roots vs centri vs turbo vacuum
 

I want to get educated on how vacuum works on the these 3 types of units especially in the case of using check valves or not using them when it comes to catch cans and the possibility of sucking oil in. So from my understanding with a roots type blower like my Maggie there is no need for a check valve as the snout on the blower will always be under vacuum is this a valid statement if not please elaborate either way how this works and if you would explain how this may differ from a centri or turbo setup where I believe a check valve may be needed. thanks in advance

On my procharger setup, I do not have a check valve. I made my own catch can setup with a breather. One end is connected to the intake manifold and the other to the valve cover. Works great for me at 13lbs of boost.

Only need a check valve if you are going from a pressurized source then back to the crankcase to prevent boosting the crank case. If you vent like he said above no issues. Basically if the part running from intake to can is pressurized you need a check valve.

Would you not be losing boost through the breather with this setup? Under boost, your intake manifold is pressurized and the hose leading from your manifold to the catch can would vent out through the breather on the can.

Yes he would. Under boost it would be blowing air out the breather/filter unless he has a check valve.

So I have a rx single valve can that does not have a check valve because I broke the old one and was told by a couple sourced on here I did not need to replace it with a check valve since I have a Maggie/roots blower then not needed due to the way pressure works with this application I have a hose from the snout to the can no check valve between and obviously the hose from valve cover to can I vent my motor with an oil fill breather cap so can someone elaborate why this May or may not be true

Maybe a better question is wat purpose is the check valve keep air from going back into the can from the blower snout or what ?? Sorry I don't yet know how the pressure works and what direction it does in my application my set up works fine it seems I just want to understand it a little better

The snout of a Maggie does not see boost, only vacuum because it is before the rotors in the supercharger.