2G How to run oil catch can

[Ramsey91]

This is probably gonna be a dumb question but I’ve been trying to search and find the answer and haven’t.

How should I route my catch can? This is the setup I’ll be doing for SD and you can see both hoses coming from valve cover. Closest side of catch can is the in and other side is the out. This will be vented as well, just want to keep the filter clean for now.

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[Dericsh]

That catch can looks sealed, unless I’m missing something?

You can’t just hook those two hoses together, you need to pull the vapors out with a vacuum source. One solution is to order a second matching can and set them up like the following diagram.

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Check this thread out for a good read about other options,

https://www.dsmtuners.com/threads/pcv-oil-catch-can-setup-need-some-advice-on-an-install.457953/

 

[Ramsey91]

This is probably gonna be a dumb question but I’ve been trying to search and find the answer and haven’t.

How should I route my catch can? This is the setup I’ll be doing for SD and you can see both hoses coming from valve cover. Closest side of catch can is the in and other side is the out.

That catch can looks sealed, unless I’m missing something?

You can’t just hook those two hoses together, you need to pull the vapors out with a vacuum source. One solution is to order a second matching can and set them up like the following diagram.

You must be logged in to view this image or video.

Check this thread out for a good read about other options,

https://www.dsmtuners.com/threads/pcv-oil-catch-can-setup-need-some-advice-on-an-install.457953/

It’s vented I just have the filter still in the package to keep it clean until the car is ready for tuning and the bolt is in in the top keep stuff from getting inside.

That why I’m wondering exactly how to route it for flow. unless I still need two cans. I also won’t have an intake coming off the turbo

I’m trying to run this setup

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[Dericsh]

I’m not sure what your goals for the car are, but that is going to be an ineffective setup. There’s a lot of info on the PCV system, how it works, and how different catch can setups work in the following article, which was also referenced in the thread from my previous post.

The 4G63T PCV System

IntroductionWith very few exceptions, no topic generates more debate than the PCV system used on our turbo DSMs. I think it is mostly because of the huge amount of confusing and sometimes misleading information that has been posted in the forums over the years. It is for this reason that I...

www.dsmtuners.com

 

[CKOPOCT]

As you'll see in the very thorough writeup, you need to actively draw the air out of the crank case. Just blocking off the intake manifold (non-boost vacuum source) and the pre-turbo inlet (boost vacuum source) means your engine isn't having the gasses actively drawn out. Sure, if the catch can is vented that'll mean you won't blow your dipstick out of the tube... but it will still leave combustion and moisture nastiness in the head and block, creating an acidic and moisture environment that will be bad for your engine over time.

With the intake operating under both vacuum and positive pressure, a standard PCV setup won't work. The diagram @Dericsh posted is the best catch can setup for a boosted car. The writeup shows a single can option, but it doesn't do as good a job because it only focuses on one side of the vacuum/boost equation.

Running Speed Density doesn't affect the routing of the catch cans.

 

[Drakart1z]

Keep your pcv system hooked up to vacuum and a check valve in-line. You’ll thank yourself very soon

I’m running stock pcv with a check valve so under boost it doesn’t push boost into the valve cover. I’m running 24psi. Before the check valve I would blow my dipstick out. Now with the valve it doesn’t even think about it.

 

[Ramsey91]

I’m not sure what your goals for the car are, but that is going to be an ineffective setup. There’s a lot of info on the PCV system, how it works, and how different catch can setups work in the following article, which was also referenced in the thread from my previous post.

The 4G63T PCV System

IntroductionWith very few exceptions, no topic generates more debate than the PCV system used on our turbo DSMs. I think it is mostly because of the huge amount of confusing and sometimes misleading information that has been posted in the forums over the years. It is for this reason that I...

www.dsmtuners.com

Thank you, I’ll follow your advice and read up on this

 

[Ramsey91]

As you'll see in the very thorough writeup, you need to actively draw the air out of the crank case. Just blocking off the intake manifold (non-boost vacuum source) and the pre-turbo inlet (boost vacuum source) means your engine isn't having the gasses actively drawn out. Sure, if the catch can is vented that'll mean you won't blow your dipstick out of the tube... but it will still leave combustion and moisture nastiness in the head and block, creating an acidic and moisture environment that will be bad for your engine over time.

With the intake operating under both vacuum and positive pressure, a standard PCV setup won't work. The diagram @Dericsh posted is the best catch can setup for a boosted car. The writeup shows a single can option, but it doesn't do as good a job because it only focuses on one side of the vacuum/boost equation.

Running Speed Density doesn't affect the routing of the catch cans.

Appreciate the info. That helped me understand it a lot more.

And only reason I thought that was because I wasn’t planning on doing an intake on a 20g but I’m using my gt30 instead so I’ll be keeping the intake.

 

[Blakedwight4]

Keep your pcv system hooked up to vacuum and a check valve in-line. You’ll thank yourself very soon

I’m running stock pcv with a check valve so under boost it doesn’t push boost into the valve cover. I’m running 24psi. Before the check valve I would blow my dipstick out. Now with the valve it doesn’t even think about it.

Can you post pics of where you have the check valve and specify the direction it’s facing please?

 

[steve]

Can you post pics of where you have the check valve and specify the direction it’s facing please?

I'll point you to https://www.dsmtuners.com/threads/the-4g63t-pcv-system.366890/ just like was done for the OP in post 4. If you don't understand after reading it let us know what you don't get.

 

[Blakedwight4]

I'll point you to https://www.dsmtuners.com/threads/the-4g63t-pcv-system.366890/ just like was done for the OP in post 4. If you don't understand after reading it let us know what you don't get.

I understand via the diagrams the direction, but is it recommended to place check valves between valve cover and intake, AND one between pcv valve and part of the intake past throttle body? Side note I do not have a catch can setup.

 

[steve]

I understand via the diagrams the direction, but is it recommended to place check valves between valve cover and intake, AND one between pcv valve and part of the intake past throttle body?

A functioning OEM PCV is part check valve and part metering oriface. Problem is the typical replacement PCV today doesn't do such a great job at being a check valve so you might need a check valve in-line to keep boost from filling up the crankcase and blowing out the rocker cover into the turbo intake.

You shouldn't need a check valve between the rocker cover and the turbo intake. When the engine is working off boost the flow should be from the air filter to the rocker cover through the PCV to the intake manifold picking up any vapors from the crankcase in the process.

Under boost you have to seal off the intake manifold path but any crankcase pressure had to go somewhere and the flow reverses to exit via the turbo intake (which is a low vacuum source). Since the direction changes you can't really put a check value between these two.

I don't have any experience with directional catch cans but that's what the example with multiple check valves is for.