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Would a vented catch can connected to the intake manifold cause a boost leak?
Guys,
I'm trying to get my head around an issue with my recently Procharged ride and am wondering if it is related to using a vented catch can.
Here is my setup:
The connections go like this:
Intake Manifold Port > Splitter (for BOV boost reference) > Catch Can
Valve Cover > Catch Can
Valley Port x Capped Off
My understanding with the MM catch can is that under vacuum a little plastic disc inside the air filter acts as a check valve and closes the filter off so that the vacuum is maintained.
However, under boost I can only assume that this works in reverse? Meaning that some boost goes down through the Intake manifold port, into the catch can and out of the breather? Am I right?
I have the same can & it is the same way. But on your stock air box the small line that is running from the oil can fill up on the z51 car IS THAT HOOK UP BREATHING AIR CHECK IT AND SEE IF NOT DRILL A HOLE INTO IT SO IT DOES.
That is from David at MMS I had to drill a hole into mine small line that is crazy have a hook up from the oil can to the air box but then it does not work it was line it had not been drilled out.
From the looks of it you are not running meth are any kind of gauge's also. Robert
Last edited by robert miller; 05-27-2017 at 09:02 AM.
Can you post a pic robert? I am also having troubles deciding how to route my MM catch can with a procharger setup
Mine is like this also this way is for a blower set up. Message me your email and if you have the wild mms can set up for a blower will email you the drawing that David emailed me buddy. Robert
My understanding with the MM catch can is that under vacuum a little plastic disc inside the air filter acts as a check valve and closes the filter off so that the vacuum is maintained. I agree.
However, under boost I can only assume that this works in reverse? Meaning that some boost goes down through the Intake manifold port, into the catch can and out of the breather? Am I right? No, the hose from your "vacuum manifold" is connected to a check valve on the catch can, which replaced your PCV valve that you capped off. It allows air flow during vacuum but not under boost. So under boost it won't "bleed off".
My understanding with the MM catch can is that under vacuum a little plastic disc inside the air filter acts as a check valve and closes the filter off so that the vacuum is maintained.
I agree.
However, under boost I can only assume that this works in reverse? Meaning that some boost goes down through the Intake manifold port, into the catch can and out of the breather? Am I right?
No, the hose from your "vacuum manifold" is connected to a check valve on the catch can, which replaced your PCV valve that you capped off. It allows air flow during vacuum but not under boost. So under boost it won't "bleed off".
ah ok, that's a relief. So the plastic disc on the catch can filter is to relieve positive pressure from the valve cover? And a separate check valve exists for the vacuum manifold connection?
ah ok, that's a relief. So the plastic disc on the catch can filter is to relieve positive pressure from the valve cover? And a separate check valve exists for the vacuum manifold connection?
ah ok, that's a relief. So the plastic disc on the catch can filter is to relieve positive pressure from the valve cover? And a separate check valve exists for the vacuum manifold connection?
James email to you man. Look at the pic of the hook up that the stock air box ha from his drawing. Robert
In case you realize its not the catch can. If you're losing boost with a procharger kit, it may be your belt tensioner is seized. It happens to many procharger kits. Take it a apart, grease it well. Fixed mine and another member on here. Went crazy looking for leaks before then.
all my cans look the same but they are not the same, or work the same
here is a copy from the first catch can page on my website
The RACE can is an open vent catching whatever liquids come from the crankcase.
It is completely passive, not connected to your incoming air supply at all, and PCV is completely deleted. That means zero blow-by fumes consumed by your engine, but that also means the fumes will go to your engine bay and sometimes, the cabin. *sensitive noses beware*
The DRAFT can hooks up two ways:
1. This is spliced directly in-line of the stock PCV system between the intake manifold and stock pcv return.
This catches oil normally consumed by the PCV (dirty side) and gives some crankcase pressure relief. Because it relies on OEM PCV regulation; HP capacity is limited to 'near stock'.
