APC intimidator breather element?

[CXhatchboy520]

How would this affect the engine in terms of performance, emissions, etc. What does it exactly do anyway, does it vent gases from the valve cover, or does it vent crankcase pressure?

[Weston]

Don't use breathers unless maybe if you have FI. People say that using them will keep oil from getting into your intake, but that's total BS. The line that is replaced with a breather is the PCV system's inlet, however some oil will occasionally go the other way. But that's nothing compared to the line between the PCV valve and the intake manifold. Pull off the throttle body and look at how much oil is inside your intake manifold. It's a lot more than the little grease spot that you might find in the intake tube. There is an oil seperator in the valve cover, but it apparently doesn't work so well.

If you want to keep oil from getting into the combustion chamber, start with an oil catch can (it goes on that line between the PCV valve and the intake manifold).

Breathers do not increase power, they do not keep oil from getting into the combustion chamber, and they do not to any other good.

[fodo]

but err...i've always heard of taking that tube out to prevent hot air from the engine recycling back into the intake...and the last thing you need is hot air being recycled...at least in teh summer here it's 100+ outside. i'd think that in the summer time, use the breather but in the winter time use the tube.

[Weston-work]

Like I said, that breather hose is normally the inlet. Air is flowing from the intake to the valve cover, not the other way around. So, no hot air is being recirculated, except for what's going into the intake manifold itself (where oil sneaks in), but a breather filter wont do anything about that because it's on the other side of the system.

The PCV system keeps the crankcase under positive pressure, which reduces the amount of blow-by (which means better compression and better power). Replacing the breather hose with a little filter screws that up.

[monicle]

hrmmm last time i checked the intake is connected to the intake manifold which is in effect a large vaccume (hence all vaccume lines being connected to it). If this is infact the case then the intake/tb/manifold would be sucking air FROM the valve cover not pushing air into it. This is the same reason that an oil catch can works. If the intake / valve cover situation is working the way you stated (Air is flowing from the intake to the valve cover) than how would oil ever get caught in the can? Oil does get into your intake system from the valve cover and it does eventually get burnt up. A breather would alleviate oil from getting into your intake but not really fixing the problem however a catch can would be a better answer to this issue. as far as how it would affect the performance... oil is combustable ie. it burns in an fi situation you want your injectors being the only thing putting combustable fluids into your cylinders. get rid of the trace ammounds of oil that are in the air that you put in there and you lower the chance of pre combustion.

[Weston]

The catch can goes on the line between the PCV valve and the intake manifold, that's how it collects oil. The PCV valve is a one-way valve, so all it does is send crap into the intake manifold. Now how does it get pressure to open the valve and do that? Either I have so much blow-by that it can pressurize the PCV valve (even with it escaping through the breather hose), or air is coming in through the breather hose. Guess what... air is in fact coming in through the breather hose.

If a significant amount of oil were coming out of the breather tube, my throttle body would be all gunked up too, but it isn't... just the intake manifold and it's no small amount. So it's hard to come to a conclusion other than the fact that the oil is coming through the PCV valve.


From Team-Integra.net's expert:

The honda crankcase breather is a POSITIVE pressure ventilation system.The air from the intake blows into the valve cover. It is NOT a negative pressure ventilation system...it does NOT suck air from the valvecover to the intake.

Breathers remove the source of positive ventilation that repressurizes the POSTIVE CRANKCASE VENTILATION (PCV) valve.

There is less pressure in the crank when you add a breather at the valve cover. The consequence of this is you get more positive blow-by from the combustion chamber past the piston rings and into the crankcase. More blow-by means less cylinder pressure...less cylinder pressure means the burn is slower and less complete...the result is more emissions and less power.

If you want to do this right and remove oil vapor from the circulating crankcase before it goes into the intake valve then, get an oilcatch can and put a breather on the catch can. Then place the catch can in between the valve cover breather and the PCV valve.

Disconnecting the breather tube, which blows fresh intake air into the valve cover, and placing a breather on the valve cover just creates more blow-by and emissions. Eventually you have so much blow-by, you lose power.


