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I am having trouble figuring out how to hook up the oil catch can. Please let me know where I am supposed to hook it up. I did search, I just didn't get a clear enough answer. Am I supposed to unplug the PCV hose, and plug the catch can in between? Pictures would help.

Thanks!
 

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A crankcase vents air as well as oil. Using a breather and nothing else is very unsafe esp if its near the ext. mani. (some like to run this way here)

You need to run one hose from the valve cover breather into the catch can and the other from the can runs into Intake tract. Vent the catch can with a breather... You can see my crankcase tube run along side the charge pipe into the catch can. Breather is on the middle left side. Return hose goes into intake pipe. Sorry for the messy pic:

 

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I have a question. On my setup the guy who installed everything used one hose connected to the PCV hose(I believe), and the other hose he used as an "escape" and its supposedly vented out of the car (which it is not since the hose is too short).

Did he do this incorrectly? Should the other hose be connected to the intake piping?
 

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I have a question. On my setup the guy who installed everything used one hose connected to the PCV hose(I believe), and the other hose he used as an "escape" and its supposedly vented out of the car (which it is not since the hose is too short).

Did he do this incorrectly? Should the other hose be connected to the intake piping?
You can reconnect it back to the intake but it's not necessary.



I let the other end of my catch can vent out.
 

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I still a little confused about the Catch can. Some have them and some do not. How do you know if you need one? Higher boost pressures cause oil blowby out the pcv valve??????? I'm still on low boost sooo.... if this is the case I guess I would not have this problem ........umm.......yet.......
 

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I still a little confused about the Catch can. Some have them and some do not. How do you know if you need one? Higher boost pressures cause oil blowby out the pcv valve??????? I'm still on low boost sooo.... if this is the case I guess I would not have this problem ........umm.......yet.......
You get one because it makes a nice conversation piece when you check your oil at the nearest gas station and if you notice oil blowby coming out of the PCV. But if you fall in that category, you should have the motor checked out first. Blowby could be a sign of a worn out motor that needs a rebuild so a catch can could be masking a problem.
 

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venting your catch can will make it stink in your cabin when you come to stops at lights.

On the skylines, I run one hose, linked to each breather to the can, the other hose to the intake (pre turbo) Using a filter, all you will be smelling is oil. And since my skyline runs pig rich, I would smell gas and oil if I left it vented. After 1 summer of running the catch I barely had any blow by on a car that commonly fills bottom rows of intercoolers with oil....

Apparently you need the positive pressure or something of the intake to suck the gasses from the valve covers.
 

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Nice to see People from my Hood!

I noticed the SG Can Tire in your build thread pic right away. I'm also a Grover (well acerage close buy). See you picked up your car from Will at JDM Connection. Cool. Good Guy. I sold him a house a while back and my sister in law used to live right across the street. Small world. Your putting down some pretty big numbers in that skyline :jawDrop:

Nice piece of work:

Rob
 

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I noticed the SG Can Tire in your build thread pic right away. I'm also a Grover (well acerage close buy). See you picked up your car from Will at JDM Connection. Cool. Good Guy. I sold him a house a while back and my sister in law used to live right across the street. Small world. Your putting down some pretty big numbers in that skyline :jawDrop:

Nice piece of work:

Rob
Hey def small world! I don't live in SG, I was picking up my car that same day. Will has sold me all the skylines I've bought, great guy to deal with. I need to get some updated pictures, That build thread is missing the RB25DET lol; which is a large part of the reason I'm pushing that power. Rb20 would disintegrate at 350rwhp, especially on stock bottom end.

Def never see an IS300 modified at all in Edmonton, except for the sub racing car that claims to have 600+ rwhp, which I highly doubt seeing as it looks like an ez motorsports special.
 

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You can reconnect it back to the intake but it's not necessary.



I let the other end of my catch can vent out.
You can also drive a car without a gas cap on.

It's possible, but dumb.

The PCV system takes metered air from the intake tube. Flows it through the block collecting unburnt hydrocarbons and other harmful gasses from the block. Then this gets sucked into the intake manifold and burned up in the engine.

The PCV valve is open under vacuum(TB closed/off-boost) sucking air through the system. Under Boost the valve closes and keeps the block from being pressurized.

The block will only become pressurized if the PCV stays open during boost or you have more blow by from the rings then the engine vacuum can suck off. This is why you would have oil coming out of the intake tube.
 

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so should I ditch the whole "vent out of car" thing and just connect that other tube to my intake? I'm running a belt driven s/c and any oil that gets in that unit could be bad news.

Will this throw off the MAF reading though?
 

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so should I ditch the whole "vent out of car" thing and just connect that other tube to my intake? I'm running a belt driven s/c and any oil that gets in that unit could be bad news.

Will this throw off the MAF reading though?
You're supposed to have it connected to the intake. If you have so much blow by that you are saturating your super charger profusely then you need to check your pcv valve, or your piston rings.

The whole purpose of your catch can is to catch the oil before it goes into your intake.

Because what you're doing could've been achieved by just routing the line open instead of to the catch can. That line blows air out. It doesn't suck air in. Having that filter on there is pointless.
 

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I am still slightly confused. Are you going between the PCV and intake manifold or are you going between the other vent and the air intake tube???
 

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I have always installed mine and my customers' between the PCV and intake manifold. The picture shows the other side. I'm just confused a little.
 

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^^ Thats how must peeps do it here, IMO to avoid pressurizing the catch can with boost and being a vacuum and boost leak.

IMO Zar nailed the fundamentals, but through experience these check valves are not all that good, you have to work around them or upgrade them. Classic example of reading something, then spouting it on the internet instead of actual experience.

If boost does get past the PCV check valve at the manifold (which it does), the flow of the PCV system goes "backwards" (from manifold boost) pressurizing the crank case some (along with the blow-by)-- Worse if the OE check valve at the other side remains. IMO by deleting the OE tube over the exhaust manifold side (being replaced by some common hose to intake or filter) alleviates this some, as the OE tube has a well hidden built in check valve that is not perfect. IMO it more like free flowing into the crank case, a restriction if blowing the other way. I suppose for N/A design its good enough to prevent the OE intake track from seeing (and getting dirty from) all that crank case crap. But on an S/C (motor not blown) setup I've seen that check valve allow a lot of blow by through- thus justifying the catch can (if you don't want all that crap going through your blower, intercooler etc). Same with a Tnetics setup, the OE check valve (within the OE tube that goes from PCV to OE intake pre TB- the one that was described as leaky) is deleted so the intercooler was loaded with oil.

The peep here that said he sees no build up in his catch can (of typical .net placement) also has a GTE swap, were the PCV valves are probably of higher quality/boost specific and his pistons are designed for the higher pressures- reducing blow by.
 
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