Has anyone removed their PCV hose to the intake and put a breather in?
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Three50won
10 Year Member
- Jul 11, 2010
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You won't notice any difference. I have breather elements on my valve covers and in fact I think most of us enthusiasts do...
Right now I have an oil separator inline on the hose cause my blower sucks oil through that hose. I still get some bucking that I can't seem to get rid of short of a tune. So, I was wondering if this would help. I would think the only issue is emissions.
And do you leave the PCV valve in?
trinity_gt
10 Year Member
If you don't evacuate the crankcase properly you can get condensation buildup. You'd probably notice the oil cap developing a white, milky residue on it which would be an indicator as to what the rest of the engine would look like internally. You'd increase the rate of oil decrepitude and if you didn't keep up with changes you'd also increase sludging.
You might also notice a distinct foul odor coming from under the hood as crankcase fumes vented through those open filters.
Interesting that you're getting oil in there. I've got a fully plumbed PCV and don't have that issue that I'm aware of.
You might also notice a distinct foul odor coming from under the hood as crankcase fumes vented through those open filters.
Interesting that you're getting oil in there. I've got a fully plumbed PCV and don't have that issue that I'm aware of.
trombonedemon
Well-Known Member
The milky substance only appears on my oil cap during cold nights and winter.
If you plan on passing inspection, you might wanna keep you PCV settup, at least that was one of the things that was checked on my engine inspection. Plus those breathers start to get saturated w/oil over time.
trinity_gt
10 Year Member
The milky substance only appears on my oil cap during cold nights and winter.
It's water mixed with the oil and you can be sure it's in more places internal to the engine than just the oil cap.
Water vapor in the air condensing on cold internal engine components just like on a glass of cold beer. When the engine runs, this water gets mixed with the oil turning it milky. If the oil gets warm enough, the water "boils" out of the oil and the PCV evacuates it (and other fumes and gases) from the crankcase.
Without positive ventilation, contents of the crankcase will never really be ideal. An engine without PCV is much more likely to build up sludges and acids in the oil etc.
Personally, I'd rather find out why my engine is pumping excess oil out the PCV than mask the problem by disabling the system. For example, excess crankcase pressures caused by excessive blowby due to ring or cylinder wall damage or wear...
1fun281
Member
I removed the pcv, and just ran dump tubes from the valve covers to below the car, just a heater like hose. Doesnt hurt anything.
98COBRA281
10 Year Member
i just run dumps out the bottom of the car too, it doesent gunk up the intake manifold, or burn the oil in the motor, and cleans up the engine bay too!
This provides an outlet for excess crankcase vapor pressure, but doesn't evacuate crankcase vapor properly. Air is not drawn through one valve cover, through the crankcase, and out the other valve cover, "cleaning" the air (vapor) in the crankcase.
I replaced the air inlet tube on the driver side valve cover with a breather, but still have the air tube from the passenger side valve cover's pcv valve to the plenum. I did this to reduce oil in the big air inlet tube, and to clean up the engine bay. I think vapor evacuation is still adequate, i.e. the system still performs as designed, with the exception of a small amount of un-metered air entering the intake. This should lead to a slight lean condition, which I hope is either negligible or a slight performance improvement (I wonder if the computer has accounted for this?).
trinity_gt
10 Year Member
This is actually a pretty sizeable vacuum leak.
In the OE setup, the source of air for the driver's side VC comes from the intake duct, after the MAF. As you note, air enters the driver's side VC, passes through the crankcase and is pulled into the plenum. Again, in the OE setup, this air is accounted for by the MAF. In your setup though, the air is being pulled from under the hood and the MAF doesn't know about it. This isn't the equivalent of a small pinhole or crack in a vacuum line: All the PCV hoses are fairly sizable.
You probably won't notice it at idle since the PCV valve is basically closed then. If the valve did stick, you'd probably have a crazy idle since you'd be getting unmetered air bypassing the IAC valve and throttle body. At part-throttle cruise, when the PCV is open, the PCM is probably just compensating with fuel trims when in closed loop. It would be interesting to see the ST and LTFTs out of curiosity.
At WOT, it is technically a vacuum leak but the volume of air entering the engine past the wide-open throttle body probably swamps whatever the PCV is contributing. As well, since you're feeding to the plenum, at WOT there's not a lot of vacuum there anyway so the amount of unmetered air is fairly small.
So it's really at part-throttle that this becomes a concern. If the leak isn't too bad the PCM will just adjust for it. Still... it is a vacuum leak
This is what I would really like to know about, how the PCM adjusts for it...
