Oil catch can - using T to connect PCV and breather???

[tsi1991awd]

So I'm installing a catch can that I made from a Husky filter element used for air compressors. It has one in and one out on it. Can a T fitting be used to connect the PCV and breather hoses and then have one hose into the IN portion of the catch can?

I'm not sure if the T will interfere with oil flow into the can (if any oil comes out at all) that is my main concern.

 

[fuzzydoodle]

Are you re-circulating both back to the intake manifold? I dont see why a t would be a problem, as long as it is a decent sized one it should not clog, plugging off the nipple on the intake tube would be needed.

I have the same "catch can" only on the VC to intake, I am going to put a separate one for the PCV to intake manifold as soon as I gather motivation. Which could be a while. But proper maintenance on the PCV valve "should" eliminate that concern.

 

[tsi1991awd]

The way I have it set up is there's the breather hose going to a 3/8 brass T fitting. I have a 1/8 brass barb fitting in the valve cover where the PCV valve was....running hose to the T fitting. Running a hose from the 3rd nipple of the T fitting to the IN portion of the filter element, and running a hose from the OUT portion to the intake manifold (where the PCV would usually connect.

 

[No_Skillz]

This setup has the same effect as venting both PCV and VC breather to atmosphere. Keep in mind that you have lost the circulation functionality of the OEM setup, which requires more frequent oil changes due to faster motor oil contamination.

 

[tsi1991awd]

I ran into a problem using that setup. Installed it today and took it out and I'm guessing it couldn't release pressure fast enough because I saw a puff of smoke and then went straight home, popped the hood and there was oil sprayed all over the bay. The dipstick blew out.

So I crimped the dipstick tube just a bit for a tighter fit and just put a breather filter on the breather nipple. The PCV is going to the Husky air filter element and then that is going to the nipple on the intake manifold.

Hopefully that helps out a bit.

 

[No_Skillz]

That won't work. Your PCV is open under vacuum (idle, anything not boost), and will pull in unmetered air if your VC breather is open. You need to connect the VC breather to the intake somewhere after the MAF but before the turbo if you want to do this. (OEM Setup)

Furthermore, remember that your PCV catchcan will be seeing the same pressures as your intake manifold. You could use a checkvalve or simply make sure that your catchcan can hold the pressure without leaking.

 

[kenamond]

When the IM is at vaccuum, the PCV opens and ***fresh*** air is pulled from the intake pipe, through the VC breather, into the crankcase, out the PCV and into the IM. This is what the "V" in PCV means: ventilation. Under boost, the PCV closes (it's a special check valve), and all the blowby past the rings exits through the VC breather into the intake pipe.

The PCV valve is also a metering orifice. At idle, it lets a specific amount of air through. If you get rid of it, you probably have to futz with your BISS to get a good idle.

If you eliminate any of that system, you're defeating its purpose. If you don't have a PCV valve that closes under boost, you boost your crankcase, and the dipstick tube pops and sprays oil all over the place. If you leave the VC breather open to atmosphere, the air that gets sucked in at vaccuum (idle, light cruise, when shifting) is unmetered and you run lean for a bit.

The "correct" way to do it is to put an in-line catch-can on the VC breather that has one inlet and one outlet, no others. And on the PCV-to-IM line, install a check valve from USplastics in the line and then put a catch can (one inlet, one outlet, nothing else) between the PCV and the check valve. The check valve keeps the you from boosting your catch can, and it acts as a backup for the PCV when it craps out and starts leaking under boost. You can't use a single catch can for both unless it's a two-chamber model with completely segregated chambers.

If you're bored, search for the thread by FORMONTOYA with a title like "Stupid PCV question". It's long, but it goes over all the wrong ways as well as the correct ways. It'll also have a lot of part numbers and links for catch cans and check valves.

 

[tsi1991awd]

Then why do people use the catch cans from JM Fab or RRE? All they are is a can with a breather filter. Both the PCV line and breather line go to the can and the port on the intake manifold is blocked off. THAT serves no purpose whatsoever.

Also I did notice one thing, after I got rid of the breather to the intake tube and the PCV, there was no smoke coming from my exhaust. It used to smoke all the time, when it first started up it would smoke a lot and then after it warmed up, it still smoked but not as much. Now there is no smoking.

What is wrong with doing it the way I did? From what I understood the PCV was mainly for emissions

 

[No_Skillz]

Some people get route both PCV and VC breather to atmosphere because they don't need the fresh air circulation function (think purpose built drag that get their oil changed every run). Others either don't have the foresight to see long time effects or just don't care.

Keep in mind that dumping both to atmosphere prevents crank case pressure due to blowby from the rings - one of the purposes of the original system.

Your smoking issue could be from any number of problems such as burning oil or a boost/vac leak. It should be troubleshot once other systems are set up correctly or in a manner which you intend to keep.

