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CP Piston & Ring Set for Subaru EJ257 WRX STI- Bore (99.75mm)-Size (+0.25mm)- CR (9.0) - Set of 4


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CP Pistons are designed to be used with an 83mm Stroker Crank in an EJ257 block with a standard-length connecting rod. This combination works out to a 2.6-2.7L depending on bore size. This compression ratio is slightly higher than stock.

These pistons, like many aftermarket pistons, are made of 2618 alloy. 2618 is a strong, durable, forged aluminum alloy that can withstand a large amount of abuse in race applications.


Dedicated forgings

Balanced to + or 1 gram

Wrist pins provided at no cost

Pin fitting provided at no cost

Accumulator Grooves

Dual forced pin oilers

Pick lock grooves

Fully CNC machined

USA Made


2004-2007 Subaru STi, 2008-2014 Subaru STi Hatchback, 2015 + STi

Actual Product May Vary from Image.


This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to

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