It doesn't need to have any vacuum. Your goal isn't to try to pull any oil out. What gets out on it's own is fine. We don't need a vacuum as we don't have a crank spinning in this space so that won't help us. You only need to catch what does come out. The factor runs it back to vacuum in the intake manifold to burn it. It's all about emissions and simplicity.

 

I think the idea is to "vacuum" out the water vapor and oil vapor from low temp operation...esp in colder humid climates like Seattle.....Then the water vapor won't condense with the oil vapor into the gunk that I had in my oil inlet piping

 

i got grease or oil in my Air intake tube as well. other than this modification any other method?