You guys are on crack. Your turning something very simple into rocket science.

ok.....

1) supreamS14The PCV is designed to suck in blow by gases. You don't put a catch can here.

If you decide to keep it recirculated into the intake, you put it AFTER the MAF like the stock system.

Quote »Like I said in my previous post, when you boost, your PCV valve closes so you need another source of vacuum to scavenge the crank case blow by. Stock system uses the turbo inlet as the source. Turbo inlet always sees vacuum so this would be an ideal place for crank case blow by to go to when you are boosting.

If you dont have that... crankcase blow by doesnt get scavenged effectively because of no suction. You are just venting to the ATM.[/quote]Incorrect.

The intake does not contain vacuum (this is a confusing term, so i'm going to hereby call it suction... the force that would "suck" blowby gases from your crankcase). The intake is a low pressure zone, with air rushing from a high pressure zone to fill it (ambient air). As long as your filter is not clogged or your pipe narrows near the filter, there should be no "suction" in the intake tract.

Think of it like this, what happens to vacuum in an intake manifold, when you open up the throttle plate in an naturally aspirated car? It immediately goes to atmosphere (101.3kpa/0 vacuum, 0psi, 0 bar, 1atm, etc. etc.). Why is this? Its not because your engine isnt sucking in air, its because theres no longer any "suction" because the opening allowing air in is big enough that the suction force experted in any other ports with more resistance is negligible.

To explain this using a real-world example consider the following:

You have a vacuum cleaner with a 1" diameter hose. Put a Y splitter on the end of it, both sides with 1" diameter hoses attached. Turn the vacuum on and stick one hose in a buck of water, does it suck up water? no. It doesn't because the path of least resistance is the hose thats exposed to atmosphere, which is big enough that there is no "suction" at the other hose thats in a higher resistance medium. Now try sticking your hand on the end of the other 1" hose thats in open air (ie: closing your throttle plate). Now all of a sudden the suction force increases greatly within the hose, and water gets sucked up (i hope you used a wet-vac for this experiment).

Think of the crank case as your bucket of water. With the PCV valve closed (under boost) there is only 1 place for gases to exit... thats out of the valve cover breather (via your intake on stock setup). Thus, air cannot freely flow into the intake from the crank case, because air cant enter the crankcase equalizing the presussure. Thus we have 2 equal very mildly low pressure zones, and 0 air flow.

Why then do blowby gases (and oil and other nasties) go from the crankcase to the intake? Due to blow-by.. as the term blow-by gases suggest. Blow-by is combustion gases that leak out from around the rings and valve seals during the combustion and exhaust stroke (mainly combustion). No engine has a perfect seal, its not possible. Even right after break-in, your car has imperfect ring seal.

Basically, what this means, is your crank case, in reality, is a high pressure zone (if you've ever seen the result of someone plugging up their PCV and valve cover vent, you'll know exactly what i'm talking about), while your intake tract is very near atmosphere. Whether your valve cover is connected to the intake, or vented to air, the amount of vented blowby gas will be near identical.

The only time blowby gases are actively REMOVED from the crank case is when the PCV valve is open. In this situation, intake manifold suction (due to the pistons trying to draw in air, but the throttle plate being closed causing low pressure with no sufficient high pressure zone to negate suction) draws air in from the crankcase. Now the crank case is a low pressure zone relative to atmosphere, and the valve cover breather draws in clean fresh air. Here is a diagram to help you visualize it:



Now that i've addressed those issues, how DO you hook up your catch can?:

Well,

Option 1:

Leave your PCV Hooked up. Plumb your catch can between the valve cover breather and the intake behind the maf:

Advantages:

- Working PCV for best blow-by scavenging. - No blowby gas/oil vented into the enginebay

Disadvantages:

- Can dirty up intercooler piping to some extent.- Ugly line going to your intake.- If you have a lot of blowby, it could change your A/Fs to some extent (i dont see this being an issue)

Option 2:

Leave your PCV Hooked up. Plumb your catch can into the valve cover breather and put a little filter on the opposite end

Advantages:

- Working PCV for best blow-by scavenging. - absolutely no blow-by gas being introduced into the intake tract. Blowby gas only being consumed by engine under vacuum.- Catch can fills up slower than option 3.

