Purpose of an oil catch tank (can)

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Gold Digger
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Purpose of an oil catch tank (can)

Postby Gold Digger » Fri Jun 08, 2007 6:20 am

So, Eikon and I were talking, and discussing, about what the catch tank is used for and how it is installed and where the hoses are routed.

Here is my thought on it.

It's purpose is to remove/prevent as much oil blow-by from the valve cover breather lines that are routed back into the turbo inlet, just behind the MAFS.

It's supposed to be routed like this.

From the turbo side valve cover breather outlet to the catch tank inlet.From the catch take outlet to the turbo inlet behind the MAFS.

To look something like this.



So, is this correct, way off, close...help a couple of old guys out here and let us know what is right.


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krayton
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Postby krayton » Fri Jun 08, 2007 6:26 am

exactly right on.

BUT, you dont need it like that. they route it back to the intake for emissions reasons.

so you can just put the valve covers to the catch can, and have a vent on the catch can, then plug up the intake.

just remember that the valve covers need to breath.

i dont know why though, but i always hear SRs need their breather stuff all plugged in. i remember a friend saying he was losing power by having the catch can vented.

but all the aussie boards say you can open vent your catch can (on the rb). ive been doing it with no ill affects

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Re: Purpose of an oil catch tank (C33LaurelRacer)

Postby Eikon » Fri Jun 08, 2007 6:27 am

to follow up on this...

Does Blow-bye (the oil and air that seeps into the cylander head) have any harmful effects on the location you put it to? (pre turbo or intake manifold)


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Postby krayton » Fri Jun 08, 2007 6:33 am

pretty sure you dont want it to see boost

hopefully someone can chime in and check that

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Postby Bronze MFP » Fri Jun 08, 2007 6:58 am

idealy you'd want the hose that goes from the intake manifold to the left valvecover to rout to the catch can too, then block off the inlet at the intake manifold. if you have the breather from the catch can hooked up to your intake it has to be before the turbo so it will only see vacume. if its after the turbo it will see boost and will pressureize your head and that will negate the reason you have the pcv system in the first place

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Re: (krayton)

Postby Gold Digger » Fri Jun 08, 2007 7:10 am

Thanks for the input on this guys. Keep it coming if you have more.

And if anyone has pictures of an installed and functional catch tank, please post up.

I'm off to bed, so I'll check in later.

-Neal

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Re: (C33LaurelRacer)

Postby 300Plus » Fri Jun 08, 2007 7:49 am

yea thats exactly how you want it. And you DO want to have the line going back to the air intake (behind the maf) because that is what will suck the oil vapor out of the crank case. If you just vent the catch can it will work, but the big hp racers all agree that you want the crank case to be a lower pressure = vacuum

and you DEF don't want to let it see boost, it would push boost into the valve covers and crank case blowing gaskets and causing reverse blow by

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Postby Coolwhip » Fri Jun 08, 2007 10:39 am

Applying vaccume to the can creates better results. Also, a drain from the can to the oil pan is niffty to drain oil back into the system by the pickup and the flow of the crank will pull the oil (some what like how the oil drain line operates on the turbo).

There are some great technical write ups and practices when it comes down to the whole setup and routing of catch cans.

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Re: (Coolwhip)

Postby Bwana » Fri Jun 08, 2007 12:29 pm

Here are a couple links to old threads in the CA forum that Ryan has up in the FAQ sticky about catch cans... alot of ideas and info.

Thread 1

Thread 2

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Re: (Bwana)

Postby themadscientist » Sat Jun 09, 2007 12:18 am

I let mine vent straight to the atmosphere. Not saying it is better, It's just what I do. Both my RB and CA are this way.

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Re: (themadscientist)

Postby Shocker » Sat Jun 09, 2007 2:43 am

themadscientist wrote:I let mine vent straight to the atmosphere. Not saying it is better, It's just what I do. Both my RB and CA are this way.
same on my 25, I took the line that comes out of the intake cover on the side running a single -8 an line to my catch can that has a breather. Then connected the two valve covers like stock and my exhaust side has a breather on it.

