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The EJ257 engine, known for its robust performance in Subaru vehicles, has gained a significant following among car enthusiasts. This guide will take you through the process of building an EJ257 engine from stock to an impressive 700 horsepower, focusing on custom internals and an upgraded fuel system.
Understanding the EJ257 Engine
The EJ257 is a turbocharged flat-four engine that powers several Subaru models, particularly in the WRX and STI line. With a displacement of 2.5 liters, it is known for its ability to handle modifications while maintaining reliability.
Stock Specifications
Before diving into modifications, it’s essential to understand the stock specifications of the EJ257 engine. Here are some key details:
- Displacement: 2.5 liters
- Power Output: Approximately 227 hp
- Torque: 236 lb-ft
- Compression Ratio: 8.2:1
Step 1: Custom Internals
To achieve 700 hp, upgrading the internal components of the EJ257 is crucial. Here are the components to consider:
- Pistons: Opt for forged pistons designed for high horsepower applications.
- Connecting Rods: Use lightweight, strong rods to handle increased power.
- Cylinder Head: Port and polish the heads for better airflow and efficiency.
- Cams: Install performance camshafts to enhance power delivery.
Step 2: Upgraded Fuel System
A reliable and efficient fuel system is vital for supporting higher horsepower levels. Consider the following upgrades:
- Fuel Injectors: Upgrade to larger fuel injectors to accommodate increased fuel demands.
- Fuel Pump: Install a high-flow fuel pump to ensure adequate fuel delivery.
- Fuel Pressure Regulator: Use an adjustable fuel pressure regulator for fine-tuning.
- Fuel Lines: Upgrade to larger diameter fuel lines to reduce restrictions.
Step 3: Turbocharger Upgrade
To reach 700 hp, a turbocharger upgrade is necessary. Choose a turbo that can provide the desired boost levels while maintaining reliability. Here are some options:
- Garrett GTX3076R: Known for its efficiency and power potential.
- Precision 6266: A popular choice among high horsepower builds.
- Blouch 20G-XT: Offers a good balance of spool time and power output.
Step 4: Engine Management
A proper engine management system is crucial for tuning and maximizing performance. Consider the following options:
- ECU Reflash: A custom tune can optimize performance for your specific setup.
- Standalone ECU: Provides full control over fuel and ignition maps.
- Tuning Software: Use software that allows for real-time adjustments and data logging.
Step 5: Supporting Modifications
In addition to the main upgrades, several supporting modifications will enhance the overall performance and reliability of your EJ257 build:
- Exhaust System: Install a high-flow exhaust to reduce back pressure.
- Intercooler: Upgrade to a larger intercooler for better cooling efficiency.
- Intake System: Use a high-flow intake system to improve airflow into the engine.
- Oil Cooler: Install an oil cooler to maintain optimal oil temperatures.
Final Thoughts
Building an EJ257 engine to 700 hp requires careful planning and quality components. By focusing on custom internals, an upgraded fuel system, and supporting modifications, you can achieve impressive power while maintaining reliability. Always consult with professionals and ensure proper tuning for the best results.