JE Pistons 291061 Forged FSR Pistons Set 99.5mm for Subaru WRX STI EJ25/EJ257

Vehicle Fitment

• 2004-2017 Subaru Impreza WRX STI, EJ257
• 2005-2006 Subaru Legacy GT, EJ257
• 2005-2006 Subaru Outback XT, EJ257

Fitment Notes

• Sold as a matched set of 4
• Piston rings and wrist pins included

Features

• 2618 T6 high tensile forged aluminum alloy
• Forged Side Relief (FSR) design minimizes friction and power loss
• Reduced skirt width and shorter wrist pin for saved weight
• Smooth-flowing radii for excellent flame travel
• No deburring or preparation required on dome/dish
• Accumulator groove reduces ring fluttering, improves ring seal
• Skirt coating reduces friction, wear, and operating noise
• Compatible with boost and nitrous applications
• 100% engineered, forged, and machined in the USA

Specifications

• Bore: 99.50mm (3.917in)
• Stroke: 79.0mm
• Rod length: 130.5mm
• Compression height: 30.7mm
• Compression ratio: 8.5:1 (with .026 gasket)
• Dish volume: -16.5cc
• Weight: 407 grams
• Material: 2618 T6 forged aluminum

Included Components

• 4x Forged pistons
• Wrist pins
• Tru Arc locks
• JE Pro Seal piston rings

Product Description

The JE Pistons 291061 is a set of 4 forged Sport Compact FSR pistons engineered specifically for the Subaru EJ257 engine, covering the 2004-2017 Impreza WRX STI and 2005-2006 Legacy GT and Outback XT. Forged from 2618 T6 high tensile aluminum alloy in the USA, these pistons are specifically engineered for extreme applications up to and including professional competition, where higher compression ratios, elevated boost, and heavy nitrous usage demand the added tensile strength this alloy provides.

The Forged Side Relief (FSR) design minimizes friction and power loss through a reduced skirt width, while saving additional weight with a shorter wrist pin. An accumulator groove helps reduce pressure from combustion gases, cutting down on ring flutter and improving ring seal for consistent power delivery, and an available skirt coating further reduces friction, wear, and operating noise depending on the application.

This piston set is intended for engine builders and EJ257 owners running serious boost or nitrous who need genuine, race-proven forged pistons rather than a stock-replacement cast piston. High-quality wrist pins, Tru Arc locks, and JE Pro Seal premium piston rings are included, and the dome/dish requires no deburring or preparation before installation.