Can anyone tell me what the purpose of the valve cover ports is? You know....... the ones that NW catch can kit deals with. Why are they connected to the intake venturi?

 

It's all very complicated and has references to the Bernoulli principal and crap like that.
In short, I am informed by Rob at Needswings that the big hose ( the one at the back on the left side ) is to equalize pressure in the engine, the 2 little ones ( that go to the catch can ) are to suck the bad old oil fumes out of the engine and poke them back through the throttle body so they can be burned. The catch can stops that.

I got real smart one time and decided I didn't need the big hose, so I capped it off at the cover and the air intake pipe. Bad mistake. The engine made noises you would swear was a water pump going bad, it got all happy again when I replaced the hose.

N'es pas ?

 

One more ? Does the NA car have these ports? I really haven't looked closely at the NA engine.

 

Look carefully at my attached picture in this and the previous post.
Mine is an N/A.