully tuned.

Learn more about ringland failure here!

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