Beneath an aluminum cover sits BMW M’s latest engine revision. Designated the S63tu (technical update), this V8 represents an evolution of the S63 previously employed in the X5 M and X6 M. The fundamental architecture remains unchanged—both versions feature a 90° twin-turbocharged, twin-scroll V8 with BMW’s cross-bank exhaust headers, variable valve timing on intake and exhaust, and direct fuel injection.
The differences emerge in specific components and calibration. The new M5’s S63tu incorporates a higher compression ratio of 10:1 compared to its predecessor. BMW now classifies it as a “newly developed” engine due to the extent of modifications.
Technical Revisions
New pistons enable the increased compression ratio. Boost pressure decreases slightly by 0.1 bar, while larger intercoolers expand cooling capacity. The turbochargers themselves are new units with larger turbine diameters. The valvetrain introduces Valvetronic variable valve lift on the intake side, while throttle bodies function primarily as limp-home fallback systems. BMW has comprehensively revised the electronic engine management system to support a 7,200 rpm redline.
Power and Efficiency Trade-offs
The S63tu produces 560 horsepower and 553 lb-ft of torque—a gain of just five horsepower over the X5 M and X6 M. This modest increase reflects BMW M’s stated prioritization of efficiency and drivability over peak output. BMW engineers could theoretically extract additional power, but M’s philosophy extends beyond headline figures.
Compared to the previous E60 M5 generation, efficiency improvements are significant. According to BMW’s official specifications, the new F10 M5 achieves 30% lower fuel consumption while producing 10% more power and 30% additional torque. On the EU test cycle, the M5 recorded 9.9 liters per 100 kilometers (28.5 mpg) with COâ‚‚ emissions of 232 g/km under EU5 standards. Note: These figures represent different test cycles and generation comparisons; real-world results vary based on driving conditions and individual driving habits.
Thermal Management and Compact Layout
The S63tu places both turbos and catalytic converters within the V of the cylinder banks—a compact design that creates thermal challenges. Consequently, BMW developed an extensive cooling system featuring large intercoolers and aerodynamic front-end design to direct adequate airflow to radiators and engine components.
This compact turbo placement offers benefits for response characteristics. By reducing the distance from exhaust valves to turbo turbine blades, exhaust gases reach the turbine more quickly, building intake boost faster than conventional turbo installations. This design reduces, though does not eliminate, the delay between throttle input and turbo spool-up that typically characterizes turbocharged engines.
Cross-Bank Exhaust Design
BMW’s patented cross-bank exhaust manifold distributes exhaust pulses evenly across both turbos. Each cylinder bank contributes to one scroll of each turbo, ensuring both scroll elements receive consistent exhaust flow across the RPM range. This design contributes to audible characteristics distinct from conventional turbocharged V8s.
Torque Characteristics
The S63tu delivers full torque at 1,500 rpm, developing 100% of available torque in the lower RPM band. Torque remains at peak levels until 5,750 rpm before gradually decreasing toward the 7,200 rpm redline. The engine produces approximately 405 lb-ft immediately above idle.
Compared to the naturally aspirated E60 M5 V10—which peaked at 507 horsepower at 8,250 rpm but required 4,000+ rpm for peak torque—the S63tu’s torque delivery is significantly lower in the RPM range. The turbocharged engine’s 3,250 rpm wider effective torque plateau represents a fundamental difference in power delivery character. While redline drops approximately 1,000 rpm from the V10 era, usable power remains distributed across a broader RPM window.
On-Track Impressions
During testing, the S63tu’s throttle response proved responsive compared to other turbocharged performance engines. The low-end torque delivery enables aggressive acceleration from moderate speeds. In comparison to BMW’s X6 M—which shares the same engine family—the M5 demonstrates quicker power delivery characteristics, particularly in mid-range acceleration scenarios.
The engine’s broad torque plateau supports varied driving styles, from sustained highway acceleration to dynamic road courses. Only in higher gears does any lag become apparent between throttle application and acceleration response.
Engineering Philosophy
The S63tu represents modern performance engineering prioritizing broad usability and efficiency alongside peak power. The engine achieves these goals through extensive component revision and electronic calibration rather than displacement or boost increases.
BMW M will provide additional testing and performance data through upcoming track evaluations and comprehensive first drive reviews.
Technical Specifications Summary
- Engine: 4.4L Twin-Turbocharged V8
- Compression Ratio: 10:1
- Horsepower: 560 hp
- Torque: 553 lb-ft (available from 1,500 rpm)
- Redline: 7,200 rpm
- Fuel Efficiency (EU cycle): 9.9 L/100km (28.5 mpg estimated)
- Emissions: 232 g/km COâ‚‚ (EU5)
Note: EU test cycle figures may not reflect real-world driving conditions. Individual results vary based on driving habits, traffic conditions, and vehicle configuration. (Photos Credit: Daniel Kraus, Shawn Molnar)
