I was at a car show Sat., and saw I C6Z with an interesting doodad attached to the motor, but I haven't a clue what it is/does. It was driven by a small cogged belt, and hung of the pass. side head. There were electrical harness connects, and a rather large, but wimpy pulley to drive this thing. The owner wasn't around to ask, and the car appeared to be NA, including a lack of NOS. There were also a pair of small cannisters, mounted horizontally on top of the air cleaner shroud. There was alot of CF bling, and the car had LTs. I know this' a crummy description, but maybe someone knows exactly what this stuff is.

 

A picture would be nice here!

 

It sounds a lot like a reciprocating driven, externally cooled flux capacitor

 

sounds like a vacuum pump

 

Yep.

 

 

Is this for venting the crankcase?

 

yes it is.

 

C5 C6 's are notorious for having oil sucked into the intake manifold via the PCV system---The C5's LS1's were really bad-- On the LS6 they finally changed the PCV location and the entire valley---didn't help much---On a modded engine --cammed it's even worse----I cahanged from a stock LS6 intake to a FAST I stood the LS^ up against the wall with the TB side on the ground--The next day i was shocked to see a 10" puddle of oil in my garage under the manifold !!!
Since then i have tried many many things to cure this problem---catch cans---PCV valve etc----I finally tried a coelesating filter and wha la--NO OIL----The l clear bottl on the bottom gets full about every 1000 miles--unbeleivable--
I would guess this is some sort of catch can assembly--probably used in a racing application converted to the C6----The oil fouling intake is a huge deal---Especially with synthetic oils and a dry intake like on a gen 3 engine---The oil realy sticks on the internals &carbons up badly--
and contaminates the intake charge--

 

I too installed a catch can on my H/C/FAST LS6, but I didn't get hardly any oil in about 3k miles of regular driving. I had it vented from the valley, and T'ed into the line from the pass. side valve cover. Now I'm installing an A&A Vortech, which eliminates the catch can.