BMW M5 F90 Tuning Guide
BMW S63B44T4 Tuning Guide
The BMW S63B44T4 engine is a 4.4-litre twin-turbocharged V8 that powers some of BMW’s most prestigious performance models, including the M5 F90, M5 Competition F90, M8, M8 Competition, X5M, X5M Competition, X6M, and X6M Competition. Known for its solid foundation and impressive factory power output, the S63B44T4 offers great tuning potential for those looking to push the limits of its performance. Whether you're aiming for more power, better throttle response, or an improved driving experience, this tuning guide will outline the key modifications, expected power gains, and considerations for maintaining a tuned engine.
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Power Gains and Tuning "Stages"
Tuning the S63B44T4 engine can unlock significant performance improvements. The process typically progresses through different "stages," each involving specific upgrades to the engine, exhaust, and ECU. The tuning gains you can expect will depend on the stage of modification and the supporting hardware.
Please note "Tuning Stages" are used to give you, the reader, an easy way to categorise certain modifications. They are not to be stuck to religiously, always discuss required hardware and tuning with your chosen tuner, they are the best people to advise for your application specifically.
Stage 1: ECU Remapping (Software Tuning)
The most basic and common form of tuning is ECU remapping, often referred to as a Stage 1 tune. This involves modifying the engine control unit (ECU) software to optimise fuel delivery, boost pressure, and ignition timing for more power without any hardware changes.
- Expected Power Gain: Approximately 50-100 bhp (37-75 kW) increase, depending on the specific model and software.
- Supporting Hardware: No hardware changes are required for Stage 1 tuning. However, an upgraded air intake or performance exhaust may further enhance the gains.
This tuning stage is ideal for drivers seeking improved performance without making major modifications. It is also a less invasive option, with minimal impact on engine reliability when done correctly.
Stage 2: Upgraded Intake, Exhaust, and Chargecoolers
Stage 2 tuning involves adding supporting hardware to complement the ECU remap. This typically includes a performance intake system, upgraded intercoolers, and a high-flow exhaust system. These modifications help to increase airflow into and out of the engine, allowing it to produce more power efficiently.
- Expected Power Gain: Around 100-150 bhp (75-112 kW) increase over stock, depending on the specific parts and tuning.
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Supporting Hardware:
- High-flow intake system: Improves airflow to the engine for better combustion.
- Performance exhaust system: Reduces backpressure, increasing power and improving sound.
- Upgraded chargecoolers: Enhance the cooling of intake air, increasing power potential.
At this stage, the engine is likely to be running more aggressively, and proper tuning is crucial to avoid pushing the limits of the stock components. Stage 2 tuning offers an excellent balance between power gain and reliability.
Stage 3: Turbochargers, Fuel System, and Supporting Mods
For those seeking substantial power gains, Stage 3 tuning involves more extensive hardware upgrades, including larger turbochargers, an upgraded fuel system, and further exhaust and intake modifications. Stage 3 tuning is typically pursued by enthusiasts who are looking to significantly increase horsepower and torque.
- Expected Power Gain: Power gains of 200 bhp (149 kW) or more are achievable with this level of tuning largely dependent on turbo size.
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Supporting Hardware:
- Upgraded turbochargers: Larger turbos increase boost pressure and airflow, enabling much higher power outputs.
- Upgraded fuel system: Larger injectors, high-flow fuel pumps, and a fuel pressure regulator to support the increased fuel demand.
- Performance chargecoolers and intake manifold: These upgrades help to manage the increased air volume and temperature from the larger turbochargers.
Stage 3 tuning significantly increases performance, but it also places much greater demands on the engine, drivetrain, and cooling systems.
Maintenance Considerations for Tuned S63B44T4 Engines
While the S63B44T4 is a robust engine, tuning increases the stress placed on various components, especially if the car is used hard or driven on track. It is crucial to be aware of the impact that increased power and aggression can have on engine longevity. Here are a few key areas to focus on for maintenance:
1. Engine Oil and Cooling System
Higher power output requires more frequent oil changes. It is recommended to replace the engine oil every 5,000 miles (8,000 km) if the car is tuned or driven hard. A higher-performance synthetic oil may be necessary to withstand the increased temperatures and stresses. Additionally, with increased power, the cooling system should be checked regularly to ensure the engine does not overheat, especially if the car is used on track.
2. Brakes and Transmission
Tuning the S63B44T4 engine for higher power output puts more strain on the transmission and braking system. Consider upgrading to stronger, high-performance brake pads and rotors to cope with the additional heat generated by aggressive driving. The transmission fluid should also be replaced more frequently (every 30,000 miles or 48,000 km) to maintain smooth shifting and prevent wear on internal components.
3. Turbochargers and Intercoolers
Turbochargers are a critical component in any tuned engine, and with increased boost levels, it’s essential to regularly check their condition. Inspect the turbochargers for signs of wear, including unusual noises or loss of boost pressure. A well-maintained intercooler system is also important to ensure the intake air temperature remains low, so clean and inspect the intercoolers regularly.
4. Fuel System and Air Intake
As the fuel system is upgraded during tuning, regular inspection of the fuel injectors, pumps, and lines is essential. Ensure that the fuel pressure is within specifications to avoid lean running, which can damage the engine. The air intake system should also be cleaned or replaced periodically, especially if a performance air filter is used.
Conclusion
The BMW S63B44T4 engine offers tremendous tuning potential, from mild increases in power through ECU remapping to extreme performance levels with larger turbos and supporting hardware. As with any performance modification, it’s essential to consider the impact on maintenance and ensure that your vehicle is serviced regularly to handle the increased stresses of higher power output. Whether you’re looking to improve throttle response, gain a significant power boost, or achieve the ultimate track-ready setup, there’s a range of tuning options available for the S63B44T4 engine that can transform your BMW into a high-performance machine. However, be mindful of the additional maintenance requirements to keep your car running at its best.
Remember to check out our model specific pages if you are looking to modify your BMW