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Vacuum pipe with vacuum boost

Vacuum pipe with vacuum boost


Cars with manual gearboxes are fitted with an ejector device to boost the brake vacuum.

The ejector (1) has three hose connections. The pressure hose is connected to the charge air pipe (2) and the suction hose to the intake manifold (3). The pressure difference between the two connecting points provides a flow of air through the nozzle (6).

Since the inlet in the nozzle (5) is tapered, the air speed will increase and create an increased vacuum in the hose connected to the brake servo (4) through an ejector effect. To prevent the air current from taking the wrong direction, the connections to the brake servo and charge air pipe are fitted with non-return valves (7).