Just that? What exactly is it for? I'm curious, I tried following the hose to see where it runs but it gets down where I can't see it!

 

I wonder as well.

 

If you are talking about the little hose on the side of the air filter, it is the suction hose to the AIR pump tucked behind the left head light.

 

What does the AIR pump do?

 

Let me see if I can get this right. THe AIR pump is a pollution control device put on engines in the early 70's (I think). It pumps outside clean air into the exhaust manifold to help burn anything that got through the engine unburned. It boosts the oxygen content right at the hottest exit of the engine to incenarate things that would be pollutants heading for the atmosphere. They used to be driven off a belt on the engine, robbing a little HP. The ones on the LS1's are electric and they only run when nessasary. I mainly hear mine run when the engine is first started and cold, and turn off after a couple of min. Can anyone else add anymore to this? Later>>>>>

 

Is that what that high pitched noise is right when I turn the car on? It stops after a minute or two. I did not know that...

 

I always wondered what that noise was. It sounds like a hose being purged, and you hear a little "whoosh". I am glad to know that that is not something wrong.

 

It leads filtered air (obviously) through the AIR pump and in some way extends the life of the cats. That's what I read anyways. It only runs for the first five minutes of open loop engine operation. I could be wrong.

 

So thats what it does, cool now I know, and knowing is half the battle

 

I'm not driving my Z28 as much because of the weather but I cranked it up the other day and heard that loud hissing sound (it was very cold that day) and before I could pop the hood it was gone.

Thanks for clearing that up. It was a little bothersome not knowing.

 

you're almost right
The fresh air is added to the exhaust at startup while the motor is running rich to speed the catylist up to temp. Once the catylitic converters "light" the air pump turns off. This is a help in reducing emissions sooner after startup.
The filtered air is to increase the life of the pump itself. Because auto manufacturers have to guarantee that all emissions equipment will last 50,000 miles.

 

So when the pump stops working, I can just rip that sucker out of there, right?