I've noticed significantly less oily crap on the inside of the big air inlet tube. This is not a minor concern, as I have a nitrous sprayer jutting into the air tube. I don't want that getting gummed-up.
trinity_gt
10 Year Member
It's all about the O2 sensors and the feedback they supply.
At the risk of oversimplification, the PCM makes a zero-order estimate about how much fuel to supply based on the MAF reading. It does so and then looks at the O2 sensor to see if what it did produced the expected results. If, after some time, the O2 sensors are showing a consistently lean (or rich) mixture, the PCM will adjust another term in the fuel delivery equation that relates to "trim" -- small adjustments -- designed to account for everything from sensor variance to aging to fuel pressure fluctuations and even vacuum leaks... The trim may add a bit of fuel (if the O2 sensors show leaner than expected) or is may remove a bit (if the O2 sensors show richer than expected.)
If you have a scanner look a the long and short-term fuel trims. They are the indicator that the PCM is learning and adjusting and accounting for the engine's closed loop fuel needs.
I don't have a scanner, can't afford one.
I have mil eliminators (for the offroad h-pipe), how does this affect the PCM's ability to (relatively) accurately adjust fuel trims?
trinity_gt
10 Year Member
I don't have a scanner, can't afford one.
I have mil eliminators (for the offroad h-pipe), how does this affect the PCM's ability to (relatively) accurately adjust fuel trims?
It doesn't. The rear O2 sensors are used only to measure the effectiveness of the catalytic converters. They aren't used for fuel feedback.
1fun281
Member
All this information sounds right in my area, ive been chasing a CEL code P1151, It is Lack of O2 switches. What do you think is causing this, im down to bad O2 sensor since it is coming from bank 2 sensor 1 only. It said other problems maybe fuel injector related, or fuel pressure. But my fuel pressure gauge reads perfectly, and vacuum leaks, but cant find a single vacuum leak on the motor!
trinity_gt
10 Year Member
O2 sensors are basically wear items. I'd replace the sensor before digging too far into anything else.
BrightBlue00GT
I am even OLDER than Hawk!
I'm chasing down what I think might be a small vacuum leak somewhere, maybe in the EVAP system, but that's another story. I was also recently thinking about removing the PCV valve and install breathers on both sides, thus the interest in this thread.
From what I've read elsewhere you can remove the PCV and install a breather on each side with no related problems. Or you can of course leave the PCV alone. But what you can't do is run the two together i.e leave the PCV and also run a breather. Does this sound about right? It made sense to me anyway.
So, if I did remove the PCV and go with breathers, how do you connect the breather to the passenger valve cover? With such little room under the inlet tube where the PCV goes I don't see how I could mount one there.
Any suggestions?
From what I've read elsewhere you can remove the PCV and install a breather on each side with no related problems. Or you can of course leave the PCV alone. But what you can't do is run the two together i.e leave the PCV and also run a breather. Does this sound about right? It made sense to me anyway.
So, if I did remove the PCV and go with breathers, how do you connect the breather to the passenger valve cover? With such little room under the inlet tube where the PCV goes I don't see how I could mount one there.
Any suggestions?
trombonedemon
Well-Known Member
Breathers are not for daily drivers. You will get fumes in your car wich would be just like sucking on your tail pipe. Leave your PVC system as is or replace w/a couple of catch cans running hoses from each of the valve covers (Remove the PVC valve and replace w/the right size spout). The engine will force the fumes/blowby through the hoses w/crank case pressure.
Cap off your vacuum running from the bottom of the upper intake. Its way too strong for engine. (In my opinion a Ford desighn flaw) You will suck fresh oil in your intake, thus lowering your octane levels. The vacuum will force the oil off of your bearings and to the sides of your engine, thus starving your topend of fresh oil, yes the vacuum there is that strong.
Use the side of the "Cold air intake" thats below the IAC nozzle to vent the gasses. Breathers are a bad idea all together if you drive your stang daily, the smell is horrendous, yes, stronger then the deisel engines. Yuck.
Cap off your vacuum running from the bottom of the upper intake. Its way too strong for engine. (In my opinion a Ford desighn flaw) You will suck fresh oil in your intake, thus lowering your octane levels. The vacuum will force the oil off of your bearings and to the sides of your engine, thus starving your topend of fresh oil, yes the vacuum there is that strong.
Use the side of the "Cold air intake" thats below the IAC nozzle to vent the gasses. Breathers are a bad idea all together if you drive your stang daily, the smell is horrendous, yes, stronger then the deisel engines. Yuck.
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