Bypass valve question
#1
12-24-2010, 10:55 PM
Join Date: Sep 2010
Location: Sparta, Wisconsin
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Bypass valve question
Real quick here. I have the procharger kit on my 01 crew cab 4x4. Been trying to figure out how to get the boost to come on sooner for towing...........Ive done a search and came up with several options but just noticed the adjustment screw on top of the factory bypass valve. Is this unit from procharger adjustable to make it close sooner thus giving me boost at the lower rpm's Im looking for? Please tell me the solution may have been staring me in the face all along. I can't find anything in the manual about adjusting it and figured Id aske before I go messing with it and screw the thing up.
#2
12-25-2010, 01:20 AM
Since you have a centrifugal supercharger about the only way you can get better response on the low end would be the spin the supercharger faster.
The bypass valve simply recirculates excess air from the supercharger, the biggest issue is really with the throttle blade being only moderately open during most situations. It is the biggest roadblock on air volume entering the intake manifold and without excess air volume in the intake you'll have a hard time building manifold pressure.
Even if you had 15psi in front of the throttle body if you can't get enough air volume into the intake manifold you'll still be seeing vacuum.
The bypass valve simply recirculates excess air from the supercharger, the biggest issue is really with the throttle blade being only moderately open during most situations. It is the biggest roadblock on air volume entering the intake manifold and without excess air volume in the intake you'll have a hard time building manifold pressure.
Even if you had 15psi in front of the throttle body if you can't get enough air volume into the intake manifold you'll still be seeing vacuum.
#3
12-27-2010, 12:39 PM
Just so you know there is a spring in the diaphragm that applies pressure to keep the valve closed. Vacuum when not in boost is what keeps it open. As you accelerate there is less vacuum available to keep the valve open so it starts to close. When you floor it vacuum is removed and the spring pushes the valve closed till more boost can be produced to help push the valve closed. All you can do is adjust it so it is opens under the least amount of vacuum till you reach compressor surge then back it off just enough to remove the surge. This adjustment will insure that all the available boost is sent to the engine as soon as possible. How much extra? I don't know. The valve itself leaks and Procharger insists that this is normal so either live with a leaking valve or replace it with one that doesn't leak. As was suggested replace the pulley(s) to increase the boost. That will increase the lower rpm boost thus making boost sooner.
