I have a GReddy catch can I and I was searching on how it should be installed on my boosted LS. I read a lot of stuff and none of it is sitting well with me. The comon conception is that it should be installed between the PCV and the IM. I don't see why this would do any good.

The PCV opens proportionally to vacum. It is closed under boost. This means no gases are intering the IM through the PCV under acceleration. Once the throttle is lifted and the engine makes vacum the gasses are evacuated through the valve and sent into the motor at the best possible time. This means that at the time when the "detonation inducing" gasses are being expeled the motor is not under load. It seems to me that to get rid of the PCV valve would allow the gases into the combustion chamber at the worst possible time, under load.

Now before I had the catchcan, I would see oil in the turbo inlet pipe and I concluded it was being sucker out of the breather in the valve cover and pulled through the turbo and compressed into the IM. Yuck. That's why I got the catch can in the first place. Since the PCV valve is closed under boost there is only one place for the gasses to go and that is through the oil galleys in the head and out the breather. It doesn't take much convincing either considering there is a turbo compressor making a lot of vacum at the end of the line from the breather to the turbo inlet piping.

Since I've installed the catch can, my throttle plate has stayed clean and it's obvious the line going into the can is oily and the line coming out of the can that's going to the turbo inlet piping is clean.

This goes against almost everything I read on this site about catch cans but it makes total sense to me. Please feel free to post your opinion about this.

 

My thaughts are exactly the same. TTT bump to see if anyone can share more. I suppose your catch can was installed between valve cover (?) and turbo intake (?) I was definetly thinking of doing that with my setup. An oily residue is noticeable, in trace amounts, in my intake tube as well.

 

i'd rather have a vac pump, and not return any gasses to the intake manifold. just occasionally drain the excess oil out of a catch can.

Brad

 

I will be using a exhaust evacuation system.

 

Man, that exaust vacum things sounds like a real solid idea. So would you just get a nipple welded to your exhuaust that runs at an anlge opposite the flow of gas? I suppose this would make vacum. I wonder how much?

 

Can you post some pictures of you catch can setup? So you put it betweent the breather on top of the valve cover and the turbo inlet?


[Modified by Ek00si, 5:55 AM 1/20/2003]

 

greddy catch can is just a big aluminum box...is not baffled...if you're running a catch can from the PCV valve back to IM, you'll need to run a baffled catch can...

if you;re running a greddy, you just need to run it from the valve cover breather to the intake pipe..all it does is push oil vapor from blow by back to the head, instead of entering the IM....

stan

 

So...which is most efficient? What would be the best for a properly fuctioning crank case system?


[Modified by Ek00si, 5:59 AM 1/20/2003]

 

baffled...

 

The most efficient is an open atmosphere setup. It's just not EPA friendly.

 

so would a endyn catch can system suffice?

http://www.theoldone.com/components/breather/

 

any baffled is fine...

I dont; run catch can...just leave the oil chamber as it is, the outlet is out to open atmosphere , then run a filter from the valve cover breather to intake pipe..

stan

 

Thats right, I have done this on many boosted cars and it works good.

I will give you some more details soon if you are interested, once I get a parts list together.It will also be EPA friendly to a point.