catch can installation help needed w/diagrams!

[toyotahachiroku]

stock

after reading a few different posts i came up with this

what do you think guys?

under no vacuum, it could go either way.

under vacuum it should vent either side depending on which side has more vacuum. also, putting in a second one way valve will make sure no "extra" air will get through to the manifold side.

under boost it should vent to the air filter side. even if on the intake manifold side leaks boost through the pcv in the other direction, it wont ever pressurize the can because it can escape through the air filter side.

there were so many schools of thought on this when i was researching how to hook up a catch can. let me know what you guys think.

 

[tissimo]

no pcv valve needed on the intake, there is no pressure there.. and doesn't matter if air is leaked into the intake manifold (cause its map based)

Looks good to me..

 

[annoyingrob]

putting in a second one way valve will make sure no unmetered air will get through to the manifold side.

No such thing as metered air on a 1JZ

I like the setup though. I'm going to copy it, and use it on my car.

Edit: I just had a crazy idea. Drain the catch can into the oil pan so all the condensed oil just goes right back into the engine

 

[toyotahachiroku]

the drain back condensed oil has been done ages ago by bmw. i had that stock on my E30 M3. i believe it was called a oil seperator valve or something...one side hooks up to valve cover, one side to the oil return to the oil pan and one side to the intake manifold...hahaha

oh...if i dont put a valve on the intake side...wouldnt it act like a vacuum leak though? the map might get the correct reading but im still letting more air than i should though?but i guess teh stock one is kind of like that as well...

 

[annoyingrob]

the drain back condensed oil has been done ages ago by bmw. i had that stock on my E30 M3. i believe it was called a oil seperator valve or something...one side hooks up to valve cover, one side to the oil return to the oil pan and one side to the intake manifold...hahaha

oh...if i dont put a valve on the intake side...wouldnt it act like a vacuum leak though? the map might get the correct reading but im still letting more air than i should though?but i guess teh stock one is kind of like that as well...

Correct. It would suck in more air, and cause your car to idle slightly higher than it would without the valve. You are also correct that the car expects this in a stock system.

 

[Rich]

Just a detail; the things you call 'pcv' are called a one-way valve. The whole system as you have drawn it up is called the pcv > Positive Crankcase Ventilation.
And yes, you can leave out the one-way valve on the intake. The only way pressure could enter the system is through the connection on the intake manifold which you have already protected by that one-way valve there.

 

[88mkIIIproject]

I like the setup, I will have to try it on my car. I like the idea of returning the oil back into the system...

 

[tsuper92]

i don't think draining the oil back into the pan is a good idea.it will have condensation in it and could contaminate the oil in your pan.my .02$

 

[toyotahachiroku]

 

[Rich]

i don't think draining the oil back into the pan is a good idea.it will have condensation in it and could contaminate the oil in your pan.my .02$

I agree, no way that sh*t is going back into my engine. And toyotahachiroku, just because some car manufacturers do return the oil from the cc into the oil pan doesn't mean it is good for your engine. Just look at the pcv system of a stock 1jz, it works but it's not good for your engine.

A car manufactor has to compromise; they can ask a client to check and fill up oil and window washing fluid, but they can't ask them to drain a catch can every month and be stuck with cans full of sludgy oil. If you look at the people who buy new bmw's, no way they're gonna mess with tapping of oil from a catch can. So bmw's solution is one step better than toyota did on the 1jz, but in the aftermarket you can do it properly all the way.

 

[toyotahachiroku]

its just to show you guys such a system exist. but i never said it was a good idea. when i owned the m3, i had that separator valve removed from my car. it was a system that was prone to failure. dont get me started! the valve was such an after thought too! and, it was standard on the north american versions in order to meet emissions standards.

i think the plumping with the pcv valve in a 1j is a much better idea stock compared to stock. also, replacing a pcv valve run you maybe maximum $10 bucks. replacing that damned bmw part $200 and up. why do you guys think i sold the m3 for a 1j supra? haha