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Rb20det Oil Catch Can Setup?


32JEZ
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i have set mine up with the the hose from the manifold going into the the plenum side breather and that one still goes into the exaust side so the hose of that goes to the catch can then the return goes to the intake

if you ran the hose straight from the plenum into the intake pipe and then the two breathers straight into the catch can would they need an extra breather on the catch can with a little filter to stop the can pressureising

i was under the impression the hose from the plenum into the breathers forced possistive pressure through the breathers forcing the oil into the intake??? is this correct

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hey 32jez

this is how i've set my catch tank up.

hope it helps and its legal just had my car roadworthied with it and neat :ninja:

cheers

post-55765-1241211258_thumb.jpg

the roady doesn't mean shit if that bov was on it at the time of inspection lol. Another point i got pulled over on sunday and was told by the cop that catch cans are illegal altogether. apparently alters the way then engine operates lol.

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  • 2 weeks later...

for some reason i set up mine wrong (plenum ball bearing thingy blocked) and it started blowing a sh%t load of blue smoke. so definitely dont set it up that way. grrr now i know tho

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wannaslide, a better way, you should have all the pipes from the rocker covers run into one pipe that goes to the catchcan, then run a pipe from the catch can to the intake pipe. This will separate the oil/air a bit better. The way you have done it, the passenger rocker cover can pump oil straight to the intake pipe.

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grrrr.

even though mine is setup correctly now

it is still blowing enough blue smoke to fill the street?

makes me want to convert back to stock :rofl:

my catch can has a breather running up the middle and a top mount so i have blocked the top but not the bottom onel

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wannaslide, a better way, you should have all the pipes from the rocker covers run into one pipe that goes to the catchcan, then run a pipe from the catch can to the intake pipe. This will separate the oil/air a bit better. The way you have done it, the passenger rocker cover can pump oil straight to the intake pipe.

that is not a better way as you are halving the breathing capacity of your engine..

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roadworthied with with bov to atmo? always been an iffy one for me, never know with the cops.

on topic, is it better to drain to sump or see what ur actually usin?

Edited by Jason32gtst
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roadworthied with with bov to atmo? always been an iffy one for me, never know with the cops.

on topic, is it better to drain to sump or see what ur actually usin?

depends on engine and useage.. stock engine would barely put a drop in the catch can if driven on the street/ occasional track time.. other end of the scale, you have a built engine running big boost on a track constantly, this would need a drain back to the sump.

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Hey Guys,

Let me know what you think.

I have set it up so both valves from the rocker covers go to the inlet of the catch and the outlet of the catch splits to plenum and intake valves...

The dodgy red drawing is where the tubes arn't visible.

I am not sure if I am happy with the setup because as 45ULT said, I am halving the breathing capacity of the engine......but upon saying that, I am not going to vent to atmo cause I dont want to get yellowed....

Also, since I have installed the catch I notice a fuelly burning smell after giving the car a bit of a work out.....I am wondering if there is now positive pressure in the crank and because I have halved the breathing capacity and this could be causing oil to push past my seals?

Any input would be appreciated.

post-40125-1276520020_thumb.jpg

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wow....read a really interesting article about setting up a catch can on an RB20

http://forums.gtrcanada.com/gts-tech/t-diy...tion-51506.html

'The point of having a catch can is to separate oil from blowby gas. The reason why is oil affects octane of fuel that affects how much ignition timing you can run. More ignition timing + lower octane fuel = engine knocks.

The way the factory PCV system works -

PCV valve on intake manifold is open at idle and when engine is under vacuum. PCV valve closes as engine transistions to boost (around 0 on boost gauge), so blowby gas is vented (actually sucked by turbo, engine at higher rpm's, boost levels) the opposite way to PCV valve, into intake piping infront of turbo via exhaust camcover breather vacuum hose that goes to intake pipe infront of turbo. That's why camcovers are connected together via a vacuum hose, as both camcovers can be vented into intake manifold when engine is at idle or into intake piping infront of turbo when engine is under boost.

Since oil + blowby gas exiting camcovers happens at higher rpm's, boost levels and PCV valve will be closed when engine is under boost, the catchcan has to intercept oil + blowby gas via vacuum hose from exhaust camcover to intake pipe infront of turbo.

This oil, blowby gas exiting camcovers happens at higher rpm's, higher boost levels. What happens is boost or vacuum for NA engines at higher rpm's leaks past rings, (known as blowby gas) creating more blowby gas in sump and since oil moves to head, blowby gas gets shifted with oil via oilpump, oil gallery's, etc to inside of camcovers and out the cam cover breathers.'

