Brian Crower Mitsubishi 4G63 Eclipse/Evo

1990–2007 Mitsubishi Eclipse / Mitsubishi Lancer Evolution 4G63 31.5mm Exhaust Valve

Part #: BC3105-1

Overview

The Brian Crower Mitsubishi 4G63 Eclipse/Evo 31.5mm Exhaust Valve is a high-performance replacement component designed specifically for enthusiasts seeking to optimize their turbocharged Mitsubishi engines. Whether you're building a street-driven project, a spirited track car, or an off-road machine, this valve offers the durability and precision needed to support increased power levels and reliable operation.

Constructed with quality materials and engineered for perfect fitment, this single exhaust valve helps improve exhaust flow, reduce heat retention, and support higher RPM operation. It is an ideal upgrade for those looking to enhance engine responsiveness, efficiency, and overall performance of their Mitsubishi 4G63-powered vehicles.

Key Features

Designed with performance in mind, the Brian Crower Mitsubishi 4G63 exhaust valve features several key attributes that make it a top choice for engine builders and tuners:

• Manufactured from premium, heat-treated steel to withstand high exhaust temperatures and aggressive driving conditions.
• 31.5mm diameter, optimized for improved airflow and exhaust scavenging, supporting higher horsepower and torque output.
• Precision-machined to exact specifications for perfect seating and sealing, ensuring reliable compression and combustion efficiency.
• Engineered for compatibility with stock or aftermarket valve springs, making it suitable for a wide range of performance builds.
• Designed to support high-RPM operation and increased boost levels common in modified turbo setups.
• Durable construction helps resist warping, cracking, and wear over extended use, providing long-lasting performance.
• Part of Brian Crower's renowned line of performance engine components, trusted by tuners and racers worldwide.

Construction & Design

This exhaust valve is crafted from high-quality, heat-treated steel, ensuring exceptional strength and heat resistance necessary for demanding engine conditions. The 31.5mm diameter is carefully machined to precise tolerances, promoting optimal airflow and exhaust gas evacuation. Its design incorporates a robust stem and a durable head, which together provide excellent longevity and resistance to thermal fatigue. The valve's surface finish and seating surfaces are meticulously finished to ensure a tight seal and consistent performance, even under high stress and elevated temperatures.

Installation & Fitment

This single exhaust valve is designed as a direct replacement for the factory component on Mitsubishi 4G63 engines found in Eclipse and Lancer Evolution models from 1990 to 2007. Installation requires standard engine disassembly procedures, including removing the cylinder head. Proper valve installation and seating are critical; therefore, it is recommended to have a qualified mechanic or engine builder perform the upgrade. No special modifications or tuning are necessary solely for installing this valve, but overall engine tuning is advised to maximize performance gains.

• Direct replacement for OEM exhaust valves in Mitsubishi 4G63 engines
• Requires cylinder head removal for installation
• Compatible with stock or aftermarket valve springs
• No cutting or drilling required

What's Included

• Single exhaust valve (BC3105-1)
• Installation instructions (if provided)

Ideal For

• Performance enthusiasts building or upgrading Mitsubishi 4G63 engines
• Turbocharged Mitsubishi Eclipse and Lancer Evolution owners seeking increased durability and flow
• Engine builders aiming to support higher horsepower and RPM ranges
• Rebuilders restoring or maintaining high-performance Mitsubishi engines