Ok, I have been searching for a while and haven't found anything directly related to using the stock boost solenoid and power fc to control boost after going to a single. I just finished installing my apex rx6b kit and am ready to hook up the last few vacuum lines and plumb the wastegate. I know the power fc is supposed to do a pretty good job with the twins and also did a good job when I swithed over to running them non-sequential. Why not use them to control the waste gate on my single?

I undestand that there are two ways to hook up the wastegate.
1) use only the lower nipple on the wastegate and connect it to the compressor housing thefore running off the spring. or
2) tee into this line and connect it to a stepping motor (avcr) and then connect the other end to the top nipple.
In order fo this to work, you need a three way stepping motor; a Common, a NO, and a NC layout. This allows the pressure that you apply to the top of the diaphram to escape when you pulsate the stepping motor.

This 2nd setup cannot be acheived with the stock solenoid because it is ony a two way style. It is normally closed, which is what you would need, but after it opens, it will pressurize the upper part of the diaphram and when it coses again there is no place to release this pressure to restore the spring. With a 3 way style the pressure vents out the NO side. So why can't we do it this way.

Run a line from the compressor housing to the lower nipple on the wastegate. Put a tee in the line and run it to the stock solenoid (the one with the white dot that is active upon setting the Power fc to single mode) By utilizing the NC style solenoid, we acheive the lowest boost setting determined by the spring. In case of failure the solenoid will fault closed which is what we want. As we increase the duty cycle we vent pressure away from the spring and raise the boost. This does not give us the finest control over the wastegate as we would get by using the top nipple and having a pressure differential, but should work. Also, does having the vent side of the solenoid plumbed back to the suction side of the turbo help response. I would think that having it this way as opposed to just venting it to the atmosphere would help the response time.

Please let me know if there is a problem with my logic.
also, what is the stock spring in the wastegate set to? I have read that it comes with a 14.7 lb spring. If this is true, how do we get lower boost that this?

Thanks
mike