CP Piston & Ring Set for Subaru EJ257 WRX STi – Bore (99.75mm) – Size (0.25mm) – CR (8.2)

SKU: SC7422-4 CP Piston & Ring Set for 2004-2014 Subaru Impreza WRX STI EJ257 – Bore 99.75mm – Size 0.25mm – CR 8.2 CP forged piston and ring set SC7422-4 delivers reliable power for Subaru EJ257 turbo engines in 2004-2014 Impreza WRX STI models. This 0.25mm oversize kit features 99.75mm bore and 8.2:1 compression ratio to support high-boost setups while ensuring engine durability. Includes matched rings and pins for complete rebuild readiness in performance Subaru builds. Key Features Forged 2618-T61 Alloy: Provides high tensile strength to handle extreme cylinder pressures in turbo EJ257 applications Accumulator Groove Design: Reduces ring flutter under high RPM and boost for improved sealing and power retention Skirt and Crown Coatings: Anti-friction skirt coating lowers drag, while crown coating protects against detonation in boosted environments Precision Ring Pack: Includes forged steel top ring, cast iron second ring, and three-piece oil ring set for optimal compression and oil control 30mm Compression Height: Matches EJ257 specs with 22mm x 1.02mm wrist pins and spiro-locks for direct fit after machining Product Notes Engine block must be bored and honed to 99.75mm prior to installation Pistons ship balanced as a matched set of four Inspect rods and bearings during rebuild for best results Installation Notes Professional installation recommended. Requires cylinder boring to 99.75mm and ring gap verification per CP guidelines Compatible with stock EJ257 connecting rods. ARP rod bolts advised for high boost This Part Fits Year Make Model Submodel 2004-2012 Subaru Impreza WRX STI 2007 Subaru Impreza WRX STI Limited 2011-2012 Subaru Impreza WRX STI Limited 2010 Subaru Impreza WRX STI Special Edition 2013-2014 Subaru Impreza WRX STI Why Choose CP Pistons? Engineered for motorsports with decades of piston forging experience Hand-built in the USA for consistent quality in every set Proven design trusted in drag racing and rally Subaru builds Frequently Asked Questions Q: Does this fit all EJ257 engines in 2004-2014 STI models? A: Yes, designed specifically for EJ257 2.5L DOHC turbo in USDM Impreza WRX STI variants after block machining to 99.75mm bore Q: What material are the pistons made from? A: Forged from 2618-T61 aluminum alloy with hard anodized top ring grooves and anti-friction coatings for durability Q: What warranty is included? A: Limited lifetime warranty against manufacturing defects when installed by certified professionals Shipping & Handling Method: UPS Ground or FedEx Ground Availability: In stock – ships same or next business day Packaging: Securely boxed with foam protection Weight: 5.8 lbs Reviews There are no reviews yet. Be the first to review “CP Piston & Ring Set for Subaru EJ257 WRX STi – Bore (99.75mm) – Size (0.25mm) – CR (8.2)” Cancel replyYour email address will not be published. Required fields are marked *Your rating * Rate… Perfect Good Average Not that bad Very poor Your review *Name * Email * Save my name, email, and website in this browser for the next time I comment.