chevyredneck8

iTrader: (4)

I've read multiple posts arguing about PVC setup most being 8 plus years old and no clear winner about the best setup.

I have an HSR with 2 PCVs valves one in each cover teed together and going into the top hookup of my throttle. Is this a good or bad setup in everyone's experience????

Currently I'm tracing trying to figure out my lower idle vacuumed and was wondering if my pcv valve may have anything thing to do with it. Would this setup help or hurt my vacuumed?

Thanks guys

Drac0nic

The PCV setup is designed so that it goes through the engine. You end up with one PCV valve that connects to vacuum on the engine at the intake or throttle body, then you end up with another one that connects to the throttle body or the air intake on a port that gives it fresh, filtered air pre throttle body. I'm not saying it's the best but it's the way that the OEM intended for a PCV system to work. If you have the engine fully sealed like that you could wind up with blow by issues or oil leakage pretty easily I would think.

chevyredneck8

iTrader: (4)

So on a TPI throttle body the top port feeds fresh air to the left valve cover for the crankcase and on the right valve cover it pulls air into the intake.

If this is the case is there should be a difference in the valves on the left and right? One to allow air in and the other to allow air out like a positive crankcase ventilation on one and a negative on the other? So the left side should have been a breather filter from the factory correct? Both of mine was pcv valves when I got it and thought I was missing how it pulled air in the crankcase

1982Z28Modified

Your PCV setup is correct. Having a breather on one side introduces moisture into the crankcase. The engine vacuum is not strong enough to "suck in" gaskets. Putting a vacuum in the crankcase is a good thing. Helps seal the rings. Removes blow-by. The engine does not need "fresh air" flushed into it.

sofakingdom

iTrader: (1)

The PCV system CANNOT work without fresh air. If the PCV takes air OUT of the crankcase, air has to come back IN from somewhere.

It needs a PCV valve with full-time manifold vacuum on it (of course); and a source of clean filtered make-up air to go back into the motor, so that it doesn't draw dirt into the motor.

A setup with PCV valves into both valve covers is therefore not correct.

Furthermore, if you have a MAF car, the make-up air has to come from BEHIND the MAF; otherwise, it amounts to un-metered air entering the intake, that the MAF doesn't know about and therefore can't tell the ECM that it's there, and therefore the ECM doesn't add fuel for it. Which is why the MAF TB has 2 outlets having to do with PCV: one comes from behind the throttles and has vacuum on it, and therefore goes to the PCV valve; and the other comes from in front of the throttles, but of course it's behind the MAF, so the air that passes through the engine gets metered properly.

Set it up properly, and you'll find that the car idles better, gets better gas mileage, and altogether runs better. Plus of course, with the PCV working right, your crankcase and your oil will stay cleaner, since it will constantly be getting flushed out with fresh air like the system is designed to do.

chevyredneck8

iTrader: (4)

Still the big question is what a proper set up for a supercharged engine. I currently have a breather on one vavle cover and a pcv valve back into the intake on the other . I know I dont want a NA setup because that could force boosted air back in the crankcase. I would like to copy a factory style like a Buick GN if that's feasible. Input please??

ASE doc

The GN system should work for you. The OE boosted applications I see alot of have the fresh make up air connection before the charger, in the inlet air stream. They then use a crankcase pressure control valve that vents excess pressure and check valves that open to draw crankcase gases when the inlet is in vacuum, and then close to prevent boost pressure from entering the crankcase. Keep in mind, the OE PCV systems were intended for a stock engine with no excessive crankcase gases, like are caused by doubling engine output with cam, heads and intake or with supercharging. Unless you have some really great ring seal, your factory PCV system will not keep up with the crankcase pressures of your heavily modified engine.

You can also use a vacuum evacuation system on the crankcase to remove combustion gases and pressure. I run a Moroso vacuum pump, regulated at 15", on a sealed crankcase with two breather tanks on the outlet side of the pump. The pump maintains a constant 15" in the crankcase and improves ring seal. Important when running narrow, low friction rings and bigger power numbers, especially on an engine that only makes 14" intake vacuum at idle.

1982Z28Modified

I have no idea for a engine that is blown. But this I do know...

The pre-eminent sofa with his self-righteous opinions, usually in CAPS so we know how right he is. Numbnutts, the engine has blow by which needs to be removed. the blow by does not need to be flushed out with fresh air. The engine does not produce enough vacuum to do this. Remove your breather. Look and see what comes out of it. Air is really not sucked in. Crankcase fumes will come out.

You really think a system first developed in the 60's is correct 50 years later? No improvements have been made? No engineering has not been done?

So tell me sofa, what harm will running two PCV and no fresh air cause?

Really 15,383 posts in 8.9 years equals almost 5 a day. Do you have a job?