Contour Enthusiasts Group Archives Forums Modifications Forced Induction Ever have that "not fast enough" feeling? .82A/R!

Originally posted by TC'd Swazo:

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Let me see if I am reading what you're saying correctly....

When you tied the valve cover vents into the IAC, you were puffing blue smoke? Once you let them vent to atmosphere, it went away?

Right now that is how I have my valve cover vents (venting to atmosphere..) but I'd like to tie them into the intake with an oil seperator inline with a 1-way check valve.

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Valve cover vents have to be tied before the turbo inlet, NOT after the discharge tube!

Otherwise yes, you will suck all kinds of oil!

The valve cover vents aren't really vents anyway. They are supposed to be the inlet for clean, already metered air to go into the heads and then down to the crankcase to flush out any fuel/oil vapor or blowby and pull it back into the engine to be burnt instead of let out to atmosphere.

Leaving the valve cover "vents" open to atmosphere does not stop this flow but it does allow non-metered air to be sucked in and throws off the Adaptability of the PCM.
WE all know the PCM has learning modes; well it uses some of the A/F values calculated from light load and idle to fill the cell values for higher load conditions.
So if you are fuggin up the values at idle like that then they are also screwing it up at moderate load when less PCV air is entering the engine.

Under boost the PCV closes off most of the air going back into the crankcase and any blowby pressure that builds up will push out the valve cover vents back into the intake BEFORE the turbo, and get sucked right on into the turbo and therefore into the engine and burnt. There will always be lower pressure right before the turbo so that there is no buildup of crankcase vapor under load.
See?
It is a win-win situation in all cases. Hook it up right.