timestamped
Senior Member
- Thread starter
- #1
I’ve been running one of these on my Focus ST, along with a PCV (dirty side) catch can for about 10 years, tuned for about 5 years up to ~24 psi max boost.
Early on, mostly stock, I was noticing some oil traces going to the turbo inlet from the CCV breather that, most of the time, lets clean filtered air enter the valve cover while the intake manifold pulled crankcase pressure from the PCV side. Under boost, the PCV valve shuts (mostly, the Focus ST PCV valve is a bit leaky, perhaps by design) but everyone runs a check valve between PCV can and the IM. With no way to vent pressure towards the IM, and the turbo sucking in air, any positive crankcase pressure under boost can push blowby vapors out the CCV vent towards the turbo.
Installing a CFM breather seemed to reduce / eliminate it, as it gives another exit for crankcase pressure under boost, and I have not had any issues since. I haven’t seen anyone running one on this platform (also a direct-injected 2.0 turbo), so thought I’d throw it out there for the community to digest. Not sure if there is enough clearance from the hood.
https://www.c-f-m.com/performancepa...Honda-D-B-H-F-J-K-Series-Engines-762p1625.htm
If you want to see one on my FoST:
Early on, mostly stock, I was noticing some oil traces going to the turbo inlet from the CCV breather that, most of the time, lets clean filtered air enter the valve cover while the intake manifold pulled crankcase pressure from the PCV side. Under boost, the PCV valve shuts (mostly, the Focus ST PCV valve is a bit leaky, perhaps by design) but everyone runs a check valve between PCV can and the IM. With no way to vent pressure towards the IM, and the turbo sucking in air, any positive crankcase pressure under boost can push blowby vapors out the CCV vent towards the turbo.
Installing a CFM breather seemed to reduce / eliminate it, as it gives another exit for crankcase pressure under boost, and I have not had any issues since. I haven’t seen anyone running one on this platform (also a direct-injected 2.0 turbo), so thought I’d throw it out there for the community to digest. Not sure if there is enough clearance from the hood.
https://www.c-f-m.com/performancepa...Honda-D-B-H-F-J-K-Series-Engines-762p1625.htm
If you want to see one on my FoST:
Sponsored
