Exhaust manifold
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 BMW X3, 2016 BMW X3, 2015 BMW X3, 2014 BMW X3, and 2013 BMW X3. However, it is still accessible from the selected car via links, so may be relevant.
The exhaust manifold features air-gap insulation and a 6 into 2 runner system. Combining three exhaust runners provides ideal flow characteristics to power the twin-scroll turbocharger. The exhaust manifold and the twin-scroll manifold are welded together to form a single unit.