R50 oil breather pipe

[Ss82]

See the oil breather pipe that goes from the head to the air filter box, when I remove the air box to fit a cone do i need to plumb this back into the air pipe or can I get away with jus leaving it out?

Or is it a vacuum pipe?

[badwolf340]

Think it would be more of a PCV valve (of sorts) and if left out may upset the idle but would not think a vacuum pipe

[Ss82]

Cool cool ill plumb it back it, I know if I leave the one out my leon it drives like a slag