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Discussion Starter #1
Question again,

What does the tube on the Valve cover do? because the SRI I got has a place for MAF, but it does not have a hole for the tube to valve cover. what should I do? Should I buy those tiny filter cone for that opening on the valve cover?

Thanks,

Steven
 

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Focus "Sleeper"
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It vents pressure from the crankase. Yes, buy a small little filter for it, cut the hose about 3 inches from the valve cover, and attatch the filter.
 

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C2H5OH
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Or block it and see this in the oil pan:





But the Valve Cover Breather and PCV systems function like this. At closed throttle there is little vacuum in the air intake tube. So the majority of the blow by gases and taken in through the PCV valve. This is accomplished by the vacuum in the intake manifold (after the throttle body), at this stage the valve cover breather is not really used. During Wide Open Throttle and heavy load there is greater vacuum in the intake tube simply due to the amount of air rushing in. This is when the valve cover breather is used. It functions to help keep the oil pan at below atmospheric pressure (in an ideal situation).

Basically what I am trying to tell you is do not just leave it open or put a little filter on it. Route it back to the intake tube at least, after the MAFS would be best to cut down on oil spray onto the MAFS (more of an issue with forced induction).
 

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Discussion Starter #4
you guys need to stop moving your head LOL

how should I Route it back to the intake tube if there is not opening...
 

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Discussion Starter #5 (Edited)
I am going to get a picture of my SRI... guys wait a bit!!

done upload the picture...
see, it is not like a Ebay one, because it does have an opening for MAF...
but it does not have a opening for the valve cover tubing to go into...
what should I do?
should I just better off put the filter on the stock pastic intake tubing?

will this SRI help my car to save some gas and run smoother?
 

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Discussion Starter #7
from a guy on the forum~
with my spark plug wires~
 

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FocusXtreme
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i think i kno why he sold it! you are kinda screwed unless tou can tap into the pipe, youcant use the stock pipe cause that black tube goes into the box not the tube
 

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Discussion Starter #9
i got it with Ford Racing wire for $45... so don really care...
maybe I will drill a hole and put tube behind the MAF...
and then put JB well (dono how to spell)...
 

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DONT run it back into the intake.... all your doing is putting hot air back into the intake.

All of us turbo guys just run a vent line down below the engine and let it vent to atmosphere.... and no you dont need a filter on it... the filter is a very bad idea, they tend to clog quickly.... then the motor will build up pressure again in the block.
 

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Discussion Starter #11
so just leave the original tube and put it under the engine?
I am N/A guy, would it matter?
 

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FocusXtreme
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you can get a longer piece of tubing from auto zone and make it longer to vent it out ofthe engine bay
 

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Discussion Starter #13
if it could be vent it out...
why it is route to the air box?
 

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omn-nom-nomnomnomnom
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PCV explained on Wikipedia. [read]

erm... Don't feel that anyone's been clear on the way the crankcase venting works yet. I'll give it a shot. If I use a few smilies will I keep your attention?

[popcorn]

Fresh air goes in the breather on the valve cover, mixys its way down through everything, and exits through the PCV valve in the crankcase. The airflow is designed to evacuate the whole crankcase of moisture and acid-forming gases. After talking a bit with Pete, I'm definitely puzzled at how the air makes its way through the oil channels through the head to the crankcase. Notice that any V-style engine uses a breather (fresh air inlet) on one valve cover and a PCV valve (which needs vacuum, either intake manifold or draft tube) on the other valve cover. This strongly indicates airflow through the crankcase, or at least that is how the system was designed, so it's gotta work, right? [scratch]

Anyway, the part of this system that most people tinker with is the breather tube, which is normally a hose with a small foam filter in the OEM airbox. This location was chosen because it is a good source of clean fresh air... this works fine until you go to install your SRI or CAI and discover no provision for your breather. A small hose and a filter will work perfectly, just be sure to use gravity to keep the oil out of the filter. This filter will become oily over time, this is just oil mist. If you get dripping, you probably just need to raise the filter, since it is mounted too low. [thumb]

Some people use catch cans to stop the mess. A catch can won't hurt anything if mounted higher than the valve cover outlet, but its not worth the trouble IMO. They are often installed too low, which allows them to catch oil that sloshes during lateral acceleration, quickly filling the can & possibly causing a bigger mess than the oily filter they were supposed to prevent. [:I]

Another suggestion is to hang an unfiltered hose. [nono] I have to strongly advise against this, because it will allow anything (bugs, dust, grime, water, etc) to float right under your valve cover, and mix around inside your engine! Another reason not to use a draft hose for a breather tube is that it will probably keep your crankcase ventilation from working correctly at all: Fluid mechanics tells us there will be vacuum in a 'dangling' hose as soon as your vehicle gets moving, and you're wanting clean air to go IN the breather, not the other way around. If you use both vent tubes, you'll have equal vacuum pulling from both the top and bottom of your crankcase, which will eliminate airflow. This allow lots of nasty gases and things to hang around in your crankcase, eroding and generally being gross.

