Opinions on OCC

[Fobio]

Hey guys...any thoughts on oil catch cans? I know there are some legals issues inviolved as well...but I'm figuring that it may help with certain situatuions that may cause smoke to come out from the exhaust that IS NOT due to a bad turbo-seal...

Any thoughts?

[CanadaGTO]

I like them, but it's a pain to install on this car, with one of the ends having to go on the underside of the Intake manifold. There are no legal issues as long as you don't vent anything to air.

Be sure to get a baffled Catch Can. The vast majority are not baffled, but it makes a large difference.

[Walrus]

Ok.. I read some of the discussions on M3F. From my experience, a second OCC is needed, in addition to the one they are putting on the PCV line. The PCV allows blow by gases and oil MIST from the crankcase to be sucked into the intake manifold and burned, only when the intake manifold is at a lower pressure than the air intake/before the turbo (where the valve cover vent usually connects). This occurs under part throttle. When under boost, the PCV shuts, preventing pressurization of the crankcase.

With the PCV line running UP to the intake, oil accumulating on the walls of the hose will tend to drain back down to the crankcase.

However, the rest of the time the valve cover vent is blowing back in front of the turbo. Under boost with the PCV shut, blow by pressure is going up the block into the valve cover, and DOWN the vent hose to the intake. If the PCV is leaking, now you are getting manifold pressure added to this. Any oil that accumulates in that hose, will tend to drain down to the intake, and into the turbo compressor. You're burning it off and don't notice when driving hard, but stop and idle, or turn the car off for a while and then start it up - that oil that has drained down the line gives you smoke.

I think you need an OCC on the valve cover vent as well. Or, I'd put it there first.

I miss having a turbo.