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Discussion Starter #1 (Edited)
So I went to the dealer and was talking with a mechanic and parts guy about the PCV system is routed.


Theres a port on each Valve cover according to the schematic drawing he showed me.

Now it didnt show where these hoses connected to other than the VC.


So Now my questions are:

IF the Mishi Kit is using the factory PCV system and locations, how is this venting the valve covers?
- If a PCV is used, they're usually a one way check valve, So when the car is not in boost, it should draw air from manifold.
So what will happen when the manifold is under boost? The PCV valve should close and when that does, What is now venting the valve covers?

As we know the crankcase suffers more pressure when the car is in boost and need ventilation the most.


Im just still skeptical of this can that everyone ran out and bought. (Apparently Mishi is out of stock of them according to Z1 motorsports as I asked them about it and they didnt have many answers with this can)

According to their own video on YouTube, it did accumulate oil for X miles.. Which is fine, but was this during normal driving when car is in VAC?
It would still collect oil just like a non turbo'd engine.


I just dont see any benefit of this model specific can as it just connects to the factory PCV system.



Now I had mentioned that I had Black oil on my oil filters and air box had a layer of oil which makes me wonder if theres no check valve and just connects
from manifold to inlets. Which means no PCV valve. But IDK about this Mishimoto system..

I seriously dont think thay did homework on this and just did the normal naturally aspirated engine route.


( On a side note, on YouTube i saw a vid about changing spark plugs and they guy noticed oil in his intercooler, Which is what we all are trying to avoid.)


Again, Venting to atmosphere or a closed system Being vented from the source VC's is optimal.


I was looking at Vibrant vented can, but wondering where to mount it.


 

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I could not edit my previous post.
I just dont see any benefit of this model specific can as it just connects to the factory PCV system.
Mishimoto's OCC kit for the VR30 is designed to filter the PCV that can cause oil from the crankcase to enter the intake manifold due to the vacuum pulling the combustion gases out of the crankcase; the OCC sits in this path to filter out much (expectation; not specifically measured) of the oil.

I have it Mishimoto's OCC installed; as others have seen and documented, I found a lot of oil captured in the can after 1000 miles. Do I believe the Mishimoto OCC kit is the best design? No, I do believe there is room for improvement; however, it is a fantastic option. Do not let perfection get in the way of greatness. (Frankly, any decent quality OCC would work just fine -- I did not want to fabricate my own mounting bracket, so I went with the Mishimoto kit; in fact, I did buy everything except the mounting bracket a week before the kit was announced, so I still have those parts in a box.)
 
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Discussion Starter #4
Just going to leave a few other resources to read:
The PCV must remained sealed; you should never vent-to-atmosphere on the PCV. You can vent-to-atmosphere on the blow-by hoses to the compressors.
Why must it remain sealed? Besides the EPA regulations which automakers need to follow, just searching google and picking whatever to post doesnt answer the question. I dont need to read your search results.


On the blow by hoses to the compressors? Need an explanation on this also.


Ive been using catch cans way before they were labeled oil-air separators and know what they're for and where they need to hook to to perform the best.


Defending mishimoto when their design is flawed which i stated in the post doesnt mean its a good design, it just tells me they just do what they always do and just stick a can between the PCV and the Vac inlet. Which is fine if it wasnt a turbo'd engine.

Turbo'd engines need venting and some even vent it to the exhaust pipe and blow the oil out the pipe. But usually thats a race situation where oil is drained right after the race. But venting to atmosphere is perfectly fine as whatever pressure builds up in the case will be expelled naturally. Thus saving the piston rings.

In a perfect non atmosphere venting world, you would use 2 cans (1 for each valve cover ) and needs to be in a VAC only which is before the turbo.
 

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Why must it remain sealed? Besides the EPA regulations which automakers need to follow, just searching google and picking whatever to post doesnt answer the question. I dont need to read your search results.
The crankcase is pressurized and the PCV is designed as a vacuum, so that vacuum in the intake pulls air through the crankcase, forcing the post-combustion gases out. Without a vacuum, all of those gases are not purged and eventually become blow-by past the piston rings. Additionally, venting to atmosphere on this will smell like hot garbage.

