DESCRIPTION
Note. No information available on 911 Turbo.
The 944 Turbo uses a water cooled turbocharger with an electronic absolute charging air pressure control and exhaust by-pass valve.
Turbocharger is bolted on a bearing flange on the left side of engine. The coolant circuit of the turbocharger consists of temperature switch, electric circulation pump, and an additional thermostat in water pump housing.
OPERATION
The turbocharger rear balance shaft bearing is lubricated by oil from the oil supply line through an inlet flange on turbocharger. After lubricating oil has flowed through bearings in turbocharger, return oil flows through the return bore and return line into oil sump.
A vent line is connected on side of engine support that leads to oil filler neck. Turbocharger is connected to engine coolant circuit. Engine coolant is pumped from coolant expansion tank by an electric coolant pump when turbocharger temperature reaches 180°F (82°C) an additional thermostat opens to make a connection between engine coolant and turbocharger coolant circuits.
When temperature switch senses coolant temperature of 240°F (115°C) in return lines, the electric circulation pump will pump coolant from expansion tank to turbocharger back into expansion tank. A check valve in expansion tank prevents coolant from flowing back into turbocharger. (Scheme 7)
Scheme 7
Poses Online