donniekak said:

The only thing I read had a direct line to both ports. The top port has to be left open to atmosphere. I must have missed one of your posts.

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We're on Boost said:

This setting which you showed set to 19psi is, as far as I know, the same thing as "crack pressure" in AEM boost controllers, which is what I have.
It's just a way of keeping the valve slammed shut until you hit 19psi or whatever number you put in there.
It will stay slammed shut because you are giving it 100% ( or the max it is capable of) until you hit 19psi.
Then when you hit 19psi it switches over to the tables that you have filled out with whatever numbers you want.

The other field there that is labeled "Lock at 0% below" is just there so that the solenoid can take a rest all the while you are running in vacuum (no boost). Usually you set that to somewhere near 0psi or just a little above, like 1 or 2 psi, at which point the solenoid starts getting 100% signal so it wakes up and keeps the valve slammed shut.

In my car, 19psi is a tad bit high for pulls from low rpm in 3rd gear if I'm going uphill. I will get bucking as the revs climb past that point. What happens there is, as soon as 19psi is reached, my duty cycle drops from ~100% to my setting which was only 46% the last time I fiddled with crack pressure. At that low rpm the boost won't stay up to 19psi with only 46% duty cycle so the boost drops all of a sudden. Then the controller puts duty cycle back to 100% so boost comes back up. It might cycle back and forth like this a couple times before revs come up to the point where 46% is enough to hold it above 19psi. In 2nd gear, the revs come up so fast that I don't have this problem, so 19psi would be ok in 2nd gear. But for the sake of 3rd gear (and 4th) I set my crack pressure to 17psi.

Now I have my duty cycle set to 55% so I could probably have my crack pressure set a little higher.
The AEM boost controller is kind of simple-minded. It doesn't have the tables like ECMlink has. All it has is, you tell it what duty cycle you want, and what "crack pressure" you want. And that's about it.

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