Source for Vacuum Bypass Actuator

Al T

Registered User
12" of vacuum is not holding my bypass open anymore. I've had to add a spring to help it stay open and ensure it only closes when I open up the throttle. This together with the whistling sound it creates indicates to me I've probably got a hole in the diaphram and need to replace the actuator. What's the recommended source for these?

Cheers!
Al
 
Stupid question but...is that thing supposed to stay open at idle and close as it goes into boost? If so this could explain the low level droan I am getting at idle becuase mine stays closed.
 
The bypass valve should stay closed at between 0-3" of vacuum at 8" of vacuum it should be fully open (horizontal position). Of course, also closed during boosted conditions!

Vacuum opens the valve to recirculate air to the supercharger to help prevent cavitation.
 
Valve position

Yeah . . . Valve is normally closed and high vac is supposed to hold it open, therebye allowing the blower to circulate its output with minimal resistance [pressure]. Result is the low power consumption. When you open up the throttle, vac lessens and the valve begins closing. This cuts off the short circuit. This begins building air pressure in the intake manifold. If yours is staying closed and your hearing a drone, chances are your charger is loading up unneccessarily.
 
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