What is the significance of the +.25mm size on these pistons?

The +.25mm size indicates that these pistons are 0.010 inches larger in diameter than the standard bore size for your engine. This is typically used when an engine's cylinders have been bored out during a rebuild to restore them to the correct specification.

What is the benefit of using 2618 alloy forgings?

Domestic 2618 alloy forgings are chosen for their exceptional strength and ability to withstand high temperatures and pressures commonly found in performance engines. This makes them a reliable choice for demanding applications.

Are these pistons compatible with all exhaust systems?

This piston set is designed for engine internals and does not directly interact with exhaust systems. However, for optimal performance with modified engine components like these pistons, you may want to consider an upgraded exhaust system that can better handle increased exhaust flow.

Specifications

Brand: Manley Performance
Part #: 632202C-4
UPC: 807298088037

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

Name: Manley 04+ Subaru WRX/STI EH257 99.75mm Bore +.25mm Size 8.5:1 Dish Piston Set
Brand: Manley Performance
SKU: manley-performance-manley-04-subaru-wrx-sti-eh257-99-75mm-bore-25mm-size-8-5-1-d-t14-4326494
Price: 827.84 USD
Availability: InStock

$827.84

Only 4 left in stock

Manley 04+ Subaru WRX/STI EH257 99.75mm Bore +.25mm Size 8.5:1 Dish Piston Set. Forged from 2618 alloy for superior strength and durability.

Key Features

Fits 2004 and later Subaru WRX and STI models.
Features a 99.75mm bore and a +.25mm size (0.010 inches larger than stock).
Dish piston design results in an 8.5:1 compression ratio.
Constructed from domestic 2618 alloy forgings for superior strength and performance.
Includes premium chrome moly wrist pins for added durability.
Exacting standards for ring lands and grooves enhance ring seal and power output.

⚠️ 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

Manley Performance is well-known for building robust engine components that serious builders trust. This piston set is designed for 2004 and later Subaru WRX and STI models, featuring a 99.75mm bore and a +.25mm size, meaning they are 0.010 inches larger than stock. The 8.5:1 compression ratio dish design is a key factor in how your engine will perform and respond.

These pistons are forged from domestic 2618 alloy, a material chosen for its exceptional strength and ability to handle high performance demands. They come equipped with premium chrome moly wrist pins, and Manley's unique fixturing process ensures the ring grooves are perfectly square to the skirt. This attention to detail results in better ring seal, which translates directly to more power. The cam and barrel skirt profiles are carefully shaped to generate significant power while also being considerate of your cylinder walls, promoting longer engine life.

When rebuilding or modifying your Subaru's engine, using pistons built to exacting standards is crucial. Manley adheres to strict specifications for piston ring lands and grooves, which is vital for maintaining a solid seal and preventing blow-by. This set is a solid option for anyone looking to build a high-performance engine and wants components that can withstand the rigors of demanding use. Please note that this part is not CARB approved and cannot be shipped to California.