BC0919 – Polaris XP Turbo (16-up) Stroker Kit 78mm w/Custom MOAR Rods

For the serious Polaris XP Turbo builder targeting dominant, reliable horsepower, incremental bolt-ons eventually hit a thermodynamic wall. The Brian Crower BC0919 Stroker Kit is the definitive solution, a precision-engineered short-block transformation designed to maximize displacement and structural integrity for forced induction. Combining a massive 78mm stroke crankshaft with proprietary Custom MOAR connecting rods, this kit doesn’t just modify your engine—it re-engineers its core mechanical DNA. It is the cornerstone for builds demanding unshakable bottom-end strength to support elevated boost pressure and RPM, translating directly to monumental gains in torque and power across the entire rev range. This is not an upgrade for the faint of heart; it is the calculated choice for constructing an absolute, class-leading powerhouse.

Core Engineering & Design Philosophy

The BC0919 kit addresses the fundamental limitations of the stock Polaris ProStar 925 turbocharged engine. The factory rotating assembly, while robust for OEM specifications, becomes the primary liability when pursuing significant power levels beyond simple tuning. Brian Crower’s approach is holistic: increase displacement for greater air-mass capacity while simultaneously fortifying the rotating assembly to handle the exponentially increased inertial and combustion forces. The 78mm stroke increases engine displacement substantially, providing a larger cylinder volume for boost to act upon. This results in a more efficient burn and greater work output per combustion cycle. However, a long-stroke configuration imposes severe new stresses. This is where the symbiotic design of the crankshaft and MOAR rods proves critical, engineered as a unified system to manage these forces without compromise.

Component Breakdown: Crankshaft & MOAR Rod Synergy

At the heart of the BC0919 kit is a 4340 chromoly steel crankshaft, precision-machined to a 78mm stroke. This material is chosen for its exceptional tensile strength and fatigue resistance, far surpassing the OEM nodular iron unit. The crankshaft is fully counterweighted and balanced to BHJ balancing standards, minimizing parasitic vibrations that can destroy bearings and cause harmonic failures at extended RPM. It is designed as a true drop-in component, utilizing standard bearing sizes for reliability.

The legendary Custom MOAR (Massive Overkill Axis Racing) Rods are the perfect complement. Manufactured from premium 4340 chromoly steel via a forging process that aligns the grain structure for ultimate strength, these rods feature a proprietary “H-beam” design. This design offers an optimal balance of stiffness and weight, resisting the column buckling and stretch induced by the increased stroke and cylinder pressure. The ARP 2000 cap screws are included, providing clamp force far exceeding OEM specs to keep the rod cap secured under extreme loads. This crankshaft-and-rod combination transforms the bottom end into an anvil, capable of withstanding the punishment of high-boost, high-RPM operation.

Performance Benefits & System Impact

Installing the BC0919 Stroker Kit recalibrates the entire performance envelope of your Polaris XP Turbo. The benefits are systemic and profound:

• Substantial Displacement Increase: The 78mm stroke significantly increases total engine cubic centimeters, creating a larger “pump” for forced induction. This yields greater low-end and mid-range torque, reducing turbo lag and improving throttle response.
• Foundation for Extreme Power: The fortified rotating assembly provides the mechanical confidence to safely explore power levels well beyond 200+ horsepower with supporting modifications (turbo, fuel, tuning).
• Enhanced Durability & Longevity: The over-engineered components reduce stress on individual parts. The stronger rods and crank minimize flex and bearing shock, leading to improved reliability even under sustained hard use.
• Optimized for Boost: Increased displacement means the engine can move more air per revolution at a given boost pressure, effectively making your turbocharger more efficient and increasing its effective range.
• Professional-Grade Balance: The factory-balanced assembly ensures smooth operation, protecting the valvetrain and drivetrain from destructive harmonics that plague poorly balanced stroker assemblies.

The kit’s impact necessitates complementary system upgrades. As detailed in resources on forced induction theory, such as this technical article on displacement and boost dynamics, increasing stroke alters volumetric efficiency and thermal loading. Therefore, a comprehensive upgrade path including high-flow fuel injection, advanced intercooling, and professional calibration is mandatory to realize the kit’s full potential safely.

Vehicle Fitment & Installation Notes

The BC0919 kit is engineered as a specific, direct-fit solution for a targeted range of Polaris Turbo models. Correct fitment is critical for function and reliability.

Primary Vehicle Fitment:

• Polaris RZR XP Turbo (All models, including Dynamix) – 2016, 2017, 2018, 2019, 2020, 2021+
• Polaris RZR XP Turbo S
• Polaris General XP Turbo

Installation Considerations: This is a major internal engine modification requiring significant mechanical expertise. The installation process entails complete engine disassembly and removal of the OEM crankshaft and connecting rods. Professional machining and assembly are strongly recommended. Key steps include verifying clearances (piston-to-valve, rod-to-cam, etc.), potentially machining the block for crank clearance, and performing a meticulous blueprinting assembly with precise torque sequences. The engine control unit (ECU) must be professionally retuned to account for the increased displacement and altered engine dynamics. Failure to do so will result in catastrophic engine failure.

Technical Specifications & Kit Contents

The BC0919 is a complete rotating assembly kit, providing all critical components for the stroker conversion. Below are the definitive specifications.

The BC0919 Stroker Kit from Brian Crower represents the pinnacle of purpose-built performance engineering for the Polaris XP Turbo platform. It is the unambiguous choice for builders who define their limits by engineering, not conjecture.