2. For those that want to keep the breather closed when possible, but do not want to or can not hook up to the intake manifold;
the PCV system is completely deleted, and this can is connected only between the engine and your main air filter. This is high flow and can handle a lot of HP but also recirculates more of the fumes directly to your engine as part of total air supply. The amount of DRAFT can be influenced by clean side fitting selection and vac/restriction generated by your air filter.
The PCV can is the max effort bells and whistles fix for people who want a PCV system and high HP.
Clean air still comes into the crankcase to filter out particles/fumes/moisture during regular driving and is constantly scavenged back out by intake manifold vac (just like stock).
We block boost from entering the can / engine, we catch the oil before it is consumed, we relieve any crankcase pressure created from high HP, and we recirculate very little of these fumes during full load, so the engine can make power with as much clean fresh air as possible. Because of the special configuration; we are no longer 'restricted' by the factory system, and can connect to the crankcase with full-flow or multiple fittings to accommodate high hp.
all of my wild kits (above included) use the PCV can
I believe that answers the questions. It would be a really silly move for me to ship so many of these if I had not thought of the simple things like a vacuum or boost leak wouldn't it You can also see / believe it for yourself by simply trying to blow into the catch can from the intake manifold side to test the boost protection, or suck / blow from the crankcase side to test the one way pressure control.
So, David - you're telling us to suck and blow in order to satisfy our curiosity? I think I'll just install my MM can and take your word for it. Looking forward to installing mine this summer. Thanks for the explanation.
So, David - you're telling us to suck and blow in order to satisfy our curiosity? I think I'll just install my MM can and take your word for it. Looking forward to installing mine this summer. Thanks for the explanation.
LoL!
I get asked 'how do I know it is working' so there is the answer.
Much easier to do that then have all the testing equipment I developed for the real tests!
I get asked 'how do I know it is working' so there is the answer.
Much easier to do that then have all the testing equipment I developed for the real tests!
David, would there be any benefit (or negative effect) in teeing the valley port into the catch can with a check valve to prevent boost entering the valley port?
Or if not into the catch can, maybe into the air intake?
David, would there be any benefit (or negative effect) in teeing the valley port into the catch can with a check valve to prevent boost entering the valley port?
Or if not into the catch can, maybe into the air intake?
The valley plate on c7 has a fairly good seal under backfire/boost in stock form compared to previous gen, so you could do that if you wanted.
But while it is true that air shared between two hoses would move slower than the 10an by itself (speaking of the wild kit). it does not seem to pay off in any tangible fashion thus far from myself or customer reports.
If you needed additional volume I would run both independently to the can (my PCV can), and gut the pcv valve so that it does not restrict outbound crank flow. Mounted direct to the can it is also already boost protected by my PCV. I would rate that dual inlet setup at 1500hp capacity.
As seen here leaving the dry sump side alone and doing the 10an/1khp 'wild' is working perfectly for me around 1kwhp through the A8.
The valley plate on c7 has a fairly good seal under backfire/boost in stock form compared to previous gen, so you could do that if you wanted.
But while it is true that air shared between two hoses would move slower than the 10an by itself (speaking of the wild kit). it does not seem to pay off in any tangible fashion thus far from myself or customer reports.
If you needed additional volume I would run both independently to the can (my PCV can), and gut the pcv valve so that it does not restrict outbound crank flow. Mounted direct to the can it is also already boost protected by my PCV. I would rate that dual inlet setup at 1500hp capacity.
As seen here leaving the dry sump side alone and doing the 10an/1khp 'wild' is working perfectly for me around 1kwhp through the A8.
Great can David & again thanks for all the help on your set up buddy.. Robert
05-27-2017, 03:21 AM
Would a vented catch can connected to the intake manifold cause a boost leak?
Look at the pic of the hook up that the stock air box ha from his drawing. Robert
You can also see / believe it for yourself by simply trying to blow into the catch can from the intake manifold side to test the boost protection, or suck / blow from the crankcase side to test the one way pressure control.
I think I'll just install my MM can and take your word for it. Looking forward to installing mine this summer. Thanks for the explanation. 