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Old 10-19-2015, 01:43 PM   #21
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but if it doesn't pull enough vacuum who cares if it pulls vacuum?

One of the reasons I'm so against it is that everyone I've seen do it for science thus far has concluded that it sucks. (pun lol)

it sucks really hard by not sucking hard enough
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Old 10-19-2015, 01:43 PM   #22
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There is no doubt that a venturi installed in flow will create vacuum, what is in question is if it's enough of a vacuum to make the whole deal worthwhile, plus whatever negative effects it might add.

You could use a PC watercooling flow meter, then compare the unit-less number to the "flow" of the stock PCV. I think they are cheap, might spin in air?

They output a square wave like a computer fan, donno if you can hook that to the MS3?
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Old 10-19-2015, 01:45 PM   #23
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Square wave is perfect for input into MS. If it can put vacuum on the crankcase with the amount of blowby I have I will be impressed.

Got a spare flow meter around? Would be pretty easy to test.
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Old 10-19-2015, 01:48 PM   #24
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Ahh, all the flow meters I've ever used were just rpm sensors on the pump itself. Don't think I've ever actually used one before.

I think they're pretty cheap though, this one isn't pretty so it's cheap.

Liquid Flow Meter - Plastic 1/2 NPS Threaded ID: 828 - $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits
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Old 10-19-2015, 01:49 PM   #25
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Think that will work with air?
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Old 10-19-2015, 01:52 PM   #26
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Quote:
Originally Posted by 18psi View Post
but if it doesn't pull enough vacuum who cares if it pulls vacuum?

One of the reasons I'm so against it is that everyone I've seen do it for science thus far has concluded that it sucks. (pun lol)

it sucks really hard by not sucking hard enough
What is hard enough?

I'm not installing this as a PCV replacement. I'm installing it to aid in PCV when in boost.
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Old 10-19-2015, 01:53 PM   #27
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I imagine with enough volume it will spin pretty decent, maybe?

Hard enough is arbitrary, but I'd say if it doesn't pull equal or more vac at WOT than the manifold at full overrun it's a waste.
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Old 10-19-2015, 01:54 PM   #28
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if that's what you're doing, than a "test" is likely gonna be a waste of time, since the stock pcv will likely handle 95% of what you're throwing at it
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Old 10-19-2015, 01:56 PM   #29
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Hmmm. I'll keep looking. I'll put the bung in next time the downpipe comes out and go from there. Ya'll know where to find my results
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Old 10-19-2015, 01:57 PM   #30
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Are you really out there ripping it in boost so damn often? Don't you use those brakes? Every time you do the stock PCV does what it do best, and what you are trying to do may interfere with that.
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Old 10-19-2015, 01:59 PM   #31
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I like boost

I've been thinking about how it would interfere. And I think by setting it up the right way they can work in harmony.

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Old 10-19-2015, 02:01 PM   #32
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rabblerabblerabble

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Old 10-20-2015, 06:19 PM   #33
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Right. So the crankcase needs an air input source, fair enough.

Im not sure i understand your analogy deezums, surely if blowby is generated at a certain flowrate, and the same flowrate is heading outward of the crankcase, problem solved. Anyway, no matter, fooger has me convinced. Something about humidity, condensation, and water in oil. I failed my engineering degree on the thermodynamics, but after a ton of google-fu i found a few people agreeing with what you said, so im sold.

Thats a shame really, because with an air input source id bet keeping the crankcase under vacuum is out of reach. Sure an exhaust slashcut might get the flowrate but its no dry sump vacuum pump. Ah well. Better than venting to atmo at least.

In for flow rates for the exhaust slashcut. Id bet 1L/sec per 100hp would be way more than enough.


Edit: A bong rip like that would turn me into a crisp muching giggling wreck. wow.
Edit 2: Slashcuts work pretty well... https://www.miataturbo.net/general-m...-thread-55877/

Last edited by sparkybean; 10-20-2015 at 07:11 PM.
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Old 10-21-2015, 01:22 PM   #34
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I disagree with the notion that the crankcase needs air to flow through it.
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Old 10-21-2015, 01:24 PM   #35
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Quote:
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Reading map against a sealed off slashcut won't really tell you anything relevant, either.
Won't knowing the pressure of vacuum it can pull and the size of the tube dictate the flow?

(Disclaimer, I have 0 fluids knowledge.)
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Old 10-21-2015, 01:36 PM   #36
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Sealed slashcut should provide vac on crankcase, while 'sipping' out vapors. Think of a coffee-cup with no vent-hole.

"Flow" slashcut should provide close to ambient pressure, while evacuating crummy vapors in crankcase quickly.

Pick your poison I guess. I opted for flow, since atmosphere is as far as I can reason, almost as good as vac as far as power/seals are concerned, and I had this shinny moroso catch an I could use as a nice CCV intake.

Looking back I seriously should have kept stock PCV system with a sealed catch-can in-line. My setup is faaaar too complicated for benefit it provides. Plus I have like $300 in AN lines and Fittings and crap.
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Old 10-22-2015, 01:41 PM   #37
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Has anyone actually got around to testing a slashcut? Even something simple like a shop Vac in the blower mode with a vacuum meter, could provide some useful/useless info I think. The hard part I find with the slashcut, Is that they are pretty dependent on tube size and the angle that it is introduced to the vac. stream.

The stupid check valve that that would be needed (I think to prevent fireworks) requires .5 psi (or 13.5 IW) (or 1 inhg) just to get the thing to open. That's the part that I have a hard time with. You need a boatload of vacuum just to get the thing to open up.
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Old 10-22-2015, 01:43 PM   #38
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Q: do you love the smell of burnt oil and your rear bumper coated with it?
A: get a slashcut

The whole bong rip analogy had to have been made by someone ripping a bong. That's how bad it is
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Old 10-22-2015, 01:44 PM   #39
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Hmmm. Mine's welded in to my test-pipe, so I could theoretically get out the old shop vac and do some testing. Will try to rig something up in the next couple days.

I have the full vibrant set up. Stainless E-Vac, AN-10 everything, AN-10 inline check-valve.

Shop is slowing down with winter, so it is high-time for science.
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Old 10-22-2015, 01:50 PM   #40
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Angle of the insertion, amount it protrudes into the vacuum source, all seams important as well. I totally agree with the dislike of oil smell and mario cart antics, but what about the catch can?

OK, so now you need 10ft. of -10 hose, a check valve and a catch can. I don't see much vacuum being left. Test it Choo.
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