Convertible Exhaust Rattle -L99 only - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

cam62 · 04-03-2013, 07:35 AM

Ok.. I've finally had enough of this. Took it in to the dealer some time ago and they provided a service bulletin that this is normal. Can't seem to find the original paperwork they gave me about the service bulletin, but the link provided here is the content. While the article state 2011, (which I had the same complaint about), I now have a 2012 with the same springs and annoying rattle.

Apparantly there are these little spring loaded doohickies that cause it and GM says normal. It has something to do with minimizing AFM sound.

Now that I have the Range V8, and before I buy a new exhaust, has anyone figured out a way to defeat this rattle?

I was hoping/expecting the rattle to go away when I got my range V8. While it definately occurs less often, it still occurs. I suspect it has something to do with pressure in the exhaust.
I am considering some steel banding to keep them from functioning.

Any thought's, input?

"
The 2011 Camaro Convertible SS equipped with the 6.2L engine (RPO L99) and the 6-speed automatic transmission (RPO MX0) may have a metallic or spring-type rattle noise that is usually heard at idle when parked next to a wall or when pulling into or out of a garage.

The exhaust system for the 2011 model year has been revised to reduce exhaust noises heard during Active Fuel Management (AFM) mode. This revision includes a spring-loaded valve placed in the exhaust system before the muffler.

It is characteristic of this spring-loaded valve to make some noise during engine operation or when tapping on the exhaust pipes. No parts should be replaced or repaired for this noise.'

http://www.archivedsites.com/techlin...tle-noise.html

HDRDTD · 04-03-2013, 10:13 AM

They 'might' also be there to help combat drone at highway speeds, but I'm not sure.
Since you have probably voided your warranty already by installing the Range V8, I suppose you could try to force them open with some sort of clamp, and that might be the first thing to try, to see if it has any effect on the drone.
If holding them open solves the problem, I don't see why someone couldn't just place a small tack weld on the rotating mechanisim to keep them open permenantly.

GnyaTek · 04-03-2013, 10:39 AM

The Range device isn't supposed to leave any signature on the ECM as it plugs into the diagnostics and "bypasses" the shifting decision. It doesn't disable the AFM, it fools the onboard computer into thinking that the parameters to engage the AFM haven't been met.

If the dealership won't take care of the issue, I would recommend taking it to another to have it checked out to confirm that it is butterfly valve issue or something else.

Others here have had similar issues with both 2011 and 2012...

http://www.camaro5.com/forums/showthread.php?t=275303

The butterfly valve can be opened, partially or fully, by prying the end of the spring up out of the corner using pliers and rotating it to the next position (uncoiling the spring). This can be done up to 4 times to get to the fully released position. I have been tempted to try this to see how it changes the exhaust note, but have been wondering how much of a PITA it would be to undo the process getting the spring re-tensioned if I didn't like the result.

cam62 · 04-03-2013, 10:43 AM

Let's not let this turn into a thread whether or not the range device will or will not void the warranty. Already too many discussions about that.

Wow.. i completely missed that thread you posted the link to.

Since there is a service bulletin about it, that specifically states this is normal and not to do anything about it, I'm not planning to waste my time and take it to another dealer.

I may fool around with your suggestion of prying the spring up out of the corner. Since I'll be getting an exhaust at some point in the future. It may just be sooner, rather than later

GnyaTek · 04-03-2013, 10:49 AM

Agree with ya there cam62 ... am wary of the product.

That being said, and since I haven't heard anything in person regarding the butterfly valve spring release process, I am leaning toward waiting and saving up some "mad money" for full exhaust replacement (Solo Mach XC cat back) and possibly LT headers with HF cats ... and then just tune out the AFM. Even if I go just with the exhaust, the spring rattle would be a moot point.

GnyaTek · 04-03-2013, 10:55 AM

Quote:

Originally Posted by cam62

I may fool around with your suggestion of prying the spring up out of the corner. Since I'll be getting an exhaust at some point in the future. It may just be sooner, rather than later

Oh .... and also, if you do this can you please let me know how it worked for ya? I am definitely interested in hearing the difference. Get an audio clip of before/after if ya can! (and perhaps at each quarter stage between!)

Do you happen to be planning a trip to Atlanta over Memorial Day for F-Body Gathering?

cam62 · 04-03-2013, 11:15 AM

[QUOTE=GnyaTek;6376184]Agree with ya there cam62 ... am wary of the product.QUOTE]

Maybe you misunderstood. I don't want this thread to be a discussion warranty issue.

I am completely sold on the Range v8 product. For me, it's one of the best and easiest mods I have gotten for my car.

cam62 · 04-03-2013, 11:16 AM

Quote:

Originally Posted by GnyaTek

Oh .... and also, if you do this can you please let me know how it worked for ya? I am definitely interested in hearing the difference. Get an audio clip of before/after if ya can! (and perhaps at each quarter stage between!)