On the blow by hoses to the compressors? Need an explanation on this also.
If you follow the hoses, they connect the valve covers to (driver's side) turbo and (passenger's side) a coupler connected to the turbo. The service manual has multiple diagrams that show the paths; alternatively, if you get the car completely off the ground, it is not too difficult to follow the hoses. I am unsure of their precise purpose and an uneducated guess will not benefit us much here. One quick diagram reference as my care-meter is quickly dissipating: https://www.infinitiq50.org/forum/attachment.php?attachmentid=78813&d=1533831165

In a perfect non atmosphere venting world, you would use 2 cans (1 for each valve cover ) and needs to be in a VAC only which is before the turbo.
The VR30 does not connect the crankcase to both valve covers; only the driver's side valve cover is connected to the crankcase, forming the PCV.

Defending mishimoto when their design is flawed which i stated in the post doesnt mean its a good design, it just tells me they just do what they always do and just stick a can between the PCV and the Vac inlet. Which is fine if it wasnt a turbo'd engine.
I am defending the design as it filters the PCV, and multiple people have shown the amount of oil that is captured. Mishimoto's design is accomplishing a lot! Whether it is the best package for the VR30 engine, it is not perfect as it does not filter the hoses running from the valve covers to the two compressors; however, it is a great product without being perfect and 3x the cost.
 

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Malby is correct as far as the valve cover vent routing- In the below diagram you'll notice numbers 4 and 8. These go from the respective valve covers to the inlet on each turbo. The point of this is you'll draw a vacuum on the crankcase due to the compressor impeller drawing in air. This vacuum on the crankcase aids in piston ring sealing....which is why it's better than simply venting to atmosphere. However it is still possible to get oil misting sucked into the turbo's from this.

#14 in the diagram is the line that Mishimoto tackled which is the line from the valve cover to the intake manifold which is where you'll get a bunch of crap sucked back into the intake. The 2nd pic below is the routing of the PCV valve based on driving conditions (idle vs. cruise vs. WOT). My main gripe with Mishimoto's kit is the price and the location they chose to mount their OCC. I built my own for about $20 that looks the same as their's but isn't in the way of the BOV location that people choose to use.
 

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If you follow the hoses, they connect the valve covers to (driver's side) turbo and (passenger's side) a coupler connected to the turbo.

The VR30 does not connect the crankcase to both valve covers; only the driver's side valve cover is connected to the crankcase, forming the PCV.

it is not perfect as it does not filter the hoses running from the valve covers to the two compressors; however, it is a great product without being perfect and 3x the cost.

So I have two cans. What should I do?

Connect one can on the driver's side to the PCV (Mishimoto setup), and the use the other can separately to vent the valve cover on the passenger side (only)? Or BOTH valve covers using connecting tubing? Passenger's and driver's?

Thoughts???





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So I have two cans. What should I do?

Connect one can on the driver's side to the PCV (Mishimoto setup), and the use the other can separately to vent the valve cover on the passenger side (only)? Or BOTH valve covers using connecting tubing? Passenger's and driver's?
You could use one catch can on the PCV (most important) and the other catch can on one of the valve cover-to-turbocharger paths.
 
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So something like this?
(Sorry about the "crude" drawing)
Oof, that is crude. Conceptually, yes, that is what you are after.

Physically, it would be either hose #4 or hose #8 in the diagram below for the second catch can/air-oil separator; hose #14 would be for the first catch can/air-oil separator.
 

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Oof, that is crude.

Lol!

I know... They're pretty bad.

I'm co founder and Chief Technology Officer for Phoenix Energy. We connect over the internet to commercial automation systems and remotely detect faults, "tune" mechanical machines and equipment...among other things. We also control their lights and air conditioning.



That particular diagram we were discussing the mission critical nature of controlling buildings from a distance, especially retail customers.

My Engineering and Executive team are always laughing at me about my "crude" drawings as well. But hopefully they get the point across?

I also leave my wife little notes around.

One was especially memorable:



Thanks for your help...

Keith






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Discussion Starter #12
Oof, that is crude. Conceptually, yes, that is what you are after.

