i tried setting it up as u have stated but i get positive crankcase pressure if i undo my rocker cover cap u can hear the pressure forcing its way out so i disconnected it

if it's set up like platinum's, all you're changing over the stock set up is there's a can in the middle of the line where oil can collect, rather than going back into the intake. Some original photos have not been recovered yet.

vlt5spdwag, do you have any pics of yours? if i'm hooking it up like the pics above, does it matter which breather you use, or would it be better just to use a Y piece?

is this ok, both rocker hoses running to can with no filter? What are the problems with this?

That is the way not to do it... but your setup isn't exactly factory so I'm not sure if any other arrangements have been made - from the look of it through it would do bugger all and build up pressure. Sure there's no filter on it? Where does the turbo breather go to? also, is that garden hose? it would look heaps better if you just got some black hose and fed it under and back up. Some original photos have not been recovered yet.

Quote: Originally Posted by ATMO_BT1 is this ok, both rocker hoses running to can with no filter? What are the problems with this? Thats how i got mine setup yeah?

If you have a breather it's okay as the gases just vent into the atmosphere. Anyone else shed some light on it?

i think the "proper" way to hook up a catch can is to have both breather hoses going to it, however you still need it to return crankcase gases to the plenum. i'm still unclear about how the pcv system works to be honest. i thought that the line going from the rear of the rocker cover to the pre-turbo pipe is just to complete the system - ie, at idle crankcase gases go through the open PCV valve, and to avoid building a vacuum in the crankcase, air needs to be sucked back in somewhere as well. however (and this is what i'm not sure about) i have been lead to believe that the rear one also vents gases (and therefore blowby oil) while on boost. if this is the case, you'll definately want to hook the rear one up too - who cares if you have oil going in at idle, its while its on boost that you want it filtered out. having said that, my motor uses a bit of oil. there is absolutely none in the cooler piping or the rear breather line. the front breather hose has a little in it and you can see a light film in the plenum that has come from that. if someone could clear up exactly how it works that'd be great. i've seen posts on skylinesaustralia forums on how to hook up a total closed system (ie, both breathers to a can, gases back to plenum, oil into sump) which is legal, and i thinkthe guy who did it maintains and builds cars for track racing for a living. this gives me the impression its probably the "right" way to do it.

see its fine to put a catch can in between the breather nozzle and the PCV (providing u leave the rear where it was from factory) but if u put both into the can when u hit boost and get blow by all the pressure from the cylinder enters your crankcase this is what forces the oil out at such speed causeing it to vapourise, your PCV what work because your plenum is under pressure. now even at idle i found if i hook both rocker breathers together and into a sealed can then a line from the sealed can to the PCV it still had crankcae pressure the safe way to do it is to me run both breathers to a closed catch can with a vent filter on top now this is illegal but the way i understand it to work if your way is correct why dont more people do it, its very logical because its EPA approved and people could hook it up that way if they wanted to with their existing catch cans try running your car at idle and put your finger over the PCV u'll find it tries to suck your finger in so as soon as your guage goes into pressure the PCV will be forced closed

Quote: Originally Posted by ATMO_BT1 is this ok, both rocker hoses running to can with no filter? What are the problems with this? That separator must have a filter on it or another line running back into the inlet tract surely? It should have a line coming off it running into where you have the garden hose connected just after your air filter.... There is a difference between an oil/air separator and a catch can! As was mentioned the oil/air separators when left sealed (with no filter) and running back into the inlet tract are legal as obviously the waste gases are still going back throught the inlet and out the exhaust. The catch cans with breathers venting to atmosphere are illegal for obvious reasons as they do not recycle the waste gases in any way. Some original photos have not been recovered yet.

The whole point of a catch can is to CATCH the oil and oil vapour, and STOP it from entering the engine inlet tract.Oil and oil vapour is low octane and induces pinging(detonation) That is why you direct both the rocker cover fittings in to the can with the can having a filter on it, to VENT it to atmosphere, not into the engine. That is why people do away with the PCV system OK!!!!!!!!!!!!!!!!

finally people making sense

ok, now i'm really confused and scared to start my car. can anyone shed any more light on the matter??? preferrably either a mechanic or someone who has a sealed type catch can?

lol catch cans are good for us, but cops HATE them its illegal which is only thing stopping me from installing. because of the venting of oil gases into the air it is considered a hazard and can ignite or some**** like dat. but im gonna do it soon id rather save my engine and get a canary den kill my engine quicker

its a good thing to get canaried for or epa'd on if they are gonna do it no matter what it takes 5 mins to put it back to stock

I have a sealed oil/air seperator i've just put on my 30/25. Both rocker cover hoses are fed into the can and an internal pipe directs the oil/air to the bottom of the can. The can is full of steel wool (inside stockings so no wool gets into the engine) to act a as a filter. One hose goes back to the plenum via the PCV valve. So when the engine is in vacuum, the filtered air gets returned to the engine. Another hose goes to the inlet before the turbo so when the car is on boost and the PCV valve is shut, the filtered blow-by air returns to the system via the turbo & cooler. This is setup exactly as "sydneykid" on the skylines aust. forum describes and works perfectly. Its also very legal as everything is returned to the engine.

so, if the PCV valve is closed on boost, should I have the can: 1) where it is now? (as platinum's setup) 2) rear breather to one fitting on the can and other fitting from the can to where its plumbed back into the turbo inlet? 3) front and rear breather plumbed in with a Y piece to one fitting on the can and the other fitting from the can to the turbo inlet and block the PCV off somehow?

u dont block the pcv u just leave it there run 2 hoses to the catch can and run a hose off the can with a filter on the end and if u want place it facing the road so if oil does manage to get that far it just sprays onto the road as a mist instead of a mist over youe engine bay

how about intead of potentially spraying oil on the road and killing some poor unsuspecting driver, i just plumb it back into the turbo inlet. would that work? it'd save me blocking up that hole too... also, would it matter if i did block off the PCV? just to avoid any possible leaks?

lol if u plumb it back through the turbo there is no point of having a ctach can that and as soon as that hot oil hits the heat soaked blade your gonna get a smoke show and cause that poor unsuspecting driver to stack his car cause he cant see lol its a mist man not an oil slick