Manley 04+ Subaru WRX STi (EJ257) 83mm Stroker 99.75mm +0.25mm Bore 8.5:1 Dish Piston Set with Rings

Manley Performance is well-known for building strong engine components that professional builders trust. If you're working on a 2004-2012 Subaru Impreza, especially one where you're looking to get more out of the engine, this piston set is a solid choice. These aren't just stock replacements; they're built to handle more power and last longer under demanding conditions.

These pistons are forged from 2618 alloy, which is a strong material that holds up well under high heat and pressure. They feature proven cam and barrel skirt profiles, designed to help generate power while also being easier on your cylinder walls during operation. The ring lands and grooves are machined to very precise standards, which is key for getting a good seal from your piston rings, and that directly translates to more power. Manley uses a unique process that machines the skirt and ring grooves in one go, ensuring they are perfectly square to each other for optimal performance.

This set includes tool steel wrist pins, which are known for their durability. The pistons have a dish shape and are sized for an 83mm stroke with a bore of 99.75mm, which is +0.25mm over standard. They also have a compression ratio of 8.5:1, making them suitable for boosted applications where you need to manage detonation. Keep in mind that these pistons are not CARB approved and cannot be shipped to California. You'll also want to refer to the manufacturer's installation instructions for proper setup and any additional hardware or machining requirements.