catch can an PCV systems

[slw240sx]

ok guys, this time i dont have a problem, i know its a first huh??!?!?

ok im putting in a catch tank this week, should i

A.) route it back into the intake plenum

B.) let it vent into the atmosphere through a filter or out to the ground

does it make a differance regarding vacum, and pressure in the engine, is it bad to let it just vent open, should i re route it back for the good of the motor??

thanks guys Jon

[JDM_1990_S13]

if you have a leaking valve seat, piston ring etc or something you will be spraying oil all over.

[slw240sx]

but is it bad for the motor not to have it plumbed back into the intake after the catch can?

[chezina]

I would also like to know if it's bad for the engine?I always thougt the recirculation was for enviromental/emission reasons, but i heard also(only a few months ago) that it's needed for the head (kind of extra lubrication for the whole valve assembly,esspecially valve guides). So i'm not shure about this.

[slw240sx]

i also heard that the recircularion is needed to help the piston rings seal better against the cylinder wall!

[WDRacing]

Keep the vacuum tube from the intake to the PCV valve installed. But have the other vacuum tube dump into the catch can. No problems will occur. I've run this way for the last 3 years with no problems.

Having your crankcase vent plumbed into your intake is like saying it's ok to occasionly vent oil mist into the engine for consumption. Not really the best thing.

WD

[slw240sx]

i was going to tee both vavle cover lines into one, then have it goto the catch tank, filter out the oil and run a single line into the intake plenum free of oil

[the_invisible]

The reason why you want a catch can is because you don't want oil to be recirculated back into the intake manifold while the crankcase gas is vented back into the engine. If you have a catch can, just route the PCV back into the intake system. If you are not running a catch can, then you can simply add a filter to vent the crankcase to the atmosphere. make sure you clean the filter once in a while.

A catch can simply catches the oil that get spitted out along with the crankcase gas. The crankcase gas will simply re-enter the intake manifold without the oil.

Does anyone know what I mean???

[slw240sx]

i know and understand the purpose and theroy behind them, just wanted to know if there was a certain vacum pressure that needs to be maintained by having it. i guess you could say a closed looped type of pcv system !

[WDRacing]

Nope, no need to have a vacuum line going from the catch to the intake.

[the_invisible]

yup, no need for PCV circulation. The vacuum of the PCV wouldn't affect anything. It is just an emission device to allow crankcase gas to re-enter the engine for combustion. Many people gained some hp for disabling the PCV system by replacing the PCV end with a breather filter. However, it is illegal.

[slw240sx]

hehe yeah well i think venting blow by gases being illegal are the least of my worries !

[the_invisible]

haha...then go for it! Vent it to the atmosphere through the catchcan and outward with a piece of small filter. This way, your blow by gases will be vented while the oil wont be vented out, making oil mess in your engine bay. If you vent your blow by gasses to the atmosphere, just remember to put a filter at the end of the exit tube. This way, dirt wont enter into the engine. But I bet you know this already.

Anyways, besides being illegal, does venting the blow by gases alter emission test readings????

[slw240sx]

it may just little, but main purpose is to vent the gases of blow by out of the crankcase when combustion process is done some of the exhaust goes through the rings and into the crank case creating pressure... ahhh i dont know how to explain it all out an its late ill do a write up later!@!!

[the_invisible]

I see what you are saying.

But the PCV is just a device to prevent harmful gasses from relieving into the atmosphere. It doesn't prevent and reduce emission like the CAT and EGR and AIV. Or am I wrong?

Anyways, I am thinking about disabling the AIV. Do you think that if I have my cat is really warmed up before the emission test, my CAT would be hot enough and not need the AIV to heat my cat during emission idle test?

[float_6969]

no, if you're keeping your cat, you need the AIV. The Air Induction/Injection Valve puts atmospheric air into the exhaust so that there is oxygen present to combust the excess gasses that are in the exhaust. Without it you're cat won't be nearly as effective, and you'll get worse emmisions. It is just a simple valve that is run off of a vacuum. It doesn't use any hp, I'd just leave it on. Or, you can just move to KS and then you don't have emmissions to worry about!

[the_invisible]

oh okay, I guess I will just leave it on. However, the problem is that the easy install kit comes with the hole plug. It's worth 19 bucks. If I request HT to take them out, they only take out 5 bucks from the easy install kit.

Why to people disable this feature anyways?

[slw240sx]

well mine has somthing that looks like a cat , and i could prob stuff one into it with out a problem!!!!