Question on L99 and muffler delete - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

mjross · 10-28-2012, 04:22 PM

I've been reading posts for the better part of this morning and still can not find an answer to the L99 muffler delete AFM question. I really like the sound of the SS with the mufflers removed. However, there seems to be an issue with the L99 and muffler removal due to the sound when the AFM kicks in (or something like that). Can someone please educate me on this matter? Also, if you have an L99 automatic and have performed this modification, what do you think? I have also wondered if you can purchase this fix from some manufacturer? Any help in understanding this issue would be greatly appreciated. Thanks for your time.

Keep on Rockin,

Mj

amerimuscle · 10-28-2012, 04:46 PM

I have an L99 with a Borla "ATAK" cat-back and so i can hear the variations in exhaust sound/note when AFM is active. My findings are that under very light throttle (i wanna say around 1100-1300 RPM) the car makes a somewhat strange vibrating sound (aka drone) until u apply heavier throttle and get it out of that AFM RPM range and then the exhaust will kinda pop or drop in tone and then it sounds fairly normal. does that help??

kfm237 · 10-28-2012, 04:46 PM

AFM is Active Fuel Management.. It basically deactivates 4 cylinders while cruising for gas milage.. Basically turning your V8 into a V4... When AFM is on in 4 cylinder mode or transitioning between 4 & 8 cylinders the exhaust note is not so desirable! The exhaust on the L99 (auto) is designed to mask the noise of the AFM and is quieter than the LS3 (manual).. The solution is to tune the AFM off in the Computer of the car.. This can be done with a hand held tuner that can be purchased or by a performance shop that tunes cars... But once you tune the AFM off, your engine warranty can be voided..

mjross · 10-28-2012, 05:04 PM

Thanks guys but I'm wondering about the L99 automatic when the mufflers are removed (deleted) and it's just straight pipe to the tips. Some posts give the indication that you have issues with AFM and drone. However, it appears that other posts indicate no major issues. I like the sound (and look) with no mufflers or baffles or what ever they are called. I'm just trying to get a feel for what to expect and if it is a bad idea. Thanks for your responses but I would still like to hear from L99 owners that have straight pipe in place of the mufflers/baffles/suitcases/what ever they are called. Thanks for your time.

Keep on Rockin,

Mj

Godon Hutchinson · 10-28-2012, 05:40 PM

I deleted mine about a yr ago and love the sound of it. You do get some drone at certain rpms.i just dont pay any mind to it. And i allawys run in m mode and shift with the paddles which helps stay out of the rpm band that produces most of the drone.

GunnyG · 10-28-2012, 06:03 PM

Quote:

Originally Posted by Godon Hutchinson

I deleted mine about a yr ago and love the sound of it. You do get some drone at certain rpms.i just dont pay any mind to it. And i allawys run in m mode and shift with the paddles which helps stay out of the rpm band that produces most of the drone.

+1! SS w/muffler delete only. Sounds great, but when AFM kicks in, I downshift...or better yet, punch it!!! Is it 4 cylinders shutting down or 2? I'd hate to think it's 4...saw that in an earlier post above.

Alot9439 · 10-28-2012, 06:19 PM

I did the muffler delete, you are going to start hearing AFM more but still its no big deal at least for me you could always drive in M or get a tune. their is a increase in volume but, still it won't be that loud due to the fact you have that huge center resonator. I had the muffler delete for a few weeks decided it was not loud enough

replaced the huge resonator with a resonated x-pipe couldn't be happier.

i2disturbedSS · 10-28-2012, 06:26 PM

I had no mufflers for about 5months+. Never hated it or the sound. I dont know what some ppl were talking about

.
Its not a bad idea either. The swicth to 4cyls never got on my nerves. People always told me my car sounds nice. On start up it was loud and I loved my car even more everytime I started it up. At hwy speeds it was a nice hum. Even compare to some of the aftermarket catbacks no mufflers on a stock L99 sounded the same or better...

Just recently I now have LT headers with no cats and no mufflers.
LOUD

lol

mjross · 10-28-2012, 06:39 PM

Thanks for the additional info, it helps a lot. If anyone else has input, please chime in. Thanks for your time.

