Manley 04+ Subaru WRX STi (EJ257) STD Stroke 100mm +.5mm Bore 8.5:1 Dish Piston Set with Rings

If you're rebuilding the engine in your 2004-2012 Subaru Impreza WRX STi, especially if you're aiming for more power or need to replace worn components, a solid set of forged pistons is crucial. These Manley pistons are built to handle the demands of performance engines, offering a significant upgrade over stock components. They feature a dish design that results in an 8.5:1 compression ratio, which is ideal for boosted applications where you need to control detonation.

Manley uses domestic 2618 alloy forgings for these pistons, a material known for its exceptional strength and ability to withstand high temperatures and pressures. This makes them a reliable choice for serious engine builds. The pistons also come with premium chrome moly wrist pins, and Manley pays close attention to the precision of the ring lands and grooves. This exactness helps ensure a better seal with the piston rings, which translates directly to more efficient combustion and improved power output. The cam and barrel skirt profiles are designed to work smoothly with the cylinder walls, reducing wear and noise while still generating substantial power.

What sets these pistons apart is Manley's unique manufacturing process. Their specialized fixturing allows them to machine the skirt and the ring grooves in a single operation. This ensures that the ring grooves are perfectly square to the piston skirt, a detail that contributes to optimal ring seal and overall engine performance. It's this kind of attention to detail that makes Manley a popular choice among professional engine builders and tuners looking for dependable performance.

Keep in mind that these pistons are not CARB approved and cannot be shipped to California. If you're building a high-performance EJ257 engine, these pistons are a well-built option that offers the strength and precision needed for demanding applications.