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I'll even lead by example heres mine in progress shot, pcv is done atm,
Can you see the hose going from the turbo inlet to the OEM valve cover fresh air? Notice there is no can. That hose is my engine's life line. I pull the hose and check for oil residue once every couple months.
If I ever find even a hint of oil. I can start getting ready to replace the engine. There will never be any can for my application (daily driver). But some applications do require external oil storage. Its just a bad sign to them on daily drivers is all.
Just do what you drew here. You CAN* if you want remove the breather from the can, because it's really only there in case there's too much for the single line going to the filter to vent preventing your rear seal or something from blowing out.
It'll suck through the can when you're not in boost, and when you're in boost it'll vent/suck back through the filter and then if needed out through the breather.
One last option I promise 😁. If the can breather is not necessary needed then could I not just do like below
-2 x 10mm line from each valve cover to inlets of catch can
-1x 10mm line from outlet of can to inlet manifold (check valve in line)
-breather filter on oil fill
-valley port blanked.
I really don't need a check valve in the line going from the outlet (clean side) of the catch can to the supercharger inlet barb, since there is only vacuum present there ... However, my catch can is of the Gen5 PCV type, so there is a one-way check valve already installed in the outlet (clean side) fitting of the catch can.
BTW ... I could not close my hood when the catch can's top mounted filter was attached, so I removed it and sealed off the top cap (see photo below).
Thanks I suppose your setup is slightly different as the inlet connection doesn’t see boost.
its strange how MM vent driver valve cover / blank valley on one boosted setup and the opposite on another. So valley blanked and driver valve vented.
I wonder if I could use a small breather filter on the oil cap OR valley port and it be sufficient.
Last edited by SteveSierra; 03-30-2019 at 09:52 AM.
[QUOTE=Turbo6TA;1599136182]Here is how my catch can is installed with my SC:
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This setup is not ideal
1.Is there any PCV for idle/cruise, the most important purpose of PCV for daily drivers? It says "vacuum" but its on the TB Snout so I am not sure
2. the fresh air vent tube is at a small, undesirable location. The flow rate off the valley is insufficient to support pcv by itself. The valley covers are intended to be supplementary crankcase flow, not a stand-alone source.
To fix this system
1. Move the line going from the can to the intake manifold vacuum and install a 1-way check valve (PCV valve) If it doesn't have vacuum or a valve (can't tell)
2. Utilize the other valvecover for fresh air vent source by moving it to the pre-throttle body (or pre compressor of super/turbo) as in other pictures.
You can leave the valley vent or not, it doesnt matter, however it was never intended to be used by itself.
A pcv system is one of those things you can connect or utilize completely incorrectly and have no idea that its wrong sometimes.
For example if you just ran two -10AN lines from both valve covers to breathers and called it a day. It would "work" fine. But there will be no PCV.
Having actual PCV in the crankcase means looking at a gauge and making adjustments to dial it in. Otherwise using factory OEM components.
One last option I promise ��. If the can breather is not necessary needed then could I not just do like below
-2 x 10mm line from each valve cover to inlets of catch can
-1x 10mm line from outlet of can to inlet manifold (check valve in line)
-breather filter on oil fill
-valley port blanked.
This is also quite terrible. The path for blow-by to get to atmospheric (or below) conditions needs to be short as possible. There should be a hose going from the (right side in this picture) directly to a low pressure source for wide open throttle (the pre-throttle body tube after the air filter). You DON'T want it running all over the place, especially back into the engine and then out again. That is a disaster.
Also the filter is negating all PCV action. You are completely disabling the PCV system by installing a two way filter anywhere. Not to mention it will pull in un-metered air and become untunable for maf cars, and difficult to tune in vacuum situations with varying qualities of air coming in that filter all the time.
If you want one for WOT I can also
I can also make a more informative version for adjusting pressure and where pressure differentials exist etc... but I think its unnecessary?
Also as to the can. catch can purpose is to catch oil. So if the engine starts blowing oil on either side (right side from WOT with a broken piston, or left side due to poor maintenance/baffle performance) you can always add a can to either side. In most FI applications I put a can on the right side (fresh air side) to keep oil out of the compressor (super/turbo). Left side isn't supposed to give any trouble because OEM design their baffles to prevent oil from engaging this line. So if you are seeing oil there (on the left intake suction side) its probably due to a clog, carbon buildup, damaged baffle, improper hose route, poor maintenance, etc... and not the way the system necessarily started out.
