Convertible Exhaust Butterfly Valve - Service Bulletin - Page 2 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Michael Rophone · 04-15-2013, 01:34 PM

I was annoyed at the random, but constant, tapping noise at idle coming from the rear.
The first time I heard it was sitting idling in my driveway.
I thought someone was having roof-work done next door...but it was Midnight.

I don't know what the second owner ever did.

layzurguy · 04-17-2013, 12:22 PM

get some headers and exhaust....problem solved

steveintulsa · 04-17-2013, 10:40 PM

I just spot-welded mine open (after muffler delete), Much better full range sound at idle.

layzurguy · 04-17-2013, 10:55 PM

Quote:

Originally Posted by steveintulsa

I just spot-welded mine open (after muffler delete), Much better full range sound at idle.

Right on!

ZL1DropTop · 05-30-2013, 11:28 AM

I believe I have experienced this problem. I brought mine to the dealer and they told me there was a programming update that they did. Service guy said that it may or may not resolve the problem entirely, and that if it didn't, there was no fix for it. It seems to have fixed the problem as of right now, but not sure if it's a permanent fix. Glad to have found this information though.

willhe64 · 05-30-2013, 11:57 AM

This is for the L99 only. My LS3 vert does not have these.

Pkrimmer · 06-11-2013, 09:42 PM

I have new borla ateck all the way back. New borla headers and tune. What a differance in sound. They know your coming but very quite on the expressway.

SS PANTHER · 06-12-2013, 03:24 AM

Would the Range AFM disable unit help keep the butterfly valves open all the time? If not, what is the best way to keep them open without putting in a new exhaust system? Any disadvantages to getting rid of the valves or having them permanetly open? Thanks in advance.

sswiss3000 · 06-12-2013, 01:56 PM

Quote:

Originally Posted by SS PANTHER

Would the Range AFM disable unit help keep the butterfly valves open all the time? If not, what is the best way to keep them open without putting in a new exhaust system? Any disadvantages to getting rid of the valves or having them permanetly open? Thanks in advance.

No, the exhaust baffles are not computer controlled or anything. Those butterfly valves are only opened when there is enough exhaust pressure (ie. RPMs).

On the other hand, you can either cut them out or simply wire them open if you have the Range AFM disabler installed, as they are designed to reduce the coffee grinder noise you get when the L99 engine goes into 4 cylinder mode.

SS PANTHER · 06-12-2013, 01:59 PM

Quote:

Originally Posted by sswiss3000

No, the exhaust baffles are not computer controlled or anything. Those butterfly valves are only opened when there is enough exhaust pressure (ie. RPMs).

On the other hand, you can either cut them out or simply wire them open if you have the Range AFM disabler installed, as they are designed to reduce the coffee grinder noise you get when the L99 engine goes into 4 cylinder mode.

Thanks for the info.

cam62 · 06-12-2013, 05:20 PM

Quote:

Originally Posted by sswiss3000

No, the exhaust baffles are not computer controlled or anything. Those butterfly valves are only opened when there is enough exhaust pressure (ie. RPMs).

On the other hand, you can either cut them out or simply wire them open if you have the Range AFM disabler installed, as they are designed to reduce the coffee grinder noise you get when the L99 engine goes into 4 cylinder mode.

Explain "wire them open". I was going to find some to weld them open. If I can "wire them open" myself I would rather go that route first.

whidobie · 06-12-2013, 05:40 PM

Everything is normal just like the convertible tops.

sswiss3000 · 06-12-2013, 10:05 PM

Quote:

Originally Posted by cam62

Explain "wire them open". I was going to find some to weld them open. If I can "wire them open" myself I would rather go that route first.

Cam62,

As I just wanted to see what it would sound with the baffles open, I simply took a long wire and wrapped one end around one of the metal tabs on the out side of the Springs. Then I manually twisted the valve open and strapped the other end of the wire to the exhaust hook at the very back end of the car. This way the wire holds the valve at the open position

Admittingly, this method could be considered a "bit" low tech

, but it works and can be easily reversed at any time.

pannhead51 · 06-13-2013, 09:21 AM

Quote:

Originally Posted by sswiss3000

Cam62,

As I just wanted to see what it would sound with the baffles open, I simply took a long wire and wrapped one end around one of the metal tabs on the out side of the Springs. Then I manually twisted the valve open and strapped the other end of the wire to the exhaust hook at the very back end of the car. This way the wire holds the valve at the open position

Admittingly, this method could be considered a "bit" low tech

, but it works and can be easily reversed at any time.

So was the sound louder/better ?

04-17-2013, 12:22 PM	#16
layzurguy Ride On!!!! Drives: 2012 SS Ragtop Join Date: May 2012 Location: Race City USA Posts: 605 View My Garage	get some headers and exhaust....problem solved __________________

05-30-2013, 11:57 AM	#20
willhe64 Drives: 2012 45th Vert, 2011 4x4, 9sec Vega Join Date: Mar 2012 Location: Canada Posts: 2,188	This is for the L99 only. My LS3 vert does not have these. __________________ I feel it only fair to warn you, I have a black belt in CAPS LOCK.

04-15-2013, 01:34 PM	#15
Michael Rophone Drives: Yes Join Date: Nov 2009 Location: PA Posts: 646	I was annoyed at the random, but constant, tapping noise at idle coming from the rear. The first time I heard it was sitting idling in my driveway. I thought someone was having roof-work done next door...but it was Midnight. I don't know what the second owner ever did.

04-17-2013, 10:40 PM	#17
steveintulsa Drives: 2010 rs/ss Join Date: Feb 2010 Location: Tulsa, OK Posts: 102 View My Garage	I just spot-welded mine open (after muffler delete), Much better full range sound at idle.

05-30-2013, 11:28 AM	#19
ZL1DropTop Drives: 2013 Camaro ZL1 Convertible Join Date: Jan 2013 Location: Houston, Texas Posts: 94	I believe I have experienced this problem. I brought mine to the dealer and they told me there was a programming update that they did. Service guy said that it may or may not resolve the problem entirely, and that if it didn't, there was no fix for it. It seems to have fixed the problem as of right now, but not sure if it's a permanent fix. Glad to have found this information though.

06-12-2013, 03:24 AM	#22
SS PANTHER Drives: 2013 SS Supercharged Convertible Join Date: May 2013 Location: SoCal Posts: 2,714	Would the Range AFM disable unit help keep the butterfly valves open all the time? If not, what is the best way to keep them open without putting in a new exhaust system? Any disadvantages to getting rid of the valves or having them permanetly open? Thanks in advance.

06-12-2013, 05:40 PM	#26
whidobie Drives: 2011 Camaro Convertible 2SS RS Join Date: Dec 2010 Location: Bergen County, New Jersey Posts: 270	Everything is normal just like the convertible tops.