2002 GM 5.3L PCV - plunger style vs fixed orifice

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I have a 2002 Tahoe 5.3L with 247k miles. Over the last 1,000 miles or so, it's had a little hesitation and slightly rough idle. I checked the PCV and it was a Fram plunger style. It had a good bit of gunk on it and in it.

I replaced it with a fixed orifice unit (BWD #PCV-484) and the idle is smoother and engine seems to run smoother and quieter overall. I used to have a slight hissing sound before that I wasn't sure where it was coming from. It's now gone with the PCV change.

I read a couple threads mentioning the fixed orifice valve over the plunger type. What's the "science" behind it? Does the fixed orifice pull more or less on the crankcase at idle and part-throttle compared to the plunger? What difference should I see in oil consumption? (currently uses 1 quart every 5-6k miles)
 
I was taught ( back in the '70s') that the check valve in the PCV was an flame arrester in case of a a manifold backfire. It may have double duty as a flow regulator for less bypass air into a carburetor for a smoother idle.
 
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