 

[Dsmj89]

I suggest you go to home depot, buy 2 husky air compressor inline filters for catch cans with their fittings, and connect one from the vc to the catch can, to the intake and the other from the pcv valve to the catch can to the intake manifold. Make sure you take out the filter inside for proper ventilation inside the can.
I am currently using this setup on mine and there is no ill effect. http://www.dsmtuners.com/forums/hangout/318310-new-95-gst-5.html
It's a good cheap mod that will do the same thing as those expensive name-brand catch cans for half the cost, and the best part is you're still following the oem flow path of the lines, only with a can in the middle to catch that sludge.

 

[No_Skillz]

This is the correct way to do it if you want to keep all OEM functions. It's how I have mine set up as well. The only downside is that it's a bit more clutter.

However, I chose to keep the tiny filter element. The inlet and outlet in the canister is divided with the filter. Without it they are very close together and it would defeat the purpose if oil got through. Besides, with the filter and after 10k+ miles, it's still very free flowing.

I installed a checkvalve between the filter and IM at the PCV side to eliminate any possible boost leaks. Thinking about it now, I could probably eliminate the PCV altogether with this setup in place...

 

[tsi1991awd]

Can one of those Fram G2 filters work instead of the Husky when connecting the breather to the intake?

Also, what about the PCV line...I have a 1/8 barb fitting. I had to tap the PCV hole....is there an ill effect running that bard fitting to the catch can, then to the IM?

 

[Dsmj89]

I wouldn't suggest using the fram filters, i tried this route once and i got so much blow-by you won't imagine, my oil dipstick would always pop out and it was a p.i.t.a. to clean up the oil spill under my hood and around the bay.
Leave your pcv valve in place, you don't want to tamper with your factory pcv system, otherwise you will be defeating the ventilation purpose of the system as stated above.
Just run the setup as i posted and you will be just fine.

 

[tsi1991awd]

When using the Husky filter element, there is an IN and an OUT. Do you connect the valve cover breather to the IN portion, then put the OUT hose on the intake or what?

 

[Dsmj89]

Have the arrow on the top of the catch can pointing to the vc.

 

[tsi1991awd]

So the hose from the intake to catch can will go on the IN portion and then the OUT will go to the VC. Got it.

If air flows in that direction, then why does oil end up in the intake tube? There is a film of oil in my intake tube and if I take off the upper intercooler piping there is a bit on the metal part that has the BOV connected to it and a bit on the lower portion of the UICP....I think that's from the VC blowing it into the intake. Why would that happen if the airflow goes from the intake to VC?

 

[Dsmj89]

The airflow goes from the intake to the vc under vacuum only, after that, when boosting it is reversing the airflow pattern from the vc to the intake, and there you have your reason for the oily build up on your intake/intercooler pipes/intercooler.
Hope it made sense the way i put it.

 

[tsi1991awd]

So then what is the PCV doing during that time? I assume it is pulling air at vacuum and when boosting it is pushing air into the crankcase and it exits through the breather?

 

[Dsmj89]

It's not so much pushing air, more like it's getting air pulled out. When you start to build boost, the pcv valve shuts closed, and then a new airpath for ventialtion is opened = the intake, and when coming to a stop, the pcv valve path is re-opened, and vice-versa.

 

[No_Skillz]

No, the V in PCV stands for valve. It closes under pressure and should not introduce any pressure into the crank case.
[It stands for "Ventilation"]

If you only have a barb, you definitely need a checkvalve in place.

I don't remember which way the arrow faces on the Husky canister, but I have VC breather going into the fitting which empties OUTSIDE of the filter ring, intake connects to fitting leading into the INSIDE of the ring. This way oil builds up in the canister and not in the space inside the filter.

 

[tsi1991awd]

I have a barb, and I'd like to keep it because I already tapped the hole and it's going to be a bi*** to get anything else in there....where can I get a checkvalve and what is a good one to get?

 

[No_Skillz]

Anything similar to: Check Valves - US Plastic Corporation

They are cheap and hold pressure very well. I have mine installed IM > checkvalve > catchcan > PCV so the catchcan never sees pressure. You'll want to consider an upgrade if you run more than 150psi.

 

[tsi1991awd]

They are cheap and hold pressure very well. I have mine installed IM > checkvalve > catchcan > PCV so the catchcan never sees pressure. You'll want to consider an upgrade if you run more than 150psi. [/QUOTE]

So I can just get the 3/8" one and be good...sine I'm running 3/8" hose? Also, what did you get, the PP or Kynar? And one last thing, which way does the valve install?

 

[No_Skillz]

I honestly don't remember and I don't think it matters. Size is up to you - matching hose size is good. The valve needs to be installed so that flow is the same as PCV. It should allow air to flow toward the IM but stop air flowing into the crank case. Just blow into the valve to find out which way it flows.

 

[tsi1991awd]

I just bought another one of those husky filters and installed it from the intake to the VC breather. Now I have two.

Does Home Depot carry those check valves? The only reason I ask is because I don't know if it will have an ill effect running my car without the check valve for a week or so until the valve arrives.