Physically, it would be either hose [URL=https://www.infinitiq60.org/forum/usertag.php?do=list&action=hash&hash=4]#4 [/URL] or hose [URL=https://www.infinitiq60.org/forum/usertag.php?do=list&action=hash&hash=8]#8 [/URL] in the diagram below for the second catch can/air-oil separator; hose #14 would be for the first catch can/air-oil separator.
Thanks for posting up the schematic for the hose layout..


Personally, I would run cans on both #4 and #8 hoses AND the PCV system.



The goal here is not NOT introduce oil into the intake system and i think this diagram is REALLY helpful.


Now... Where to put 3 catch cans?!?!?


 

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Personally, I would run cans on both #4 and #8 hoses AND the PCV system.
...
Now... Where to put 3 catch cans?!?!?]
Absolutely. If you can cover all three, you are going to be in the best possible situation. If you figure out how to fit three catch cans into our cramped engine bay, please share!

Also, it may be worth considering a 2-in-1 catch can (for example, AMS' air-oil separator for the GTR is a custom 2 cans in one physical frame design). That could make it easier to find a location, unfortunately it will hold less (though the two hoses going back to the turbo inlets should have less oil in comparison to the PCV, so this could still be a great option).
 
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Absolutely. If you can cover all three, you are going to be in the best possible situation. If you figure out how to fit three catch cans into our cramped engine bay, please share!

Got it figured out!

I'm "reversing" my 4 guage wiring set up for my subs in the trunk and repurposing it to relocate my battery to the trunk.

This frees up enough space in the engine bay, and then some for the cans (or anything else I might want to stay in there ;).



Now as far as the dual ( or even three?) can setup, I got my cans from another GTR dual can setup. The GTR dual can instructions say that, of course, the PCV and the "valve breather" cans must be isolated systems from each other.

But what about using one can with a "tee" or something to pick up oil/air vapors from BOTH valve covers? Can that be done, or is there a concern where each valve cover needs its own can?

Here's the link to the GTR Mike Norris dual can installation (which are the cans I have)

https://media.wix.com/ugd/eaafb8_ace523cab1af4fc2b8311a6092afe6fa.pdf



Now that I'm gonna have some "recovered real estate" under the hood with the battery relocation, the number of cans (two or three) is less of a concern. The Mike Norris cans have the drains on the bottom of each can, so I will union the drains together in one outlet.

Looking on the web I actually saw some Nissan twin turbo Z setups are running...three (3) cans!




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You can union the valve covers to 1 can and leave the other can for the intake/PCV lines. I know Mike very well, he makes quality stuff.

Thanks. Yes, Mike was very helpful. His cans are $185 ea. I figured I would look to our “big brother” GTR for guidance on a dual catch can setup.



This has now come full circle back to the diagrams I posted 2-3 months ago when I bought the two Mike Norris cans.





Gonna mount them tandem, in the soon-to-be-empty, battery area.






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Discussion Starter #17
Just going to point out,

If you do merge everything to 1 line, be sure to use larger tubing. Like a -10 or similar.
 

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Discussion Starter #18 (Edited)
The crankcase is pressurized and the PCV is designed as a vacuum, so that vacuum in the intake pulls air through the crankcase, forcing the post-combustion gases out. Without a vacuum, all of those gases are not purged and eventually become blow-by past the piston rings. Additionally, venting to atmosphere on this will smell like hot garbage.


^^

This makes NO Sense.

Against my better judgement to not spoon feed the noobs, Im going to tell you how your post is flawed and break this down like a fraction since your posting wrong information and seems everyone following your flawed info.

Yes, The PCV is a vacuum. I does pull oil vapors out of the crank case. But theres ALWAYS blow by past the rings in EVERY CAR. It is worse in turbo engines as the compression is not static and get much higher and varialble based on boost pressure. Meaning, theres MORE Blow-by when cylinder pressure are higher.

The PVC is there to take that oil vapor and send it into the engine so it does not vent to atmosphere ( Against EPA guidelines) This crankcase pressure DOES NOT NEED A VACUUM!!! Why? Because its pressurized. It will push itself out on its own and does not need a vacuum to help it along.



