Quick oil catch can routing question. What is more ideal? Running the catch can outlet in to the front of the intake manifold or into cold air intake tube? Which catch can set up is more effective? Or is it best to run a Y fitting coming from both PCV valves out of the engine into the catch can and then another Y connection out to both the intake manifold and cold air intake? If running the set up without The Y connection is it just better to run into the intake manifold or cold air intake tube?

 

If you're buying an assembled kit then it should detail everything out for the install.

 

unfortunately every kit I’ve seen (2 can set up) runs just the PCV. Instructions for all other 2 can set ups cover both the PCV side and the CCV but that is for engines unlike ours that have only one throttle body intake tube Intlet from the CCV and one intake manifold inlet from the PCV

 

Since our engines are normally aspirated and port fuel injected, the benefit of a catch can is small.

If I was to put in a catch can, I would connect it between the rear port on the valve cover and the intake.
This will help to keep the throttle body a little cleaner.

I wouldn't use a "Y" connection, as I believe there is a designed pressure difference between each bank..
Some have noticed the driver's side (bank 2) catch cans seem to fill up must faster than the other side. (bank 1)

 

If someone could post some pics and/or a diagram it'd be great! I know I see two "ports" for the hoses on the front of the plastic intake manifold, but I am guessing on where the "rear ports" are exactly on the valve covers?

 

From what I understand, it's where the 3/4" hoses from the intake pipes connect to (The two hoses that connect to the intake tubes a little bit before the TB).

 

This is from my rough understanding of the system, please feel free to correct me if I'm wrong. The purple circles are the PCV valves, the red circles are the breather ports (whose function I think is to provide fresh air to fill the cavities when the PCV system spurts out crank case gases). The grey circle in the back has equalizer hoses to balance the pressures inside the intake manifold.

 

Oh the purple circles are lower than they should be. Just follow the black hoses coming out of the intake manifold to reach the PCV valve. I accidentally circled the fuel pressure regulator on the left side.

 

The question here is if you want to use 1 or 2 catch cans.

Assuming you have a VHR the most simple setup would be 2 catch cans. You would essentially modify the oem system to filter the PCV gasses and send them back into the manifold.

For a single can, it would need 4 ports or a Y between the 2 PCVs to the single can and out the outlet towards the manifold where it would need another Y to enter into both ports.
Why both ports? each port goes to a single bank so both ports would be needed.

 

At this point, I think I've decided to forego the catch cans entirely and instead go with a PCV delete kit or something. Essentially just cap off the ports at the intake manifold/plenum and then run an external filter type setup on the valve cover side.

I'm sure some people will give me s*** for it or has negative opinions of such a setup;... but from what I'm finding in my research, it's not going to hurt anything on an NA setup.

 

supposedly the concern is the pcv/ccv system requires or at least benefits from having vacuum to help “suck” out the blowby and crank case pressure. I think this is more of a concern on the pcv ports.

i vent to atmosphere on the ccv (or whatever the rear ones are) and have the pcv go to a single 2 in port 1 out port can, then I Y the out port right before the 2 intake manifold ports. was pretty simple and cheap to setup.

 

The gasses will come out eventually, the issue is heavier fuel gasses wont. They'll mix with the oil and once they do it will take a good heated drive for the oil to evaporate them as well as suffering from diluting the oil as well. With the now added small pressure from removing vacuum means that any type of excess pressure (more than the vents can flow) will make it's way out somewhere.

If you owned two exact cars and vented all the gasses, you'd end up with leaking seals faster on the vented car than one with a proper working PCV.

It's just one of those multi purpose systems that unfortunately gets bad rep when these gasses enter the manifold and coat it in a film. Right of the bat you think it wrong/factory defect, etc.
Even expensive supercars have some sort of closed crank ventilation.

Not to sound apocalyptic but these are the results and the issue is that they happen over time. I've put 25k on my engine after doing the chains and you forget things after this time has passed.

 

That's awesome, can you share any pics of the setup? Or a diagram? lol

so you're recommending not to run any kind of PCV delete setup? Are you saying we should just all leave our cars with the factory PCV system as is? Or are you saying we should run a catch can instead?

Idk, I mean I hear what you're saying about even expensive cars having some kind of CCV system. My understanding of that is more related to emissions and maintenance than anything else? Meaning, it costs money for a manufacturer to design something that doesn't result in gunked up intake manifolds etc... especially with all these DI engines (like our VQ) out there... note: look up how many issues BMW 335 guys have with having to get their manifolds "walnut blasted" from all the gunk buildup...

So not only does it cost extra money if a car company wanted to design some kind of factory "catch can" setup, but it also increases the potential for added maintenance costs for the owner over time (i.e. having to check the catch cans, drain them, have regular interval checks, incorporated into a factory OEM warranty...)

Just because it's BMW or an expensive supercar manufacturer doesn't mean they design everything perfectly. This brings me to the next thing: emissions. I always wonder how much differently car companies might design vehicles if there were NO such thing as any emissions tests at all... like back in the day lol....

I just can't see a vehicle manufacturer company sitting around the drawing/engineering boardroom and actively all deciding that a PCV system that routes extra gunk back into the intake system to be a great idea for performance and longevity... It SEEMS much more likely that a PCV system is the compromise they have to deal with to remain compliant with our friends at the EPA and our current adminstration lol

 

EPS Tuning Open Breather Conversion Kit, VQ37VHR - Nissan 370Z / Infiniti G37 Q40 Q60

I was looking at this kit... turns out it's discontinued. Too bad. Looks decently made.

• Completely eliminates oil consumption through the intake tract as well as the ancillary octane reduction
• Helps keep ports/valves clean and free-flowing
• NEW dual 10AN PCV adapter fittings & lines maximize the venting area
• Ideal for NA engines - not recommended for use with FI engines
  

 

I also found this list of options from another forum I figured I'd share here:


Here are the typical options people use to approach this:

1. Catch Can in line with the PCV.
Pros:Retains PCV functionality.
Cons:Doesn't perform very well especially under high boost - oil just passes straight through. Works better for NA applications.
2. Breathers on valve covers
Pros:Deletes PCV completely
Smoother idle due to not having idle air weaving through the engine
Cons:Oil dirties up the surrounding area.
3. Breather on one Valve Cover. PCV still connected to other.
Pros:None
Cons:Vacuum Leak
Still pulling oil vapor
Worse gas mileage
Unmetered air.
This is bad. I don't know why so many do this but you are effectively drawing air through the motor without it going through the MAF.
4. Remote breather to both covers
Pros:Smoother idle, clean intake. Gunk pools in the can.
Cons:None