Oil Catch can

[DisEpyon]

hello,

Im planning on welding me an oil catch can and im trying to get some interesting ideas, instead of the cylinder can type.

I came across this picture of some one else car and im wondering if this would be a good design. The only thing that i dont like is how the back port on the left side of the valve cover extends that long to the breather tank.

Would it be better for the port to go to the breather tank, or just stay with the intake manifold?

http://i106.photobucket.com/albums/m271/disepyon/22_2sized.jpg

Thanks, Brent

[WizardBlack]

You can't have one set up to go to a catch can and not the other. Let me explain, you have two vents. One is the crank<->valve cover vent that goes to the intake pipe and the other is the valve cover to intake manifold vent. They work like this in stock form:
1. The crank/valve cover vent is hooked to the intake pipe. At idle and in vacuum, the turbo doesn't pull enough vacuum to be much use, but in boost it does. This vent works best in boost.
2. The valve cover/intake manifold vent has a check valve in it so boost doesn't get pushed into the valve cover. It only works when in vacuum and the intake manifold pulls good vacuum to ventilate it then. This vent works best in vacuum.

You see that they work together to get the job done. If you have a MAF equipped car, you have to be careful. You can either vent your catchcan to open air with a filter or recirculate it.
1. If you vent to air, you must do both. If you only did the crankcase/valve cover vent, in vacuum you would see air pulled like this:
intake manifold -> vent tube -> check valve -> valve cover -> other vent tube -> catch can -> open air. You would therefore have open, unmetered air pulled in when in vacuum and therefore run LEAN in vacuum. Boost would be unaffected.
If you plumb your catchcan back into the intake pipe, you could do the single vent line and leave the other one (on the intake manifold) alone.
Alternatively, you run BOTH vents to the catchcan and breathe it to atmosphere. Additionally, you cap off the tap you just opened on the intake manifold and the intake pipe. (I prefer this way, myself and this is what the image you posted shows)
2. If you recirculate the catch can, the crank vent is easy, but the intake manifold/valve cover vent is trickier. You have to remove the checkvalve from the valve cover and hook it up between the catch can and the intake manifold. Then it will essentially 'catch' all the lines and you won't have a leak. Make sure that the collected vent lines, after they are routed through the catch can, go back into the intake pipe after the MAF and before the turbo. Use the same spot as original if you can.

I hope that clarifies things.

[DisEpyon]

wow, nice post

helps alot more

when you said that you have to have both vents to the catch can, thats what i was going for. i just want to make sure it was ok to untap it from the manifold(kind of used to being around honda people and knowing how the motors on those cars are vented.) and i hardly see any sr use a breather tank style like this, its always the same old regular cylinder catch can for (one side use) like you said. so i wasnt to sure about it.

Ok, so right now im using the stock maf, would it be best to wait until i get a standalone unit to get rid of the maf, or is it safe for me to go ahead and make this?

do i still need the check valve or get a fitting thats open?

im using a greddy manifold, so pluging up the port is easy.

the one im gonna make will be a little different from that pic, i dont like how they did some of the stuff.

thanks, brent