Off-Brand Vibrant PCV Scavenge Fittings

Bdsankey

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Does anyone have any experience with these evac fittings? https://www.amazon.com/gp/product/B07J69G4YN/ref=ox_sc_act_title_1?smid=A17PPRRJETTLJ1&psc=1

I am looking at installing a Vibrant catch can (4 port, closed system) and running the lines into the exhaust. This post is not a "will it work" thread (we know it does), this is more so a post to determine if these off brand fittings work as well as the vibrant ones or if I need to scour the web/ebay to find genuine vibrant fittings.
 

MAXX IT OUT

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Mar 1, 2013
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How much vacuum does the Vibrant fitting or these style pull? I am thinking about in installing 1 or 2 in my new down pipe, but not sure if its any better than my current vented catch can.
 

Bdsankey

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How much vacuum does the Vibrant fitting or these style pull? I am thinking about in installing 1 or 2 in my new down pipe, but not sure if its any better than my current vented catch can.
That I don't know, but I do know it is more than atmospheric pressure in regards to it *should* hit negative (vacuum) as opposed to just 0psig. I'm planning on putting 2x of these in my lower downpipe half as well as in a customers LLY I just wrapped up.
 

Chevy1925

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Oct 21, 2009
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generally -1 to -2psi is what ive seen/found. higher the exhaust velocity, the more you gain from it. 2 hoses/venturi's seem to work best as well so either one from each valve cover or a large catch can with two breathers in from the valve covers back to 2 breathers out.
 

Bdsankey

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generally -1 to -2psi is what ive seen/found. higher the exhaust velocity, the more you gain from it. 2 hoses/venturi's seem to work best as well so either one from each valve cover or a large catch can with two breathers in from the valve covers back to 2 breathers out.
Thats the plan, just wanted to make sure these fittings are decent. I know vibrant one are what have been used/discussed but are no longer produced.

I figure 2x -10 hoses should be sufficient as that is what is on the catch can (I don't recall what my merchant PCV reroute fitting size is but I'll make it work). Plan is to weld the fittings in the downpipe just after the bend to point rearward as it should have good velocity and still keep heat. Putting them before the bend I am worried about a potential backup/not as high of velocity.
 

gmc502

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Jan 16, 2011
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think you could weld these in to the up pipe and let the hotter exhaust gas burn up the oil fumes?
 

coker6365

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I know other have had luck with these, however, I did not. Had a 1/2" in the original downpipe and it actually created positive pressure and back fed exhaust soot to the valve covers. Rocker area looked like oil/soot mixture when we pulled the heads.

Maybe 2 1/2" fittings will work. We just run our to atmosphere now and everything was spotless when we pulled heads this time.

Sent from my SM-G965U1 using Tapatalk
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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think you could weld these in to the up pipe and let the hotter exhaust gas burn up the oil fumes?
not unless you want to pressurize the crank case. Up pipes are under positive pressure the moment you start to come on boost (actually before boost comes on but close enough).
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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Phoenix Az
I know other have had luck with these, however, I did not. Had a 1/2" in the original downpipe and it actually created positive pressure and back fed exhaust soot to the valve covers. Rocker area looked like oil/soot mixture when we pulled the heads.

Maybe 2 1/2" fittings will work. We just run our to atmosphere now and everything was spotless when we pulled heads this time.

Sent from my SM-G965U1 using Tapatalk
you had the venturi put in at the same angle as the slit at the end of the nozzle? was it facing correctly inside? if its not put in right, it will add pressure to the system and if there is any back pressure in the exhaust, it will do the same.
 

coker6365

Coker6303's ***** Daddy
Dec 4, 2011
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you had the venturi put in at the same angle as the slit at the end of the nozzle? was it facing correctly inside? if its not put in right, it will add pressure to the system and if there is any back pressure in the exhaust, it will do the same.
I will have to look, that downpipe is on the shelf. And it may have been some sort of off brand contraption since it was already in the downpipe when we pieced together the kit. My situation has a lot of variables I am sure. We just simply went to atmo with it and done.