And even the Saturn guys know this: http://www.turbosc2.com/pcvmods.htm

[stu]

Here you go, I see these all the time, so I thought I'd post one.

http://www.beesandgoats.com/images/turbo/pcvsystemna.gif

[STIBungy]

Nice drawing. Is that intake tube mandrel or crush bent? :D

[monicle]

Well all I know is whats on the back of the box. http://www.jackmoves.com/monicle/greddy.gif

[Weston-work]

Well, that's silly. But remember that not all PCV systems are like Honda's.

[monicle]

Thats true but their drawing is clearly the drawing of a honda engine bay. Shoot it even says "SI" on the valve cover.

[Mr. NoSkills]

http://www.introspeed.com/pictures/Catch_Can_Diagram.jpg

[Mr. NoSkills]

most hondas have an oil seperator on the back of the block. the real catch can will remove that, run a line from it to the catchcan that has the pcv valve and back up into the intake manifold.
if you look on the back you'll see a little black box and has this pain in the ass hose that goes right up into the intake manifold.

[V8SpankR]

I just used a cheapo $3 fuel filter from PepBoys for mine and then I stuck a little filter on the other on the exit side. Looked decent and did the job.

[Brian]

I used to have a catch can that replaced the pcv and oil separator on the back of the engine block up to the intake manifold. That is where the bulk of your oil vapor enters the engien. After 30K miles my supercharger looked like new inside. YOu should see the superchargers from the guys that ran without a catchcan on the pcv....

[rmcdaniels]

Is that why my intake manifold looks like the supercharger has been blowing motor oil all over it? Is there enough getting through to cause increased oil consumption, because I've noticed that my car uses more oil since I supercharged it. It also makes a little puff of white smoke, but only when I first start it up, then it doesn't do it again until I shut it down and leave it for a while.

[rmcdaniels]

tdjb-potc, thanks for the great drawing, I finally understand how my PCV system works, or at least I think I do. Looking at the illustration on the back of the Greddy oil catch tank, it looks like they put it on the wrong end of the system. It should be on the other side like in Stu's drawing, otherwise all it does is look pretty, unless the outside air is very heavily laden with used motor oil, in which case you have much bigger problems than oily residue in your intake manifold. It seems kind of obvious now, despite the quote from From Team-Integra.net's expert, who seems to have gotten it completely backwards.

It looks like the best option would be something like Stu's drawing that relocates your PCV valve to someplace on the other side of a filter from your crankcase. I know my mechanic gripes about PCV valves getting clogged with oil residue and failing, it all makes sense now, oh no, I've been struck by a blinding flash of the obvious. I can't see! aa;sldkppvcac[adspjvc'adfvfkl;ldkf s'lf 'wevgfwe 'pdwfvre.

[Ntegra Dryvr]

I read on team-integra.net that you can put a breather filter on the oil catch can once it is installed into the exit line. Is this true or is it better to just run it back to the intake manifold or wherever it goes? Would this somehow affect the circulation system of how things work to just have a line going to your oil catch can and then a breather on the other end?

[rmcdaniels]

I actually built one using an air filter for a compressor I got at Lowes. I used a couple $3 PCV valves that I drilled out for the 90 degree elbows (necessary because the PCV valve has to be kept upright to work). It has caught a significant amount of oil and the filter is black with crud, which I believe would otherwise have been sucked into my supercharger. When I removed the PCV valve that was in the car, it was so full of crud that it would not close. I just put a breather filter on the pipe on the valve cover because it is only an intake.

[rmcdaniels]

This filter allows me to keep the functionality of my PCV system, but filter out the crud that would normally get blown into my SC. I checked out the Greddy catch can, but there's no guts inside it, just two tubes that come out right next to each other,and it costs way too much for what you get. Of course it a damn good-looking device.

[GimPin]

BWAAAHAHAHAHA I made an identical catch can for my DSM over a year ago.... I thought I was the only one getto enough to buy car parts from home depot only thing different is I put a T fitting after the can and put a breather filter on the top of the T

[rmcdaniels]

Yeah, one of these days I'll try to get it correctly mounted (vice zip-tied to my fuel filter) and make it look like something that should be under the hood, but right now I have bigger problems (like getting enough fuel) and it does the job. I got the idea for this off of a guys site where he did this to his brand new Dodge Neon SRT-4.

[GimPin]

its funny cause I walked down every isle in Home depot looking for somthing that would work as a catch can and that is what I found :D

[rmcdaniels]

That is funny, that's the same thing I did, but at Lowes.