Do you happen to be planning a trip to Atlanta over Memorial Day for F-Body Gathering?

Will do, but I don't think it will make much difference. According to the service bulletin it there there only to help with AFM sound.

Nope,no trip in the near future for me. As much as I would like to.

GnyaTek · 04-03-2013, 11:31 AM

Quote:

Originally Posted by cam62

Quote:

Originally Posted by GnyaTek

Agree with ya there cam62 ... am wary of the product.

Maybe you misunderstood. I don't want this thread to be a discussion warranty issue.

I am completely sold on the Range v8 product. For me, it's one of the best and easiest mods I have gotten for my car.

LOL, to clarify, I was in agreement that I didn't want the thread to be warranty discussion or pros/cons of the product discussion.... not that I thought that you were wary of the product. I am interested in the seeing the results of the product, but wary of potential hidden issues. My AFM isn't driving me to madness yet (after 26k miles or so), so I will probably just wait and tune it out when/if I go headers route.

HDRDTD · 04-03-2013, 12:25 PM

Quote:

Originally Posted by cam62

Let's not let this turn into a thread whether or not the range device will or will not void the warranty. Already too many discussions about that.

Wow.. i completely missed that thread you posted the link to.

Since there is a service bulletin about it, that specifically states this is normal and not to do anything about it, I'm not planning to waste my time and take it to another dealer.

I may fool around with your suggestion of prying the spring up out of the corner. Since I'll be getting an exhaust at some point in the future. It may just be sooner, rather than later

My apologizes, I did not intend to turn this into a warranty issue at all. In fact, I had never heard of the Range 8 and had to look it up to see what it was. I saw it was a device that plugged into the port, and I new that there are many people that thik they can 'have a tune' and simply reflash it back to stock before taking it to the dealer for warranty work, and it doesn't work that way. The dealer can tell.

Again I apologize for not knowing what I was talking about.

Please continue.

babytiger · 04-03-2013, 01:06 PM

Muffler delete, just before those butterflies and you will be golden. Problem solved.

cam62 · 04-03-2013, 01:56 PM

Quote:

Originally Posted by babytiger

Muffler delete, just before those butterflies and you will be golden. Problem solved.

I'm sure !

babytiger · 04-03-2013, 01:58 PM

Quote:

Originally Posted by cam62

I'm sure !

Seriously. Have an exhaust shop cut off just before the butterflies, scrap from there back (mufflers included). Weld in some pipe, make sure they give you room to drain the rear diff, weld on some nice tips and your done. About $100, best bang for buck mod you'll ever do.

Mr. iNCREDIBLE · 04-03-2013, 02:04 PM

they are there for the AFM drone, when the car kicks to 4-cyc mode they close, the rattle happens when it kicks back to 8-cyc mode.

however, slow accel with the car staying in 8-cyc mode (like stop and go traffic) creates a similar vibration to the AFM mode and they slightly open/slightly close and rattle and are annoying.

I had mine welded open. fixed the issue, drone doesn't bother me, as I have stated I have had 3 vehicles with an AFM system, all with exhaust of some kind and I am not bothered by the drone.

My exhaust/muffler guy charged me $25 and simply welded a small bar across the springs so they can move.

here, I made a photochop for you: need to weld a bar on 2 sides, we did the side and the bottom, keeps the thing from moving.. but you will hear drone if you have an axel back, and might even with OEM mufflers.

04-03-2013, 07:35 AM	#1
cam62 Drives: 2012 IBM Vert 2SS/rs Join Date: Jul 2011 Location: Tampa, FL Posts: 1,157 View My Garage	Convertible Exhaust Rattle -L99 only Ok.. I've finally had enough of this. Took it in to the dealer some time ago and they provided a service bulletin that this is normal. Can't seem to find the original paperwork they gave me about the service bulletin, but the link provided here is the content. While the article state 2011, (which I had the same complaint about), I now have a 2012 with the same springs and annoying rattle. Apparantly there are these little spring loaded doohickies that cause it and GM says normal. It has something to do with minimizing AFM sound. Now that I have the Range V8, and before I buy a new exhaust, has anyone figured out a way to defeat this rattle? I was hoping/expecting the rattle to go away when I got my range V8. While it definately occurs less often, it still occurs. I suspect it has something to do with pressure in the exhaust. I am considering some steel banding to keep them from functioning. Any thought's, input? " The 2011 Camaro Convertible SS equipped with the 6.2L engine (RPO L99) and the 6-speed automatic transmission (RPO MX0) may have a metallic or spring-type rattle noise that is usually heard at idle when parked next to a wall or when pulling into or out of a garage. The exhaust system for the 2011 model year has been revised to reduce exhaust noises heard during Active Fuel Management (AFM) mode. This revision includes a spring-loaded valve placed in the exhaust system before the muffler. It is characteristic of this spring-loaded valve to make some noise during engine operation or when tapping on the exhaust pipes. No parts should be replaced or repaired for this noise.' http://www.archivedsites.com/techlin...tle-noise.html Attached Images __________________ rx catch can;vmax ported throttle body;bowtie delete;SLP SS emblem;CAI cold air intake