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Bdsankey

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you had the venturi put in at the same angle as the slit at the end of the nozzle? was it facing correctly inside? if its not put in right, it will add pressure to the system and if there is any back pressure in the exhaust, it will do the same.
I don't think I'll have back-pressure issues with the 4" and including how short it is before the stack.

I know other have had luck with these, however, I did not. Had a 1/2" in the original downpipe and it actually created positive pressure and back fed exhaust soot to the valve covers. Rocker area looked like oil/soot mixture when we pulled the heads.

Maybe 2 1/2" fittings will work. We just run our to atmosphere now and everything was spotless when we pulled heads this time.

Sent from my SM-G965U1 using Tapatalk
My only concern with this is potentially getting flagged at the local track. Friend of mine's Cummins got flagged and told he had to have a catch can (it wasn't puking oil either).
 

gmc502

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not unless you want to pressurize the crank case. Up pipes are under positive pressure the moment you start to come on boost (actually before boost comes on but close enough).
thanks for reminding me about drive pressure,,brain farted on that one.:D
 

WolfLMM

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Nov 21, 2006
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generally -1 to -2psi is what ive seen/found. higher the exhaust velocity, the more you gain from it. 2 hoses/venturi's seem to work best as well so either one from each valve cover or a large catch can with two breathers in from the valve covers back to 2 breathers out.
Exactly, and yeah diesel exhaust is slow, so they do work but not very well. They’ll pull nice vacuum on a NA gas engine.
 

WolfLMM

Making Chips
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Nov 21, 2006
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I know other have had luck with these, however, I did not. Had a 1/2" in the original downpipe and it actually created positive pressure and back fed exhaust soot to the valve covers. Rocker area looked like oil/soot mixture when we pulled the heads.

Maybe 2 1/2" fittings will work. We just run our to atmosphere now and everything was spotless when we pulled heads this time.

Sent from my SM-G965U1 using Tapatalk
I did too. The problem is diesel exhaust is too slow. I had much better results just venting to atmosphere. We all know the physics behind the design, but sometimes the practicality of them come into question. I too just vent to the atmosphere now. Simpler and works every time. Jmo
 

Bdsankey

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I did too. The problem is diesel exhaust is too slow. I had much better results just venting to atmosphere. We all know the physics behind the design, but sometimes the practicality of them come into question. I too just vent to the atmosphere now. Simpler and works every time. Jmo
Good to note. I need to do something as just running a hose to the ground is going to get me flagged at the local track as they believe it is a safety concern.
 

DuramaxRamRod

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Oct 11, 2014
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not unless you want to pressurize the crank case. Up pipes are under positive pressure the moment you start to come on boost (actually before boost comes on but close enough).
But what about the flow through the up-pipe? Its not deadheaded so it shouldn't push into the crankcase.
 

Bdsankey

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But what about the flow through the up-pipe? Its not deadheaded so it shouldn't push into the crankcase.
It's physics at the end of the day, air/fluids (air can be analyzed as a fluid) will always flow from high pressure to low pressure via the path of least resistance. The crankcase is under MUCH less pressure than the up-pipes are thus the exhaust flow will try and go into the crankcase via the lines ran to the up-pipes.
 

DuramaxRamRod

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Oct 11, 2014
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It's physics at the end of the day, air/fluids (air can be analyzed as a fluid) will always flow from high pressure to low pressure via the path of least resistance. The crankcase is under MUCH less pressure than the up-pipes are thus the exhaust flow will try and go into the crankcase via the lines ran to the up-pipes.
But this is an evac/eductor type fitting. Besides pressure there is also velocity, which also plays a role in fluid flow. Otherwise eductors would not exist.
 

Bdsankey

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But this is an evac/eductor type fitting. Besides pressure there is also velocity, which also plays a role in fluid flow. Otherwise eductors would not exist.
I've never seen a fitting like this in a high pressure scavenge situation in an industrial setting. The other thing you will be doing is impeding flow in the up-pipe to a large degree.
 

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