Way i see it a catch can collects maybe 100ml between service ,if youve got a plate with a 7mm hole you still get a certain amount of hot raw abrasive carbon passing through a bit of misty oil collects that stopping it going back to the inlet ,Ive just done injectors no1 cacked itself, pulled the EGR off ,wiped a fine layer of collected carbon/oil mix ive got a plate no, catch can thats after 85k of driving do around 40k odd per year and if nothing at all it acts as a upper cyl lubricant so catch cans in my eyes are a waste of$$$$$$$$$