My diagram shows the 'dirty air' from the catch can 'outlet' being sucked into the supercharger inlet barb ... There is always vacuum at the SC inlet barb because it is downstream of the throttle body.
I really don't need a one-way check valve in this vacuum line because there is no positive pressure in this line even during boost (just the way this SC is designed) ... In my case, I did buy the "PCV" version of the MM catch can which does include a check valve screwed into the catch can 'Outlet', but in my application, it really is not necessary.
BTW ... The 'filtered fresh air' line that attaches to the crankcase valley cover barb is just that ... filtered fresh air that enters the crankcase ... It gets it's filtered air upstream of the throttle body between the throttle body and the air filter element.
My diagram shows the 'dirty air' from the catch can 'outlet' being sucked into the supercharger inlet barb ... There is always vacuum at the SC inlet barb because it is downstream of the throttle body.
When you put a picture of a vacuum hose attached near the TB you need to specify which side of the blade it is on. Otherwise it is confusing to anyone looking at it. Its like putting a number without units, I have 100boost. 100 what? 100 kg/cm^2 or 100kpa or 100psi or what I can't tell
I really don't need a one-way check valve in this vacuum line because there is no positive pressure in this line even during boost (just the way this SC is designed) ...
I like the idea of having fewer components in general, the reason at least one checkvalve is typically necessary is because as intake pressure 'diracs' (sudden instant draw of a complete cylinder in a perfect model at the last possible instant) there are positive pressure pulse area, or rather there is always some pressure above atmospheric on the trailing ends of full cylinder draw events due to the fluidic nature of air (the reason we leave the intake valve open after the piston begins moving up is because the momentum of air is still carrying it into the cylinder), for example the effect of 'water hammer' as the intake valve shuts sends a positive pressure pulse away from the intake valve. I get that the supercharger lobes or compressor components are air-tight between the chamber where the throttle body rests, I can see why you wouldn't need to worry about any such things. Yet I would still want to high-speed log crankcase data to be sure, and consider that a single high quality check valve is also cheap insurance against other failure-related issues. For example maybe a lope fails after 225,000miles to the point it no longer seals perfectly and now there is 'boost' blowing back into the crankcase, at least if you had a high quality $40 checkvalve there it would save the $xxxx engine from needing more maintenance and more oily mess.
BTW ... The 'filtered fresh air' line that attaches to the crankcase valley cover barb is just that ... filtered fresh air that enters the crankcase ... It gets it's filtered air upstream of the throttle body between the throttle body and the air filter element.
so... sorry to say that this is the only problem I really see. I owned an LS6 rear valley cover but decided not to use it. I got a good look at it. The size of the orifice, and position of that valley cover is just barely adequate for OEM pcv valve diameter. I forsee trouble in the future because of the small diameter orifice throught there mainly. I don't just mean the hole on the end where the hose goes, I mean the entire unit is designed tightly, as if for merely supplemental flow. It was never intended to be used as a sole source. One little tiny piece of hose crust is going to cause all kinds of hell and headache if it gets in that thing, anywhere. I rapidly suggest you uncap the sealed up hole somewhere else in the crankcase and get an additional filtered source attached at the least.
When you put a picture of a vacuum hose attached near the TB you need to specify which side of the blade it is on. Otherwise it is confusing to anyone looking at it. Its like putting a number without units, I have 100boost. 100 what? 100 kg/cm^2 or 100kpa or 100psi or what I can't tell
I changed the diagram showing the position of the throttle body: Attachment 48348247
my diagrams are only useful if the catch can is not modified like you did. without the pressure release and configured as this you will probably blow a main seal.
Originally Posted by Turbo6TA
I changed the diagram showing the position of the throttle body:
my diagrams are only useful if the catch can is not modified like you did .. without the pressure release and configured as this you will probably blow a main seal.
I have good rings on a low mileage engine ... Do you think with a tight engine, such as mine, that my piston rings will allow so much combustion gas to pass by them at WOT / high RPM, that it will pressurize my crankcase enough as to blow out my crankshaft main seal?
03-28-2019, 11:05 PM
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