Breather is sucking air. Normal?

[Diabolic]

I feel dumb for asking this but I've honestly never paid attention. I'm chasing the possibility of a vacume leak in my Vortech powered 93 Lightning. Tonight I noticed I never hooked back up the hose from my VC to the tb. Now I realize this is a no no with a supercharged engine so I was going to vent the breather about 7" after the MAF meter into the back of the SC. This is when I noticed that the breather is drawing a lot of vacume at idle. Enough to suck my finger to it. I've never noticed this before and it got me to second guessing myself about routing the tube to the SC inlet. Both ends of the hose would be sucking. Does this mean I have another leak somewhere like a blown intake gasket?

[blownragtop]

Perfectly normal – where do you think the air for the PCV system is coming from? In a perfect world you’d pull filtered air from between the MAF and the supercharger but the old Vortech kits like mine are just pulling unmetered air through a repurposed fuel filter.

[Diabolic]

But that air being sucked through the nipple on the breather needs to be routed to the SC inlet side? The part that bothers me is that the breather is sucking and the SC inlet is sucking. They would be pulling in opposite directions. This is ok?

[Diabolic]

I'm going to route the breather back into the SC inlet. It makes sense that i have vacume there because the PCV is hooked up as well.

[Diabolic]

So in theory if the intake gasket were blown and allowing air to escape between the intake and the head, then it would create a suction in the lifter valley, correct? Since I have my PCV valve operational, it also creates a suction in the crankcase which is what I could be feeling at the breather. If I were to unplug and cap off the PCV valve then the suction at the breather should stop unless it's a blown intake gasket correct? My thinking is that the pull I feel at the filler hole is being created by the PCV. I'm just trying to make sure for 100% that my lower intake gasket isn't blown.

[dumpycapri85]

So in theory if the intake gasket were blown and allowing air to escape between the intake and the head, then it would create a suction in the lifter valley, correct? Since I have my PCV valve operational, it also creates a suction in the crankcase which is what I could be feeling at the breather. If I were to unplug and cap off the PCV valve then the suction at the breather should stop unless it's a blown intake gasket correct? My thinking is that the pull I feel at the filler hole is being created by the PCV. I'm just trying to make sure for 100% that my lower intake gasket isn't blown.

This is correct . You should not feel any suction with the pcv cap and you should not let the breather pull un metered air . This is the reason the factory pcv system pulls air from behind the meter on mass air setups . If you are a sd setup then it does not matter .

[Diabolic]

Yeah I hooled up a hose from the breather to the SC inlet. Just about where the silicone hose clamps to the air intake of the SC. Hets a huge pull of air from there and the truck runns terrific! I've been driving it all day.