<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">

Look at the first picture. Air (filtered) goes into the intake plenum under slight vacuum. That air goes into the valve cover, down the oil passages, and into the oil pan crank area.
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Wrong. The valve cover breather only sucks in air when Idling or in very low load conditions. Under moderate to high load conditions the Valve cover breather line will reverse airflow and push air out towards the Intake.(The Helms manual shows the airflow direction when the car is idling NOT when load is applied.)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">
Since the intake is always under higher vacuum if sucks the oil/air/vapor mixture OUT of the crankcase and into the intake plenum. Got it? The PCV valve is nothing but a damn check valve. It only lets air OUT, not IN. Try blowing on both ends, you'll see what I mean.
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Wrong. For A Naturally aspirated Vehicle the Engine is under High vacuum when the car is Idling or the Throttle plate is almost closed. When you open up the Throttle plate the vacuum inside the plenum drops. At WOT the vacuum is almost non- existant(This is why the crackcase gasses are released through the Valve cover breather - the PCV line going to the IM cant keep up!)

For A boosted Vehicle the IM would go from High vacuum - low vacuum - no vacuum - positive pressure .... depending on the load given.

The PCV Valve is not just a check valve ... if you read the links you posted you will see that the PCV valve allows a certain amount of airflow through under different vacuum conditions. Please don't give anyone an impression that they can simply substitute a check valve in place of their PCV valve is clogged.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">
Now look at the second picture. WRONG! It shows air going out of the PCV valve at the same realitive vacuum. IT WON'T WORK! The PCV is a weighted to only operate within a high vacuum differential. In this case, you might as well not have the valve there at all. </TD></TR></TABLE>

Again read your own literature you provided ... The PCV valve works under mild, moderate and high vacuum conditions ... NOT just "within a high vacuum differential".


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">
Remeber the crankcase is supposed to be under vacuum at all times. Like 10 mmHg or less. You can't generate that from a pitot tube setup shown. There isn't enough velocity.
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Keep one thing in mind here ... this is the Forced induction forum - many individual on boosted vehicles vent their crankcase in open atmosphere without the assistance of any vacuum. This is a simple and effective setup for a boosted car because of the amount of blowby in the crankcase. Any vacuum assistance will only help the situation(as Long as the vacuum present does not exceed 14-15" of vacuum ).

I don't just know this information from studying how the PCV system works ... I actually tested all my theories in real driving conditions with a Calibrated Dewyer Magnehelic Pressure Gauge...

go here for the tests
https://honda-tech.com/zerothread?id=697498

 

One More thing guys .... I haven't forgotten about my promises to test an electric vacuum pump on the crankcase of a boosted B18C engine ... I'm running some preliminary tests .. within a month I'm going to test it on a dyno also.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dasher &raquo;</TD></TR><TR><TD CLASS="quote">One More thing guys .... I haven't forgotten about my promises to test an electric vacuum pump on the crankcase of a boosted B18C engine ... I'm running some preliminary tests .. within a month I'm going to test it on a dyno also. </TD></TR></TABLE>
Has anyone tested this on b series engines:

designed to reduce pressure buildup in the engine crankcase. The benefits of this system are better piston ring seal, less intake charge contamination, and reduced chance of oil leaks while increasing your engine performance. The kit includes two chrome-plated push-on valve cover breathers, breather grommets, check valves and 3 1/2 in. long threaded tubes. The tubes must be welded into collectors.
I think it would be a lot cheaper than an electric pump.

 

thats an old trick ... it does work if its positioned correctly ... but there are few problems ...

1) Cant run a cat
2) oil vapors will burn in exhaust causing smoke to exit " can you say smokescreen"
3) Vacuum pull is not as effective as an electric or mechanical vacuum generator.

 

Pics of that kit look like it's for some old fashioned low tech V8 mulletmobile that probably didn't come with cats anyway.

Neverthless it is a possible solution to this problem.

-Michael

 

The kit is universal, but yeah that one comes setup with everything for a v8 or enough parts for 2 of our cars. I am building a type 4 turbo engine so no emissions for me and no cats

How much do those vac pumps run anyway. BTW, it has got to be better than just opening it up to the atmosphere as far as vacuum is concerned. So it would work better than just opening it up to the atmosphere and cheaper than a pump right?


Modified by devnull at 9:07 AM 5/11/2004

 

yep.. definetly cheaper ..

 

I thought this might help some more. http://www.autoshop101.com/forms/h63.pdf

Very good page of how the sytems works.