[Z06] How do you get rid of the "exhaust popping" on deceleration?
03-17-2011, 12:08 AM
#1
Melting Slicks
Thread Starter
How do you get rid of the "exhaust popping" on deceleration?
I've just purchased a 2011 Z06 and the only thing that drives me up the wall about this car is the hidious sounding popping coming from the exhaust when the car is decelerating in gear or between spirited shifts 
This sound reminds me of a cheap car with leaky header gaskets!
Are there moisture drain holes or something else that needs to be plugged on the head pipes to cure this? What is causing this? I've tried to do a search on this forum but came up empty handed.
This sound reminds me of a cheap car with leaky header gaskets!Are there moisture drain holes or something else that needs to be plugged on the head pipes to cure this? What is causing this? I've tried to do a search on this forum but came up empty handed.
03-17-2011, 12:13 AM
#2
Le Mans Master
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St. Jude Donor '12
I've just purchased a 2011 Z06 and the only thing that drives me up the wall about this car is the hidious sounding popping coming from the exhaust when the car is decelerating in gear or between spirited shifts This sound reminds me of a cheap car with leaky header gaskets!
Are there moisture drain holes or something else that needs to be plugged on the head pipes to cure this? What is causing this? I've tried to do a search on this forum but came up empty handed.
This sound reminds me of a cheap car with leaky header gaskets!Are there moisture drain holes or something else that needs to be plugged on the head pipes to cure this? What is causing this? I've tried to do a search on this forum but came up empty handed.
03-17-2011, 12:19 AM
#3
Instructor
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That is actually an enhancement starting in 2011 ... described at 4:30 http://www.youtube.com/watch?v=YOvS3JN4AKM
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03-17-2011, 01:46 AM
#5
Safety Car
And I thought I was the only one who hates all that popping and farting! 
Factory exhaust systems were usually designed to eliminate those rude sounds. But Corvette designers attending Corvette events saw that many owners change to louder aftermarket systems and they actually seem to like all the popping on decel. So although earlier Corvette mufflers were tuned to be quiet on decel, the popping was not tuned out of NPP or the new Z06 system. On the original Z06 system the exhaust control module closed the bypass valves immediately when lifting off the accelerator. New designs starting with the 2008 NPP keep the valves open during decel to make more noise. Most owners seem to like the popping (kinda like most Harley owners like the loudest straight pipes possible), but you can't please everybody.
The popping is not caused by an external leak but by air and fuel not completely shut off. After several seconds of decel you can hear when the fuel does shut off and it gets quieter. I was able to eliminate the popping on an old carbureted 1980 Corvette that had stock 350 and straight pipes. The trick was to unseal the idle mixture screws and adjust them for max idle speed, then back off the idle set screw to close the throttle plates as much as possible for a low idle speed. While not EPA-friendly, this completely eliminated all the popping on decel. There's no such fix though for new fuel injected cars. The ECM keeps the idle speed high until you stop, contributing greatly to the popping.
I was able to reduce the popping a bit on my 2006 Z's B&B Fusion exhaust by adding a Dr Gas x-pipe. It gave it a nicer tone and tamed the popping to more reasonable level. But now the 2011 has an x-pipe from the factory. Even if you swapped mufflers with an earlier Z06 you still might have the popping because your module keeps the valves open when you lift.
Maybe you can get used to all the noise and be consoled by the fact that most Corvette owners think it sounds cool as hell...
.
Factory exhaust systems were usually designed to eliminate those rude sounds. But Corvette designers attending Corvette events saw that many owners change to louder aftermarket systems and they actually seem to like all the popping on decel. So although earlier Corvette mufflers were tuned to be quiet on decel, the popping was not tuned out of NPP or the new Z06 system. On the original Z06 system the exhaust control module closed the bypass valves immediately when lifting off the accelerator. New designs starting with the 2008 NPP keep the valves open during decel to make more noise. Most owners seem to like the popping (kinda like most Harley owners like the loudest straight pipes possible), but you can't please everybody.
The popping is not caused by an external leak but by air and fuel not completely shut off. After several seconds of decel you can hear when the fuel does shut off and it gets quieter. I was able to eliminate the popping on an old carbureted 1980 Corvette that had stock 350 and straight pipes. The trick was to unseal the idle mixture screws and adjust them for max idle speed, then back off the idle set screw to close the throttle plates as much as possible for a low idle speed. While not EPA-friendly, this completely eliminated all the popping on decel. There's no such fix though for new fuel injected cars. The ECM keeps the idle speed high until you stop, contributing greatly to the popping.
