10-28-2014, 12:22 PM | #15 |
Drives: ‘13 1LE Join Date: Jul 2013
Location: Earth
Posts: 3,904
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^^^exhaust clamp a very common problem in retrospect.
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10-28-2014, 12:41 PM | #16 |
Drives: 1LE Join Date: Feb 2013
Location: East Coast Man
Posts: 550
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When I rev the car at idle, as the RPMs drop back down, I can hear a rattle type sound. I thought this was normal "back pressure" stuff, particularly in concert with the NPP flaps (fuse pulled)? Doesn't happen under any other conditions.
My supercharged Mustang made the same sound -- goose the throttle at idle, as the RPMs just start to drop back down, there was this slight metallic rattling that traveled through the exhaust. With the Mustang, I didn't know if it was normal. Then, I heard the exact same thing on this car and chalked it up as normal. Am I wrong? |
10-28-2014, 07:18 PM | #17 | |
Drives: ‘13 1LE Join Date: Jul 2013
Location: Earth
Posts: 3,904
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Quote:
Make use of you warranty here. You can hear it, therefore they will hear it. I doubt GM will have a TSB out writing, " rattle is normal". As for the conditions of your rattle, as you would goose the throttle and let the rpm's drop...that is precisely when mine exhibited this type of noise . |
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07-17-2015, 08:27 PM | #18 |
Cool, thanks for posting.
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08-03-2015, 07:08 PM | #19 | |
Drives: 23 LT1 / 19 Z06 / after 6 5th gens Join Date: Jan 2014
Location: MI
Posts: 1,957
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Quote:
My O-rings are on order. I'll keep you guys posted.
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08-03-2015, 07:46 PM | #20 | |
Quote:
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08-03-2015, 09:57 PM | #21 |
Drives: 23 LT1 / 19 Z06 / after 6 5th gens Join Date: Jan 2014
Location: MI
Posts: 1,957
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i'll get as much info as possible when i go in for the o-ring install
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08-03-2015, 10:41 PM | #22 |
Drives: 1969 Z28, 1982 Z28, 2014 SS/RS/1LE Join Date: Nov 2013
Location: Michigan
Posts: 886
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I am finding they all do it! Mine got worse and worse. I put a whole long story about it on Facebook a while back. Took it in and dealer agreed that something was bad inside the system. Replaced the entire cat back NPP under warranty. As soon as they started the car...same rattle! WTF? New everything! I found gravel in the heat shield and thought that would fix it, nope. I adjusted the flap rods from the vac valves so they would not rattle, no change. It is just internal to the mufflers. I have been listening to others with NPP at shows and hear the same sound. So I guess it is just part of the system. Some say they don't hear it, but I do when I listen to THEIR car! LOL Maybe we are just too picky or hear too well!
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08-04-2015, 03:25 AM | #23 |
Tri-County Camaro SWFL
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Mine werent bad at all. The put on HFC and it got much worse. This problem ranges from pieces of welds getting in to the exhaust to lose band clamps. I have yet to find what mine is.
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08-06-2015, 09:33 PM | #24 |
Drives: 23 LT1 / 19 Z06 / after 6 5th gens Join Date: Jan 2014
Location: MI
Posts: 1,957
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The O-rings came in, but the tech realized it was a bulletin for Non-NPP,convertable cars. So he went back to the drawing boards. Called around and finally got an answer. Here's his explaination: There are a couple of locators spotwelded to the pipes to help line up properly during exhaust install. These locators serve no purpose after the install and usually break off after some time. Once they break off, they tend to stay held on the pipe by a metal tab that's also in the same location. He was told to slightly bend the tabs outward and let the locators fall out. Sure enough, this fixed my annoying low rpm rattle issue. I have to hand it to the guy, he took this very seriously and even offered a couple times to order a new exhaust system, but these two little locators were the problem rattling on the pipes. I'm sorry I don't know the location of these tabs on the pipes, I was out test driving a 1le when he was working on my car. Who would have thought, two almost dime sized chunks of metal could be so annoying
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08-07-2015, 01:16 PM | #25 |
Drives: 2015 Red Rock ZL1 Join Date: Dec 2014
Location: Panama City Beach, Florida
Posts: 1,097
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This is one of the reasons I ordered my build without the NPP exhaust. I listened to sound clips and it sounded great, but the idea of air valves and moving parts for the exhaust worried me. I ordered the new Lower Cover (Rear Fascia) p/n 22829477 $111.68 w/$75.00 core charge at the dealership and the Corsa Performance Quad-Tip exhaust p/n 14971. It was an easy swap and everything fits perfectly. I have a couple cheesy videos on YouTube so you can hear it. I just bought a Go Pro so hopefully I can add some better videos soon.
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Alex
2015 Red Rock ZL1 Panama City Beach, FL |
02-18-2016, 08:24 AM | #26 |
Drives: 2014 RRM ZL1 M6 Join Date: Jul 2011
Location: IL
Posts: 659
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Are there any videos of this sound? I believe I may have this sound now.
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02-18-2016, 11:25 AM | #27 |
Drives: 15 Summit White 1LE Join Date: Oct 2015
Location: San Diego
Posts: 20
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Great timing on the resurrection of this thread. My 2015 that has 1K miles on it has been doing this and it drives me nuts. I guess I will be taking it in to the dealer soon.
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02-18-2016, 08:11 PM | #28 |
Drives: 2014 SS/RS 1LE Join Date: Sep 2014
Location: U.S.A
Posts: 100
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Daily Driving with NPP here and I get different sounds and rattles intermittently at different temperatures. After a couple years, I suspect most of the baffling has been removed from the mufflers and it's causing some weird sounding resonance in warmer temps. I thought I heard a pop from around one of the catalytic converters the other day LOL
When I lift the car the entire exhaust is cold and feels secured to the engine and hangars. A guy at a local shop mentioned getting all the pipes spot tig welded together... not sure on this recommendation but it might help. |
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