oil catch can install

[teedoff00]

IJ, could you re-post the PCV valve you are using? The link you had posted doesn't work.

Would this work? It supposedly has 5/8" on each side, however one side is not barbed. But would the construction withstand moderate boost conditions?

Thanks!
edit: link below, forgot to include it...

 

[IJ.]

It's a Fuel Miser 102 from memory, all steel barbed both ends -8 and -6 from memory.

 

[teedoff00]

Huh, well I didn't seem to find anything on any kind of Fuel Miser valve, but would something like this work?
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_PCV-Valve-Purolator_5850312-P_5_R|GRPFILTAMS____

Thanks!

 

[IJ.]

This is the one I used as being barbed it was easier to install.

http://shop.advanceautoparts.com/we...-Valve-Purolator_5850495-P_5_R|GRPFILTAMS____

 

[teedoff00]

Perfect! Thanks for the info IJ.

 

[iskrem]

So this will work right (basicly original system with catc tank inbetween)? )

 

[BoostJunkie]

Thats what I am thinking iskrem.

 

[hvyman]

thats the correct way.

 

[Enraged]

This is the one I used as being barbed it was easier to install.

http://shop.advanceautoparts.com/we...-Valve-Purolator_5850495-P_5_R|GRPFILTAMS____

I got one of these the other day, but blowing on it, it seems to leak air. Will this be an issue under boost? I tried a few similar pcv valves and they all seem to leak a bit.

 

[IJ.]

Once it has some Oil in it they seem to seal much better, the leak is tiny and shouldn't make any difference in use.

 

[MarkIII4Me]

So this will work right (basicly original system with catc tank inbetween)? )

I don't think that will work correctly. From reading through all the posts it appears that the line running from the tb/intake manifold needs to pass over the valve covers and then go to the catch can inlet to push the vapors during idle (good idea to use 1-way valve after tb to prevent pulling vapors into the intake manifold under boost). The catch can outlet needs to be connected to the turbo intake pipe to pull vacuum under boost (pulling vapors from the valve covers).

Is this correct? I'd really like to know since I'm installing my catch can shortly.

 

[jdub]

The routing is correct. The PCV (check) valve needs to be in the line from the T to the turbo intake air pipe (accordion hose), orientated so it only allows flow to the intake pipe. That will allow any boost pressure from the TB orifice to flow to the intake and will put max vac on the catch can off boost since it will block any air from the accordion hose.

A 2nd PCV valve next to the TB will not hurt, but needs to be orientated to allow flow to the TB...it will prevent any possible catch can pressurization under boost. Not absolutely necessary since the pressurized flow is small due to orifice size and will follow the path to the accordion hose (least resistance) like stock. Plus, the air has already been metered at the AFM.

 

[MarkIII4Me]

The routing is correct. The PCV (check) valve needs to be in the line from the T to the turbo intake air pipe (accordion hose), orientated so it only allows flow to the intake pipe. That will allow any boost pressure from the TB orifice to flow to the intake and will put max vac on the catch can off boost since it will block any air from the accordion hose.

A 2nd PCV valve next to the TB will not hurt, but needs to be orientated to allow flow to the TB...it will prevent any possible catch can pressurization under boost. Not absolutely necessary since the pressurized flow is small due to orifice size and will follow the path to the accordion hose (least resistance) like stock. Plus, the air has already been metered at the AFM.

Seems simple enough. So both the intake pipe and the intake mani are pulling pressure through the catch can, which in turn pulls vapors from the valve cover. Right?

My catch can has seven ports on the top as well as the bottom. If I run lines from both valve covers to the cc bottom ports (either separately or T'd), a line from the intake manifold with a check valve to a top cc port, and a separate line from the turbo intake pipe with a check valve to another cc top port, I should be all set; right?

I figure this way I'd be pulling all the vapor through the bottom of the cc and through the steel wool, leaving the oil and moisture on the bottom of the can. I guess I'd have to raise the lower lines so they don't fill will too much oil though.

Sound good?

 

[Enraged]

The routing is correct. The PCV (check) valve needs to be in the line from the T to the turbo intake air pipe (accordion hose), orientated so it only allows flow to the intake pipe. That will allow any boost pressure from the TB orifice to flow to the intake and will put max vac on the catch can off boost since it will block any air from the accordion hose.

A 2nd PCV valve next to the TB will not hurt, but needs to be orientated to allow flow to the TB...it will prevent any possible catch can pressurization under boost. Not absolutely necessary since the pressurized flow is small due to orifice size and will follow the path to the accordion hose (least resistance) like stock. Plus, the air has already been metered at the AFM.

maybe im mistaken, but that seems backwards to me. under boost, you dont want any air going to the catchcan, as that will pressurize the crankcase, so the PCV valve should go between the T and the throttle body, not the T and the accordian hose, correct?

the accordian hose will always be pulling vacuum (it will never be pressurized) so why would you need a PCV valve there?

also, isn't there a small check valve in the stock TB just for this reason?

 

[jdub]

1st rule: The crankcase is pressurized due to blowby.
2nd rule: Air pressure (or vacuum) will follow the path of least resistance...keep this in mind.


