Question about PCV

[VenomousSVT]

I have an 01 cobra 16psi d1-sc procharger... I have the standard PCV on drivers side and the tube going intot the valve cover on passenger side... whould anyone recommend bypassing the pcv or at least putting a filter on the passengar side cover? I have read all the hype about it being good or bad but I have always heard that on a blower car it is better to either vent or go with a catch can.

Thanks,
Travis :read:

 

[Wicked]

I'll show you my setup.

It confuses most people.

I use the (1) PCV in the normal location. An (2) adjustable valve on the driver side tube. I also use a (3) check valve on the pass side with a breather.

(1) The PCV works like normal. Under boost it closes and prevent boost from pressurizing the crankcase.

(2) Here's where I start confusing people. The adjustable valve is set such that at idle, I pull about 6 inches of mercury on the crankcase. Normally the crankcase is at atmospheric pressure, not vacuum. Too much vacuum is bad as it can cause vacuum leaks around engine seals. The vacuum must be regulated. I use a valve to do this, I'd like to add a spring adjustable pressure reg. in the future. Racers use a similar setup with their vacuum pumps. I am using the engine as my vacuum pump.

(3) By using the engine vacuum as the source to evacuate the crankcase, it turns off at WOT via the PCV valve. If the crankcase begins to pressurize under long WOT jaunts, the check valve in the pass. side opens and allows crankcase to vent to atmosphere. So the check valve hold vacuum in teh crnkcase but opens under pressure.


Before this setup, I ran breathers on both sides. The breathers quickly got oil soaked. My current setup gets no oil in either the vacuum tube on the driver side or the breather on the driver side. I am quite pleased with it and especially proud since i am the first to have it, that I've seen. Another plus is you gain power by evacuating the crankcase as it aides ring seal. Normal crankcase pressure using a PCV system is not evacuated, only ventilated.

On another note, I also, for a while, ran a breather on only the pass. side. This allows a large vacuum leak through the crankcase but it does work.

 

[Wicked]

Oh yeah, here are my pics.

 

[SlowSVT]

Venomous

Retain your PVC system.

You want to maintain a slight vacuum in your crankcase at all times. Just venting the crankcase won't purge the piston blow-by gasses that will contaminate and thin your motor oil. Gasoline in your oil will produce varnish inside your engine as well.

What you want is fresh air entering though the valve cover on one side and vacuum applied to the breather on the other valve cover. Run the vacuum hose to the intake track up-stream of your supercharger. There it will always see vacuum regardless of manifold pressure and produce a good cross flow of air in one side of your engine and out the other.

Run an oil catch can in between the valve cover and the intake tract to minimize oil being injested into the engine. That will minimize deposites on the back side of the intake valve and combustion chamber. Here are a couple of ideas:

http://www.accmachtech.com/pcvcatchcans.htm

http://www.seanhylandmotorsport.com/online/product_info.php?cPath=30&products_id=1054

I would accually run both of these. It's a bit expensive but should stop any oil injestion cold in it's tracks.

Good luck

 

[Wicked]

As I said, "It confuses most people". As simple as it is, some people can't understand it and therefore to them its wrong. Well it works better than anything else I've seen.

I guess I should also add that I have used an industrial size air/oil/water seperator on mine and the seperator would fill up way to quickly with gas, oil, and a lot of water.

And the normal PCV system can not be complete if you run a blow-thru configuration because you do not have a metered fresh air source like the stock setup. Not sure what setup he's running. If you run the breather on the pass side you are ventilating with unmetered air and you ecu will have to make up for the extra unmetered air. Not a problem really, I ran this way for a long time.

The way I'm doing mine now is lighter and cleaner and really pulls a vacuum on the crankcase. I have pulled the vacuum hose on the driver side after a couple thousand miles and rubbed my finger inside it and it is super clean, no oil residue whatsoever.

 

[blown01cobra]

As I said, "It confuses most people". As simple as it is, some people can't understand it and therefore to them its wrong. Well it works better than anything else I've seen.

I guess I should also add that I have used an industrial size air/oil/water seperator on mine and the seperator would fill up way to quickly with gas, oil, and a lot of water.

And the normal PCV system can not be complete if you run a blow-thru configuration because you do not have a metered fresh air source like the stock setup. Not sure what setup he's running. If you run the breather on the pass side you are ventilating with unmetered air and you ecu will have to make up for the extra unmetered air. Not a problem really, I ran this way for a long time.

The way I'm doing mine now is lighter and cleaner and really pulls a vacuum on the crankcase. I have pulled the vacuum hose on the driver side after a couple thousand miles and rubbed my finger inside it and it is super clean, no oil residue whatsoever.

Can you post up a list of all the parts that are needed.

 

[Wicked]

Can you post up a list of all the parts that are needed.

Thats where it gets even more complicated.

1) My valve. At least similar to this. I got this free from work. A point to note is the valve must be tuned. If it is not tuned for each specific application it will not work correctly. My valve is only open about 1/2 turn to operate at the level I need.
http://www.swagelok.com/PRODUCTDETA...2-S2&Price=&Picture=SS-1RM4-S4.jpg&CTSCKey=58

2) The check valve for the passenger side. I used a check valve from the vacuum brake booster of a Honda Odyssey(freebie!). Your check valve may be different as long as it open at low pressure and seals completely. You will also want something compatible with petroleum/gasoline since you don't want it to break down when it is exposed to gas/oil vapors. Notice the bulge in my pass. side hose, thats the check valve. It allows flow out of the pass. side cover but not into. The check valves purpose is, in the event of long WOT time, the crankcase may start to pressurize and the breather/check vlave allows the pressure to escape.

Other than that I used a normal breather from the ricer section at Autozone, stock PCV, and miscellaneous hose and clamps.