Disadvantages:

- blow-by gas vents into your engine bay under boost. Some people find that this causes an unpleasant odor, depending on how much blow-by your engine has. I have yet to notice this in person on any car i own or any of my customer's vehicles

Option 3:

Unhook and plug your PCV. Plumb your catch can into the valve cover breather and put a on a little filter/leave open the opposite end.

My drift car currently uses this option (sheer lazyness, i didnt have enough vacuum ports on my manifold to run both PCV and brake booster)... i am converting to option 2 as soon as i get time to work on it.

Advantages:

- absolutely No blow-by gas entering your combustion chamber.- Does not require a filter on the catch can as air will never flow into the valve cover.

Disadvantages:

- blow-by gas vents into your engine bay. Some people find that this causes an unpleasant odor, depending on how much blow-by your engine has. I have yet to notice this in person on any car i own or any of my customer's vehicles.-Blowby gases are not scavenged from the motor.

Option 4: With PCV either hooked up or unhooked, put a filter on the valve cover breather.

Advantages: Same as running to a catch can and not recirculating into the intake.

Disadvantages: filter gets oil soaked, and oil starts dripping off the thing and makes a big mess all over your engine, also if you sit it in the same location as the picture earlier in this thread, it drips all over your exhaust manifold, are you get under-hood smoke, a fire hazard, and constant oil burning smell. Bad news.

Pictures:

Option 3 (my drift car):

Option 2 (PDM Racing's Fatboy, notice the T at the back of the valve cover near the stock catch can loaction, and the line running over to the catch can mounted to the right):

Can't find a picture of option 1.

Great post man, very informative. Still have some questions though.

So it's okay to route it like this: Leave the PCV and T hooked up....run the front end of the T to the catch can, then the catch can to the intake, inbetween the maf and turbo. And take off the stock catch can and just route a hose from the rear part of the T to the back of the engine, where the stock catch went?

Also, doesn't the catch can have to be lower then the PCV or T to work properly? I also heard it's a good idea to put some stainless steel pads, like sos pads, in the bottom of the catch can, so that'll seperate the oil from the air, is that right? Just want to make sure it's affective to run it this way? Thanks again.

Ey yi yi

My head hurts

vise on my jaw!

To easy

You know that factory 'catch can' thingy? It's actually an oil air sperator, and it actually works perfect for it's application, which is seperating vapors from actual oil. If you can, try your best to retain this. The block vent (the tube in the back drivers side of the block) connects to the bottom of this.

The PCV on the passenger side of the valve cover? Yea that little goofy thing. Hook it up to your intake like you should.

The valve Cover T? To simple. If looking at it from the drivers side fender, the right side of the T should connect to that black factory oil air seperator. The left side should goto a catch can top.

Now, you also have a catch can. Obviously the left side of the T goes into this, but the other side of the catch can should be routed directly back to your intake tube. To easy.

FWIW: Remember to use oil rated hoses, or they will sweat like a fat chick in a summer class.

The key is to keep a positive vacuum source on the upper end of the entire crank case. This helps out with ring seal and helps create power.

WOW AWESOME THREAD. ok so i still have my factory oil are seperator box thing, from there the hose goes to the T in the valve cover, then from the T i have it going directly to my intake just before the turbo. I'm using the stock pipe from air filter to turbo. sound correct?

Yep, sounds right to me.

And if you want to throw in a catch can, just put it inbetween the T and the stock intake pipe....at least that's what I'm going to do.

I wish there was some nice clear pics of this. I tried looking at the SR pic thread with little luck. I also wish I didn't get the worst sr swap DVD in the world.

having the mini filter on my t caused serious problems for my car.i now have smoke coming out of the t and oil in my # 4 cylinder.could this cause piston ring failure.
Modified by RPS13 DRIFTER at 1:39 PM 2/5/2008

RPS13 DRIFTER wrote:having the mini filter on my t caused serious problems for my car.i now have smoke coming out of the t and oil in my # 4 cylinder.could this cause piston ring failure.

Could also be a simple Valve Cover spark plug o ring failure.

Oh and PS: Don't bump threads after 20 minutes. Lame.

yeah thats what it is.but my valve cover bolts are stripped.

We

RPS13 DRIFTER wrote:yeah thats what it is.but my valve cover bolts are stripped.

