An engine system may include a first intake line configured to supply external air to an intake manifold mounted in a cylinder block of an engine, an intake bypass valve disposed on the first intake line, a second intake line configured to bypass the intake bypass valve, a first exhaust line, through which exhaust gas discharged from an exhaust manifold mounted in the cylinder block flows, an exhaust bypass valve disposed on the first exhaust line, a second exhaust line configured to bypass the exhaust bypass valve, a turbo charger operated by exhaust gas passing through the second exhaust line, and configured to pump intake air flowing in the second intake line, a controller configured to control the intake bypass valve and the exhaust bypass valve, and a turbine housing configured to surround a turbine of the turbo charger. The turbine housing may be made of a material the same as that of a cylinder head of the engine.