pic is of a standard bleed valve MBC connected on a turbo.
This should help out the folks looking for a how to plumb a MBC.
The next pic (with the little black box / 2 wires) is of the bleed MBC with the solenoid plumbed in the correct place to turn it into a 2 stage MBC.
All that has to be done is to ground 1 wire & run "+" from the switch to the remaining wire - the Red one.
That little black box connected to the MBC/Turbo is a OEM boost solenoid from a 4G63 GVR4.
The next pic is a charcoal canister purge solenoid from a Subaru that should be able to get the job done too.
Any solenoid used should be function tested which is super easy
1. take the solenoid & blow into 1 of the fittings - no air should pass through the solenoid & out of the open fitting
2. Wire the solenoid to power & ground (may take 2 tries if the harness colors are not obvious red (+) & black (-)) - this should open the solenoid & allow air to pass through - repeat the blow-thru test this time you should feel air coming through the open port.
The solenoid used should have a port size that roughly matches the MBC's bleed port (the one that remains open to the atmosphere). If the solenoid ports are too small they may not be able to bleed enough air causing the boost levels to drop.
Have fun
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