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The Subaru EJ255 engine, known for its robust performance and reliability, has become a popular choice among enthusiasts looking to push the limits of their vehicles. With the right modifications, reaching over 600 horsepower is achievable. This article will focus on upgrading the internals of the EJ255 engine using Cosworth pistons and Manley valves, two components that can significantly enhance performance.
Understanding the EJ255 Engine
The EJ255 is a turbocharged flat-four engine produced by Subaru. It is part of the EJ family and is commonly found in various Subaru models. The engine features a DOHC design and is known for its ability to handle high power outputs. However, to reach the 600+ horsepower mark, specific upgrades are necessary.
Why Upgrade Internals?
Upgrading the internals of the EJ255 is crucial for achieving higher horsepower levels. Stock components may not withstand the increased stress and heat generated by higher boost levels. By replacing these components with high-performance alternatives, you can improve engine reliability and performance.
Key Components for Upgrade
- Cosworth Pistons
- Manley Valves
- Forged Connecting Rods
- Upgraded Turbocharger
- High-Performance Fuel Injectors
Cosworth Pistons: A Game Changer
Cosworth pistons are designed for high-performance applications. They offer several advantages over stock pistons, including:
- Increased Compression Ratio: Cosworth pistons typically have a higher compression ratio, which can lead to better combustion efficiency and power output.
- Durability: Made from high-quality materials, these pistons can withstand higher temperatures and pressures.
- Weight Reduction: Lighter pistons help reduce overall engine weight, improving throttle response and performance.
Manley Valves: Enhancing Airflow
Manley valves are known for their strength and ability to handle high-performance applications. Upgrading to Manley valves can provide several benefits:
- Improved Airflow: Larger valve diameters allow for better airflow into and out of the combustion chamber, which is essential for high horsepower builds.
- Increased Durability: Manley valves are designed to withstand the rigors of high-performance engines, reducing the risk of valve failure.
- Better Heat Resistance: These valves can handle higher temperatures, ensuring consistent performance under extreme conditions.
Installation Process
Installing Cosworth pistons and Manley valves requires careful attention to detail. Here’s a general overview of the installation process:
- Disassemble the Engine: Remove the engine from the vehicle and disassemble it to access the internals.
- Remove Stock Pistons: Carefully remove the stock pistons and connecting rods from the engine.
- Install Cosworth Pistons: Install the new Cosworth pistons, ensuring proper orientation and clearance.
- Replace Valves: Remove the stock valves and install Manley valves, ensuring proper seating and alignment.
- Reassemble the Engine: Reassemble the engine with all new gaskets and seals to prevent leaks.
Tuning for Maximum Performance
After upgrading the internals, tuning the engine is essential to achieve optimal performance. A professional tuner can adjust the engine management system to accommodate the new components, ensuring the engine runs efficiently and reliably.
Tuning Considerations
- Boost Levels: Adjust boost levels to maximize power without risking engine damage.
- A/F Ratios: Ensure proper air-fuel ratios for optimal combustion.
- Ignition Timing: Adjust ignition timing to improve throttle response and power delivery.
Conclusion
Reaching 600+ horsepower on the EJ255 engine is an attainable goal with the right upgrades. By investing in high-quality components like Cosworth pistons and Manley valves, you can enhance performance and reliability. Proper installation and tuning are crucial to ensure your engine performs at its best. With dedication and the right parts, your Subaru can achieve remarkable power levels, making it a true performance machine.