Molly

Hi, I tried to my mityvac to test the valve, but as it is not installed, am not sure the best way to test it. Do I cover the large two holes and pull vacuum on the vacuum nipple? What should I be seeing?

black944 turbo

You can suck on the nipple and it will open. It should hold open until you let go of vacuume. This is for a stock valve or an aftermarket with the same weight spring.

Naplesguy06

To suck the nipple is always a nice thing.

Herramienta espe

The vacuum signal test is good, but you should also check it under positive pressure - at least the amount that your wastegate will allow. The early bypass valve with the 951 part number had a plastic diaphragm and could more easily fail. If yours is the more modern 993 part, It is more robust.
Apply 1 bar to the turbo outlet side of the valve to ensure that it holds.

Willard Bridgham 3

If you can blow through the valve from any port, it's toast.

Molly

That test worked thanks.

The cool thing is that on the new valve I can blow into one of the holes to add pressure, then pull some vacuum with my mityvac and it makes the blow-off sound. So basically I can walk around my house doing that and pretending that I am a 400 hp wrx.