The hardest thing about this setup was tuning it such that the vacuum level was just below the point where the motor starts "singing" after you shut it down. The singing as I call it is the vacuum sucking air past engine seals, probably not a good thing. Tune such that the vacuum level is just below that point. The way I have mine, if I shut the car off and loosen the oil cap, you can hear the vacuum escaping. The maximum vacuum at idle is about 4-6 inches of mercury.

 

[TheHolyCobra]

I'll show you my setup.

It confuses most people.

I use the (1) PCV in the normal location. An (2) adjustable valve on the driver side tube. I also use a (3) check valve on the pass side with a breather.

(1) The PCV works like normal. Under boost it closes and prevent boost from pressurizing the crankcase.

(2) Here's where I start confusing people. The adjustable valve is set such that at idle, I pull about 6 inches of mercury on the crankcase. Normally the crankcase is at atmospheric pressure, not vacuum. Too much vacuum is bad as it can cause vacuum leaks around engine seals. The vacuum must be regulated. I use a valve to do this, I'd like to add a spring adjustable pressure reg. in the future. Racers use a similar setup with their vacuum pumps. I am using the engine as my vacuum pump.

(3) By using the engine vacuum as the source to evacuate the crankcase, it turns off at WOT via the PCV valve. If the crankcase begins to pressurize under long WOT jaunts, the check valve in the pass. side opens and allows crankcase to vent to atmosphere. So the check valve hold vacuum in teh crnkcase but opens under pressure.


Before this setup, I ran breathers on both sides. The breathers quickly got oil soaked. My current setup gets no oil in either the vacuum tube on the driver side or the breather on the driver side. I am quite pleased with it and especially proud since i am the first to have it, that I've seen. Another plus is you gain power by evacuating the crankcase as it aides ring seal. Normal crankcase pressure using a PCV system is not evacuated, only ventilated.

On another note, I also, for a while, ran a breather on only the pass. side. This allows a large vacuum leak through the crankcase but it does work.

Wicked, would your setup work on a N/A car or is the vacum pressure you have created (and vented when it becomes pressurized) only good on boosted applications? I like your setup, and I understand why you have this setup on your car. Correct me if I am wrong, but the PCV system is to make sure harmful gases that leak into the crankcase don't get released into the atmospehere. With that said, your system takes the gases that are in the crankcase, and creates a vacum to suck them out so they don't get reintroducd into the air intake. When under WOT at times, pressure might be built up into the crankcase, so your check valves (located on both sides) release the pressure if there is any, thus, recreating a vacum in the crankcase.

My question is though, if the pressure is evacuated through your system, where does the normal oil/junk that is in the PCV system go? Also, what is the benefit of your system over a stock PCV system? I'm sorry if these questions are common sense, but I don't understand the PCV system in depth.

Thanks in advance,

THC

 

[Wicked]

Wicked, would your setup work on a N/A car or is the vacum pressure you have created (and vented when it becomes pressurized) only good on boosted applications? I like your setup, and I understand why you have this setup on your car. Correct me if I am wrong, but the PCV system is to make sure harmful gases that leak into the crankcase don't get released into the atmospehere. With that said, your system takes the gases that are in the crankcase, and creates a vacum to suck them out so they don't get reintroducd into the air intake. When under WOT at times, pressure might be built up into the crankcase, so your check valves (located on both sides) release the pressure if there is any, thus, recreating a vacum in the crankcase.

My question is though, if the pressure is evacuated through your system, where does the normal oil/junk that is in the PCV system go? Also, what is the benefit of your system over a stock PCV system? I'm sorry if these questions are common sense, but I don't understand the PCV system in depth.

Thanks in advance,

THC

Those are good questions.

First, the check valves allow any pressure to be vented, just like anyone else running breathers. However, in my system, using the engine vacuum to evacuate the crankcase keeps the breather from being used much at all. So even though technically I use a breather in much the same way everyone else does, I am only using after long WOT jaunts and not 100% of the time. This prevents the breather from ever getting oil soaked.

The stock PCV is to ventilated the oil such that fuel and water vapor do not condense and deteriorate the oil. The vapors are sucked back into the intake but the crankcase is not actually under a vacuum due to the fresh air vent that is normally connected to the intake tube in the tb ducting.

The reason I can not use the stock PCV setup is mainly due to my MAF being in a blow thru setup. I have no metered fresh air source that isn't boosted.

Now I think this is better than the stock PCV system, especially on a boosted car, because by pulling a vacuum on the crankcase, vapors are more quickly removed. My pulling a vacuum also causes fuel and water that have condensed to evaporate at lower temperatures.

This is not for everyone but it works better than anything else I have tried.
YES it can also be used in a NA application, no difference at all.

 

[Method36]

Way to revive an old thread with my first post... what is the ideal vacuum at idle? I ran this same setup and set the vac to 10". Is this too much? I thought 8-10 hg inches was the norm. What do you all think?

 

[HandsomeRob]

Check out my Oil Seperator write up in my Sig!!
It works amazing
Make sure you read!!

 

[Method36]

Cool, I'm running an inline DIY catch can similar to your setup, and agree it does work. You can see the proof.

 

[ballx4xlife]

I just finished my turbo kit on my 94 cobra. I puff out a lot of oil when I'm up higher in rpm's so I figure it's my pcv. I emailed the guys I bought the kit from and they said to get a separator and a catch can if I wanted. He said stay away from a filter on the valve cover. What do you guys recommend? I don't quite understand the difference between the separator and a catch can? As of right now, I'm looking at purchasing the Jegs oil/air separator for $47, which is much cheaper than the other ones I've found. Should I go ahead and buy the Jegs one or should I buy a different one. I am trying to stay on a budget if that helps. Thanks