I was able to reduce the popping a bit on my 2006 Z's B&B Fusion exhaust by adding a Dr Gas x-pipe. It gave it a nicer tone and tamed the popping to more reasonable level. But now the 2011 has an x-pipe from the factory. Even if you swapped mufflers with an earlier Z06 you still might have the popping because your module keeps the valves open when you lift.
Maybe you can get used to all the noise and be consoled by the fact that most Corvette owners think it sounds cool as hell...
.
Last edited by ZL-1; 03-17-2011 at 02:10 AM.
03-17-2011, 02:00 AM
#7
Tech Contributor
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Most car freaks love the sound of a good muffler that lets you hear the sound of a car backing down. The old Glass Packs were great once you shut off the ignition while coasting and then turned it back on so the fiberglass packing would burn/blow out. After that they could wake eveybody for 2 or 3 blocks with just one shot of the throttle and letting the car coast down while in gear.
Here you are trying to get rid of something that people worked hard to get.
Bill
Here you are trying to get rid of something that people worked hard to get.
Bill
03-17-2011, 02:28 AM
#8
Safety Car
Most car freaks love the sound of a good muffler that lets you hear the sound of a car backing down. The old Glass Packs were great once you shut off the ignition while coasting and then turned it back on so the fiberglass packing would burn/blow out. After that they could wake eveybody for 2 or 3 blocks with just one shot of the throttle and letting the car coast down while in gear.
Here you are trying to get rid of something that people worked hard to get.
Bill
Here you are trying to get rid of something that people worked hard to get.
Bill
BTW, we used to turn off the ignition while coasting too. It was a quick way to remove an old rusty exhaust system
. The M80-like explosion would make oval mufflers round if it didn't split open the seam
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denverfire (05-04-2016)
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03-17-2011, 06:57 AM
#11
Le Mans Master
I've just purchased a 2011 Z06 and the only thing that drives me up the wall about this car is the hidious sounding popping coming from the exhaust when the car is decelerating in gear or between spirited shifts This sound reminds me of a cheap car with leaky header gaskets!
Are there moisture drain holes or something else that needs to be plugged on the head pipes to cure this? What is causing this? I've tried to do a search on this forum but came up empty handed.
This sound reminds me of a cheap car with leaky header gaskets!Are there moisture drain holes or something else that needs to be plugged on the head pipes to cure this? What is causing this? I've tried to do a search on this forum but came up empty handed.
03-17-2011, 07:17 AM
#12
Team Owner
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St. Jude Donor '06
Must like myself ABSOULTELY LOVE IT as it gives the Z a race car sound and makes it funner for most!I mean the 06 through 10 guys pay big $ for an aggressive cat back system and my B&B Bullets do it a ton and its the best!
Your lucky the 11 Zs have more aggressive exhuast but then again maybe not b/c different strokes for different folks and you don't like it.
Here's a solution I would think. A TON Of Z owners 06 through 10 would swap you even for your complete exhaust system from behind the exhaust manifolds out the the tail pipes, and this will make your Z nice and quiet like a Cadillac. Honestly, that shoud SOLVE what you don't like and the older Z exhaust is MUCH MORE TAME sounding!
03-17-2011, 07:43 AM
#14
Melting Slicks
Thread Starter
And I thought I was the only one who hates all that popping and farting!
Factory exhaust systems were usually designed to eliminate those rude sounds. But Corvette designers attending Corvette events saw that many owners change to louder aftermarket systems and they actually seem to like all the popping on decel. So although earlier Corvette mufflers were tuned to be quiet on decel, the popping was not tuned out of NPP or the new Z06 system. On the original Z06 system the exhaust control module closed the bypass valves immediately when lifting off the accelerator. New designs starting with the 2008 NPP keep the valves open during decel to make more noise. Most owners seem to like the popping (kinda like most Harley owners like the loudest straight pipes possible), but you can't please everybody.
The popping is not caused by an external leak but by air and fuel not completely shut off. After several seconds of decel you can hear when the fuel does shut off and it gets quieter. I was able to eliminate the popping on an old carbureted 1980 Corvette that had stock 350 and straight pipes. The trick was to unseal the idle mixture screws and adjust them for max idle speed, then back off the idle set screw to close the throttle plates as much as possible for a low idle speed. While not EPA-friendly, this completely eliminated all the popping on decel. There's no such fix though for new fuel injected cars. The ECM keeps the idle speed high until you stop, contributing greatly to the popping.
I was able to reduce the popping a bit on my 2006 Z's B&B Fusion exhaust by adding a Dr Gas x-pipe. It gave it a nicer tone and tamed the popping to more reasonable level. But now the 2011 has an x-pipe from the factory. Even if you swapped mufflers with an earlier Z06 you still might have the popping because your module keeps the valves open when you lift.
