SKU: CPN-3327
CP Ring Pack for SC7021 Pistons Subaru STI 2004-2021
CP CPN-3327 ring pack provides exact fit for SC7021 pistons in Subaru WRX STI EJ257 engines. Built for 2004-2021 models this set ensures reliable compression sealing during extreme boost and high RPM. Perfect for engine rebuilds that demand consistent power delivery and durability.
Key Features
- Exact Piston Match: Sized for 99.75mm bore SC7021 pistons ensures zero gap issues and full face contact
- Chrome Faced Top Ring: 1.2mm steel ring with chrome plating reduces friction and resists blow-by in turbo applications
- Nitrided Second Ring: 1.5mm cast iron construction wears slowly maintains seal during high heat cycles
- Flex-Vent Oil Ring: 2.8mm three-piece design controls oil effectively minimizes drag for freer revving
- Pre-Honed Finish: Factory gaps set to Subaru specs 0.45-0.55mm top ring for quick break-in and long life
Product Notes
- Rings only pistons SC7021 sold separately verify bore before install
- Store in dry area avoid contamination prior to assembly
- Compact packaging protects rings during transit
Installation Notes
- Professional installation recommended.
- Use CP-specific ring expander tools to avoid ring damage
- Compatible with stock wrist pins and circlips from SC7021 kit
This Part Fits
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2004-2007 | Subaru | Impreza | WRX STI |
| 2008-2014 | Subaru | Impreza | WRX STI |
| 2015-2021 | Subaru | WRX STI | |
| 2015-2021 | Subaru | Impreza WRX STI |
Why Choose CP-Carrillo?
- Proven in NHRA Top Fuel and Pro Stock racing teams worldwide
- Forged from 2618 T6 aluminum with advanced coatings
- USA-made with tolerances held to 0.0002 inches
Frequently Asked Questions
- Q: Will CPN-3327 fit 2017 STI EJ257?
A: Yes matches all 2004-2021 EJ257 blocks with 99.75mm SC7021 pistons including sedan hatchback variants - Q: What ring materials are used?
A: Top ring steel chrome faced second cast iron nitrided oil control flex-vent steel for balanced wear and sealing - Q: What warranty applies?
A: CP-Carrillo offers limited lifetime warranty on rings against manufacturing defects when installed correctly
Shipping & Handling
- Method: UPS Ground or USPS Priority
- Availability: In stock – ships same or next business day
- Packaging: Protective box 6 x 4 x 1 inches
- Weight: 0.5 lbs
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