I'm a non-mechanic looking for some advice. I have an Injen SR ready for installation (with the inline filter on the breather hose) and I ordered an NRG oil catch can to complement it (just like the rectangular GReddy). I've read through the thread on the GReddy here:

https://www.scionlife.com/forums/viewtopic.php?t=16393

The installation seems like a piece of cake, but can someone explain to me what the PCV valve, the PCV 9mm to 18mm hose, and the breather hose all do? I need to get an idea of how I might be affecting the performance of the engine with these modifications and any problems that could arise from me fooling with the engine dynamics.

Thanks in advance.

 

Here's a pic of my set-up. The GReddy catch can is mounted to the bracket that came w/ my INJEN short ram.



I'll be installing another catch can soon, just have to fab a new bracket.

 

Thanks for posting the information guys I was looking for info about a catch can. I want to add one when I put the Injen CAI in my egg.

Anyone think about making a reducer fron 18mm to 9mm so we can use the nice hoses that GReddy provides?

 

So, you're installing a part without actually knowing what it does?

 

http://So, you're installing a part ... what it does?

Well, I understand very well why the Injen intake generates more horsepower due to allowing the engine to breath easier through less advection and the aiding of combustion through the introduction of cooler, denser air. And I understand that by installing an oil catch can to the PCV hose that my engine will stay cleaner longer due to the can removing oils and carbon in the blowby gas.

Now, what I would like to know is:

What is the PCV valve do?
Why is there a PCV hose and what does the PCV hose do?
Why is there a crankcase breather hose and what does it do?

Pretty simple questions, can anyone answer them without an attitude?

 

i ran out of time it might be in here http://auto.howstuffworks.com/engine.htm

 

It like a freakin Tornado, it does nothing, I can't believe people are falling for this. Even the stupid Ebay auctions say they are for turbo's and the only time they catch oil from a turo is when the carbon rings on the turbo smoke and oil starts getting injectedinto the motor, at whichpoint kiss the turbo good by, at least you'd know something was wrong if you were smoking. Ford has a problem with this, many Chevy engines did or do, but the only time I've seen a NA import engine need a 'oil seperator', 'oil catch can' is when the PCV valve needed to be replaced or the turbo was blown. This almost ranks on the 'voltage stabalizer' thing that is a total shot in the dark to trick people into thinking they are gaining some kind of horse power with this. If your PCV valve is not dead this is pointless, the purpose of the PCV valve is to allow the crank case to breathe, yes some, and I mean very little, oil gets past the valve, but that's what the breather is for. This 'catch can' does not appear to do anything really. I will make a bet with pretty much anyone here that I can prove this can does nothing, but on a Ford they are nearly required. This picture is from a 2000 lightning, without an oil seperator, this is the intercooler, this needs to be kept clean, Ford has a big issue with the PCV system as you can see.


If you pull your intake off and run your finger on the inside and there is not a coat of oil you do not need this can. Also if there is a thin film of oil (And I mean thin) it could be doing more good than harm. Think about it, some dust gets past your airfilter. You have a huge 'K&N style' runner that will catch some stuff as well. For sake of not coming off like a total A-hole, yeah it'll catch some oil, in about 50,000 you milght have to dump the 2 cap fulls out of it. With the hose discoloring you know there is some oil 'vapor' in that line (Which there is supposed to be right up to the PCV valve, all this box really does is make you think your keeping it from going into the motor, which you are, but it's not like it wouldn't burn off anyway. The 1 quart every 1500 miles that my Ford burned is listed in the manual as "Normal" hence why it takes 6 qt's of oil, so you burn 1 off after 3,000 miles, nifty huh?. If the intake of a xA looked anthing like that intercooler I'd preach this all over. But seeing as it can not really do much at all I rank it next to the Tornado and "Fuel atomizer" on the shelf of useless 'race parts'. On a turbo'd car it is a little different. The crank case usually is more pressurized because of the boost. This due to ring blow by and faster moving parts in the motor. Oil is slung around more, but the entire point of a PCV check valve is to stop the oil from going into the intake and allow the air to recirc.

 

You're right. After a few hours doing some surfing and reading about how the PCV valve works, the can probably won't do much except pull out some of the oil vapor from the crankcase gases which is designed to be burned anyway.

EExA, thanks for the info. I should've asked around BEFORE I bought the damn can. I'm putting it in anyways since it's on it's way here. I will just have VERY clean cylinders.

Thanks everyone...

 

hmm...a worthless mod huh? im about to order the greddy one.

 

I have a 2K V6 Mustang and yeah...Ford's PCV systems are over-acheivers, making a seperator necessary.

PCV = positive crankcase ventilation. Should have been called ACV for active crankcase ventilation IMO...active & passive are better descriptions for the two types...not that passive is manufactured anymore. Anyway, I digress...

The pcv VALVE in a normal pcv system does nothing more than close the pcv SYSTEM at high rpm's, when intake vacuum is highest. This prevents a normal pcv system from sucking a bunch of oil, not vapors, into your intake.

At normal rpm's, the pcv system is always open, circulating fresh air into your crankcase, and burning the vapors.

A normal, well-designed, healthy pcv system does NOT need a catch-can or oil/air seperator.