bgoetz

So I just installed a catch can, went from PCV to can then back to intake manifold (legal STR setup). Car seems to run fine, maybe a bit more cylinder head noise, but who knows with these engines. So I tried to pull the drain plug on the catch can and there was a really strong vacuum. Is this normal? I guess I thought pressure would be more stable with suction from the manifold and pressure being Pulled through the PCV, maybe it is and I just interrupted the flow? Anyway just want to be sure I installed it correctly.

bgoetz

I think I answered my own question and there should be a vacuum because the PCV operates from an external vacuum. So by pulling the drain plug I am short circuiting to the can, someone correct me if I am wrong. I was just surprised by the amount of vacuum!

stupkid

Yup there should be vacuum. When I first installed my catch can. I left the breather filter that came with it on top and started the engine. Rpms were spiking everywhere wildly driving just down the road. So I took off the breather filter and put a bolt in its place.