What is the advantage of forged pistons over cast pistons?

Forged pistons, like these from Manley, are made from a stronger alloy and are heated and hammered into shape. This process creates a denser, more durable piston that can better withstand the high pressures and temperatures found in performance or heavily modified engines compared to cast pistons.

What does the '+.25mm' size indicate for these pistons?

The '+.25mm' designation means these pistons are slightly larger than the standard bore size for your engine. This is typically used when engine cylinders have been re-bored during an engine rebuild to ensure a proper fit and seal with the cylinder walls.

Are any other components needed to install these pistons?

Yes, installing pistons requires additional components such as piston rings, connecting rod bearings, and potentially new rod bolts. It's also recommended to have the connecting rods balanced and checked for straightness before installation. Always refer to the manufacturer's installation guide for a complete list of required parts and procedures.

Specifications

Brand: Manley Performance
Part #: 632202CE-4
UPC: 807298088112

Manley 04+ Subaru WRX/STI EH257 99.75mm Bore +.25mm Size 8.5:1 Dish Extreme Duty Piston Set

Name: Manley 04+ Subaru WRX/STI EH257 99.75mm Bore +.25mm Size 8.5:1 Dish Extreme Duty Piston Set
Brand: Manley Performance
SKU: manley-performance-manley-04-subaru-wrx-sti-eh257-99-75mm-bore-25mm-size-8-5-1-d-t14-4326495
Price: 963.51 USD
Availability: InStock

$963.51

Only 7 left in stock

Manley 04+ Subaru WRX/STI EH257 99.75mm Bore +.25mm Size 8.5:1 Dish Extreme Duty Piston Set. Built for high-performance builds needing extreme durability.

Key Features

Fits 2004 and later Subaru WRX and STI models.
Forged from domestic 2618 alloy for superior strength and performance.
Features cam and barrel skirt profiles for efficient power generation and reduced cylinder wall wear.
Precisely machined ring lands and grooves enhance piston ring seal for improved power.
Includes premium chrome moly wrist pins for added durability.
Pistons are 99.75mm bore size and +.25mm oversize.

This piston set is designed for 2004 and later Subaru WRX and STI models. Please verify compatibility with your specific vehicle's engine configuration.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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About this part

Product Details

If you're rebuilding the engine in your 2004 and later Subaru WRX or STI, especially for a high-performance application, a solid set of pistons is crucial. This set from Manley is built to handle the demands of serious engine work, offering a significant step up from stock components for durability and power potential.

Manley uses domestic 2618 alloy forgings for these pistons, which are known for their strength and ability to withstand high temperatures and pressures. They feature proven cam and barrel skirt profiles designed to generate power efficiently while also being kind to your cylinder walls during operation. The ring lands and grooves are machined to strict standards, which helps ensure a better seal from your piston rings, leading to improved power output. These pistons are also a +.25mm size, meaning they are slightly larger than standard bore size, which is common when re-boring cylinders during an engine rebuild.

Included with this set are premium chrome moly wrist pins, and Manley's unique fixturing process allows for skirt turning and ring groove machining in a single operation. This ensures the ring grooves are perfectly square to the piston skirt, which is vital for proper ring seal and overall engine health. Keep in mind these pistons are not CARB approved and cannot be shipped to California.