what's up with all this catchcan talk???

what's the big deal about these catch cans? I am clueless to their function. I've seen them on full blown race cars but do they have any benefits to street driven cars?? I currently have a little K&N filter on the valve cover breather tube and have had no problems with it so far and I am running my stock PCV valve too. Can someone explain the benefits of the oil catch can and what it's purpose is? Sorry, to bring it up again but nobody has explained it.

sjoback- I picked that damn Greddy cach can up...don't ask http://www.hostboard.com/ubb/biggrin.gif Any way, can you add baffles and where would I get them? Shit, did you have a pick of the inside of your catch can? Come on help a brotha out http://www.hostboard.com/ubb/cool.gif

I think what blue92 also meant was... other than being emissions compliant, what is the significance of the catchcan to a simple breather on the valve cover? Or is the oil still entering the intake track somehow?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by b18c1-ek:
I think what blue92 also meant was... other than being emissions compliant, what is the significance of the catchcan to a simple breather on the valve cover? Or is the oil still entering the intake track somehow?<HR></BLOCKQUOTE>

Actually the last two paragraphs answer that question. The crankcase breathers do not allow oil to invade the intake tract. But takes your set-up out of its OEM intake configuration.

See Luds post below:

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by lundgren:
I've seen on some systems, mostly AEM, that the blower sucks air the wrong way, sucking oil vapor out of the crank case via the intake tube from the valve cover. Oil vapor increases the flash point of the intake charge and leads to engine pre-detonation.

Ideally one would construct something like the following drawing, but short of this, the crank case breather is 2nd best so that under full boost the above doesn't happen.

http://www.netbsi-kc.com/integra/images/temp.gif

Sometime this summer I'm going to do something like this, but for now I just have the crank breather. The cut must be anged so that air flowing in, is forced up, and even if the blower is sucking it won't pull air out, due to the angle of the pipe.

<HR></BLOCKQUOTE>

Also check here for more info.
http://www.hostboard.com/ubb/Forum40/HTML/001839.html

here I will post TOO's diagram AGAIN -- that pretty much sums it up. I'm sure everybody is tired of me posting this.... but I never did like telling people to do a search through the archives.

http://138.23.206.216/car/misc/Catch_Can_Diagram.jpg

enjoy

oh BTW - also benficial on a normally aspirated engine.

[This message has been edited by sjoback (edited September 06, 2000).]

Is the moroso setup the preferred closed system configuration among the people here?

i think i'll order one.

------------------
'98 GSR JRSC with all sorts of high-performance, high-tech, overpriced stuff packed in all over the place.
http://www.donia.org/clandestine

nah its not preferred. well I prefer it, but the JAZ is cheaper. depends if you have strict smog also.

I just wanted to make a quick comment on the angled cut of the hose going to the intake. I'm not trying to step on any toes but I don't think that will do much for you. I'm not completely clear on the reasoning behind it to begin with. The pressure difference between the intake and the engine is what creates the flow to begin with. Thats why you guys are putting a filter to minimize the oil making its way back to the intake track. An angled cut doesn't change the pressure difference so its not going to change the flow rate of the air or the oil. Am I missing something in the reasoning?

Just trying to understand....

Hehehe http://www.hostboard.com/ubb/smile.gif just finished installing the intake system and the catch can..man I had tons of problems with the catch can..from can't getting that PCV valve adapter into that hole on top of the oil separator to the stripped O2 sensor wire. So I was down under the car fixing it under 105 degress heat here in Houston and what ran across my mind was...Damn, Holden got the same damn car but yet his PCV valve is so accessible w/out wires running all over it and no stripped O2 sensor...why the hell am i have go through all this sh*t? ...okay I got a little jealous there http://www.hostboard.com/ubb/smile.gif

Hey I had my share of problems too!

First I tried to "gut" a PCV valve. I had to saw it into three sections, clean it out and glue it back together.

I guess the glue hadn't set, because when I put it in the bung the next morning, the bottom piece went in while the rest of it broke off at the glue line! Nothing I tried could get it out.

I drove around for 2 days like that until I got a monstrous set of bent needle nose pliers. They pulled it out first try.

I think the whole process took me 5 days. What a moron!

Greg

regg, what do you mean by a pick? I haven't ever looked in the greddy can.

dunno where you would get baffles, they're just pieces of metal. like on the moroso, the neck of the can extends down. so, the air that enters the side of the can smaks into the baffle (the neck that continues down) and then has to go down and back up around to go out up top.

easier to see than explain. course I suck at explaining.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by sjoback:
regg, what do you mean by a pick? I haven't ever looked in the greddy can.
<HR></BLOCKQUOTE>

Nah man, I was trying to say(w/ my non spelling ass) did you have a picture of the inside of your catch can. I have the Greddy and it is empty show piece. Trying to see what I need to add to it. Thanks man

hahaa.. I was like WTF? nah I don't have a pic, unfortunately.

its like TOO's diagram, but it doesn't extend that far. its just like an extension of the neck. so that there is an obstruction in the path, that way the oil is seperated out.

Keep in mind there are two ways for oil vapor to enter the intake.

The first is the valve cover breather. Without a supercharger creating high vacuum or an aftermarket intake that sucks on the hose rather than blows into it, you won't get oil vapor from this source.

The second, and more important, source is the PCV system. Gases and oil vapor are MEANT to travel out of the crankcase, through the PCV valve and into the intake. Once you put FI into the mix, the volume of gas and vapor only increase.

Because of the location of the PCV valve, simply replacing it with a filter is not possible. You have to run a hose to a remote filter. Once you're going that far, you may as well install a catch can, whether the legal or illegal setup. The illegal (open) setup results in zero oil vapor reaching the intake, but does not help evacuate the crank case like the legal setup. Not evacuating the crank will cause your oil to get dirty faster. It's a tradeoff. Make your own choice. (CA CARB Nazi's make getting pulled over with an open system a problem).

You benefit from the reduced detonation risk. This can help with high boost levels and/or advanced timing.

Greg