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The Subaru EJ255 engine is well-known among automotive enthusiasts for its potential to deliver impressive power. Achieving 500 horsepower from this engine requires a combination of upgrades, including forged pistons, a bigger turbocharger, and an upgraded fuel system. In this article, we will explore each of these components in detail to help you understand how to reach this power goal.
Understanding the EJ255 Engine
The EJ255 is a turbocharged flat-four engine that has been used in various Subaru models. It has a reputation for being reliable and tunable, making it a popular choice for modifications. To achieve significant power gains, it’s crucial to understand the engine’s design and limitations.
Upgrading to Forged Pistons
One of the first steps in building a high-performance EJ255 is upgrading to forged pistons. Stock pistons are not designed to handle the increased pressures and temperatures associated with high horsepower applications.
- Benefits of Forged Pistons: Increased strength and durability, better resistance to detonation, and improved performance.
- Recommended Brands: Wiseco, CP-Carrillo, and Manley.
Choosing the Right Compression Ratio
When selecting forged pistons, it’s essential to consider the compression ratio. A lower compression ratio is often better for high-boost applications, while a higher ratio can improve responsiveness. Aim for a balance that suits your power goals and driving style.
Installing a Bigger Turbocharger
A bigger turbocharger is critical for achieving the airflow necessary for 500 horsepower. The stock turbo on the EJ255 may not be capable of supporting such power levels.
- Popular Turbo Options: Garrett GTX3071R, BorgWarner EFR 7163, and Blouch 20G-XT.
- Considerations: Lag, boost threshold, and compatibility with existing components.
Tuning the Turbo System
After upgrading the turbo, proper tuning is essential. A professional tune will ensure that the engine runs efficiently and safely with the new turbo. This involves adjusting fuel maps, ignition timing, and boost levels.
Upgrading the Fuel System
To support the increased power output, an upgraded fuel system is necessary. This includes larger fuel injectors, a high-flow fuel pump, and possibly a fuel pressure regulator.
- Recommended Fuel Injectors: 1000cc or larger, depending on the turbo and power goals.
- Fuel Pump Options: Walbro 255lph, DeatschWerks, and AEM.
Fuel Quality and Type
Using high-octane fuel is crucial for high-performance builds. It helps prevent knock and allows for more aggressive tuning. Consider using E85 or other high-octane fuels if your setup supports it.
Supporting Modifications
Reaching 500 horsepower isn’t just about the engine components. Supporting modifications are necessary to ensure reliability and performance.
- Upgraded Intercooler: A larger intercooler will help manage intake temperatures.
- Exhaust System: A high-flow exhaust system will reduce back pressure and improve efficiency.
- Engine Management: A standalone ECU or a high-quality tune is essential for managing the new setup.
Conclusion
Achieving 500 horsepower on the EJ255 engine is an ambitious but attainable goal with the right upgrades. By investing in forged pistons, a bigger turbo, and an upgraded fuel system, along with supporting modifications, you can unlock the full potential of this engine. Always remember to tune your vehicle properly to ensure safe and reliable performance.