Basically, you leave the tubing going to the PCV valve in the plenum as this CLOSES under boost....so you only need to run the catch can between the two rocker cover valves and into intake piping infront of turbo...

Edited by Douse
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I know I am talking to myself here, but i am posting so it helps other people who read this thread...

This is the new way I have set up my oil catch can.

Under boost/revs all positive crank case pressure goes through the catch can and back in to the intake just before the turbo. The PCV valve only sucks into the plenum under vacuum (idle).

post-40125-1276574158_thumb.jpg

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  • 2 weeks later...
  • 1 month later...

Im about to install my catch can and from what ive read and the different setups ive seen douse's setup looks the best and most logical way ive seen. I mean why have more hoses and joiners in the bay when they are not needed?

The only way to see if oil is going into the PCV is to clean it out then give the car a boost then take it out and inspect for oil. Im goin to have a go at installing this on the weekend while I install my new turbotech boost controller :(

The catchcan im goin to install is a D1 spec one from justjap with 9mm inlets

Cheers

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  • 2 months later...
  • 9 months later...

just wanted to dig up this old thread and ask some questions, i want to plumb my catch can (r32 rb20) back into the oil system, but dont know how. Any tips? At the moment ive just taken the hose off the intake pipe and put it to my catch can. So only one of the two nipples on the catch can has a hose on it, the other one is just to atmo.

thanks !

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  • 5 months later...

Most people, well almost everyone in NZ pretty much run 2 hoses from the rocket cover to the catch can only. And the can has a breather filter on the top maybe 2 if needed.

very basic and very easy setup. This is for RB 20, 25 and 26. basically because most people run custom front facing plenums on their nismos and there is no inlet/outlet valves on them for the return pipe anyway, also they have sometimes have custom intake pipes with no hose inlets so because of those reasons its just the way its always been. for all cars actually, mitsi, subi nissan etc etc.

Im not saying its right because i dont really know what is the "correct" setup is or if there even is one but its just the way it is in NZ.

But because there apparently is some stupid rules in this country over this issue Im picking that Douse's latest setup would be the best way to go by.

Heres an example of a typical setup in NZ

post-89260-0-94936000-1327583658_thumb.jpg

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  • 1 year later...

Most people, well almost everyone in NZ pretty much run 2 hoses from the rocket cover to the catch can only. And the can has a breather filter on the top maybe 2 if needed.

very basic and very easy setup. This is for RB 20, 25 and 26. basically because most people run custom front facing plenums on their nismos and there is no inlet/outlet valves on them for the return pipe anyway, also they have sometimes have custom intake pipes with no hose inlets so because of those reasons its just the way its always been. for all cars actually, mitsi, subi nissan etc etc.

Im not saying its right because i dont really know what is the "correct" setup is or if there even is one but its just the way it is in NZ.

But because there apparently is some stupid rules in this country over this issue Im picking that Douse's latest setup would be the best way to go by.

Heres an example of a typical setup in NZ

Ceff.jpg

Sorry to dig yet another thread from its grave, but I got my opens recently and have been getting stuck into my r32 gtst so I can drive it already..

Taking off cooler piping to fit new adaptor plate/pipe for new recirc. BOV.

Noticed there was quite a bit of oil in the cooler pipes..

So catch can time! Just wondering.. Not sure if these are illegal all together (QLD) or are LEGAL if they are plumed back into the air intake..

Question is can I use this exact setup but instead of the air filter ontop, maybe a pipe going back to the intake?

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Sorry to dig yet another thread from its grave, but I got my opens recently and have been getting stuck into my r32 gtst so I can drive it already..

Taking off cooler piping to fit new adaptor plate/pipe for new recirc. BOV.

Noticed there was quite a bit of oil in the cooler pipes..

So catch can time! Just wondering.. Not sure if these are illegal all together (QLD) or are LEGAL if they are plumed back into the air intake..

Question is can I use this exact setup but instead of the air filter ontop, maybe a pipe going back to the intake?

I believe the NZ setup is illegal under adr due to it letting crankcase vapours out (filter would do shit all except bad stuff getting in i guess)

I know I am talking to myself here, but i am posting so it helps other people who read this thread...

This is the new way I have set up my oil catch can.

Under boost/revs all positive crank case pressure goes through the catch can and back in to the intake just before the turbo. The PCV valve only sucks into the plenum under vacuum (idle).

post-40125-1276574158.jpg

This is the best setup for a street car IMO

Edited by pipster11
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