Keep on Rockin,

Mj

2SS45th · 10-28-2012, 06:44 PM

Quote:

Originally Posted by GunnyG

+1! SS w/muffler delete only. Sounds great, but when AFM kicks in, I downshift...or better yet, punch it!!! Is it 4 cylinders shutting down or 2? I'd hate to think it's 4...saw that in an earlier post above.

It's four cylinders.

woodside783 · 10-28-2012, 07:38 PM

do it but have the amf tuned out the drone is horrible

Firerader · 10-28-2012, 08:02 PM

We have an L99 and I pulled the rear mufflers the second day I owed it. We pulled out of the muffler shop and it sounded ok but I wasn't impressed. We hit the highway, the AFM kicked in and the sound made my wife start to cry. Yep it was not pleasing to our ears. After some research I found out that buying the auto got me the AFM which the 6 speed car doesn't have. I also learned the exhaust systems on the two cars is different. The L99 car has basically a third very large muffler the LS3 doesn't have.
First we ordered a tuner and shut the AFM off. You don't see 1 or 2 mpg difference either way. Next we found a full oem LS3 exhaust system ($65.00) that had the rear mufflers deleted leaving basically straight pipe. We installed that system and now we absolutely LOVE the sound. We always get complements on the sound of the car. We do plan on a full 3" system in the future but I can tell you it will be basically a straight pipe system. Now I have to say my wife and I agree the car should be NASCAR loud.
Good luck.

BronxxBombers213 · 10-28-2012, 08:12 PM

i have solo axle back and no drone.. sure you could hear AFM but it doesnt drone or get annoying at all IMO... as long as you leave the center resonator youll be fine

mjross · 10-28-2012, 08:40 PM

Hmmmmmmm.....................this is where I get confused! Firerader's experience was not very positive. However, others have found the modification to be OK. I guess the experience is not the same for everyone, but that's OK. The information you have provided helps a lot. If others have input I'd still like to hear your take on this. Thanks for your time.

Keep on Rockin,

Mj

10-28-2012, 04:22 PM	#1
mjross Drives: 2014 Vette Stingray,2017 Camaro 2SS Join Date: Oct 2012 Location: Idaho Posts: 302	Question on L99 and muffler delete I've been reading posts for the better part of this morning and still can not find an answer to the L99 muffler delete AFM question. I really like the sound of the SS with the mufflers removed. However, there seems to be an issue with the L99 and muffler removal due to the sound when the AFM kicks in (or something like that). Can someone please educate me on this matter? Also, if you have an L99 automatic and have performed this modification, what do you think? I have also wondered if you can purchase this fix from some manufacturer? Any help in understanding this issue would be greatly appreciated. Thanks for your time. Keep on Rockin, Mj

10-28-2012, 07:38 PM	#11
woodside783 Casey Woodside Drives: a very fun car Join Date: Jun 2010 Location: Tn Posts: 1,906	do it but have the amf tuned out the drone is horrible __________________ Instagram @caseywoodside http://youtu.be/CSc9aPh_X_w

10-28-2012, 08:02 PM	#12
Firerader Drives: 2017 50th Anniversary/Hennessey Join Date: May 2012 Location: Roanoke, Tx Posts: 130	We have an L99 and I pulled the rear mufflers the second day I owed it. We pulled out of the muffler shop and it sounded ok but I wasn't impressed. We hit the highway, the AFM kicked in and the sound made my wife start to cry. Yep it was not pleasing to our ears. After some research I found out that buying the auto got me the AFM which the 6 speed car doesn't have. I also learned the exhaust systems on the two cars is different. The L99 car has basically a third very large muffler the LS3 doesn't have. First we ordered a tuner and shut the AFM off. You don't see 1 or 2 mpg difference either way. Next we found a full oem LS3 exhaust system ($65.00) that had the rear mufflers deleted leaving basically straight pipe. We installed that system and now we absolutely LOVE the sound. We always get complements on the sound of the car. We do plan on a full 3" system in the future but I can tell you it will be basically a straight pipe system. Now I have to say my wife and I agree the car should be NASCAR loud. Good luck. __________________ 2013 2SS/RS 1LE.