This brings me to the other part of the system, the PCV valve end. The PCV valve is attached to the front of your crankcase. The hose on the PCV valve runs to your intake manifold (well, technically, to the throttle body, but I didn't want to be confusing anyone). The intake manifold on a naturally aspirated (non-forced-induction) car will always see vacuum (when the car is on, and not backfiring). This vacuum sucks air out of the crankcase through the PCV valve, which simply keeps backfiring (or pressure from a turbo) from blowing into the crankcase. The crankcase also has an oil separator built in, that is the removable part on the front of your crankcase that the PCV plugs into.

What should you do with this hose? Probably just leave it alone. The dirty crankcase gases get sucked past the existing oil-water separator, past the PCV valve, through the entire vacuum line, an into your intake manifold & burned in your combustion chambers. [^]

If you are turbo/ non-roots-sc'ed, then you would be worried about overpowering your PCV valve under boost (positive intake manifold pressure). You could either buy a stronger PCV valve, or use a draft tube. The PCV will close if no vacuum exists, so you might want to get a special always-open version... but maybe not! Remember earlier, when I said there will be vacuum in a 'dangling' hose as soon as your vehicle gets moving? Well for this hose, this effect is exactly what we want. The dirty crankcase gases get sucked straight out to the atmosphere, screwing up their own little section of the ozone. All older vehicles use draft tubes, kindly contributing to the 'oil strips' down the center of most highway lanes. I also ride a motorcycle, so I personally the dangers of that oily strip (funny, my '74 Honda twin isn't helping that strip much itself, lol). [shhh]

The other (terribly selfish, but totally understandable) reason to run a draft tube is because you're picky: you don't want all that junk (corrosive gases, sludge, etc) re-entering the system. Your reasons might be that you cleaned out your intake manifold and don't want it getting so dirty anymore, or that you have a roots-type blower instead of an intake manifold, and you'd rather keep it nice & clean. [:D]

If you're set on installing a catch can, this lower hose is the place to do it. You'll catch any oil that would have found its way into your intake manifold if you're running the hose to vacuum there, or would have dripped on the road or your garage floor if you're running a draft tube.

[wiggle]

I'm running a plastic PCV valve for 'FI' cars, since I initially didn't realize what that meant... I thought it meant an open valve, but really I believe it is just a stronger valve. At any rate, this doesn't matter because a roots blower setup like mine will only have vacuum at the throttle body. I've been meaning to pick up an oil/water separator (aka "catch can"), then run the lower PCV vacuum hose through this additional separator and on to the throttle body vacuum connector. This will allow me to lower my harmful emissions, stop greasing the roads up, and still keep my SC internals safe from sludge. [headbang]
 

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Discussion Starter #16
It is getting too long... and it is still early...
so what do you mean by leave it alone?
I should not install the SRI?
I am only a N/A car...

I still have no Idea what I should do,
I am still with my stock box and stock intake and everything...
 

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^^ you really have no clue what you are talking about. the breather hole on your vc pushes air OUT of the vc. it DOES NOT suck air in. think about it, if you put a filter on the end of a hose attached to the vc, why would there be oil on the filter from the engine if there is a vacuum? the only way that there would be oil on this filter is if there is positive pressure in the vc causing oil spray to exit out of the vc. the reason it is connected to the intake is so that the oil that 'mists' out of the vc will be sucked up by the intake for emissions purposes so that you don't have oil all over the place.

if you don't believe me, get some sort of pressure meter, digital or analog it doesn't matter, that can read both positive pressure and vacuum and connect it to your vc breather. crank the car and it will have a positive pressure on it, NOT VACUUM. another way you can tell is just by starting your car and putting your hand or finger in front of the hole and you will feel a slight positive pressure airflow coming out.
 

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Discussion Starter #18
focusfreak03
what is your recommandation?
 

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omn-nom-nomnomnomnom
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Yeah, sorry if that post was rambling, it was late.

focusfreak03: sorry, nope. don't wanna be rude, but are you just guessing?

executionerhk: I said 'leave it alone' in reference to the lower hose, the one attached to your PCV valve. For the upper hose, aka 'breather tube', which is attached to your valve cover,

...the part of this system that most people tinker with is the breather tube, which is normally a hose with a small foam filter in the OEM airbox. This location was chosen because it is a good source of clean fresh air... this works fine until you go to install your SRI or CAI and discover no provision for your breather. A small hose and a filter will work perfectly, just be sure to use gravity to keep the oil out of the filter. This filter will become oily over time, this is just oil mist. If you get dripping, you probably just need to raise the filter, since it is mounted too low.
I wrote all that hoping people would understand how the system works... instead of relying on other guys on forums to tell them what to do... :) Ah well, I guess that works too.
 

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Discussion Starter #20
so i leave the PCV valve alone...
and unplug the breather tube and leave it alone as well?

I just have no idea about what the post about...
basically there are gas coming out from the valve cover and need to be burn. and there will be oil coming out...
 
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