A flow control system is provided having an engine, a turbocharger, and positive crankcase ventilation (PCV) line, and a flow regulating device. The engine has an air-oil separator and an intake manifold. The air-oil separator separates oil droplets and oil mist from a blowby gas. The turbocharger has an air inlet and an air outlet, where the air outlet is connected to the intake manifold of the engine. The positive crankcase ventilation (PCV) vent line has a first end connected to the air-oil separator and a second end connected to the air inlet of the turbocharger. The PCV vent line delivers the blowby gas from the air-oil separator to the air inlet of the turbocharger. The flow regulating device is located in the PCV vent line. The flow regulating device selectively limits the flow of blowby gas from the air-oil separator to the air inlet of the turbocharger.