Depends on the turbo, really. Some turbos have a vacuum line that needs to connect to the compressor housing, others don't. It also depends on what type of wastegate (internal/external) is being used as well as if a manual or electronic or no boost controller is installed. Could also vary depending on whether or not a boost gauge is being used. Additionally, whether the setup uses a BOV will make an effect.

Do you have a picture or more detailed information about your setup that would allow me to further contribute to the information you need?

hih