Ok after playing around I think I've worked out a way to incorporate a (over) boost controller, but I don't own one and don't particularly want to buy one if it wont work.
From what I can see, if you follow your mod above but instead of plumbing it strait into the ABV and rather than deleting the standard set up, just plumb the new pipe into the vent pipe of the VSV. This would mean the system ran exactly as stock under vacuum (as well as the delay VSV open operation on initial overrun etc) but with the added valve hold under pressure of the modified pick up location. It would also allow you to control the amount of assistance pressure behind the ABV with a boost controller, without interfering with the vacuum operation allowing the ABV to fully open under normal vacuum conditions. Obviously you're still limited to the minimum of what ever the spring holds but it allows you to raise it more incrementally (regardless of pulley upgrades). I assume it would also stop the ABV hammering open and closed with the usual ABV mods and would prolong (if it was a factor) the life of the diaphragm, spring and valve itself.
Not that I know anything about what I'm talking about I've just put this together looking at how the stock system, along with the varied modified systems, work. I'm more interested to see if the experts on here could verify my idea before I spend money on a controller.
There's not much point in adding an over boost controller as such, as the pulleys will determine how much boost can be made. Unlike a turbo, the boost with a supercharger is tied directly to RPM, so with correct pulley sizing, you will never see over boost as the supercharger can't ever spin faster than the system is designed to.
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