04-03-2013, 10:43 AM	#4
cam62 Drives: 2012 IBM Vert 2SS/rs Join Date: Jul 2011 Location: Tampa, FL Posts: 1,157 View My Garage	Let's not let this turn into a thread whether or not the range device will or will not void the warranty. Already too many discussions about that. Wow.. i completely missed that thread you posted the link to. Since there is a service bulletin about it, that specifically states this is normal and not to do anything about it, I'm not planning to waste my time and take it to another dealer. I may fool around with your suggestion of prying the spring up out of the corner. Since I'll be getting an exhaust at some point in the future. It may just be sooner, rather than later __________________ rx catch can;vmax ported throttle body;bowtie delete;SLP SS emblem;CAI cold air intake

04-03-2013, 11:15 AM	#7
cam62 Drives: 2012 IBM Vert 2SS/rs Join Date: Jul 2011 Location: Tampa, FL Posts: 1,157 View My Garage	[QUOTE=GnyaTek;6376184]Agree with ya there cam62 ... am wary of the product.QUOTE] Maybe you misunderstood. I don't want this thread to be a discussion warranty issue. I am completely sold on the Range v8 product. For me, it's one of the best and easiest mods I have gotten for my car. __________________ rx catch can;vmax ported throttle body;bowtie delete;SLP SS emblem;CAI cold air intake

04-03-2013, 02:04 PM	#14
Mr. iNCREDIBLE Drives: 2012 2SS/RS Convertible Join Date: Aug 2012 Location: SoCal Baby... Posts: 2,530	they are there for the AFM drone, when the car kicks to 4-cyc mode they close, the rattle happens when it kicks back to 8-cyc mode. however, slow accel with the car staying in 8-cyc mode (like stop and go traffic) creates a similar vibration to the AFM mode and they slightly open/slightly close and rattle and are annoying. I had mine welded open. fixed the issue, drone doesn't bother me, as I have stated I have had 3 vehicles with an AFM system, all with exhaust of some kind and I am not bothered by the drone. My exhaust/muffler guy charged me $25 and simply welded a small bar across the springs so they can move. here, I made a photochop for you: need to weld a bar on 2 sides, we did the side and the bottom, keeps the thing from moving.. but you will hear drone if you have an axel back, and might even with OEM mufflers. __________________ *I'm only responsible for what I say, not for what you fail to understand.*

04-03-2013, 10:13 AM	#2
HDRDTD Drives: 2013 Triple Black ZL1 Vert M6 ECF Join Date: Mar 2011 Location: Trenton, Michigan Posts: 7,047	They 'might' also be there to help combat drone at highway speeds, but I'm not sure. Since you have probably voided your warranty already by installing the Range V8, I suppose you could try to force them open with some sort of clamp, and that might be the first thing to try, to see if it has any effect on the drone. If holding them open solves the problem, I don't see why someone couldn't just place a small tack weld on the rotating mechanisim to keep them open permenantly.

04-03-2013, 10:39 AM	#3
GnyaTek Drives: 2011 SIM 2SS/RS Vert Join Date: Jul 2011 Location: Middle TN Posts: 1,128	The Range device isn't supposed to leave any signature on the ECM as it plugs into the diagnostics and "bypasses" the shifting decision. It doesn't disable the AFM, it fools the onboard computer into thinking that the parameters to engage the AFM haven't been met. If the dealership won't take care of the issue, I would recommend taking it to another to have it checked out to confirm that it is butterfly valve issue or something else. Others here have had similar issues with both 2011 and 2012... http://www.camaro5.com/forums/showthread.php?t=275303 The butterfly valve can be opened, partially or fully, by prying the end of the spring up out of the corner using pliers and rotating it to the next position (uncoiling the spring). This can be done up to 4 times to get to the fully released position. I have been tempted to try this to see how it changes the exhaust note, but have been wondering how much of a PITA it would be to undo the process getting the spring re-tensioned if I didn't like the result.

04-03-2013, 10:49 AM	#5
GnyaTek Drives: 2011 SIM 2SS/RS Vert Join Date: Jul 2011 Location: Middle TN Posts: 1,128	Agree with ya there cam62 ... am wary of the product. That being said, and since I haven't heard anything in person regarding the butterfly valve spring release process, I am leaning toward waiting and saving up some "mad money" for full exhaust replacement (Solo Mach XC cat back) and possibly LT headers with HF cats ... and then just tune out the AFM. Even if I go just with the exhaust, the spring rattle would be a moot point.

04-03-2013, 01:06 PM	#11
babytiger it's hers... Drives: 2011 Camaro 2SS/RS Convertible Join Date: Jun 2012 Location: katy, tx Posts: 1,202	Muffler delete, just before those butterflies and you will be golden. Problem solved.