It doesn't effect your oil levels. Its mostly just moisture and blow by. I'm going to make a few improvements on mine to see if it helps catch better. Also might try running it to atmosphere. Remove the hockey puck and plug the tip and just run the crank case hose and valve cover hose to the tank. I have been browsing so many different forums, reading up on catch cans. So many different designs to accomplish the same thing.
I've read they are not as "dusty" as steel wool. Plus they are corrosion resistant being stainless. Shouldn't have to worry about it since they will be sitting in oil. Some people don't even bother with putting anything in the can. Right now mine is completely empty and it is catching obviously. I'm going to change the inlet to the top and braze a pc of copper pipe on the end of the fitting so it directs everything towards the bottom. Should help not pull anything into the inlet pipe. I'm still getting a little bit in there. No more than what it was setup oem.
Hmm. Im running VTA and there is an excess of condensaion round the can and filter. The filter is soaked. Not sure why its doing that. Figured some more surface area inside couldnt hurt to catch the crap.
That's where I'm stumped. I don't know what is better for the engine. I think VTA is going to take away from the needed crank pressure. Where as a closed system, you may still get some blow by into the intake.