catch can question
06-01-2011, 05:56 PM
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catch can question
If your running a oil catch can what do you put in place of the vacuum port on the manifold. A standard pcv vale isnt going to hold up to boost pressure is it? My can does not recirculate the oil!
06-01-2011, 07:28 PM
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Re: catch can question
I'm confused. A catch can should normally just sit in between the vacuum between the valve cover and the the vacuum port on the manifold (that the line running from the valve cover was originally feeding to). Why are asking about what to connect to the vacuum port?
06-02-2011, 10:50 AM
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Re: catch can question
The PCV is plenty capable of holding up to boost. It's a small valve (and doesn't have a lot of internal surface area) and must be able to withstand vacuum. That usually makes them plenty strong for boost pressure.
Anyway, the bigger problem is the PCV leaking, which is the reason you need a catch can in the first place. Boost pressure is going to force the valve closed obviously, but if it leaks then you're pressurizing the crankcase. It's usually best to put the PCV valve between the intake manifold and the catch can, because the catch can will keep the PCV valve from getting gunked up and the PCV valve will also limit the pressure than the catch can will see.
You need a second catch can to go between the valve cover vent and the intake system, because that's the other leakage path out of the crankcase.
Really it's nice to have a catch can at any place where there will be a pressure differential between the engine and the intake system, which is usually just those two places (the PCV hose and the valve cover vent). Multi-head cars (V6, V8, Subaru or Porsche boxer) might have slightly different requirements obviously.
I guess I'm not really sure what the question is, because the oil catch cans just go inline with the hoses that are already there.
Anyway, the bigger problem is the PCV leaking, which is the reason you need a catch can in the first place. Boost pressure is going to force the valve closed obviously, but if it leaks then you're pressurizing the crankcase. It's usually best to put the PCV valve between the intake manifold and the catch can, because the catch can will keep the PCV valve from getting gunked up and the PCV valve will also limit the pressure than the catch can will see.
You need a second catch can to go between the valve cover vent and the intake system, because that's the other leakage path out of the crankcase.
Really it's nice to have a catch can at any place where there will be a pressure differential between the engine and the intake system, which is usually just those two places (the PCV hose and the valve cover vent). Multi-head cars (V6, V8, Subaru or Porsche boxer) might have slightly different requirements obviously.
I guess I'm not really sure what the question is, because the oil catch cans just go inline with the hoses that are already there.
Last edited by Fabrik8; 06-02-2011 at 10:54 AM.
06-02-2011, 02:44 PM
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Re: catch can question
One of those three turbo cars has the right type of hose to be that close to the turbo and turbo manifold. The others could get pretty melt-y
06-02-2011, 04:56 PM
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06-02-2011, 05:40 PM
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