Crankcase Breathers

Discussion in 'Fox 5.0 Mustang Tech' started by jlhall_10, Dec 15, 2003.

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

    K&N Crankcase Filters
  2. These are to help evacuate extra pressure (i.e. crankcase) build-up; especially in supercharged applications.
  3. ok so they are not really needed in N/A applications?

    EDIT: nevermind i found my answer at the bottom of the page!
  4. 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.
  5. Remove Crankcase pressure