Z06 Exhaust Butterfly settings...

I've had my 2007 Z06 for just over a month now, awesome car!... someone told me the exhaust butterfly values you see at the rear of the exhaust system are closed for normal operation and open when you get on the accelerator... my questions are; Is this true?... my observation is they are always open.  Comments?
 
Thanks... Steve

What you were told is true, during normal driving the butterfly valves are closed and they open only under certain conditions of higher RPM and full throttle, etc.  They are closed at idle and when the car is at rest, etc. 
 
Check whether: a) what you are looking at is in fact the butterfly valve, and b) that it is closed when the car is stationary but the engine is idling.  I have what is basically the same type of system on my Porsche and the valves stay open when the engine is off, but shut as soon as it is started and at idle.  May be the 'vette is similar, I've never bothered to look.

Thanks Lee for the tip... this weekend I checked the exhaust butterfly values and you are right, they close once the engine is started and at idle (and completely open when engine of off).