There is a small misconception of how the bypass works. Air always passes through the intercooler in all engine driving conditions regardless of whether the engine is in high boost or high vacuum conditions. The bypass valve routes air through the supercharger and intercooler in a loop, when the engine doesn't require a high volume of air to make Hp.
The air exits the supercharger.........it passes through the intercooler to the lower half of the manifold. Where at this point in engine vacuum conditions the bypass valve is open, the air then enters the little plenum at the rear of the intake through the bypass valve and back to the inlet of the supercharger to start the circle again.
The reason for this is the supercharger always moves air by volume in direct relationship to how many RPMs it is turning versus it size. When the engine is under low load cruise or idle conditions it may only require 350 CFM of air to produce the Hp needed. Yet the supercharger can be pumping 750 CFM for the engine RPM, SC size and pulley combination. You need to bypass the difference of the supercharger throughput versus what the engine requires for its present running condition. If you starve the supercharger of this difference in air by volume it will quickly overheat causing the rotors to expand beyond specs, which may cause the supercharger to lock up. The bypass valve and its associated system is designed to constantly move air through the SC to keep the rotors cool. All air exiting the supercharger must pass through the intercooler. The Throttle Body is what is starving the SC for air and allowing the engine to run under a vacuum and for you to see this on a gauge, even though the SC is moving 750CFM of air when the engine only need 350 CFM of air
Great explanation. Thanks for offering that up sir.
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