It depends on the quality of the catch can.
If it can properly create a low pressure area where the oil drops out of the flow stream then they work. If they product hasn't been engineered properly it will not be as effective.
Having a medium on which the oil can coalesce on to is also key - it needs a spot to 'catch' the oil also helping the process of removing oil from the air.
If it can properly create a low pressure area where the oil drops out of the flow stream then they work. If they product hasn't been engineered properly it will not be as effective.
Having a medium on which the oil can coalesce on to is also key - it needs a spot to 'catch' the oil also helping the process of removing oil from the air.