What is the compression ratio of these pistons?

These Manley pistons feature a dish top design that results in a compression ratio of 8.5:1. This is a common ratio for turbocharged or supercharged engines that require lower compression to safely run higher boost levels.

What material are the pistons made from?

The pistons are forged from domestic 2618 alloy. This material is chosen for its superior strength and performance characteristics, making it well-suited for demanding engine applications.

Are these pistons legal for use in California?

No, these pistons are not CARB approved and cannot be shipped to California due to emissions regulations.

Specifications

Brand: Manley Performance
Part #: 632202C-1
UPC: 807298088020

Manley 04+ Subaru WRX/STI 2.5L 99.75mm Bore +.25mm 8.5:1 CR Dish Piston Set with Rings

Name: Manley 04+ Subaru WRX/STI 2.5L 99.75mm Bore +.25mm 8.5:1 CR Dish Piston Set with Rings
Brand: Manley Performance
SKU: manley-performance-manley-04-subaru-wrx-sti-2-5l-99-75mm-bore-25mm-8-5-1-cr-dish-t14-356558
Price: 206.96 USD
Availability: BackOrder

$206.96

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Manley 04+ Subaru WRX/STI 2.5L forged piston set with rings. 99.75mm bore, 8.5:1 CR dish pistons for improved performance.

Key Features

Fits 2004 and later Subaru WRX and STI models with the 2.5L engine.
Forged from domestic 2618 alloy for strength and durability.
Dish top pistons achieve an 8.5:1 compression ratio, suitable for boosted applications.
Features proven cam and barrel skirt profiles to reduce friction and cylinder wall wear.
Precisely machined ring lands and grooves ensure enhanced piston ring seal.
Includes premium chrome moly wrist pins and rings for a complete setup.

This piston set is designed for 2004 and later Subaru WRX and STI models with the 2.5L engine. Please verify fitment for your specific vehicle application.

⚠️ 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 with the 2.5L engine, this set of forged pistons from Manley Performance is a solid option. These pistons are designed with a 99.75mm bore and a dish top to achieve an 8.5:1 compression ratio, which is a common target for boosted applications where you want to run more boost safely. Manley uses domestic 2618 alloy forgings, known for their strength and ability to handle the demands of performance engines.

What sets these pistons apart is their proven cam and barrel skirt profiles. This design helps reduce friction and wear on your cylinder walls, allowing the engine to make power more efficiently. The ring lands and grooves are machined to strict standards, which is crucial for getting a good seal from your piston rings, leading to better compression and more power. Manley also uses unique fixturing that ensures the piston ring grooves are perfectly square to the piston skirt, a detail that matters for consistent performance.

This set includes the pistons, premium chrome moly wrist pins, and rings, making it a comprehensive package for your engine build. Keep in mind that these pistons are not CARB approved and cannot be shipped to California.