Breather Filter?

[whatproblems]

i saw these little filters at pep-boys that say its a breather filter... they look sorta like the cone air intakes....

could anyone tell me what in the world these are used for?

[Gsolo]

some people like the use them on their PCV system instead of leaving them hooked to fresh air at intake box. I think it's more F&F than anything else

[Mugen]

An air breather replaces the intake vent hose on your crankcase, which vents the spent gases inside your head out into the atmosphere instead of back into your intake track.

[Piloter]

You may not be able to get away with running one of these. I tried putting one on and my idle RPMs shot up to something like 4K and didn't get compensated for, including ECU resetting. Likewise for a breather filter on the catch-can...that produced idle and in-gear constant revving/dropping that nearly stalled out the engine or gave unwanted acceleration surges.