The BMW S85 B50 A is a 4,999 cc, naturally aspirated V10 petrol engine produced between 2005 and 2010. It features DOHC, 40 — valve configuration with individual throttle bodies and double — VANOS variable valve timing. Rated at 373 kW (507 PS) at 8,250 rpm and 520 Nm of torque, this high — revving engine was developed specifically for the E60 M5 and E63 M6.
Fitted exclusively to the E60 M5 and E63 M6, the S85 B50 A was engineered for ultimate driving dynamics and motorsport — derive…
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Production years 2005–2010 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/8550).
The BMW S85 B50 A is a 4,999 cc V10 naturally aspirated petrol engine engineered for high-performance sedans and coupes (2005–2010). It combines DOHC architecture with individual throttle bodies and double-VANOS to deliver linear throttle response and high-RPM performance. Designed to meet Euro 4 standards, it balances motorsport-derived engineering with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 4,999 cc | |
Fuel type | Petrol | |
Configuration | V10, DOHC, 40-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 92.0 mm × 75.6 mm | |
Power output | 373 kW (507 PS) @ 8,250 rpm | |
Torque | 520 Nm @ 6,100 rpm | |
Fuel system | Bosch Motronic ME 9.2 electronic fuel injection | |
Emissions standard | Euro 4 | |
Compression ratio | 12.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Double-row roller chain (interference design) | |
Oil type | BMW Longlife-01 (SAE 10W-60) | |
Dry weight | 215 kg |
The BMW S85 B50 A was used exclusively in BMW's E60/E63 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-reinforced engine mounts in the E60 M5 and revised intake in the E63 M6-and was replaced by the S63 twin-turbo V8 in 2011, creating strict interchange limits. All adaptations are documented in OEM technical bulletins.
The S85 B50 A's primary reliability risk is timing chain wear in early builds, with elevated incidence in high-mileage vehicles. Internal BMW quality reports from 2007 noted a significant share of pre-2007 engines requiring tensioner replacement before 120,000 km, while UK DVSA records show low emissions-related failures due to robust catalytic converter design. Extended oil intervals and short-trip driving increase chain stress, making oil quality and change frequency critical.
Analysis derived from BMW technical bulletins (2005-2010) and UK DVSA failure statistics (2007-2015). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The S85 B50 A is generally robust, but early models (2005–2007) are prone to timing chain wear. Later revisions (post-2007) with improved oil galleries significantly enhance longevity. Regular oil changes with BMW Longlife-01 spec oil and avoiding short trips help prevent premature wear. Well-maintained engines often exceed 180,000 km.
Key issues include premature timing chain wear (pre-2007), coolant leaks from plastic thermostat housing, throttle body actuator failure, and valve cover oil leaks. These are documented in BMW service bulletins and confirmed by long-term owner data. The tensioner issue is particularly critical due to cold-start oil pressure limitations.
The S85 B50 A was used in the E60 M5 (2005-2010) and E63 M6 (2005-2010). It replaced the S62-based prototypes and was later superseded by the S63 twin-turbo V8. All applications meet Euro 4 emissions standards.
Yes, though naturally aspirated. Performance gains come from camshaft upgrades, ported heads, and exhaust modifications. ECU remapping is limited but can optimize fuel and ignition curves. Forced induction kits exist but require significant modification. Stock internals handle moderate increases, but tensioner condition must be verified first, especially in pre-2007 engines.
In an M5 (E60), combined consumption is ~15.8 L/100km (~18 mpg UK). Highway driving yields ~12.5 L/100km (~23 mpg UK), while city use can reach 20.0 L/100km (~14 mpg UK). Real-world figures depend on driving style, but the engine is efficient for a 5.0L V10 of its era.
Yes. The S85 B50 A uses an interference design. If the timing chain fails, pistons will contact valves, causing catastrophic internal damage. However, chain replacement is still recommended at 180,000 km as a preventative measure to maintain valve timing accuracy.
BMW specifies 10W-60 oil meeting BMW Longlife-01 spec. Use high-quality synthetic oil and change every 15,000 km or annually. Proper oil selection is critical to protect timing components, especially in pre-2007 engines. Avoid low-detergent or non-synthetic oils.
Comprehensive technical documentation and regulatory references
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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