BC0131 – Mitsubishi 4B11 Evo X Stage 2 Camshafts – Street/Strip Spec

Unlock the True Potential of Your 4B11: Introducing the Brian Crower BC0131 Stage 2 Camshafts

For the Mitsubishi Lancer Evolution X enthusiast, the quest for power is a precise science. The factory 4B11T engine is a robust foundation, but its stock valvetrain represents a significant bottleneck for ambitious power goals. The BC0131 Street/Strip camshaft set from Brian Crower is the definitive, bolt-in solution engineered to recalibrate your engine’s breathing dynamics. These are not merely “reground” cams; they are precision-machined from premium-grade, virgin 8620 steel billet, offering a calculated profile designed to extract substantial mid-to-top-end horsepower and torque without sacrificing the drivability demanded for aggressive street use or weekend bracket racing. This is a component-level upgrade that delivers a transformative shift in power delivery, moving your Evo X from a potent stock turbo platform to a genuinely high-performance engine ready for upgraded turbos, fueling, and tuning. As a cornerstone of any serious Stage 2 or Stage 3 build, the BC0131 cams provide the volumetric efficiency needed to realize your engine’s full, untapped potential.

Engineered for Aggressive Performance: Design and Dynamics

The philosophy behind the BC0131 profile is one of balanced aggression. Brian Crower’s engineers have meticulously designed these camshafts to work in harmony with the 4B11T’s twin-scroll turbocharger architecture. The increased duration and lift profiles hold the intake and exhaust valves open longer and farther from their seats. This extended open period allows a greater volume of air-fuel mixture to enter the cylinder and, crucially, provides more time for spent exhaust gases to evacuate. This drastically reduces pumping losses and residual exhaust gas contamination of the fresh intake charge. The result is a more complete, efficient combustion cycle. The specific “Street/Strip” grind is tailored to maintain robust low-end manifold pressure while building a relentless power curve that continues to climb well past the factory redline. The use of billet steel, as opposed to cast or welded cores, ensures unparalleled structural integrity and precise lobe geometry under the high valve spring pressures required for high-RPM operation, eliminating the risk of lobe wear or failure common in inferior products. For a deeper dive into the principles of camshaft design and how duration, lift, and overlap affect turbocharged performance, refer to this authoritative resource on automotive engineering fundamentals.

Tangible Gains: The Direct Benefits of Upgraded Camshafts

Installing the BC0131 camshaft set is a transformative modification that impacts nearly every aspect of engine performance. The benefits are quantifiable and significant:

• Substantial Power Increase: Expect gains of 30-50+ wheel horsepower and a commensurate increase in torque, dependent on supporting modifications and tune, with the powerband shifted favorably toward the mid and upper RPM ranges.
• Enhanced Volumetric Efficiency: The engine becomes a more effective air pump, flowing more CFM at a given RPM, which directly translates to higher cylinder pressure and power output.
• Improved Turbo Spool and Response: By optimizing exhaust scavenging, these cams help spin the turbocharger more efficiently, potentially reducing lag and improving transient throttle response.
• Extended and Optimized Powerband: Power delivery becomes broader and more usable, with a noticeable pull that continues aggressively to 7500+ RPM, allowing you to stay in the powerband longer during gear changes.
• Foundation for Future Modifications: These cams unlock the flow potential needed to support larger turbochargers, increased boost pressure, and aggressive ethanol blends, making them a prerequisite for 400+ wheel horsepower builds.
• Retained Street Manners: Despite their performance intent, the BC0131 profile is designed to maintain stable idle quality and low-speed drivability when paired with a proper tune, making them suitable for a daily-driven performance vehicle.

Precision Fitment: Vehicle Compatibility and Installation Notes

Vehicle Fitment: The Brian Crower BC0131 camshaft set is engineered as a direct, bolt-in replacement for the OEM camshafts in specific Mitsubishi applications. Correct fitment is critical for performance and reliability.

• Primary Application: 2008-2015 Mitsubishi Lancer Evolution X (All trim levels – GSR, MR, SE, Final Edition) equipped with the 4B11T engine.
• Engine Specificity: Designed exclusively for the Dual MIVEC 4B11T engine code. They are not compatible with the 4G63 engine found in Evolution VIII or IX models, or with the standard, naturally-aspirated 4B11 engine.

Critical Installation Advisory: Installing performance camshafts with increased lift is a professional-grade procedure. It absolutely necessitates the use of upgraded valvetrain components. The factory valve springs are not designed for the increased lift and ramp rates of the BC0131 profile. To prevent valve float, bounce, and catastrophic engine failure, pairing these cams with Brian Crower’s recommended dual valve spring kit, titanium retainers, and hardened spring seats is mandatory. Furthermore, installation must include precise degreeing of the camshafts and a professional, custom ECU tune to adjust ignition timing, fuel delivery, and MIVEC phasing. Attempting to run these cams on an OEM tune or with stock valve springs will result in poor performance and likely engine damage.

Technical Specifications: The Blueprint of Performance

The table below details the exact specifications that define the BC0131 camshaft set, providing the hard data that underpins its performance claims. All measurements are taken at the industry-standard 0.050″ valve lift, allowing for accurate comparison against other profiles.

The BC0131 in the Competitive Landscape: Why This is the Right Choice

In the aftermarket for Evo X camshafts, choices range from mild “drop-in” grinds to extreme race-only profiles. The BC0131 occupies the critical sweet spot. It offers significantly more aggressive timing than OEM+ “Stage 1” cams, which often provide marginal gains, yet it avoids the extreme overlap and loss of low-end driveability characteristic of “Stage 3” or “Race” grinds. Compared to reground cores, the billet construction of the BC0131 guarantees perfect concentricity and lobe hardening from the core outwards, ensuring longevity that reground cams simply cannot match. When selecting camshafts, the pedigree of the manufacturer is paramount. Brian Crower’s reputation is built on championship-winning engines across multiple disciplines, providing assurance that the BC0131 profile is the product of rigorous dyno and track testing, not just theoretical design. For the builder seeking a definitive, no-compromise upgrade that transforms the character of the 4B11T engine while retaining real-world usability, the BC0131 Street/Strip camshaft set is the authoritative, technically-sound selection.