what is this intake hose? What's it do?
 

This isn't my setup, but i just put a K&N panel filter in and swiss cheesed the airbox. I noticed this line(The one that the tiny filter is attached to) is broke leading to some type of pump or something. What the heck is this? Something for emissions?


Attachment 45178

It goes to the secondary air pump that sits below the air box and feeds air thru one of the hard pipes that sits above your exhaust manifold to the valve sitting on the back of the head on the exhaust side.

Is it something I need to replace if its cracked/broken on the lower side? Open air goes to it still obviously...

You should. The pump should be pulling in filtered air as not to destroy it.

okay, I'm not gonna go oem and pay out the whazooo, but I'll get a patch piece to clamp/tape onto the broken section. Thanks for the help! What exactly does that air pump do? I'm new to audi's. I've owned, built, turbo'd many honda's and they don't have anything like this!

It blows fresh air into the exhaust side of the head just behind the exhaust valves.

ah, gotcha. did some reading and found that it helps with cold starts

Helps for cold idle since it doesn't come on right as you start the car.

It's mainly for emissions. It helps the cat light-off on cold starts and is also used to test the O2 sensors.

What size and degree of elbow did you use for that??