Do I need a clean air source in my catch can system.. Pics inside
09-26-2009, 06:34 PM
#1
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Do I need a clean air source in my catch can system.. Pics inside Here is my layout. Wondering do I have to add a breather or anything for a clean air source or is vacuum good enough. Here is the layout all other ports on valve covers will be blocked besides the one you see used. Thanks
09-28-2009, 04:35 PM
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I would just cap the outlet next to the intake opening. Rest of it looks like mine, but I do have a breather on the oil cap. Been thinking about removing it, since it stinks of oil when im sitting at a stop light.
10-22-2009, 09:58 PM
#7
It is my understanding that you need some form of a fresh air source for the pcv.
I got a small filter from the parts store and ran a hose to the front passanger valve cover for it. I don't get any smell out of it, but then I am pulling 16 - 18inches of vacuum at idle. Other than that my setup looks similar to your drawing.
I got a small filter from the parts store and ran a hose to the front passanger valve cover for it. I don't get any smell out of it, but then I am pulling 16 - 18inches of vacuum at idle. Other than that my setup looks similar to your drawing.
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10-23-2009, 03:16 PM
#10
Yes, you will need delete one of the hoses from the catch can and add a filter to that hose and allow fresh air in. The way you have it now there will be too much vacuum in the crank case and you will have issues with valve seals and gaskets and the oil pump will hate you.
Fresh air in will keep your oil happy. Put an adjustable flow regulator on the fresh air hose. This will allow you to control how much vacuum is in the crank case. With the oil fill cap off and the car idling, cover the oil fill tube with your hand. A small amount of vacuum felt is ideal.
This system work best with an oil fill cap that has a check valve and a breather filter on top. The cap will allow excess pressure to escape the crank case during boost but not let air in during vacuum.
Fresh air in will keep your oil happy. Put an adjustable flow regulator on the fresh air hose. This will allow you to control how much vacuum is in the crank case. With the oil fill cap off and the car idling, cover the oil fill tube with your hand. A small amount of vacuum felt is ideal.
This system work best with an oil fill cap that has a check valve and a breather filter on top. The cap will allow excess pressure to escape the crank case during boost but not let air in during vacuum.
10-23-2009, 04:50 PM
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I dont see where the factory setup draws fresh air into the crankcase. I also thought the vacuum is a good this. What if I ran a line off driverside valve cover to a hose with filter on the end would that work? But then wouldnt I have to do the same for the passenger? Do not have room to delete line on catch can.
I mean with the LS2 valley cover where on the Ls2 does the valley cover get fresh air in the factory setup with the vented valley
I mean with the LS2 valley cover where on the Ls2 does the valley cover get fresh air in the factory setup with the vented valley
10-23-2009, 08:31 PM
#12
I dont see where the factory setup draws fresh air into the crankcase. I also thought the vacuum is a good this. What if I ran a line off driverside valve cover to a hose with filter on the end would that work? But then wouldnt I have to do the same for the passenger? Do not have room to delete line on catch can.
I mean with the LS2 valley cover where on the Ls2 does the valley cover get fresh air in the factory setup with the vented valley
I mean with the LS2 valley cover where on the Ls2 does the valley cover get fresh air in the factory setup with the vented valley
Yes, run the line off the driver side valve cover with a filter on the end. The passenger line will go to the catch can along with the valley cover. The single fresh air line will be plenty. Unless your check valves are not very free flowing, it is best to use a flow regulator on the fresh air line to control the rate of flow into your intake. Vacuum is good but not too much.
10-23-2009, 08:43 PM
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just ordered speedinc. oil cap breather with check valve installed. Also couldnt you run a crossover line from valve cover to valve cover to equalize the fresh air flow?
10-23-2009, 09:24 PM
#15
If I were you:
I would cap the valley cover port.
Cap the passenger valve cover breather port.
Suck crankcase gases from the drivers side valve cover.
Allow fresh air to be pulled in from that oil cap breather you ordered.
Cap BOTH vacuum ports on the intake and the TB, of course.
Its better to pull crankcase air from the valve cover than the valley cover port because I think too much crankcase oil mist gets pulled out from that valley cover port.
All you need is one way for air to go in (oil fill cap breather) and crankcase gases get pulled from the drivers side valve cover. This will have fresh air flowing across the entire engine crankcase.
With a PCV valve in-line with the check valve, you'll be good to go.
Thats what I would do.
.
I would cap the valley cover port.
Cap the passenger valve cover breather port.
Suck crankcase gases from the drivers side valve cover.
Allow fresh air to be pulled in from that oil cap breather you ordered.
Cap BOTH vacuum ports on the intake and the TB, of course.
Its better to pull crankcase air from the valve cover than the valley cover port because I think too much crankcase oil mist gets pulled out from that valley cover port.
All you need is one way for air to go in (oil fill cap breather) and crankcase gases get pulled from the drivers side valve cover. This will have fresh air flowing across the entire engine crankcase.
With a PCV valve in-line with the check valve, you'll be good to go.
Thats what I would do.
.
Last edited by LS6427; 10-23-2009 at 09:34 PM.
10-24-2009, 12:19 AM
#16
His oil cap breather will be a one way flow only hence the check valve. It will only allow pressure in the crank case to escape under boost but will not allow air in. Without a check valve type breather, you will never maintain vacuum in the crank case during normal driving. Just a lot of air movement. Too much ummetered air if you are still on a maf. If SD, you may run into idle issues and you will have to tune it out.
I've played with this stuff for years with trial and error and is seems that a small amount of vacuum controlled by an adjustable flow control valve to the crank case is the best. There seems to be no right way and too many ways to do it. If it works, use it. It has worked this way the best for me so far.
I've played with this stuff for years with trial and error and is seems that a small amount of vacuum controlled by an adjustable flow control valve to the crank case is the best. There seems to be no right way and too many ways to do it. If it works, use it. It has worked this way the best for me so far.
10-24-2009, 12:29 AM
#17
His oil cap breather will be a one way flow only hence the check valve. It will only allow pressure in the crank case to escape under boost but will not allow air in. Without a check valve type breather, you will never maintain vacuum in the crank case during normal driving. Just a lot of air movement. Too much ummetered air if you are still on a maf. If SD, you may run into idle issues and you will have to tune it out.
I've played with this stuff for years with trial and error and is seems that a small amount of vacuum controlled by an adjustable flow control valve to the crank case is the best. There seems to be no right way and too many ways to do it. If it works, use it. It has worked this way the best for me so far.
I've played with this stuff for years with trial and error and is seems that a small amount of vacuum controlled by an adjustable flow control valve to the crank case is the best. There seems to be no right way and too many ways to do it. If it works, use it. It has worked this way the best for me so far.
You have it right IMO. A simple breather just negates the PCV and vents the engine to atmosphere.
