Idea: 2x PCV valves in series?

[Bigsyke]

Im about finished with this PCV setup. What I have is a Greddy catch can, with 2x 3/8ths NPT ports on the top, and a 1/4th NPT fitting on the side. We know the OEM PCV valves are a 3/8ths NPT size. So what I did was put a 1/2" barb (3/8ths thread) into the OEM PCV location (black seperator box), and ran a 1/2 hose to a 1/2 to 3/8ths reducer barb. From there I ran the crankcase hose to the side port on the catch can. I then installed 2 OEM PCV valves on the top two ports. The reason they are installed "on" the catch can versus before is to prevent fuel/oil vapors from clogging the PCV valves. From the 2x OEM pcv valves, I then ran them to a vacuum block ($8 from northerntool), which then goes to the brakebooster port on the IM.

Even the FSM tells us that at higher loads the PCV valve will be insufficient to evacuate unburnt fuel vapors, adn they will go through the valve cover port. I do not like this because it gives fuel/oil/water vapors the opportunity to get in contact with your oil, and engine internals. I believe this setup with the extra flow should offset the extra hosing required for the catch can. Also the OEM KA24DE engines have a flow restrictor installed in the OEM intake tube- which connects to the valve cover; which should limit the suction, so you dont have an extreme vacuum leak.

Since the KA24de is a metered system, all the extra air being sucked in from the dual PCV valves should be registered via the MAF correct? would this still cause a vacuum leak/hang? Ive experemented wtih all sorts of setups, and have always came back to either a higher flowing PCV valve, or dual PCV valves.


http://i52.photobucket.com/albums/g37/cbuettner84/1005092235.jpg

http://i52.photobucket.com/albums/g37/cbuettner84/vac.jpg

This sketch took 4 hours, but landed me an award at the guthre museum of arts.

Thoughts?

[awesomenick]

BUMP.

I want to know more. Opinions, etc.

[BustedS13]

i'd like to hear more about this.
that diagram shows two pcv's in parallel, btw.

[Bigsyke]

apologies, yes in paralell.

I have another vacuum block comming in the mail to complete this.


I found an AWSOME website where you can get vac blocks for like $8.

Thefind.com Search for NPT manifold.

[Bigsyke]

So I got it up and running today. Feels much better. The idle stays at about 900rpms.

Now I do have a question. Vacuum is vacuum right? Im worried about the length of the vac hose, and how this would cause venting issues durring low vac (high loads). I also think the high idle is from my auto ecu still being used.

[Bigsyke]

I Put it back to stock yesterday, drove about 60 miles of spirited driving. I then decided today to reinstall everything.

I also removed the OE ka24 oil restrictor and changed it out for I believe a 5/8ths barb. (intake to valve cover) - its used to prevent oil being sucked into the intake at high loads, and create a negative pressure inside the engine crank case to ease with vapors being removed via the PCV valve)
http://i52.photobucket.com/albums/g37/cbuettner84/1005092235b.jpg

Much much much better. Idle stays constantly around the same, engine sounds healthier, idles dont dip when comming to a stop due to the Auto ECU.

I think the extra air is still metered, however it feels constant.

http://i52.photobucket.com/albums/g37/cbuettner84/1005092236a.jpg

I would love to see if other people would try this, I have not had any extra blow by of oil loss. It just seems as if it would vent better at all conditions.

[slider2828]

So do you plug up the Valve cover PCV and the PCV conneciton in the intake manifold? If so how did you do that....?

Because at this point, it doesn't seem like you are pulling any more vacuum than stock....

[Bigsyke]

I dont know whats being plugged other than the OE PCV tree under the IM runners.

The Valve cover to intake arm/TB hose stays the same, I only removed the reducer and replaced it with a 5/8th barb for better flow.

The OEM PCV valve is replaced with a 3/8ths NPT fitting/nipple, and ran to the side of my catch can. From there I installed 2 OE PCV valves on the top, as shown in the pics. Those 2 PCV valves are run to a vac block, which then ends up getting vac from the Intake manifold. There is more air moving around inside the crank case.

[slider2828]

I would venture to route it not to the intake manifold, but rather see if you can route back to the turbo which is the biggest source of vacuum.... What do you think? If all your pcv's are in place, this should not lead to leakage....