The one I'm talking about is the one that attatches from the intake to the engine. What is the purpose of this? Does the port on the engine suck or blow? When installing an intake should you use another tube or is it ok to put a mini filter on it?

 

I think you should put a mini filter on it.

I have a question about this also, when you get a CAI (carb legal AEM) what are you supposed to do with the breather? For anyone who has seen that cop training video, they say it is illegal :dunno:

 

That tube is designed to draw the oil-laden fumes from the head and introduce them into the intake charge where they will be burned off. It's an emissions-control system.

A CARB certified, emissions-legal intake needs to have a welded pipe fitting that allows this tube to be reconnected and continue to function like the stock intake tubing.

In that SDPD video that [Damnit] is alluding to, the mini-filter is illegal because it allows those fumes to ventilate to the atmosphere.

So, if you are in CA or any state that follows our emissions laws, using a mini-filter is de facto illegal.

 

Your talking about the hose coming off the top of the valve cover and connecting to your intake? It's part of your pcv system. There are fumes in the crankshaft that need to ventilated in order to keep them from coroding inside. the suction from your intake creates this suction that's needed to extract the air.

The Breather filters sometimes are put on because the fumes from the crankshaft go into your cylinders and take up a space where oxygen could be in there. with these filters... though your crankshaft won't have any sort of suction to vent it (unless you running a turbo ).

Now what you can do is use an "oil catch can," which acts like a filter for the fumes but still retaining the suction.