S50B32

The S50B32 is a naturally aspirated inline-six gasoline engine produced by BMW. It is part of the BMW S50 engine family and was primarily used in the E36 M3 model for European and North American markets, though with distinct internal specifications. This engine displaced 3.2 liters and featured a bore of 86.4 mm and a stroke of 89.6 mm. It utilized double VANOS (variable valve timing) technology, a significant advancement at the time, controlling the timing of both the intake and exhaust camshafts independently to optimize performance and efficiency across the rev range.

In European E36 M3 models, the S50B32 produced approximately 321 horsepower (236 kW) and 350 Nm (258 lb-ft) of torque. North American E36 M3s received a slightly different version, often referred to as the S50B30US, which, despite the name, had a 3.0-liter displacement and produced around 240 horsepower (179 kW). The true 3.2-liter S50B32 was eventually offered in later E36 M3 models in North America, closer in output to its European counterpart. The engine is renowned for its high-revving nature, responsive throttle, and distinctive exhaust note, making it a highly sought-after powerplant by enthusiasts. It is considered a landmark engine in BMW's history, representing a peak in naturally aspirated inline-six performance before the introduction of forced induction in subsequent M models.