An exhaust gas system configured for an internal combustion engine includes a cylinder head having at least two cylinders, a single exhaust duct emerging from the cylinder head, an individual exhaust duct provided between each cylinder and the single exhaust duct, and a reservoir of fixed volume integrated in the cylinder head and coupled to the single exhaust duct via a connecting duct. A reservoir valve is provided in the connecting duct in some embodiments. According to one embodiment, a method is disclosed in which the reservoir valve is commanded to an open position when flow through the single exhaust duct is large and commanded to a closed position when flowrate through the single exhaust duct is small. In some embodiments, a turbine, with a selectable volume upstream of the impeller, is coupled to the cylinder head.