Catch can installation woes

[manikbastrd]

So I have spent a while searching around and looking at the different options for catch can installation. There are some who remove their PCV and run a sealed can some who leave the PCV and have the can inline with the intake and valve cover, and there are about a million different setups in between. Some run the vent tube to a can some don't.

I don't really understand the point of a lot of them so I would like to revisit the GVR4/DSM gods with this question. I have a sealed Mishimoto catch can that has two ports. I want to run it on my GVR4, which is mostly stock now, but will be running a Dejon intake with a 2G MAF in the near future. I know that I can either run:
VC vent port to the CC, and then plug the other port
VC Vent port to the CC, and run the PCV tube to the other port, and block off or otherwise use the manifold (vacuum/boost) port.
PCV to CC to Intake (not manifold) port

Right now I am reading this post >>> click and it seems to be the best explanation.

Basically I would like to know how other people have run a sealed catch can to best minimize the oil going into my turbo and I/C piping.

Thanks in advance for the help!

 

[SleepinGVR4]

I run one of these....

http://www.saikoumichi.com/DC3_page.htm

If I remember correctly, I have to double check, one catch can gets a vacuum source on one end and the PCV valve is on the other end.

The other catch can has the valve cover breather on one end and the other end goes to a barb connected to my intake.

 

[manikbastrd]

Seems like for my setup, in order to minimize oil in my intake, turbo and I/C I should run the can in between the valve cover vent and the intake bung. I don't know how exactly I will accomplish this when I upgrade to the Dejon intake that has no bung for it, but I guess I will tackle that beast when it comes to it.

I am still a tad bit confused on the fact that I am running something into my intake after the MAF, which seems like it would cause me to run slightly lean since I am not metering the flow from the VC into the intake side (under boost). However if I ran it before the MAF, under vacuum I would probably be screwing with the MAF as well. Maybe I should run a check valve so that under vacuum the only flow out of the VC is into the intake manifold, and during boost the only flow is through the catch can into the intake tube? Alternately, now I am thinking that I could put a filter on one of the catch can ports and block off the intake tube port, however I would lose the vacuum applied to the catch can when the turbo is pulling air in.

Would anyone be able to weigh in on this portion of the topic???

 

[manikbastrd]

Quoting SleepinGVR4:
I run one of these....

http://www.saikoumichi.com/DC3_page.htm

If I remember correctly, I have to double check, one catch can gets a vacuum source on one end and the PCV valve is on the other end.

The other catch can has the valve cover breather on one end and the other end goes to a barb connected to my intake.



I like this setup and it makes a lot of sense!

 

[tektic]

Quote:
I am still a tad bit confused on the fact that I am running something into my intake after the MAF, which seems like it would cause me to run slightly lean since I am not metering the flow from the VC into the intake side (under boost).



If the air is in the valve cover it is all ready metered.

Directly after the maf before the turbo will never see pressure only vacuum.

 

[SleepinGVR4]

Like the man above said. The vacuum from the intake helps the breather on the valve cover work properly.

I did a lot of research before I installed the catch can. Its set up like it would be stock while keeping oil from getting back into the intake.

 

[vr4play]

I bought a catch can from Calan on tuners. They are baffled and filtered. He makes them for different setups. I have 2 -10 AN lines going from my VC to my catch can and then one large -12 to the intake before the turbo. It pulls a decent vacuum under boost. I didn't worry about the line from the VC to the intake manifold to much although I have been thinking of adding a catch can there as well. I did put a check valve inline there to keep boost out of the crankcase as the factory pcv valve is a POS.

 

[CutlassJim]

First step before modifying anything ever should be understanding how and why the system works the way it does. Doing anything just because other people do it is a sad way to go through life. ( Not aimed at you)

You would want to keep the systems exactly like stock but with a SEALED catch can between both lines. This requires two catch cans. That's why they make a dual can.

When you get a different intake pipe if it doesn't have a bung on it weld one on. Heck weld two on and add another port to the valve cover and upgrade the performance from stock.

 

[manikbastrd]

Thanks for all the replies folks!

CutlassJim, I agree completely. I am not a fan of modifying for the sake of modifying. I wanted to install a catch can in order to prevent my I/C piping and intercooler from loosing efficiency due to oil coating.

I actually took care of this tonight, got the catch can installed in between the V/C vent and the intake tube port. I mounted it where my Cruise Control unit was (removed tonight as well and replaced the cable with a non-cruise cable). I am not happy with the way I had to run the hoses. I need to find new fittings that will work for the smaller size hoses I am using compared to the ones provided by Mishimoto. I am also looking into ways to baffle the catch can such that the oil and moisture is captured while minimizing the chance of fluids re-entering my intake system. I also plan to install an additional check valve in between the PCV and intake manifold.

Thanks again for all the useful information that has been provided!!!
-Manik

 

[Tre3zy]

i got one custom made...

 

[cheekychimp]

^^^ That's very nice. You've been making some pretty classy mods to that car recently.

 

[paul j]

I am getting ready to put 1551 back together. As some of you recall I tore it apart last fall. A catch can is one of the items I have been considering installing. Do they come on any factory turbo car of any make? Does the oil in turbo system only happen at higher than factory boost? If so what is high? I had oil in all my tubing and the engine was original and had good power, at least to my mind. Are they of any benefit on a dd cruising around town with boost very intermittently applied?

 

[manikbastrd]

I can't say whether any stockers have catch cans, but I can guarantee you that at stock boost you will get oil into your intake system. In the hopes of keeping it clean, yes it has it's benefits, but you have to do it right. I ended up doing mine from the factory vent on the passenger side, and then routed it back to the intake. This only works if the catch can is not vented. You want to minimize the amount of unmetered air getting into the system. I support catch cans 100%. I reccomend a dual catch setup as mentioned above, one for Pcv and one for the vent. If you ever take off your throttlebody, you will notice the ridiculous amount of oil and carbon built up in the intake manifold...in summary, definitely worth it, get a dual catch setup. Do it right!

 

[coyotes]

Where did you route the PCV catch can back into, the intake also? Which catch cans did you use?

 

[manikbastrd]

I just did a can for the V/C vent, to the intake. I haven't found a good setup I want for the Pcv yet. Once I find a good dual can setup I will run it though.