Born from decades of BMW performance engineering.
For over 40 years, VAC Motorsports has pushed BMW engines beyond what the spec sheet ever promised. From the iconic S14 and S38 to today’s twin-turbocharged S63, our stroker kits have powered championship builds and record-setting street cars worldwide. The VAC S63 4.8L Stroker Kit continues that legacy — precision-engineered in-house to turn BMW’s 4.4L V8 into a torque-rich 4.8L powerhouse.
Each kit is machined from premium 4340 billet steel, balanced to perfection, and paired with CP-Carrillo forged pistons for unmatched reliability. Expect an additional +1000–2000 HP potential with proper tuning and supporting mods, and even greater gains on high-boost or ethanol builds.
Why It Works
- Increased displacement boosts midrange torque and turbo efficiency.
- Race-grade materials (4340 billet steel & forged aluminum) handle extreme load and heat.
- Balanced precision for smooth, reliable high-RPM operation.
Technical Specifications
Platform Coverage: BMW S63 / S63TU / N63 (F10/F90 M5, F12/F13 M6, F85/F86 X5M/X6M, G15/G16 M8, and other derivatives with proper calibration)
Displacement:
Stock: 4.4 L (4395 cc)
VAC Stroker: 4.8 L (≈ 4765 cc) — ~8% increase in swept volume
Crankshaft (Core Component):
Material: 4340 billet steel
Stroke: 94 mm (OEM ≈ 89 mm)
Process: Fully CNC-machined, shot-peened, nitrided
Finish: Micropolished journals
Balance: Dynamically balanced to within 1 g tolerance
Pistons (Core Component):
Manufacturer: CP-Carrillo forged aluminum
Bore: 89 mm (standard fitment; no sleeves required)
Compression Ratio: 10.5:1 (boost & E85 compatible)
Design: Lightweight slipper-skirt; CNC dome for combustion efficiency
Hardware: DLC-coated wrist pins and performance ring set included
Connecting Rod Options (Performance Choice):
Manley H-Tuff Rods: 1,000 HP @ 8,500 RPM
CP-Carrillo Pro-Xtreme Rods: 2,000 HP @ 9,500 RPM
Performance Notes
- Supports up to 2,000 HP with proper engine build and calibration.
- Improved torque curve, turbo response, and top-end power.
- Ideal foundation for high-boost, ethanol, or race-fuel builds.
What You’re Getting
- 1 × 4340 Billet Crankshaft (94 mm stroke)
- 8 × CP-Carrillo Forged Pistons (89 mm bore, 10.5:1 CR) with pins & rings
- 8 × Connecting Rods (choose Manley H-Tuff or CP-Carrillo Pro-Xtreme)
Everything else (bearings, fasteners, gaskets, and oiling/cooling upgrades) is sold separately to allow full customization for your build.
Professional Assembly Recommended
Final results depend on supporting components, tuning strategy, fuel quality, and assembly. Professional machining, installation, and ECU calibration are strongly recommended.