so i recently installed a j's racing catch can, currently i have the lines routed like so:
pcv->catch can->intake manifold.


weird thing is, when i rev the car, i can hear a whoosing sound from the catch can. almost sounds like theres a leak in the catch can. however, i then tried plugging the intake manifold and just letting the catch can vent into the atmosphere like so:


and voila! the sound was gone. any idea why?! can't be a leak, otherwise i would still hear the sound using the second configuration. also, when i rev the car, i can kind of feel the metal on the catch can...expand for a lack of better words.

 

bump, i was thinking the noise is a result of the vacuum from the intake manifold pulling air from the crankcase, but i dont understand why my previous catch can didnt make this noise

 

buuump!

 

Post a vid.

I remember hearing something similar when I installed my Home Depot catch can and Krank Vents.

I got rid of the noise by taking everything apart and then reinstalling. I am thinking that perhaps we both had loose fittings upon initial installation.

 

its your vacuum same thing happened to me while installing my asm catch can....

but it happens only when driving for 30 minutes when it gets hot..