For BMW enthusiasts, the S63B44 engine represents the pinnacle of high-performance engineering. Found in iconic models such as BMW F10 M5, F90 M5, F12/F13 M6, F92 M8, X5M and X6M, the S63 twin-turbocharged V8 delivers exhilarating power and relentless torque.
However, as tuners push the limits of this engine with big turbo upgrades, aggressive tuning, and high boost pressures, the stock crankshaft often becomes a weak link. If you're chasing 1,000+ horsepower builds, track reliability, or just want peace of mind for your high-performance S63, upgrading to a forged crankshaft is the key.
Common Weak Points in High-Performance S63 Builds
Crankshaft Failures Under High Boost – The stock crankshaft, while robust at factory power levels, is prone to cracks and flexing under extreme torque loads, which can lead to catastrophic failure.
Oil Starvation & Bearing Wear – The S63's high-RPM abuse, especially in track conditions or aggressive street builds, can accelerate wear on main and rod bearings, increasing the chances of spun bearings and internal damage.
Harmonic Vibrations at High RPMs – The OEM crankshaft isn’t optimized for ultra-high RPM applications, making it vulnerable to harmonic distortions that can gradually weaken the engine’s internals.
If you're planning a big turbo upgrade, running high boost, or tuning for maximum horsepower, reinforcing the bottom end with a forged crankshaft is essential to ensure long-term reliability and peak performance.
Why Upgrade to a S63 Forged Crankshaft?
When pushing the BMW S63 engine beyond its factory limits, durability and reliability become critical. The stock OEM cast crankshaft is designed for factory power levels, but when subjected to high boost, aggressive tuning, and track abuse, its limitations become apparent. Upgrading to a forged crankshaft is one of the most effective ways to reinforce the bottom end, ensuring your engine can handle 1,000+ HP without failure. Here’s why a S63 forged crankshaft is a must-have for high-performance builds:
1️. Unmatched Strength for Extreme Power Levels
Forged crankshafts are manufactured using a high-pressure forging process, which creates a denser, more uniform grain structure compared to cast or billet cranks. This results in a dramatically stronger crankshaft that can endure the massive torque loads generated in high-performance S63 setups. Whether you're running upgraded turbos, E85 fuel, or a methanol injection system, a forged crankshaft ensures your bottom end stays intact under extreme conditions.
2️. Superior Torsional Rigidity for Maximum Torque Handling
The S63 is known for its high torque output, especially in heavily modified setups. However, the factory crankshaft can experience torsional flex, which negatively impacts power delivery and engine efficiency. A forged crankshaft is designed with greater rigidity, reducing unwanted flex and allowing more precise power transfer, resulting in improved throttle response, smoother acceleration, and better long-term reliability.
3️. Built for Endurance: Ideal for Track and High-Boost Applications
If you're pushing your BMW M5, M6, X5M, or X6M to its limits—whether on the drag strip, circuit, or high-speed street runs—a forged crankshaft is essential. Unlike the stock crankshaft, which can develop fatigue cracks under prolonged stress, a forged crank withstands continuous abuse, making it a reliable choice for demanding builds that operate at high RPMs and extreme boost pressures.
4️. Improved Oil Flow and Extended Bearing Life
Oil starvation is a common issue in high-performance S63 builds, often leading to bearing wear and engine failure. A properly engineered forged crankshaft improves oil distribution, reducing friction and ensuring consistent lubrication to the main and rod bearings. This helps prevent spun bearings, premature wear, and expensive engine rebuilds, keeping your high-revving S63 running strong.
5️. Precision Balance for High RPM Stability
KingTec Racing’s S63 forged crankshaft is precision-balanced, ensuring minimal harmonic vibrations at high RPMs. This results in a smoother powerband, reduced stress on engine components, and increased longevity. When paired with forged pistons and connecting rods, this upgrade creates a rock-solid bottom end, ready to handle extreme horsepower without compromise.
