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Old 06-08-2018, 11:55 AM   #1
MAGAUSA
 
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Drives: 2017 Hyper Blue 1LE
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Flowmaster Am Thunder NPP valve rattle?

Iíve seen some reports of this. How prevalent is this and anyone know if itís a warranty item?

My stock NPP rattles so much on one side I never use anything but track mode. Driving in Tour and esp Stealth brings this loud tinny rattle from the one side. But Iím looking for a functioning aftermarket and Iíd need the valves for start ups and cruising in the neighborhood. More rattles would be disappointing.

Anyone with experience with this system?

Thanks
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Old 06-18-2019, 01:35 PM   #2
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So I just got mine installed and it has a SIGNIFICANT rattle. It wasn't there the first couple of days, but yesterday morning I started up and went to stealth, and it was loud and prevalent.

For what it's worth, I had no issues with the Stock NPP, but I felt the sound was underwhelming so I never used it anyway. Now that I want the functionality... I don't seem to have it.
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Old 06-24-2019, 12:00 AM   #3
Baker
 
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https://www.camaro6.com/forums/showthread.php?t=556657 check this out worked for me
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Old 06-24-2019, 09:14 AM   #4
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Check the thread that Baker posted, the ziptie under the spring that is problematic (after you compress it) completely solved the problem.
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Old 06-24-2019, 10:31 AM   #5
KingLT1


 
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That is odd...the spring tension is really tight on my Flowmaster valves. Actually both exhausts were. Flowmaster sent me a replacement because the valves leak when closed creating a "hissing" sound. I thought the springs were too stiff not allowing the NPP actuator to close them. Sounds like perhaps Flowmaster reduced tension on the springs so the NPP actuators don't have to work as hard to close the valves, but then the springs rattle.
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Old 06-24-2019, 11:19 AM   #6
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Quote:
Originally Posted by KingLT1 View Post
That is odd...the spring tension is really tight on my Flowmaster valves. Actually both exhausts were. Flowmaster sent me a replacement because the valves leak when closed creating a "hissing" sound. I thought the springs were too stiff not allowing the NPP actuator to close them. Sounds like perhaps Flowmaster reduced tension on the springs so the NPP actuators don't have to work as hard to close the valves, but then the springs rattle.

Interesting, I didn't have a "hissing" problem, but I had a SIGNIFICANT rattle. The zip tie completely solved that for me, and I'm thrilled with the exhaust now.
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