[SleeperZ]

I doubt Honda's PCV system is any different than most cars. I could be wrong aboout that, but MOST if not all PCV systems do NOT run positive crankcase pressure, they run flow into the manifold through the PCV valve. The manifold is under vacuum. The source of the air comes from the filtered intake drawn through the valve cover.

In short, a breather will net you nothing on a n/a car, and will keep oil out of your intake on a forced induction engine. That because under boost the PCV valve is shut; the gases flow one way only, and the blowby has to go somewhere.

[rmcdaniels]

True, I should have said "sucked into my SC" vice "blown into my SC". On the subject of breathers, the breather on the pipe on the valve cover shouldn't matter because it is only an intake, while putting a breather on the catch can side of the system would make the PCV system not work. It's my understanding that the PCV system is desirable for eliminating sludge-causing moisture and fumes from the crankcase. When the car is under boost and the valve is closed, blowby pressure can escape via the breather on the valve cover pipe, but most of the time the intake manifold is a vacuum, and during that time the PCV system can work normally, just filtered so it doesn't get crud in my SC.

[GimPin]

here is what I understand about a PCV valve.... its purpose is to relieve crank case pressure so that it does not put pressure on bottom end seals and gaskets .... but I have found that they are not very efficient on boosted applications ... my experiance is with a DSM ... what I did is removed the PCV valve and put in a threaded nipple and ran it through a catch can.... before I did this I had really bad problem with the pressure in my oil pan it would shoot my oil dipstick out and spray oil all over my engine.

[rmcdaniels]

I've heard that boosted applications put more stress on the PCV system because there is a lot more blowby, and I know my last PCV valve went from new to hopelessly filthy in about 6000 miles, hence the filter to try to preserve it. I'm guessing your DSM was a turbo, which is a little different situation from my sc Civic. My sc is inside the throttle body so boost is never applied at both ends of the PCV system. If I had a turbo and left the PCV intake connected in its usual spot in the intake piping, vice using a breather, then it would seem like the crankcase would get pretty well pressurized under boost. With my sc setup, one side of the PCV system is always at outside air pressure, so under boost any excess crankcase pressure should go out the inake side of the system temporarily until I'm off boost, or at least that's how I think it should work. Do you remember if the intake side of the PCV system on your DSM was before or after the turbo?

[SleeperZ]

The intake side is ALWAYS before the turbo. No one pressurizes the crankcase - that will cause all sorts of problems (like blowing oil and popping dipsticks out ;))

[XxAlan274xX]

if u placed a catch can with a breather between the pcv valve and the manifold, wouldnt the boost from the turbo just fill the can and send all that crap back? or even leak boost from the filter of the breather? my idea was installing a check valve similar to the one used on the brake booster line and putting it between the manifold and the catch can. what do u think?

[Weston-work]

The PCV valve keeps it going one way. It can't open unless the pressure in the valve cover exceeds that of the intake manifold. When a catch can is added, the PCV valve is typically relocated to the catch can (if it doesn't already have one), so that it will not see positive intake manifold pressure.

[XxAlan274xX]

if i place the catch can after the pcv and before the manifold. as in pcv>catchcan>manifold (from down to up) but my concern is that when there is boost in the manifold, wont the boost go into the catch can and out the breather on the catch can?

[Weston]

Yes, and that's why the catch cans are supposed to have a PCV valve on them.

[XxAlan274xX]

and if they dont?

[Weston]

then add one

[XxAlan274xX]

which one would i put? the same one from the brake booster line? the hose for my catch can is 3/8 inch

[Bedlam]

Hrmm..if you had an intake that was flowing a LOT of air..wouldnt the venturi effect cause a vaccum to be created anywhere that had less pressure? I suppose a honda intake really doent move that much air..but physics are telling me that it would create a vacuum on that line...guess I never tested my ghetto ricer intake on the Si.

-Bedlam

[XxAlan274xX]

no no no...now your makin it complicated. if i had the catch can between the manifold and the pcv, when the manifold is under boost, wont the boost leak from the breather on the catch can? is there such thing as a 3/8 inch check valve? the breather im using is from jaz products and i checked it and it has no check valve. please let me know...thanks