what is the purpose of the oil catch can from greedy
?sorry dumb question but im kinda new at this.

 

Here read this it might help you out.
https://www.scionlife.com/forums/viewtopic.php?t=118054

 

basically it traps blowby oil or vaporized oil that can gum up your intake tract.

i dont exactly know if there are different variations in operation between different manufacturers,.

 

It looks pretty. If you really NEED a catch can, you NEED a new engine. They are beneficial to turbo systems and cars with bad rings mostly. But most people buy them for looks.

 

or not ....if you have an aftermarket intake system, they sometimes can increase the vacuum on the pcv line which makes the intake pull more oily vapors than its suppose especially at higher rpms because the pressure increases in the topend of the engine when your at higher rpms and the whole point on the pcv is to relieve that pressure so if there is more pressure there needs to be more vaccum to get rid of it...and there are only two places for it to go....1) once you slow down or idle the oil will travel down the intake into the cone filter 2) be fed into your throttle body/ intake manifold and either clogged up the intake or be burned up in the engine and you will literally leave the competition behind in a puff of smoke...now there are three ways to stop this from happening, well actually four...1) dont get an aftermarket intake 2) install an oil catch can to hold the oily vapors 3) the common cheapo way is the breather filter 4) a adjustable valve to reduces the vacuum at idle back to stock vacuum....the latter of the four is what I am currently going to do to my aveo because my intake has increased vacuum too much and takes oil into the enigne and burns it...so we are going to hook up a guage to see how much vac we are getting at idle and tune it down some so that it is tuned down at the higher rpms too.