catch can setups

race4gas

New member
Anyone out there using a custom catch can setup with a drain back to the oil pan? Pics would be great and why you chose to do it that way.

I plan to run an lines from the valve cover to catch can with a baffle and drain back to oil pan. I have not seen anyone running this before, just wondering why.
 

race4gas

New member
I am well aware of that but I have a gen 2 and if I remember correctly it doesn't have a drain to the oil pan or block it relases the pressure back into the intake
 

race4gas

New member
I would say not because the stock gen 3 catch can is really small I would say it would be almost useless if your lookin at making the stock amount of boost. I really don't know how efficient it is though.

Would really like to know how these greddy and cusco cans relieve the crankcase pressure, if at all.
 

GT4_ever

New member
Most universal fit catch cans go from crankcase to can to intake. I blocked off the port on my intake and routed the oil to a catch can that has a few holes to equal pressure.

No oil in intake, crankcase pressure = atmospheric pressure, life is good.

Side note, always makes me laugh when guys put those little breather filters on the end. Sure, you are filtering the air going in, but oil needs a way to go out too!
 

awolo

New member
GT4_ever, can you elaborate on your setup a bit more?

I'm pulling a lot of oil into my intake, going to setup a catch can. Trying to figure out the best way.
 

Mafix

New member
just a couple pointers for you guys.
if you are getting oil in your catch can you are not venting enough pressure from the engine. look at all the performance engine and notice the rediculous pcv setups (and yes i even have one)

do not pull pcv through the intake. i'm guilty of this as well. all it does is cause comtamination in the intake charge, which in turn causes detonation.

there is a very fine line as to what is good enough and not enough. and terminology is also important. there are catch cans and there are breather tanks. i had the prior (60$ setup) and now i have the latter (400$ setup). big difference in performance as well.

pcv systems that blow oil are a cause of torque, not horsepower. fyi. and of course ring gap.

i asked several people about rerouting the breather tank to the oil pan. 90% of the people i talked to (big time tuners, not friends) stated that under no circumstance would they re-introduce now dirty oil back into the system. i tend to agree. and if you have a system that is large enough that it does not insta-fill the tank (which everyone should)then you'll see what i'm talking (and them) about with recirculating the oil. it's f'ing nasty stuff in there.

just my .02 cents on the subject.
 

l0ch0w

New member
Ever thought of a pan Evac?

It uses a venturi tube welded into your exhaust to pull vacuum on your crankcase. Im using one like that in my setup.

For the record, the size of the catch can is unimportant, especially if it drains back into the crankcase. Whats important is the size of the pipes coming out of your valve cover, and your piston to wall clearance.

Here is a picture of the one used in my buddy's setup:
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See how the PCV hoses coming out of the valve cover go into a check valve thats welded onto a tube on the exhaust pipe!
 

Mafix

New member
old school there. the only bad thing about doing that is it makes your exhaust super nasty. no converters on that car! but aside from that, no can needed, weighs less, works just as well.
 

Mafix

New member
oh and to note:
guys using the large dual feed pcv systems are NOT using baffles in the cover. i think for most applications an improvement in the pcv system would be to add a simple catch can and remove the 2 inner baffles in the cover and only leave the 1st plate (the one you see when you flip the cover over).
 

l0ch0w

New member
Josh has run about 1000mi on his setup and its close enough to the outlet of the turbo that it all just gets burnt off. I woudnt say its super nasty or anything...

On a side note, pan evac is a little better than a vented catch can simply because it pulls vacuum on the crank case...

*ps mafix* ur intake filter is too small...
 

Mafix

New member
it's only a 4 inch intake. no where else to put it.

yes i agree that PAN is better. i never thought of mounting it super close to the turbo to light off the oil.
 

ZeroDrift

New member
Thought I'd chime in on this thread since I have some experience with catch cans and air oil separators. The oil that goes inside is actually not just oil, but rather a mixture of oil vapors combined with water vapors. This is what makes the oil contaminated and causes issues such as clogging and produces a mud like foam. Once that is heated the water evaporates and the oil is clean enough to return to the crankcase. This is what several notable manufactures do such as Ferrari and Porsche, not to mention this is common practice on piston engined aircraft. Quality air oil separators will have a heater element of some kind inside to keep the water in vapor form and is returned to the intake to be combusted.

Also, these setups need to be fairly free flowing as to not cause excessive crankcase pressures. So if you have a setup with some sort of filter, make sure its inspected and replaced as needed.
 

l0ch0w

New member
Mafix":1u14cn2i said:
it's only a 4 inch intake. no where else to put it.


there is a calculation somewhere that figures out the minimum filter surface area required at any given HP level.

That said, that filter is most likely choking your motor :p Sorry to be off topic.
 

celigts

New member
So for the 185's is it needed or better off to go for the box or cylinder style catch can?

Looking to get plans for the winter projects.
 

Spectra1

Member
On a side note, pan evac is a little better than a vented catch can simply because it pulls vacuum on the crank case...

Ok so I have read this through a few times and I think I understand most of it but im unsure what exactly pan evac is and how one would go about specifically doing this. Is pan evac when you vent the valve cover into the exhaust using the venturi set up?

Am I correct in saying: pan evac (venting into exhaust using the venturi set up?) > breather tank > baffled catch can rerouted to intake > no catch can

Also some members have been referring to needing to mount the venturi tube at the "right angle" in the exhaust....so what exactly is the right angle? Lastly how does one exactly go about creating a correct venturi tube ie shape, tube side, length?

I was going to do a simple catch can set up but I am intrigued by the idea of simply venting into the exhaust or near the turbo to be burned off. The turbo and exhaust are currently off so now would be the time to do it.

Last question, if I were to run two large lines (say -AN12) from the valve cover to the exhaust do I still need the little nipple on the valve cover that has a line going to the manifold?
 
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