Subaru Pro-Built Engines

Subaru Performance Engine Building Services

Forged Bottom Ends, Stroker Motors, Iron Sleeved Cylinders, Head Packages & More

Subaru STi

Simply put – we’ve been at this for a very long time! After investing a lot of our energy and resources, we have identified several problem areas within the factory motor design that limit your project potential.  Using state-of-the-art machinery, tools, and industry-leading brands, our motor program sports unparalleled quality and consistency that supports projects from street to track.

We choose our rod and main bearing clearances based on the ultimate RPM range that your new motor will see. We also give you the option to choose your engine’s compression ratio. You have two off-the-shelf choices between 8.5:1 or 9.8:1 unless your build requires a custom piston design. Whichever ratio you choose, please keep in mind we recommend 8.5:1 for most street builds. We typically suggest the higher compression option for builds that plan on using race gas or E85.Manley-Logo-website

Since Motion Lab is a wholesale distributor for Manley Performance and has established an alliance with other major engine parts manufacturers, we are able to provide the most proven and reliable combination of Subaru engines on the market.

Additional build information: Motion Lab typically implements the use of a torque plate for our performance line of motor builds (not used for standard rebuilds). Our build tolerances are repeatedly checked throughout the build process, which includes:

  • Individual (ring to bore) ring end gaps augmented
  • Individual piston-bore clearances checked
  • Wrist pin bore checked
  • Main, rod, and thrust bearing clearances checked
  • Strict rod bearing eccentricity measurements
  • Big-end rod bore roundness checked
  • Small-end rod bore checked
  • Crank straightness checked
  • Block decks checked

Subaru EJ255/257 (04-Present)

Subaru FA20 (15-Present WRX)