BC7911 – Polaris XP Turbo (16-up) CP Custom Pistons w/All Hardware – Specify Bore x Compression Ratio

Precision Forced Induction Dominance: The BC7911 CP Custom Piston System

In the realm of high-output side-by-side and turbocharged performance, the factory piston assembly is invariably the first and most critical point of failure under increased thermal and cylinder pressure loads. For Polaris RZR XP Turbo (2016-Present) platforms undergoing significant performance upgrades—whether through aggressive tuning, increased boost, or displacement increases—the stock forging reaches its operational limit. The BC7911 CP Custom Piston Kit from Brian Crower is not merely a replacement; it is a purpose-engineered system designed to transform the engine’s rotating assembly into a foundation capable of withstanding and exploiting extreme forced induction. Engineered by CP-Carrillo, a name synonymous with championship-winning piston technology, this kit provides the exact bore and compression ratio specification required to execute a bulletproof, high-horsepower build with surgical precision. For the builder who understands that reliable power is a function of component integrity, the BC7911 represents the definitive upgrade path for the ProStar 925 Turbo engine.

Forged 2618 Alloy & Optimized Geometry: Engineering for the Thermal Frontier

The core of the BC7911 system is its forged piston, manufactured from premium A2618 high-silicon aluminum alloy. This material is the industry standard for severe-duty, forced induction, and racing applications due to its superior thermal fatigue resistance and ultimate strength compared to the 4032 alloy often used in milder builds or OEM applications. While 2618 alloy exhibits slightly greater thermal expansion, this is meticulously accounted for in the specified piston-to-wall clearance, ensuring optimal sealing and performance once at operating temperature. Each piston features a CNC-machined crown that is not only shaped for your specified compression ratio but also strategically designed to optimize combustion efficiency and mitigate detonation—the primary destroyer of turbocharged engines. The valve pockets are precision-cut to accommodate increased valve lift and duration from performance camshafts, a common upgrade in tandem with forced induction builds. Furthermore, the skirt employs a proprietary grafal skirt coating, reducing friction during the critical break-in period and throughout the engine’s life, which directly contributes to reduced wear and consistent power output. The internal geometry, including pin boss design and ring land thickness, is optimized to handle the tremendous loads imposed by high-boost operation, preventing the land collapse and pin bore deformation that plague inferior components.

Complete System Integration: Rings, Pins, and Locks

Brian Crower supplies the BC7911 as a complete, ready-to-assemble system, understanding that the piston is only as strong as its associated hardware. The kit includes a matched set of plasma-moly steel top rings and ductile iron Napier-style second rings, a combination proven to provide exceptional seal and oil control under high cylinder pressure. The included tool steel wrist pins are of an increased thickness and length over stock, manufactured to exacting tolerances for a perfect fit within the CP piston and your chosen connecting rod. These pins are finished with a super-smooth surface to prevent galling and are paired with high-grade spiro-lox retaining rings that offer unparalleled security against pin walk, a critical failure point in high-RPM applications. This holistic approach ensures every interface within the assembly is accounted for, providing a balanced, reliable rotating assembly that can withstand the brutal environment of a modified turbocharged engine.

Technical Advantages & Build Benefits

• Forged 2618 Aluminum Construction: Provides maximum strength and fatigue resistance for high-boost and high-horsepower applications, far exceeding the capabilities of OEM cast or hypereutectic pistons.
• Custom Bore & Compression Ratio Specification: Allows for precise engine blueprinting, whether for a simple stock-bore rebuild with altered compression or for a large-displacement stroker build. This enables tuners to tailor the engine’s characteristics for specific fuel types (pump gas, race fuel, E85) and performance goals.
• Complete Kit with Premium Hardware: Includes everything needed for assembly—pistons, pins, locks, and rings—ensuring component compatibility and saving time sourcing parts. The included ring set is specifically selected for turbocharged sealing performance.
• Optimized Anti-Detonation Design: CNC-machined crown and valve reliefs are engineered to promote efficient flame travel and reduce hotspots, actively fighting pre-ignition and detonation under boost.
• Enhanced Durability & Friction Reduction: Grafal skirt coating and robust ring land design significantly reduce wear on the cylinder walls and the piston itself, leading to longer engine life and more consistent performance over time.
• Foundation for Significant Power Gains: By providing a rigid, reliable platform, these pistons allow you to safely exploit supporting mods like turbo upgrades, intercoolers, and aggressive tuning, unlocking the true potential of the ProStar Turbo engine.

Vehicle Fitment & Configuration Details

Primary Application: This BC7911 kit is engineered specifically for the Polaris ProStar 925 Turbo engine found in the following platforms:

Polaris RZR XP Turbo / XP 4 Turbo: All model years from 2016 onward.

Polaris RZR XP Turbo S / Dynamix: All model years.

Polaris General XP 4 Turbo / Deluxe: All model years.

Critical Ordering Specifications: This is a custom-built-to-order component. You must specify both required parameters at the time of purchase:

1. Bore Size: Specify the exact finished bore diameter you require (e.g., 94.0mm for stock, or larger for overbores). Always confirm bore size with your machinist after cylinder inspection/honing.

2. Compression Ratio: Specify your target static compression ratio (e.g., 9.5:1, 10.5:1). A lower ratio is typically used for extreme boost applications on pump gas, while a higher ratio can improve off-boost response for mixed-use vehicles. Consultation with your tuner or engine builder is highly recommended. For a deeper dive into selecting the correct compression ratio for forced induction builds, consider reading this technical resource on compression ratio selection from a leading performance publication.

Technical Specifications: BC7911 CP Piston Kit

Note: Final piston dimensions and weight will vary based on your specified bore and compression ratio. Professional installation and proper engine break-in procedures are mandatory to achieve the performance and longevity engineered into this component system. Always pair with a correctly sized and honed cylinder, quality connecting rods, and a performance engine management tune.