10-28-2012, 08:12 PM	#13
BronxxBombers213 Drives: 2010 Camaro 2SS RS Join Date: Nov 2011 Location: NYC Posts: 2,387	i have solo axle back and no drone.. sure you could hear AFM but it doesnt drone or get annoying at all IMO... as long as you leave the center resonator youll be fine __________________

10-28-2012, 04:46 PM	#2
amerimuscle Drives: 2011 Camaro 1SS Join Date: Dec 2011 Location: Cleveland Ohio Posts: 414	I have an L99 with a Borla "ATAK" cat-back and so i can hear the variations in exhaust sound/note when AFM is active. My findings are that under very light throttle (i wanna say around 1100-1300 RPM) the car makes a somewhat strange vibrating sound (aka drone) until u apply heavier throttle and get it out of that AFM RPM range and then the exhaust will kinda pop or drop in tone and then it sounds fairly normal. does that help??

10-28-2012, 04:46 PM	#3
kfm237 Drives: 2012 Camaro SS Join Date: Jan 2012 Location: New Jersey Posts: 139	AFM is Active Fuel Management.. It basically deactivates 4 cylinders while cruising for gas milage.. Basically turning your V8 into a V4... When AFM is on in 4 cylinder mode or transitioning between 4 & 8 cylinders the exhaust note is not so desirable! The exhaust on the L99 (auto) is designed to mask the noise of the AFM and is quieter than the LS3 (manual).. The solution is to tune the AFM off in the Computer of the car.. This can be done with a hand held tuner that can be purchased or by a performance shop that tunes cars... But once you tune the AFM off, your engine warranty can be voided..

10-28-2012, 05:04 PM	#4
mjross Drives: 2014 Vette Stingray,2017 Camaro 2SS Join Date: Oct 2012 Location: Idaho Posts: 302	Thanks guys but I'm wondering about the L99 automatic when the mufflers are removed (deleted) and it's just straight pipe to the tips. Some posts give the indication that you have issues with AFM and drone. However, it appears that other posts indicate no major issues. I like the sound (and look) with no mufflers or baffles or what ever they are called. I'm just trying to get a feel for what to expect and if it is a bad idea. Thanks for your responses but I would still like to hear from L99 owners that have straight pipe in place of the mufflers/baffles/suitcases/what ever they are called. Thanks for your time. Keep on Rockin, Mj

10-28-2012, 05:40 PM	#5
Godon Hutchinson Drives: 2010 1SS/RS Imperial Blue Metallic Join Date: Sep 2010 Location: Huntington West Va Posts: 443	I deleted mine about a yr ago and love the sound of it. You do get some drone at certain rpms.i just dont pay any mind to it. And i allawys run in m mode and shift with the paddles which helps stay out of the rpm band that produces most of the drone.

10-28-2012, 06:19 PM	#7
Alot9439 Drives: 2SS RS Join Date: Sep 2012 Location: Lubbock, TX Posts: 195	I did the muffler delete, you are going to start hearing AFM more but still its no big deal at least for me you could always drive in M or get a tune. their is a increase in volume but, still it won't be that loud due to the fact you have that huge center resonator. I had the muffler delete for a few weeks decided it was not loud enough replaced the huge resonator with a resonated x-pipe couldn't be happier.

10-28-2012, 06:26 PM	#8
i2disturbedSS Drives: 2010 SS L99 IOM Join Date: Aug 2012 Location: CA Posts: 1,923	I had no mufflers for about 5months+. Never hated it or the sound. I dont know what some ppl were talking about . Its not a bad idea either. The swicth to 4cyls never got on my nerves. People always told me my car sounds nice. On start up it was loud and I loved my car even more everytime I started it up. At hwy speeds it was a nice hum. Even compare to some of the aftermarket catbacks no mufflers on a stock L99 sounded the same or better... Just recently I now have LT headers with no cats and no mufflers. LOUD lol

10-28-2012, 06:39 PM	#9
mjross Drives: 2014 Vette Stingray,2017 Camaro 2SS Join Date: Oct 2012 Location: Idaho Posts: 302	Thanks for the additional info, it helps a lot. If anyone else has input, please chime in. Thanks for your time. Keep on Rockin, Mj

10-28-2012, 08:40 PM	#14
mjross Drives: 2014 Vette Stingray,2017 Camaro 2SS Join Date: Oct 2012 Location: Idaho Posts: 302	Hmmmmmmm.....................this is where I get confused! Firerader's experience was not very positive. However, others have found the modification to be OK. I guess the experience is not the same for everyone, but that's OK. The information you have provided helps a lot. If others have input I'd still like to hear your take on this. Thanks for your time. Keep on Rockin, Mj