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So How Do I Want To Setup My Catch Can?

Hadouken

By Hadouken,
in Engines & Forced Induction

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Hadouken Grand Master

Hadouken

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Hey SAU'ers. I have been searching the web and there are so many different ways to setup a catch can.

Seeing as I do not completely understand the breather hose setup, this seems a bit confusing and frustrating to me.

I have mocked a picture of what I think is a suitable setup.

Can one of you please guide me in the right direction?!

The green dots are where I think I should remove the hoses and block them off. But then it dawned on me, how does the catch can release pressure?! I know that venting to atmosphere is illegal. So how do i keep it as legal as possible?

Any help/guidance is much appreciated.

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Hanaldo Grand Master

Hanaldo

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If you block the PCV then you vent to atmosphere. If you leave the PCV functional then you plumb the catch can back into the intake pipe. My advice is to leave the PCV functional...

75coupe Grand Master

75coupe

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rb25 has PCV running of the throttle side cam cover, doesnt it...

when I replaced the rb25 camcovers for rb26 ones I installed an atmo catch can...

If I were to block the atmo vent on the catch can where would I plumb that back too???

Aggroman Grand Master

Aggroman

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if the catch can is properly baffled (ie it catches any oil in the vapour and drains it to the bottom) you can run a 3rd line back to the intake port..

Basically like this in my crappy 30 sec paint job, and then a return line plumbed back into the sump unless you like removing it every now and again to drain the oil buildup.. Or look up a nismo oil air seperator and do it the easy way :)

post-51757-0-71327300-1332321421_thumb.png

scotty nm35 Grand Master

scotty nm35

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Posted

Positive Crankcase Ventilation Valve, it sucks the oily gasses out of the rocker and dumps it into the manifold but only on vac.

I have a secondary sealed catch can for my PCV, it works well as I used to blow oil smoke on startup and now its clear. Keeps the manifold clean too.

Hadouken Grand Master

Hadouken

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if the catch can is properly baffled (ie it catches any oil in the vapour and drains it to the bottom) you can run a 3rd line back to the intake port..

Basically like this in my crappy 30 sec paint job, and then a return line plumbed back into the sump unless you like removing it every now and again to drain the oil buildup.. Or look up a nismo oil air seperator and do it the easy way :)

Lol, Damn nismo and their crazy prices.

OI hijackers, this is for rb26. answer my question first then you can continue

Thanks for the quick mockup.

But lets say there are only 2 ends on the catch can.

Hanaldo Grand Master

Hanaldo

Posted
Posted (edited)

But lets say there are only 2 ends on the catch can.

Then you need to block the PCV and vent to atmosphere and it's going to be illegal, simple as that. For it to be legal you need to have the PCV operational which requires a third fitting on the catch can to plumb it back into the intake.

Edited by Hanaldo
Hanaldo Grand Master

Hanaldo

Posted
Posted

Will this be efficient?

*excluding the breather though.

IMG_0196.jpg

No. The can needs to vent, whether it is to atmosphere or back into the system. I think you should read up on positive crankcase gasses. If the can can't vent then essentially what you are doing is blowing all this pressure into a sealed can, which will basically pressurize your crankcase until it pops your dipstick out and can vent.

The pressure needs to go somewhere, that's the idea behind the breather setup.

XKLABA Grand Master

XKLABA

Posted
Posted

post-36620-0-86205000-1332327099_thumb.png

this how i have done it, I turned the fittings on the cam covers to face each other and put a pipe to join them aswell as the catch can on the top of the engine, then capped off one of the outlets of that can and ran a hose from the other one to the front catch can then from there I run hose back around to the inlet of the back turbo with a T to run a hose to the PCV.

hope you can use something from this

Hadouken Grand Master

Hadouken

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Ah, I see.

So just move it to the right of that top pic.

Hook it up to the right side of the rocker cover and there where it goes to the intake. That should mean that it can at least breath and hopefully seperate the oil. correct?

SiR_RB Grand Master

SiR_RB

Posted
Posted

So the above catch can system would work if you block the pcv, the pic above has the pcv connected, and also running to a catch can who h vents to atmo?

Seems like alot of confusion when it comes to hooking one up properly

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