How to vent my motor?

Here is why I'm asking the question. My set up has the MAS in the fender after the cooler. My bypass is directly after the head unit vented to atmosphere. Procharger had the driver's side valve cover vent in the inlet tube. Unless I'm mistaken, that's where the fresh air is pulled into the motor by the passenger side vacuum created by the PCV connectting to the plenum. That would mean, the air the PCV is pulling in to the plenum isn't being metered. I moved it to the inlet tube after the MAS. This brings another possible problem.

Am I going to have issues with my crank case being presurized under boost conditions possibly causing oil to be sucked into my plenum? Blowing out my dipstick or similar problems?

Should I ditch the PCV system and run filters on both sides and the oil fill tube or is there a better solution?

Quote:

---

Originally Posted by Jonny00GT

Here is why I'm asking the question. My set up has the MAS in the fender after the cooler. My bypass is directly after the head unit vented to atmosphere. Procharger had the driver's side valve cover vent in the inlet tube. Unless I'm mistaken, that's where the fresh air is pulled into the motor by the passenger side vacuum created by the PCV connectting to the plenum. That would mean, the air the PCV is pulling in to the plenum isn't being metered. I moved it to the inlet tube after the MAS. This brings another possible problem.

Am I going to have issues with my crank case being presurized under boost conditions possibly causing oil to be sucked into my plenum? Blowing out my dipstick or similar problems?

Should I ditch the PCV system and run filters on both sides and the oil fill tube or is there a better solution?

---

It seems like it would cause a driveability problem. How does it drive at idle and low load? Seems like some of the turbo systems would have the same issues since they have the MAF sensor after the compressor. Maybe you can call Professional Mass Air Systems (the succesor to Pro-M) to see what they say about it.

What would cuase a drivability issue? The way it was or that way changed it? I can't tell that's it's helped any, but I just drove it to work since the changes. I'm going to reset the KAM and see how it drives...

I meant to say the way it was configured before with the valve cover venting into the supercharger inlet. Since it would seem to let unmetered air back into the crankcase under vacuum. In that configuration, I wonder if adding a checkvalve (basically what a PCV valve is, I believe) to the hose so that it could release blowby into the supercharger inlet, but not allow air into the hose under vacuum would work.?

In the current configuration that you have, on my '90 Mustang at least, my PCV valve would pop out if I had too much crankcase pressure. But I don't know how the PCV valve is setup on the mod motor cars like yours. Is it secured with hose clamps, or is it just a push fit in a gromet like mine?

Check valve is a good idea. My only concern is, under boost, all the pressure is going push the check ball in the passenger side PCV so all blow by will be exiting the driver's side into the inlet. Seems like an invitation to inject oil. I just went ahead and put a filter on the oil fill tube, blocked off the PCV and inlet into the plenum and left the driver's side vent in the inlet. That way, there is still a little pull on the driver's side from air passing by in the inlet and the passenger side is free to vent

Both sides of the system are push in.

Yeah, if you did the check valve, you would probably need to run the hose to an oil catch can before the check valve. You will probably also need a larger vent hose than stock too.

I'm curious how the factory turbo cars address the PCV configuration. If they run speed density though, maybe they don't have a problem with unmetered air since no MAF sensor. Not sure.

If it works the way you have it now, then great!

So far so good!