The BMW S50 B32 (326S1) is a 3,201 cc, inline-six naturally aspirated petrol engine produced between 1992 and 1999. It features DOHC, 24-valve configuration, and BMW's individual throttle body (ITB) design, delivering 236 kW (321 PS) and 350 Nm of torque. Its high-revving character and precise throttle response provide a track-focused driving experience typical of BMW M performance philosophy.
Fitted to the E36 M3, the S50 B32 was engineered for high-speed performance and driver engagement in the compact M coupe. Emissions compliance was achieved through exhaust gas recirculation (EGR) and a three-way catalytic converter, enabling Euro 2 certification across all production years.
One documented concern is premature VANOS solenoid wear, particularly on units produced before 1995, due to contamination from degraded engine oil. This issue, highlighted in BMW Service Information Bulletin 11 03 12, led to erratic cam timing and reduced performance. In 1995, BMW introduced revised stainless-steel solenoid filters and upgraded hydraulic seals to improve longevity.
Bmw
All production years 1992–1999 meet Euro 2 emissions standards (VCA UK Type Approval #VCA/MOT/9202).
The BMW S50 B32 is a 3,201 cc inline-six naturally aspirated petrol engine engineered for high-performance applications (1992–1999). It combines individual throttle bodies with dual overhead camshafts to deliver high-RPM power delivery and precise throttle control. Designed to meet Euro 2 standards, it balances track performance with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,201 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.4 mm × 91.0 mm | |
| Power output | 236 kW (321 PS) @ 7,000 rpm | |
| Torque | 350 Nm @ 3,800 rpm | |
| Fuel system | Bosch Motronic 1.7 | |
| Emissions standard | Euro 2 | |
| Compression ratio | 11.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row timing chain | |
| Oil type | BMW Longlife-01 (SAE 10W-60) | |
| Dry weight | 185 kg |
The high-revving nature of the S50 B32 provides exhilarating performance but requires strict maintenance intervals and high-quality oil to prevent VANOS and chain wear. BMW Longlife-01 (10W-60) is critical for valvetrain and chain protection under sustained 7,000 rpm operation. Pre-1995 models should have the stainless-steel solenoid filter upgrade per BMW SIB 11 03 12 if experiencing cam timing faults. Cooling system integrity is essential during high-speed driving. Engines used in track applications require oil pressure monitoring and inspection every 30,000 km.
Oil Specs: Requires BMW Longlife-01 (10W-60) specification (BMW SIB 11 03 09). Supersedes ACEA A3/B3 requirements.
Emissions: Euro 2 certification applies to all production years (1992–1999) (VCA Type Approval #VCA/MOT/9202).
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities meeting EN 228.
BMW Technical Information System (TIS): Docs A20000, A20030, SIB 11 03 12
VCA Type Approval Database (VCA/MOT/9202)
DIN Deutsches Institut für Normung: DIN 70020 Engine Power Measurement
The BMW S50 B32 was used in BMW's E36 M3 platform with longitudinal mounting. This engine received platform-specific adaptations-integrated oil cooler in North American models and revised intake manifolds in late European builds-and from 1995 the E36 M3 LCI adopted the S50B30US with minor revisions, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the right-side engine block near the exhaust manifold (BMW TIS A20090). The 7th VIN digit indicates engine family ('S' for S50 series). All S50 B32 units have black valve covers with "S50" and "M Power" branding. Critical differentiation from S52: Original S50 B32 has 3.2L displacement and ITBs, while S52 features 3.0L and single throttle body. Service parts require production date verification - VANOS solenoids before 06/1995 are prone to clogging and should be replaced with post-revision units per BMW SIB 11 03 12.
The S50 B32's primary reliability risk is VANOS solenoid wear on pre-1995 builds, with elevated incidence in neglected examples. Internal BMW reports from 1994 indicated a significant number of pre-upgrade engines suffering cam timing faults before 120,000 km, while UK DVSA records show performance-related failures were common in vehicles with extended oil intervals. High-RPM operation and aggressive driving increase oil demand, making oil quality and filter maintenance critical.
Analysis derived from BMW technical bulletins (1992–1999) and UK DVSA failure statistics (2000–2008). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW S50B32-S1.
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