CP Piston & Ring 100mm Bore 8:2 CR WRX / STI Subaru Turbo EJ255 / EJ257 Models 2004-2021

Part #: SC7421. CP's forged pistons for WRX and STI models are a game - changer. They offer excellent ring seal, higher vacuum, less blow - by, and greater durability. You'll notice a significant boost in horsepower and torque across the power band, and the peak horsepower stays strong throughout the life of the piston rings. Thanks to lightweight forgings and CP's unique machining, these pistons are top - notch. CP is all about great engineering, using the latest forging techniques and CNC machinery, and strict quality control. They have some of the highest quality standards in the industry. CP is part of Pankl Racing Systems, a high - tech racing group that supplies parts to top - level teams and elite companies. You won't find better pistons for your EJ20 or EJ257. CP also offers optional coatings. The top coating reflects heat into the combustion chamber, increasing exhaust gas velocity and improving scavenging. The skirt coating provides extra lubrication in extreme heat or heavy wear, reducing friction on the skirt. Coating options are applied to the whole set and add 4 - 6 weeks to the order time. Piston features include high - strength aluminum forgings, a super - lightweight design, full CNC machining and balancing to +/- 1 gram, an accumulator groove, double pin oilers force - fed from the oil ring, and wrist pins.

Using these CP pistons is straightforward. Just make sure to follow your vehicle's standard piston installation process. When installing, handle the pistons with care to avoid any damage. For maintenance, regularly check the piston rings for wear. If you've opted for the optional coatings, be aware that they're designed to enhance performance, but you still need to keep an eye on them. In extreme heat conditions, the skirt coating will provide extra lubrication, but it's good to monitor the engine temperature. During normal use, keep up with your regular engine oil changes as this helps keep the pistons and the whole engine in good shape. Also, note that if you choose the coating option, it will take 4 - 6 weeks extra for your order to arrive.