Wiseco 6636M865 Forged Sport Compact Piston 86.5mm Shelf Stock Single - Mitsubishi 4B11T

The Wiseco 6636M865 is a shelf-stock, single forged piston designed for the Mitsubishi Lancer Evolution X 4B11T turbocharged engine. Built at Wiseco's Mentor, Ohio manufacturing facility from aerospace-grade 2618 aluminum alloy, this piston delivers the strength and durability required for high-output forced-induction builds. It is sold individually, making it ideal for replacing a single damaged piston without purchasing a full kit.

Key Features:

• Bore Size: 86.50mm (+0.5mm over stock)
• Compression Ratio: 9:1 (calculated with 0.048" head gasket)
• Valve Relief: -4.5cc dish
• Material: 2618 aerospace-grade forged aluminum alloy
• .300" top land thickness for superior structural integrity under boost
• .200" wall tool steel wrist pin for reinforced pin bore strength
• ArmorGlide skirt coating — dry film lubricant that reduces friction, resists seizure, and allows tighter piston-to-wall clearances for quieter operation
• Textured piston crown to improve combustion characteristics and detonation resistance
• Offset wrist pin (same as OEM specification) for quietest operation
• Precision ring grooves with anti-detonation groove and enhanced ring seal geometry
• Forced pin oiling for improved lubrication under high-RPM and high-boost conditions

Wiseco is the only major aftermarket piston manufacturer in the United States that produces pistons exclusively through the forging process. Each piston design is developed using 3D CAD and finite element modeling software to optimize strength-to-weight ratio for the specific application. The 4B11T platform is well-supported by Wiseco's Sport Compact line, and the 6636M865 shelf-stock single piston ensures builders and racers can source individual replacement pistons quickly without waiting for custom orders.

Note: This listing is for a single piston only.