If you're going to do this, you can scratch off 7.01024.02.0, as I've tested all 3 and that one doesn't work properly in the 250-300Hz duty cycle range.
To use the vacuum solenoids with pressure (instead of vacuum), you'd need to keep the pressure differential across the diaphragm pushing in the same direction. So you'll plumb it to your boost signal like the attached drawing.
View attachment 103104
If you plumb either of the other two valves like this drawing, they'll work with boost pressure up to a point. Like
@JPuehl said, it doesn't work well for really high boost, but it may work for your goal of 22psi. Maybe use a 12 psi spring?
The reason it doesn't work well for high boost, is since it's designed for vacuum, 100% duty cycle only pulls on the diaphragm hard enough to balance out against full vacuum, which is around negative 14psi. So if you replumb it for boost, at 100% duty cycle you can vent 100% of the boost signal away from the wastegate up to around 14psi. But for every pound of boost over 14psi, you'll bleed 1 pound boost signal to the wastegate. So for example, if you run a 12psi spring, if you have 100% duty cycle and 22psi of boost, there would still be about 8-9 psi going through the valve to the wastegate (22psi boost - 13 to 14psi @ 100%DC = 8 to 9 psi going through the valve e). 8-9 psi is below the cracking point for a 12psi spring, but you still have a lot of exhaust back pressure trying to push open the wastegate flap at 22psi boost, so it's hard to predict how much boost you'll be able to hit for a given spring with this method.
How I'll be getting around this limitation for my build, is I'll install a regulator set to around 14psi right before the boost solenoid. That way, regardless of how much boost I run, the valve will always be capable of venting 100% of the boost signal away from the wastegate, allowing me to max out the spring. The next limitation this causes, is it limits how high of a spring value you can run, as you only have a max boost signal of around 14psi to open the wastegate.
If you do this, please know you're treading new ground, so no garantees it will work 100% as planned. I'm planning on controlling my boost this way, but haven't actually done it yet. To my knowledge, JPheul is the only one whose actually tried this out so far.
A other thing I've noticed in my testing using these vac solenoids with boost pressure, is with big changes in duty cycle, a resonance can set up inside the valve. Not sure if it would limit the life of the valve or not, but I don't like it. I've got some experiments planned to see if I can damp it out and eliminate the resonance, but haven't had a chance to try it out yet.
Good luck, let us know how it goes!
