Table of Contents
The B5 S4 is a beloved model among enthusiasts, known for its balanced performance and tuning potential. One of the most popular upgrades for this vehicle is the turbocharger replacement, specifically with the BorgWarner K16 and GT2871R turbos. This article reviews how these turbo upgrades can significantly enhance the power output of the B5 S4, taking it from a respectable 280 horsepower to an impressive 420 horsepower.
Understanding the B5 S4 Turbo System
The B5 S4 comes equipped with twin K03 turbochargers, which provide adequate performance for daily driving. However, for those looking to unlock the full potential of their vehicle, upgrading to larger turbos can yield substantial gains in power and torque.
Stock Performance Overview
Stock B5 S4s typically produce around 280 horsepower at the crank. This performance is adequate for casual driving but can leave enthusiasts wanting more. The stock turbos are limited in their ability to provide additional boost and airflow, which is where upgrades come into play.
The BorgWarner K16 Turbo
The BorgWarner K16 turbo is a popular choice among B5 S4 owners looking for a balance of performance and reliability. This turbo is known for its ability to spool quickly while providing a significant increase in power.
- Power Output: Capable of supporting power levels up to 400 horsepower.
- Spool Time: Quick spool characteristics enhance drivability.
- Durability: Built to withstand high boost levels without failure.
Installation Considerations
Upgrading to the K16 turbo requires some modifications to the existing setup. Key considerations include:
- Upgraded intercooler for better cooling efficiency.
- High-flow fuel injectors to support increased fuel demands.
- Revised engine management tuning for optimal performance.
The GT2871R Turbo
The GT2871R turbo is another excellent option for B5 S4 owners seeking maximum performance. This turbo is capable of producing even higher power levels than the K16, making it a favorite for those looking to push their vehicles to the limit.
- Power Output: Supports up to 420 horsepower with proper tuning.
- Response: Slightly slower spool compared to the K16, but offers greater top-end power.
- Versatility: Suitable for both street and track applications.
Installation and Tuning
Installing the GT2871R requires careful consideration of supporting modifications:
- Upgraded exhaust system to reduce back pressure.
- Enhanced fuel system, including a larger fuel pump.
- Custom tuning to ensure the engine runs safely at higher boost levels.
Comparative Performance Analysis
Both the BorgWarner K16 and the GT2871R turbos provide significant performance enhancements over the stock K03 turbos. Below is a comparative analysis of their performance characteristics:
- Power Gains: K16 can achieve up to 400 hp, while GT2871R can reach 420 hp.
- Boost Threshold: K16 spools faster, making it more suitable for street driving.
- Top-End Power: GT2871R shines at higher RPMs, ideal for track use.
Real-World Performance Results
Owners who have upgraded to either the K16 or GT2871R report noticeable improvements in acceleration and overall driving experience. Dyno results typically show:
- Improved torque delivery, especially in the mid-range.
- Higher peak horsepower numbers, validating the performance claims.
- Enhanced throttle response and engine sound.
Conclusion
Upgrading the turbochargers on a B5 S4 can transform the driving experience, taking power from 280 to 420 horsepower with the right modifications. Whether choosing the BorgWarner K16 for its quick spool and daily drivability or the GT2871R for its top-end power, enthusiasts will find that these upgrades provide the performance boost they seek. Proper installation and tuning are crucial to ensuring that these upgrades deliver their full potential safely and effectively.