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Re: (Shocker)

Postby 300Plus » Sat Jun 09, 2007 6:23 am

While we are on the subject, where did you guys pick up the fittings to replace the exhaust side valve cover fitting? I'm looking for a flat T instead of one that points up... that make since? I'll look for a pic

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Re: (300Plus)

Postby garage-c » Sat Jun 09, 2007 9:06 am

What I did on my 25 was take the fitting that points up and cut the bead off the forward facing leg. I then stuck the cut off end into the valve cover. This turns it into a flat T. Hope this helps.

-Ben

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Postby wawazat8402 » Sat Jun 09, 2007 2:32 pm

^^^Thats exactly what I did.

Not a great picture of what I did, but you can get the idea.


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Postby gawdzilla » Sat Jun 09, 2007 4:23 pm

the way you posted is how you would run a closed catch can. if you want to run an open one, block the intake like people are saying.

if you want to be budget, just run a hose to the GROUND.

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Re: (garage-c)

Postby Shocker » Sun Jun 10, 2007 3:16 am

garage-c wrote:What I did on my 25 was take the fitting that points up and cut the bead off the forward facing leg. I then stuck the cut off end into the valve cover. This turns it into a flat T. Hope this helps.

-Ben
gotta close up pic?

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Re: (Shocker)

Postby wawazat8402 » Sun Jun 10, 2007 10:06 am

Shocker wrote:
gotta close up pic?
I can try to get one up for you tonight or tomorrow.

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Re: Purpose of an oil catch tank (C33LaurelRacer)

Postby Kansei240sx » Sun Jun 10, 2007 8:20 pm

Venting a catch can to the atmosphere makes it completely useless......

The point of a catch can is to take the oil vapors created by the crankcase and ventilate it back to the intake before the turbo or throttle body. Doing so keeps junk or the black residue from collecting inside of the turbo or intake manifold. Well... reducing it. The vacuum created on the crankcase also creates a better seal on the valves and stems, actually creating a gain in horsepower, although not noticeable.

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Re: Purpose of an oil catch tank (Kansei240sx)

Postby Coolwhip » Mon Jun 11, 2007 1:40 am

that is why you hook up a 1 way check valve to you exhaust from your valve cover instead fo the intake. No oil back into your intake or plenium. And the exhuast creates more vaccume momentium that you end up with better sealing of the valves and rings plus some extra POWAH!

your bound to find an example some where

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Re: Purpose of an oil catch tank (Coolwhip)

Postby signalpuke » Mon Jun 11, 2007 1:54 am

Drop a piece of chain or something in the can to increase the surface area for the oil to cling to.Great write up for a $20 catch can. http://www.k20a.org/forum/showthread.php?t=10278

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Re: Purpose of an oil catch tank (signalpuke)

Postby Darius » Mon Jun 11, 2007 3:06 am

A lot of guys have used steel wool or something similar to increase the surface area for the oil vapor to stick to.

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Postby Coolwhip » Mon Jun 11, 2007 6:02 am

baffles with screens and such as people are saying knocks the oil out of the air thats passing through so that you can vent or release the air while retaining the oil. However, I will be using the screen to catch the oil and have it drain back to the pan since we all know our RB's love to leave that area rather "low".

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Re: (garage-c)

Postby 300Plus » Mon Jun 11, 2007 9:03 am

garage-c wrote:What I did on my 25 was take the fitting that points up and cut the bead off the forward facing leg. I then stuck the cut off end into the valve cover. This turns it into a flat T. Hope this helps.

-Ben
Awesome, lol I can't believe I never thought about that. since you are cutting off the barbed does it still press into the valve cover tightly ?

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Re: Purpose of an oil catch tank (can)

Postby Abaker13 » Sat May 18, 2013 5:50 pm

So im bringing back an old thread here because I have to figure this out on my RB20. I do not have a oil catch can on mine and one night while having it in the high RPMs it essentially snotted oil everywhere out of the said above PCV valve. So ive been looking into the catch can. So I hook up the catch can into the the PCV valve and then the other line goes back into the crank case? Does it matter which side? and does this mean I have to drill a hole into my crankcase cover? Thanx


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