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G37 oil catch-can Gurus with 3" intakes in the group help a brother out!! Recently got tuned and have 3 inch intakes so I lost my ccv port to the intakes. I had full plans to do dual catch cans but was running short of time so I installed a temporary pcv delete setup for my tune day. By temporary I mean capping the rear CCV ports (ones that attach to your stock intakes), capped both front intake manifold ports, and installed a drilled out aftermarket PCV valve I bought from Amazon where the oem PCV valves were on the front ports and clamped on a filter on both PCV ports. Car idled fine even before tune.
Then after I finished the tune I got around to installing my catch cans. Removed the drilled out aftermarket PCV valve I previously installed and re installed the oem valve and hooked up my cans. Tried starting the vehicle and it just struggled to idle and died very quickly. My catch can routing is shown in the first picture. "In" port on can is connected to PCV valve and "Out" port on can is connected to intake manifold. Rear CCV ports have hoses going to a breather filter.
Tried this same combo with the front oem PCV valve swapped out for the drilled out aftermarket one and the car idling would rev up from 2k-3k over and over but not die and shut off. When I turned it off I checked the cans and they were close to being full for only idling for around 5-7 minutes.
I've seen setups with 3 inch intakes where you cap the intake manifold ports, run hose from the CCV port to can and other hose from PCV port to can but those setups had a breather filter on top the can. I tried to install that setup first before anything but couldn't for the life of me, even with several different sized mounting brackets, find a location for the cans where I could fully close the hood so it wouldn't smash the breather filter on top of catch can.
**1st photo is my current setup
**2nd photo is from someone else's setup with Stillen 2.5" Long Tube Intakes not 3" so they retained their CCV connection to the intake pipe.
**3rd photo is from another person's setup with 3" intakes like me (I've installed mine exactly like this guys setup) not sure if they kept oem pcv valve installed or replaced with aftermarket drilled out valve.
If you want to use Catch-cans with PCV valves then you must keep the rear ports open, either vented with filters or drill/weld a bung on your intakes to run like factory. With the rear port capped, and when the pcv valce closes, it creates a very big vaccum. I made the mistake of capping my rear with the pcv valve up front and it pulled my oil out of my oil pan and caused my oil light to come on.
If you want to vent your front ports like how you did before/during your tune, you cna keep your rear port capped. But I think its best to vent all 4 fours if that's the setup you want to go with.
I have 3" intakes and requested my intakes to have the port welded to maintain the factory setup. its my current setup.
This is my old 3" setup where I drilled a hole and used a thread plastic barb to make the port.
Project Panda thanks for the help. So I noticed in your pics the catch can hose connections changed from old setup to your current. Is there a reason you switched input and output ports on cans?
Also so If I'm understanding you correctly, if I want to use my catch cans and no longer utilize the rear port(CCV) because I don't want to weld/drill/tap my intakes what should I do differently than what i already tried?
Like shown in my picture of my setup as well in my post I mentioned I hooked up inlet side of can to PCV and outlet side of can to intake manifold. I attached a small chunk of hose to rear port(CCV) and attached a breather filter. I tried that setup with OEM PCV valve with spring/check valve still intact, as well as tried the same setup but with a drilled out aftermarket PCV valve installed where the OEM one was ooriginally.
OEM PCV valve made the car die at idle and drilled out PCV valve allowed the car to stay idling but kept ramping up from 2k-3k and almost filled both catch cans after only a few mins.
Originally Posted by projectpanda13
If you want to use Catch-cans with PCV valves then you must keep the rear ports open, either vented with filters or drill/weld a bung on your intakes to run like factory. With the rear port capped, and when the pcv valce closes, it creates a very big vaccum. I made the mistake of capping my rear with the pcv valve up front and it pulled my oil out of my oil pan and caused my oil light to come on.
If you want to vent your front ports like how you did before/during your tune, you cna keep your rear port capped. But I think its best to vent all 4 fours if that's the setup you want to go with.
I have 3" intakes and requested my intakes to have the port welded to maintain the factory setup. its my current setup.
This is my old 3" setup where I drilled a hole and used a thread plastic barb to make the port.
Project Panda thanks for the help. So I noticed in your pics the catch can hose connections changed from old setup to your current. Is there a reason you switched input and output ports on cans?
Also so If I'm understanding you correctly, if I want to use my catch cans and no longer utilize the rear port(CCV) because I don't want to weld/drill/tap my intakes what should I do differently than what i already tried?
Like shown in my picture of my setup as well in my post I mentioned I hooked up inlet side of can to PCV and outlet side of can to intake manifold. I attached a small chunk of hose to rear port(CCV) and attached a breather filter. I tried that setup with OEM PCV valve with spring/check valve still intact, as well as tried the same setup but with a drilled out aftermarket PCV valve installed where the OEM one was ooriginally.
OEM PCV valve made the car die at idle and drilled out PCV valve allowed the car to stay idling but kept ramping up from 2k-3k and almost filled both catch cans after only a few mins.
i swapped the ports after realizing I wanted the outlet hose to the engine be the filtered port in the can. The inlet port is an open port into the can. I have metal mesh wire inside the can also.
you are pulling much more oil into the cans with the drilled out valve because during high vacuum it’s pulling up the oil. The front ports need the check valve if being used with the vacuum ports.
otherwise keep all vented to atmosphere if not using a PCV valve.
Okay so are you saying the way I had it hooked up originally with the oem pcv valve installed still and a hose with a breather filter on the rear ports should've worked?
Car didn't stay idling long and kept dying. Any advice to correct that? I don't suppose switching around my hoses to how you changed yours would make any difference in proper idle.
I understand how to do the pedal dance idle relearn but since the car kept dying after a few seconds it wouldn't stay running long enough to perform an idle relearn to see if that would correct the weird idle. Also I double checked all my hose connections to ensure they were all tight of course. I thought maybe vacuum leak was the issue at first.
Thanks again for the advice.
Originally Posted by projectpanda13
i swapped the ports after realizing I wanted the outlet hose to the engine be the filtered port in the can. The inlet port is an open port into the can. I have metal mesh wire inside the can also.
you are pulling much more oil into the cans with the drilled out valve because during high vacuum it’s pulling up the oil. The front ports need the check valve if being used with the vacuum ports.
otherwise keep all vented to atmosphere if not using a PCV valve.
Any time you use the intake or intake manifold in conjuction with a catch can it has to see two types of parameters:
1 Manifold vacuum with a controlled valve (PCV)
2 Controlled entry/exit (breather)
If you have intakes that dont come with a breather input:
You can delete the vacuum source going to the pcv but will have to gut the PCV and have the can collect whatever the PCV lets out. The other hose has to vent to atmosphere.
You can drill your intakes and have them perform like factory and place the can in between the pcv so it filters these gases (Breather gases are not that significant)
The issue is that the cans you bought are meant for recirculating systems. The first configuration would have worked if you connected the breathers to the intakes. Since you dont want to do this a breather filter and gutted PCV with a capped manifold will work.
If you had a two port catch can you could route the PCV and breather to the can and have the third port on the can with a breather filter so it can ventilate the gasses coming out of both ports of a valve cover.
09-29-2022, 04:38 PM
