Here is the link that I am asking about.

http://www.hondaautomotiveparts.com/...=BREATHER+TUBE

You see where the #4 tube turn southeast and goes into the same general direction as the #3 tube. That #4 vacuum tube goes into the upper intake arm. Now, my question is, what does that tube do?

 

its not a vacume line your talking about the line going from the head to the intake right? i believe it lets exhaust gases flow back into your intake but im not sure i know if you disconnect it and start the car there is a nice little put put put of gases comming out of it.

 

What is the 'head of the intake'?
Why would you want exhaust gases in your intake?
I've 'accidentally' had that tube out of the intake arm for about 3 months. I havent noticed any change. I replaced it today, and still, no change.

 

it vents vapor from the valve cover back into the intake to help emissions

 

leave it out of your intake and cap the hole on your intake if you want put a small breather on your head where that hose used to be ( be sure to keep the collant hose on or run a new one) the cheapest way is just to take it off an cap it but if you gotta be all pretty

 

mah bad i didnt mean head of the intake i ment
from the head or valve cover i guess... to the intake

 

Ok, capping the intake arm, I understand will slightly boost airflow and thus hp, but that breather, i've seen it on H22's but never on an F22. It will also vent the vapor? I just stick that breather right on into that hole where the tube was?