Crankcase Breathers

[jlhall_10]

what are these used for? they look like airfilters but sit on top of the valve covers.

K&N Crankcase Filters

 

[Psychdaddy]

what are these used for? they look like airfilters but sit on top of the valve covers.

K&N Crankcase Filters

These are to help evacuate extra pressure (i.e. crankcase) build-up; especially in supercharged applications.

 

[jlhall_10]

These are to help evacuate extra pressure (i.e. crankcase) build-up; especially in supercharged applications.

ok so they are not really needed in N/A applications?

EDIT: nevermind i found my answer at the bottom of the page!

 

[Michael Yount]

With a boosted application, unless the pcv system is altered, manifold boost can pressurize the crankcase -- a big no-no. The easy way around that is to be sure the pcv system has a check valve capable of keeping manifold boost out of the crankcase, and then venting the crankcase with breathers so the pressure there can escape. On a normally aspirated car, all that is handled by a properly operating pcv system.

 

[mr.nitrous]

Remove Crankcase pressure