On the stock system, it's the TB (intake manifold) that provides vac...this covers over 90% of operating conditions. Under boost, flow reverses through the TB orifice (there is no check valve)...contrary to popular belief, the intake pipe does not provide vacuum. The reverse flow from the TB under boost over the cam cover outlets "pushes" the crankcase vapors to the intake pipe. This is obviously much less efficient and is the reason guys that try to use the intake pipe as the vac source for a catch can will always fail.

On the depicted catch can system, the catch can will not pressurize for two reasons:
1) The crankcase is marginally pressurized due to some blowby, creating resistance to that path.
2) The intake pipe is not pressurized, therefore no resistance, therefore flow goes to the intake pipe. This is exactly how the stock system works.

There is no significant vacuum at the intake pipe...to get any real vacuum, you would have to block the filter inlet to the pipe.

A PCV valve at the intake pipe that allows flow in the direction of the pipe, but not in the direction of the catch can will allow the TB to put max vac on the can...flow has nowhere else to go but from the cam cover outlets, to the can, to the TB port. Under boost flow reverses through the TB orifice...it will not pressurize the can because it has a much less restrictive path to the intake pipe...the pcv valve will not restrict this reverse flow. You also need this path to the intake pipe to allow crankcase pressure escape.

Like I said, if you want to put another PCV valve at the TB, have at it. That's it for the physic lesson for today

 

[Enraged]

but in his drawing, the TB port doesnt blow over the valvecover ports. it simply goes to a T, and then the accordian pipe and the catch can. i realize in the stock configuration it works like you said, but on a modified setup like his drawing, wouldnt it just create a boost leak (especially becuase most people use larger diameter heater hose when installing a catch can, and particularly for people that arent using the stock TB)? thats how i understand it at least, and seems like why people like IJ use a PCV valve on the TB port.

 

[MarkIII4Me]

A PCV valve at the intake pipe that allows flow in the direction of the pipe, but not in the direction of the catch can will allow the TB to put max vac on the can...flow has nowhere else to go but from the cam cover outlets, to the can, to the TB port. Under boost flow reverses through the TB orifice...it will not pressurize the can because it has a much less restrictive path to the intake pipe...the pcv valve will not restrict this reverse flow. You also need this path to the intake pipe to allow crankcase pressure escape.

Does this mean I would have to have the hose from the tb T'd into the intake pipe, or will it still work to have to separate hoses with check valves; one from the tb to the cc and one from the intake pipe to the cc?

 

[jdub]

but in his drawing, the TB port doesnt blow over the valvecover ports. it simply goes to a T, and then the accordian pipe and the catch can. i realize in the stock configuration it works like you said, but on a modified setup like his drawing, wouldnt it just create a boost leak (especially becuase most people use larger diameter heater hose when installing a catch can, and particularly for people that arent using the stock TB)? thats how i understand it at least, and seems like why people like IJ use a PCV valve on the TB port.

Take the catch can out of the diagram and connect at the two T's...is it any different than stock?

Do you know what an orifice is? How is a larger hose going to affect flow though an orifice? The stock sytem has a controlled boost leak through the TB orifice and so does this modified system...connected to the exact same location on the intake pipe (accordion hose). Like I said earlier, this "leak" is metered air (post AFM) and does not affect the engine in any way.

For the third time: You can put a PCV valve at the TB if you wish. I suggested putting a PCV valve at the intake pipe to increase vacuum on the catch can vs allowing flow from the intake pipe to the TB.

You can't compare to what Ian has done...he used a FFIM and different TB...there was no orifice like on the stock TB. In his case, a PCV valve is required.

This is a really simple system...I'm wondering why it's so hard to understand. It would help if you guys read what I write (a couple times if necessary) and understand what I said.

 

[IJ.]

I'm "special"

The stock PCV is one of the only systems from Toyota I've seen that hasn't been made mindlessly overcomplicated!

The orifice while an open boost leak while under pressure has such a small area that I doubt you could measure any difference open or closed.

 

[jdub]

Seems simple enough. So both the intake pipe and the intake mani are pulling pressure through the catch can, which in turn pulls vapors from the valve cover. Right?

My catch can has seven ports on the top as well as the bottom. If I run lines from both valve covers to the cc bottom ports (either separately or T'd), a line from the intake manifold with a check valve to a top cc port, and a separate line from the turbo intake pipe with a check valve to another cc top port, I should be all set; right?

I figure this way I'd be pulling all the vapor through the bottom of the cc and through the steel wool, leaving the oil and moisture on the bottom of the can. I guess I'd have to raise the lower lines so they don't fill will too much oil though.

Sound good?

I would not pull crankcase vapor into the bottom of a can. I might be misunderstanding this, but fluid collects at the bottom and you do not want any back flow to the cam covers.

Does this mean I would have to have the hose from the tb T'd into the intake pipe, or will it still work to have to separate hoses with check valves; one from the tb to the cc and one from the intake pipe to the cc?

Route as depicted...if you want to use 2 PCV valves:
- At the TB with flow direction toward the TB.
- At the accordion hose with flow direction toward the hose.