BMW M57D30 306D2 2.9 Inline-Six Diesel Engine

Overview
The BMW M57D30 306D2 is a 2.9-liter inline-six diesel engine developed as part of BMW’s M57 engine family. Found in facelifted E46 330d models, this version introduced several internal upgrades over earlier M57 units, enhancing fuel efficiency, emissions control, and power potential. The engine is designed to support turbocharging but is sold as a base unit without the turbocharger included. Built for durability, smooth operation, and high torque capability, the 306D2 stands out as a dependable powerplant for diesel performance and long-range use.

Key Features
2.9L Inline-Six Diesel Configuration – With a displacement of 2,926 cc, the M57D30 306D2 delivers a smooth and torque-rich driving experience in a compact, straight-six layout.
DOHC with 24 Valves – Dual overhead camshafts and four valves per cylinder allow for efficient air movement and clean combustion, supporting both performance and economy.
Second-Generation Common Rail Injection – Equipped with Bosch second-gen common rail direct injection, the engine achieves precise fuel delivery for reduced emissions and improved fuel efficiency.
Cast Iron Block with Aluminum Cylinder Head – The engine uses a robust cast iron block for strength and an aluminum head for effective heat management, ideal for extended use and load-bearing applications.
Turbo-Compatible Architecture – While the engine itself is not sold with a turbo, it is engineered to accept a factory turbocharger, featuring the necessary oil feeds, mounting points, and reinforced internals.
Timing Chain System – The use of a chain-driven valvetrain ensures longevity and reduces the need for routine timing service, contributing to the engine’s long service life.

Performance & Applications
The M57D30 306D2 powered facelifted variants of the BMW E46 330d, offering a step up in refinement and output compared to earlier M57 engines when paired with the correct turbocharging setup.
BMW E46 330d (2003–2005, facelift) – This engine was fitted to facelifted versions of the 330d sedan, touring, and coupe models. Though sold as a standalone unit without turbo hardware, it was designed from factory to operate with forced induction in these applications.

Why Choose the BMW M57D30 306D2 Engine?
🔹 Turbo-Ready Design – Built to accept a factory turbocharger but sold without one, the 306D2 is ideal for OEM replacement or custom diesel setups.
🔹 Robust and Reliable – The combination of a cast iron block, aluminum head, and chain-driven cams makes this engine exceptionally durable under heavy use.
🔹 Smooth Inline-Six Operation – The straight-six configuration provides refined performance and minimal vibration, ideal for long-distance driving.
🔹 Efficient Diesel Performance – Advanced common rail injection and combustion design allow for strong torque delivery and fuel efficiency even without turbo assist.
🔹 Factory-Fit for E46 330d (Facelift) – Originally installed in facelift E46 330d models, the 306D2 is well-supported with parts and documentation for maintenance or conversion.

Conclusion
The BMW M57D30 306D2 is a strong and efficient 2.9-liter inline-six diesel engine, designed with turbo compatibility but sold without forced induction hardware. Used in facelifted E46 330d models, it offers dependable performance, excellent torque potential, and long-lasting durability. For those seeking a diesel engine platform that combines smooth operation, high-strength construction, and adaptability for turbocharged setups, the 306D2 stands as a proven and flexible choice.