Manley Performance Pistons

Fits 2004+ Subaru WRX STi with EJ257 engine

Part #: 621105C-4

Overview

The Manley Platinum Series piston set is engineered for high-performance Subaru WRX STi enthusiasts and professional engine builders seeking durability and precision. Designed specifically for the EJ257 engine, these pistons are ideal for applications requiring increased displacement and compression, supporting aggressive tuning and reliable power output. Crafted from premium 2618 alloy forgings, they deliver exceptional strength and thermal stability, making them suitable for both daily driving and high-stress racing environments. The pistons feature proven cam and barrel skirt profiles, ensuring optimal fitment and consistent performance. Equipped with tool steel wrist pins and moly skirt coatings on select models, they help reduce friction and wear, extending engine longevity. Whether you're building a custom turbocharged setup or upgrading your stock engine, these pistons provide the foundation for a robust and responsive powertrain.

Key Features

Designed with high-quality 2618 alloy forgings for superior strength and durability, these pistons feature a 75mm bore and a 9.8:1 compression ratio, tailored for the EJ257 engine. The moly skirt coatings reduce friction and enhance wear resistance, while the tool steel wrist pins ensure secure and reliable operation under demanding conditions. The proven cam and barrel skirt profiles promote optimal piston stability and consistent combustion. These pistons are engineered to support increased displacement and compression, making them an excellent choice for performance tuning and engine rebuilds.

Construction & Design

Constructed from high-grade 2618 aluminum alloy forgings, these pistons are machined to precise specifications for a perfect fit within the Subaru WRX STi's EJ257 engine. The moly skirt coatings provide a low-friction surface that helps reduce piston slap and wear, while the robust design ensures longevity under high-performance conditions. The tool steel wrist pins are designed for strength and reliability, supporting the demanding loads of tuned engines.

Performance & Response

These pistons are designed to support increased compression ratios and displacement, helping your engine produce more power and torque. The lightweight yet durable construction contributes to improved throttle response and acceleration. The optimized skirt design minimizes piston slap and noise, resulting in a smoother, more refined driving experience.

Installation & Fitment

Intended for professional engine builders and experienced enthusiasts, these pistons require precise installation and proper clearancing. They are designed to fit the 2004 and newer Subaru WRX STi models equipped with the EJ257 engine, supporting custom builds and performance upgrades.

What’s Included

The package includes a complete set of forged pistons with moly-coated skirts and tool steel wrist pins, ready for installation in compatible EJ257 engines. Additional hardware or components are not included.