Genuine OEM BMW Intercooler Cyl 1-4, part number 17515A2C232. This intercooler is a vital part of the engine's intake system, designed to cool the compressed air from the turbocharger before it is supplied to cylinders 1-4. Cooler intake air improves combustion efficiency and engine power output. Typically constructed from aluminum, this intercooler facilitates effective heat transfer. Genuine OEM intercoolers are engineered to exact standards for optimal engine performance and longevity.