Well if thats what it is, why would you blame it on your breather filter?

The reason smoke is comming out of the breather is because you don't have a catch can to catch the oil and such. Its blow-by gas, its normal if your PCV isnt hooked up. If it is, you shouldnt be getting smoke at idle.

If your valve cover bolts are stripped, fix them.

The SR has studs, so just take the valve cover off, then remove the studs and put in new ones.

i said the filter thing before i knew the spark plug gasket was leaking.i cant get them all of them off.the nuts just spin and the stud isnt spinning.

I see, well i guess its time to take it to a shop then.

Take a set of small vice grips and grab the nut. Then pull up as you loosen. The threads on the stud are probably screwed up, so the nut won't back off, but it can't pull off cause there's just enough thread to keep it there.

i'll try that thanks

Does anyone know the threading of the "T" or a part # from which I can order one? I seem to have lost mine. Also I found a decent pic of one in the forums except it's huge and mounted in the front.zerothread?id=297772

Sorry I didn't mean to bump after 20 min, I just wanted to see pics. I'm a visual person. Still interested in pics of other installs, I'll keep looking out for them myself.

The T fitting is pressed in, not screwed in.

B-TownSX wrote:Does anyone know the threading of the "T" or a part # from which I can order one? I seem to have lost mine. Also I found a decent pic of one in the forums except it's huge and mounted in the front.zerothread?id=297772

Wow 200 bucks for all that? That's a bit excessive for a simple ventilation system...

That tee is not screwed in. You can see a sort of homemade setscrew on the valve cover itself just above the tee.

steeda763 wrote:
Wow 200 bucks for all that? That's a bit excessive for a simple ventilation system...

Figure he's got at least 100 bucks in AN fittings and lines, another 50-60 for the catch can....and 40 bucks for the ease of installation?

Not 'to bad' of a deal...

That catch can is poorly designed (at least how hes mounting it).

Theres no gauge to see how full it is, and first time you take a hard corner any built up oil is going to slosh up into the hoses, which incidentally the out hose feeds right into the intake on a downward slope.

From what I seen, the oil catch cans don't even collect that much oil, but that's on my brother's evo. 2 months of driving and there's maybe a drop in there. The tank that guy is rocking is huge, probably holds more oil than the oil pan. I also agree that the horizontal mount is silly. I do like the illustration on how he did his lines. My stock oil catch can (or that's what I think it is) right behind the "T" is dented,So should I do as what he did? By removing the stock catch can, run the line to the "T", from the "T" to the new catch can, and down to the intake? I just ordered my catch can, once I get it in there I'll post pics so you can all shake your heads at me. Also, what is that plug that is zip tied to the box?

That plug is most likely for the oxygen sensor.

B-TownSX wrote:From what I seen, the oil catch cans don't even collect that much oil, but that's on my brother's evo. 2 months of driving and there's maybe a drop in there. The tank that guy is rocking is huge, probably holds more oil than the oil pan. I also agree that the horizontal mount is silly. I do like the illustration on how he did his lines. My stock oil catch can (or that's what I think it is) right behind the "T" is dented,So should I do as what he did? By removing the stock catch can, run the line to the "T", from the "T" to the new catch can, and down to the intake? I just ordered my catch can, once I get it in there I'll post pics so you can all shake your heads at me. Also, what is that plug that is zip tied to the box?

It depends on a lot of factors.

ie: where its tapped into, how much blowby you have, how well the PCV system works, baffling inside the valve cover, etc. etc.

My catch can fills up every 6000KM or so, or after a few track days. Mind you, in one 1-week long road trip i can put that on my car.

VortXxe wrote:My catch can fills up every 6000KM or so, or after a few track days. Mind you, in one 1-week long road trip i can put that on my car.

If you're filling up your catch can that often, you've got bigger issues to worry about than catch can design.

FWIW: That one posted would work just find, dependent on any inner baffeling or the sort.

Here's how mines setup, just did it today:

The inside of my catch can, I use that stainless steel as a 'baffle' and the hose coming of the T has an extra hose to route the oil down into the baffle as shown.



Here you can see the little hose for the T side of the catch can, on the right.



Here's where I mounted it, so there was a nice down-slope from the T to the catch can. Is that okay to put it there, or will I see any problems? Will the catch can touching the radiator cause any problems?



