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Old 05-01-2014, 07:29 PM
Dust Dust is offline
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Join Date: Mar 2007
Location: Frankfort, Kentucky
Posts: 227
Default Re: LSJ Cobalt/Ion Redline ECU pinout

Give me the technical on how the bypass valve operates:
The valve consists of a butterfly inside the supercharger housing. Its position is determined by an external valve (a black canister on the front right side of the housing) that is operated off of engine vaccum. The valve inside is a rubber diaphram which lifts up a lever system to open the valve, at rest it is in a down and closed position. A vaccum source from a 3 way T ontop of the supercharger creates a vaccum on this diaphram to open the valve on startup. Once the throttle blade is opened and the supercharger starts to move more air into the intake manifold, this vaccum encounters a counter force. Running off the same vaccum line that fees the MAP sensor and fuel pressure regulator, this build of pressure in the intake manifold will feed into the top of the bypass valve from the opposite side. Upon a certain pressure off the intake manifold, an equilibrium will be created with the vaccum from the supercharger inlet that had held the bypass valve open. Upon this equilibrium, this bypass valve will close, and eventually a positive pressure will be created to keep the bypass valve closed. At this point, the intake manifold is sealed, free of major vaccum leaks and a positive pressure can be created by the supercharger aka boost.
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