Maybe you can get used to all the noise and be consoled by the fact that most Corvette owners think it sounds cool as hell...
Factory exhaust systems were usually designed to eliminate those rude sounds. But Corvette designers attending Corvette events saw that many owners change to louder aftermarket systems and they actually seem to like all the popping on decel. So although earlier Corvette mufflers were tuned to be quiet on decel, the popping was not tuned out of NPP or the new Z06 system. On the original Z06 system the exhaust control module closed the bypass valves immediately when lifting off the accelerator. New designs starting with the 2008 NPP keep the valves open during decel to make more noise. Most owners seem to like the popping (kinda like most Harley owners like the loudest straight pipes possible), but you can't please everybody.
The popping is not caused by an external leak but by air and fuel not completely shut off. After several seconds of decel you can hear when the fuel does shut off and it gets quieter. I was able to eliminate the popping on an old carbureted 1980 Corvette that had stock 350 and straight pipes. The trick was to unseal the idle mixture screws and adjust them for max idle speed, then back off the idle set screw to close the throttle plates as much as possible for a low idle speed. While not EPA-friendly, this completely eliminated all the popping on decel. There's no such fix though for new fuel injected cars. The ECM keeps the idle speed high until you stop, contributing greatly to the popping.
I was able to reduce the popping a bit on my 2006 Z's B&B Fusion exhaust by adding a Dr Gas x-pipe. It gave it a nicer tone and tamed the popping to more reasonable level. But now the 2011 has an x-pipe from the factory. Even if you swapped mufflers with an earlier Z06 you still might have the popping because your module keeps the valves open when you lift.
Maybe you can get used to all the noise and be consoled by the fact that most Corvette owners think it sounds cool as hell...
Here's a solution I would think. A TON Of Z owners 06 through 10 would swap you even for your complete exhaust system from behind the exhaust manifolds out the the tail pipes, and this will make your Z nice and quiet like a Cadillac. Honestly, that shoud SOLVE what you don't like and the older Z exhaust is MUCH MORE TAME sounding!
My disappointment stems from the fact that my '88 LS7 Monte Carlo SS has ZERO "popping" to the exhaust with this exact same motor installed and clearly sounds better than ANY Z06 that I have ever heard (aftermarket mufflers included) and after all of the "hype" about the ZR1 x-pipe and new ZR1 mufflers I just got my expectations too high and certainly didn't plan on listening to pop, pop, pop, that's all. Of course being able to rowing the SS through the gears with 4.10's around town and having headers on it probably helps and I actually have quiet "DynoMax Superflow" mufflers on it
It's a free-flowing exhaust. That popping is un-burned fuel igniting in the exhaust system and is completely normal, and totally sickhouse.
And for those of you that love the popping, more power to you....not passing judgement
03-17-2011, 08:07 AM
#15
Burning Brakes
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the GTO's and F-bodies have always done this also. It's in the tune for the LS engines. DFCO = Deceleration Fuel Cut Off, the purpose is to let some gas flow through the exhaust to keep the cats from overheating. it can be removed through tuning.
Many people don't like it, others do. and It becomes much more apparent when you do an exhaust swap. I loved it on my GTO with headers and a Borla. the Vette has it, but its still very silent.
Many people don't like it, others do. and It becomes much more apparent when you do an exhaust swap. I loved it on my GTO with headers and a Borla. the Vette has it, but its still very silent.
03-17-2011, 08:09 AM
#16
Le Mans Master
the GTO's and F-bodies have always done this also. It's in the tune for the LS engines. DFCO = Deceleration Fuel Cut Off, the purpose is to let some gas flow through the exhaust to keep the cats from overheating. it can be removed through tuning.
Many people don't like it, others do. and It becomes much more apparent when you do an exhaust swap. I loved it on my GTO with headers and a Borla. the Vette has it, but its still very silent.
Many people don't like it, others do. and It becomes much more apparent when you do an exhaust swap. I loved it on my GTO with headers and a Borla. the Vette has it, but its still very silent.
03-17-2011, 08:29 AM
#19
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Right on the money. I didn't like it that much years ago but have grown to enjoy it. I guess it's a mindset. Free flowing exhaust/mufflers is going to do this when you decelerate. It's all good
03-17-2011, 09:16 AM
#20
You could revert to the earlier exhaust configuration. My 2009 Z06 didn't have the popping.
I love the sound of my ZR1 - the popping is a like a short drum solo in the middle of a great rock song.
Ryan
I love the sound of my ZR1 - the popping is a like a short drum solo in the middle of a great rock song.
Ryan
