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The Subaru WRX has long been a favorite among car enthusiasts, especially those interested in tuning and performance upgrades. One of the most popular modifications for increasing power and reliability is the installation of ARP head studs. In this case study, we will explore the power gains achieved with ARP head studs in a Subaru WRX that has been pushed to 400 horsepower.
Understanding ARP Head Studs
ARP (Automotive Racing Products) is renowned for producing high-quality fasteners that are essential for high-performance engines. Head studs are a critical component in ensuring the cylinder head remains securely fastened to the engine block, especially under high boost conditions.
Why Choose ARP Head Studs?
When modifying a Subaru WRX for higher horsepower, the stock head bolts may not provide the necessary clamping force. ARP head studs offer several advantages:
- Increased Strength: ARP head studs are made from premium materials that provide superior tensile strength compared to factory bolts.
- Enhanced Clamping Force: They maintain consistent clamping force, which is crucial for preventing head gasket failure.
- Reusability: Unlike traditional head bolts, ARP studs can often be reused, making them a cost-effective option for future rebuilds.
The Case Study: Subaru WRX Setup
In this case study, we focused on a 2004 Subaru WRX, which had undergone several modifications prior to the installation of ARP head studs. The vehicle was equipped with a larger turbocharger, upgraded fuel injectors, and a performance intercooler, allowing for significant power potential.
Initial Setup and Modifications
Before the head studs were installed, the WRX was producing approximately 350 horsepower at the wheels. The modifications included:
- Upgraded turbocharger
- High-flow fuel injectors
- Performance intercooler
- Aftermarket exhaust system
- ECU tuning
Installation of ARP Head Studs
The installation process involved removing the cylinder heads to replace the stock head bolts with ARP head studs. This required careful attention to detail to ensure proper torque specifications were followed.
Testing and Results
After the installation of the ARP head studs, the WRX was re-tuned to accommodate the increased clamping force and to maximize performance. The results were impressive.
Power Gains Achieved
Following the re-tuning, the Subaru WRX achieved a peak power output of 400 horsepower at the wheels. This represented a significant increase of 50 horsepower over the previous setup. The gains can be attributed to:
- Improved reliability under boost
- Enhanced combustion efficiency
- Ability to run higher boost levels without head gasket failure
Performance Testing
In addition to the power gains, the vehicle also showed improvements in throttle response and overall drivability. Performance testing on a dynamometer confirmed the stability and reliability of the setup.
Conclusion
The installation of ARP head studs in the Subaru WRX case study demonstrated significant power gains and enhanced reliability. For those looking to push their WRX to higher horsepower levels, ARP head studs are a worthwhile investment.
Final Thoughts
In conclusion, the combination of ARP head studs and proper tuning can unlock the full potential of a Subaru WRX. As enthusiasts continue to seek more power, quality components like ARP head studs will remain essential in the quest for performance.