Whether you’re building a 1,000+ HP track monster, a street-performance beast, or a drag-ready powerhouse, you need a crankshaft that delivers uncompromising strength and durability. KingTec Racing’s S63 forged crankshaft is designed to handle extreme power levels while maintaining OEM fitment, making it the perfect foundation for your high-performance build.
Key Features & Benefits of KingTec Racing’s BMW S63 Forged Crankshaft
1. Premium 4340 Forged Steel – Built from ultra-strong, heat-treated material for maximum durability under extreme loads.Compatible BMW S63 Models
KingTec Racing’s S63 forged crankshaft is designed to handle extreme power levels, making it the perfect upgrade for all BMW S63-powered models, including high-performance sedans, coupes, and SUVs:
BMW M5 (F10, F90) – The ultimate high-performance sedan, perfect for big turbo setups and track builds.
BMW M6 (F12, F13, F06 Gran Coupe) – A powerful grand tourer built for high-speed tuning and aggressive driving.
BMW M8 (F91, F92, F93) – BMW’s flagship performance coupe, requiring the strongest internals for extreme power levels.
BMW X5M & X6M (E70, F85, F95, E71, F86, F96) – High-powered SUVs with supercar performance, needing a reinforced bottom end for maximum reliability under heavy loads.
What Else Should You Upgrade With a Forged Crankshaft?
Upgrading to a forged crankshaft is a critical step in strengthening your BMW S63 engine, but a truly bulletproof bottom end requires more than just a strong crank. Forged pistons and connecting rods, combined with high-performance bearings and fasteners, are essential for maximizing durability and extracting the full potential of your build.
Key Upgrades for a High-Performance S63 Engine
Forged Pistons – Designed for High Boost and Extreme Heat
Forged pistons offer superior strength and thermal resistance, reducing the risk of cracking, ring land failure, or excessive heat expansion. KingTec Racing's S63 forged pistons are designed with enhanced wrist pin support, reinforced skirts, and optimized compression ratios to handle extreme cylinder pressures without failure.
Forged Connecting Rods – Prevent Bending and Breaking Under High Torque
As power levels rise, the factory connecting rods become increasingly vulnerable to bending, stretching, or outright snapping under extreme loads. Upgrading to forged connecting rods provides significantly higher tensile strength, ensuring your engine can handle increased torque and high-RPM abuse without failure. Properly balanced forged rods also help reduce vibrations and improve overall engine efficiency.
Performance Bearings – Reduce Friction and Improve Longevity
Stock bearings can wear prematurely under high-RPM operation and heavy loads, leading to oil starvation, metal-on-metal contact, and potential crank failure. Performance-grade bearings improve lubrication, heat dissipation, and wear resistance, making them a must-have upgrade for any high-horsepower S63 build.
ARP Main & Head Studs – Essential for Boosted Applications
Running high boost significantly increases cylinder pressures, which can lead to head gasket failure or main cap shifting if the factory fasteners stretch under load. Upgrading to ARP main and head studs ensures that everything stays securely clamped, preventing structural failures under extreme conditions.
At KingTec Racing, we offer a complete bottom-end upgrade solution for the S63, including S63 forged crankshafts, pistons, and connecting rods. Whether you're building for track racing, drag racing, or street performance, reinforcing the entire rotating assembly is the key to making big power reliably.
If you’re serious about pushing your BMW S63 to its limits, upgrading to a forged crankshaft is more than just an option—it’s a necessity. High boost, aggressive tuning, and hard launches put immense stress on your engine’s internals, and without the right reinforcements, failure is just a matter of time.
At KingTec Racing, we design our forged crankshafts to handle the extreme demands of high-horsepower M5, M6, M8, X5M, and X6M builds, ensuring maximum strength, durability, and performance. But a strong crankshaft is just the foundation—pair it with our S63 forged pistons and connecting rods for a bulletproof bottom end that can take on anything from street racing to full-blown track competition.
Explore KingTec Racing’s complete lineup of S63 forged internals today and take your BMW’s performance to the next level!