The VR30 does not connect the crankcase to both valve covers; only the driver's side valve cover is connected to the crankcase, forming the PCV.
^^ This whole thing makes NO SENSE

How are the valve covers connected to the crankcase? Usually its the block, then heads attached to the block, then the valve covers attached to the head. IDK what that sentence is supposed to mean


I am defending the design as it filters the PCV, and multiple people have shown the amount of oil that is captured. Mishimoto's design is accomplishing a lot! Whether it is the best package for the VR30 engine, it is not perfect as it does not filter the hoses running from the valve covers to the two compressors; however, it is a great product without being perfect and 3x the cost.

You can wave your hands at mishimoto all you want. its your car and you can do what you want. But dont post up wrong information as according to this post, you have no clue what your talking about.
Malby is correct as far as the valve cover vent routing- In the below diagram you'll notice numbers 4 and 8. These go from the respective valve covers to the inlet on each turbo. The point of this is you'll draw a vacuum on the crankcase due to the compressor impeller drawing in air. This vacuum on the crankcase aids in piston ring sealing....which is why it's better than simply venting to atmosphere. However it is still possible to get oil misting sucked into the turbo's from this.

With the schematic drawing, Yes he is correct on the routing. The pston rings are set when the engine has its 1st start up. The vaccuum doesnt to anything but draw in oil vapor right in front of the turbos. Mishimoto has yet to design a system to NOT introduce oil vapor into the turbos.

Like I said, they just put a can in between the PCV system.


#14 in the diagram is the line that Mishimoto tackled which is the line from the valve cover to the intake manifold which is where you'll get a bunch of crap sucked back into the intake. The 2nd pic below is the routing of the PCV valve based on driving conditions (idle vs. cruise vs. WOT). My main gripe with Mishimoto's kit is the price and the location they chose to mount their OCC. I built my own for about $20 that looks the same as their's but isn't in the way of the BOV location that people choose to use.


Again...

When the PCV is closed. The Vapor now goes from the Valve covers DIRECTLY in front of the turbos.

You guys are leaving out the properties of what the PCV does. When the manifold is under pressure, it closes.


When the car is Vacuum, the pcv is open. When the car is in boost, the PCV check valve closes, THUS NO MORE VACUUM and the crankcase is now being vented infront of the turbos.
When the car is in Boost, theres more blow by and thus needs venting the most! having a Mishimoto can (which is closed off in boost) is useless as it only works when the manifold is in VAC.

{Now, since theres no BOV, the throttle plate closes when in boost.. The crankcase is venting before the turbos and that vapor is being shot backwards with the compressor surge and the oil is collecting on the clean side of the air filters.

Alright, Im done educating.. Take that info i just typed to any ASE certified mechanic, See what he says and ONLY then post up your reply. Dont start giving me search results of this and that.

FYI

This is a custom catch can. Everything vents into this can. Theres no vacuum, theres no PCV system. THis is the PCV as pressurized crankcase will vent all on its own.
Or, Use a can for the PCV and on each Valve cover to make sure no vapor gets into the intake or manifold.

 

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You're not educating anyone. You're using info to other platforms that do not pertain to the vr30ddtt. There are 3 lines from the crankcase.....2 of those lines go to in front of the turbo which pulls a vacuum on the crankcase which DOES improve piston rings sealing over a purely vented setup. This happens DURING boost when the pcv line is closed because they're entirely different lines.
 

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Discussion Starter #20 (Edited)
Dude, Just stop posting.

You and the others keep speculating this and that with no reliable info and posting wrong info which leads to alot of people down the wrong path.


Vacuum doesnt improve ring sealing. IDK where this information came from, but its wrong.


And what do you mean by other platforms? An NA engine is and NA engine. A turbo engine is a turbo engine. Thats it! This isnt some engine from outer space.


If your theory is correct, EVERY RACE ENGINE OUT THERE WOULD BE RUNNING VAC TO SEAL THEIR RINGS. You never see ANY PCV sysytem on a performance engine.



Like I said, Go check with your chuck friend or anyone with ASE certification before coming on here trying to convince me the factory PCV is optimal



EDIT: Arent you the one who said you have boosted experience? If anything Id expect you to know the difference. I expect these backyard mechanics to not know much, but you claim to know your way around a boosted engine.
 
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