And here's my setup, from the T down to catch can and through baffle and the left. Clean air comes from right side of catch can and back to intake, inbetween the maf and turbo. I also left the stock catch can in place on the opposite side of the T. Is it okay to run it like this, or are there any problems with it?

codyace wrote:
If you're filling up your catch can that often, you've got bigger issues to worry about than catch can design.

FWIW: That one posted would work just find, dependent on any inner baffeling or the sort.

No, it wouldn't work fine dependent on internal baffling. Your trying to stop liquids from flowing out of a port thats low down. Baffles wouldn't stop anything if the liquid reaches the level of the port. Why do you think catch cans are designs with the ports on the top? Now mind you that thing has a lot of volume so it may take a while to fill to that level, but then what is the point of the top half? Why even have it? Why not make it a crescent shape, with a bunch of baffles by the intake line (although even at that, what happens if your driving up or down a steep hill, or on a slant, all of a sudden your catch can capacity is decreased.

Sorry, but it is a poor design.

There are two reasons my catch can fills at the speed it does:

a) No PCV (which actually is no longer the case)b) Condensation. 98% of the fluid my catch can collects is water. This is due to the breather line just being open to atmosphere with no sort of anything on it (this is also no longer the case... mine now has a filter on it, and measures to reduce condensation).

onecrazyfoo4u, i can't see a problem with your setup... except what are those metal shaving looking things in the bottom of the first picture. Maybe its a trick of light or my monitor, but it looks like theres some sort of metal shavings in the bottom...

Well that sucks, I didn't think about it filling up or driving on a slant. How else can I do the baffling then? What do you guys do for baffling in your catch cans? Should I pull that inner hose out then? And why in the world don't catch cans come with baffling inside them already if it's fairly important? Thanks.

I wasn't referring to your design, your design is fine. I was referring to the one in the pictures further up in the threads (sitting on the fan shroud)

You've got the hoses up top, so there is no reason for oil to slosh up there unless your catch can is overflowing, which shouldn't happen.

VortXxe wrote:No, it wouldn't work fine dependent on internal baffling. Your trying to stop liquids from flowing out of a port thats low down. Baffles wouldn't stop anything if the liquid reaches the level of the port.

Bottom half (or left half from picture orientation) could be baffled and have a seperate drain. That would work just fine if their is still a consistant airflow between the entire thing. It's hard to explain, I doubt that the one pictured is that way, but it could be, and could work.

VortXxe wrote:hill, or on a slant, all of a sudden your catch can capacity is decreased.

Again, if your catch can fills up to that level, you've got bigger issues.

VortXxe wrote:There are two reasons my catch can fills at the speed it does:a) No PCV (which actually is no longer the case)

Don't buy it. I've had friends without them connected with no issues like that.

VortXxe wrote:b) Condensation. 98% of the fluid my catch can collects is water. This is due to the breather line just being open to atmosphere with no sort of anything on it (this is also no longer the case... mine now has a filter on it, and measures to reduce condensation).

Having had mine on my car, in the same setup, for nearly 15,000 miles and over 2 years, the only time it EVER began accumulating anythign was just prior to the engine melting a ringland completly through. No condensation, no water, no oil, no nothing.

Again, you've got bigger issues than simple catch cans at this point.

VortXxe wrote:onecrazyfoo4u, i can't see a problem with your setup... except what are those metal shaving looking things in the bottom of the first picture. Maybe its a trick of light or my monitor, but it looks like theres some sort of metal shavings in the bottom...

Some dirt track guys put wire mesh (0 or 1 grade) in their catch cans to help reduce oil from sucking back into the system)

Yeah that's what it is, like stainless steel mesh, like an sos pad. I heard it would help break up the oil, so it doesn't just get sucked back in the other hose to the intake. I didn't know how else to do the baffleing?

Well I checked my catch can after about a month of being installed. Not any oil in there at all, maybe a drop or two. So did I do something wrong with the install or is that normal?

Also, I pulled the stock oil separator or catch can off and just ran a hose from the back of the T down to the block connection. That's okay to do right? I don't see the point in having a separator there if it's just oil from the valve cover run back down into the block. Let me know if I should put it back, thanks!