I have no vaccuum going to my catch can its literally a hose from the pcv to catch can, and valve cover to catch can, and a breather on top of the can (vented) I'm pretty sure a vacuum source just helps get fumes out and ensures longer life for seals... But why would I care about them? Actually the only reason I have this setup is to monitor the amount of blowby I'm getting and maybe have a better chance getting through tech (keeping oil off the track) But now that I think of it I dont care if it is getting blowby - when it goes it goes