What is the benefit of using 2618 alloy forgings?

The domestic 2618 alloy forgings used in these pistons offer superior strength and performance compared to other materials. This makes them well-suited for high-performance engine builds where durability under stress is critical.

Are these pistons compatible with all Subaru WRX and STI models from 2004 onwards?

This specific piston set is designed for the EH257 engine platform found in 2004 and later Subaru WRX and STI models. It's important to verify your engine code to ensure proper fitment.

What does the 9.8:1 compression ratio mean for my engine?

A 9.8:1 compression ratio is a moderate increase over stock, designed to improve power output and throttle response. This ratio is generally suitable for naturally aspirated or moderately boosted applications, but always consult with your engine builder for optimal tuning.

Specifications

Brand: Manley Performance
Part #: 632300C-4
UPC: 807298089508

Manley 04+ Subaru WRX/STi EH257 99.50mm STD Bore 9.8:1 Dish Piston Set of 4

Name: Manley 04+ Subaru WRX/STi EH257 99.50mm STD Bore 9.8:1 Dish Piston Set of 4
Brand: Manley Performance
SKU: manley-performance-manley-04-subaru-wrx-sti-eh257-99-50mm-std-bore-9-8-1-dish-pi-t14-4323347
Price: 827.84 USD
Availability: BackOrder

$827.84

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Manley 04+ Subaru WRX/STi EH257 99.50mm STD Bore 9.8:1 Dish Piston Set of 4. Forged from 2618 alloy for superior strength.

Key Features

Fits 2004+ Subaru WRX/STi EH257 engines.
Standard bore size of 99.50mm.
Compression ratio is 9.8:1 with a dish top.
Constructed from domestic 2618 alloy forgings for superior strength.
Features Manley's proven cam and barrel skirt profiles for power and cylinder wall protection.
Includes premium chrome moly wrist pins.

This piston set is designed for 2004 and later Subaru WRX and STI models with the EH257 engine. It is not CARB approved and cannot be shipped to California.

⚠️ 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

Built from domestic 2618 alloy forgings, these Manley pistons are designed for serious engine builds in your 2004 and later Subaru WRX or STI. The 99.50mm standard bore size and 9.8:1 compression dish are specific to the EH257 engine platform, making them a direct replacement for high-performance applications. Manley's signature cam and barrel skirt profiles are engineered to generate substantial power while minimizing wear on your cylinder walls, a detail many professional engine builders rely on.

You'll find that Manley pays close attention to the details that matter for engine longevity and performance. The ring lands and grooves are machined to exacting standards, which helps ensure a better seal for your piston rings, translating directly into more power. They also use premium chrome moly wrist pins, and for some applications, offer upgrades to even stronger alloys. Manley's unique fixturing process allows them to machine the skirt and ring grooves in a single operation, ensuring the ring grooves remain perfectly square to the skirt, which is critical for proper sealing under high loads.

This set includes four pistons, ready for your next engine rebuild. Please note that these pistons are not CARB approved and cannot be shipped to California. If you're building a high-performance Subaru engine, these well-built pistons are a solid choice.