blanz

And my answer is absolutely yes!
The below images is of the unit I have installed and the contents is from over a one year period, and just 1,600 miles on the Joe Gibbs "Driven LS30" oil (5w-30).
I don't put many miles on her (2005 LS2, stage 2 cam and upgraded drivetrain parts), and one years time is usually oil change time unless I drive more than 4,000 miles.
From the color and sediment (goop) at the bottom of the can, it is apparent that moisture builds up and is present in the crankcase and vaporizes into the can, which is a good thing.
This has kept my intake squeaky clean and is well worth the expense in my opinion.
Pictures for your viewing pleasure.

1bdvet

I would think if you had a stock engine, I have LS2, not molested with any mods I wouldn't need it, and if GM would of installed if I needed it.

Iceaxe

When it comes to GM "needs" has got nothing to do with it.

With GM think "good enough", if it will save a few dollars. You build a million cars and save $10 a car and pretty soon you're talking big money.

YMMV

ART T

IMO they are needed. I just emptied the one on my 2012 base after 4000 miles and I was surprised how much oil was in it. My car has 19500 miles on it. You can buy a very nice unit on ebay for $20.00

Turbo6TA

I agree that a catch can is not "needed' in a stock LS engine ... but . >

Case in Point ... I purchased my 2011 GS new in 2011

2 years later (2013) I installed a set of headers and a got a dyno tune. Other than that, the engine stayed completely stock

When the car was 8 years old, I removed the stock intake manifold and installed a Heartbeat SC (the car had 18,000 miles on it then)

Lots and lots of oil in the intake manifold. That's when I installed a catch can along with the supercharger ... I really don't want all that oil gumming up my supercharger's rotors.

Dano523

Pull the TB, and look inside the intake manifold, and your still going to find oil in it.

Although you have a catch can on the dirty side (valley port to intake port), your not catching the oil on the clean side (valve cover to port in front of the TB port) at wide open conditions isntead.

Fast Dawg

I agree with @Iceaxe about GM and cars needs. The C6 "needs" to have a lot of things that owners are now repairing on low mileage well maintained cars.

If you look at good speed shop's build packages, they all include catch cans for the LS engines. A couple of you provided pictures that should tell doubters why they are needed.

BadAV

Are they needed? Absolutely not. Does the accumulation of condensed "gunk" in the can provide "proof" a catch can is needed? Nope, because almost all of it goes through the intake in vapor form and is burned in the combustion process. At what mileage should developing problems be considered enough miles to consider it an issue - 300k miles? There are plenty of LS based engines with 300k/400k/500k miles without catch cans. If you think adding a catch can might provide a benefit, by all means add one. Just make sure to empty it before it fills up, and be aware that they can cause problems if the condensate freezes on cars that are kept outside. I personally see the pros/cons on both sides of the equation but don't think the possible benefits are worth the cost of admission. YMMV.