Drivers side oil breather hose: Where does it go?

[SlowSVT]

I'm curious. The valve cover breather hose on the drivers side. It goes behind the engine. What does it connect to? I assume it's the intake side of the PVC system. Can someone explain?

Thanks

 

[U1arunit]

It connects to a tee of which one port goes to the rear of the blower for vacuum source and the other port goes to a hose that enters the lower intake manifold.

 

[SlowSVT]

It connects to a tee of which one port goes to the rear of the blower for vacuum source and the other port goes to a hose that enters the lower intake manifold.

That's kinda wierd. If one side enters the intake side of the blower for vacuum and the other end into the intake manifold where it will see pressure. Then on the other valve cover it connects to the intake tract where it sees more vacuum.

Is the chankcase vented to the outside at all or is the PVC a closed system?

 

[PhillyCobra]

It's closed. The passenger side is supposed to draw in fresh air (unless there's big inlet vacuum caused by the blower) and exhaust out the driver side to the intake. Obviously, under boost, the PCV valve is supposed to close, and in reality, air is sucked into the intake from the passenger side, which causes the oil residue you fing on the TB and intercooler.

 

[SlowSVT]

Let me see if I got this straight

The system works in the opposite direction then from what I thought. Air is drawn in through the intake tract on the passenger side and then out through the driver side head and into the back of the supercharger through the vacuum side or through the intake manifold when the engine is not under boost.

Then there is a check valve that closes off the line on the intake manifold when the engine is under boost to prevent the system from working backwards.

Is that correct?

If that's the case shouldn't a catch can be placed on the divers side head PVC hose instead of the passenger side or should one be placed on both sides?

 

[NyteByte]

I think we should probably have one on both sides.

I have one on the drivers side, but I think I'm gonna put one on the passenger side too, if just to keep the oil from filling up my intake, TB, and coating my intercooler.

 

[Romans8:28]

just look at your emissions diagram sticker under the hood :beer:

 

[PhillyCobra]

SlowSVT,

Your explanation is exactly correct.

It makes sense to put catch can on both ends, but don't expect it to totally solve the problem.

 

[Mike_Hawk]

You won't need the catch can if you have a passenger side breather.

Does the passenger side flow both ways, or just 1?

 

[PhillyCobra]

The passenger side is only supposed to flow into the engine from the intake, but it unfortunately reverses when the throttle is open and the SC is sucking air, creating a vacuum in the intake before the throttle body.

You can run breathers, but it does affect the tune some, as the ECM assumes some of the air running through the MAS goes through the engine vent system. You will thus run lean if you don't reprogram the ECM. The magnitude of this effect is probably small, but it is real.

 

[SlowSVT]

Thanks PhillyCobra

This all makes sense to me now.

One more question:

Wouldn't it be better to draw the air into the engine from outside the intake tract so the Supercharger/intake manifold does not have to compeat with the lower level vacuum in the intake tract? (I guess you would need to re-tune the engine to compansate)

 

[PhillyCobra]

That would be fine, as long as you filtered the air with a good breather cap. Don't want junk going in the engine! And you should retune to compensate. Manufacturer has closed system to limit pollution and make sure air is filtered.