Modded NPP
Thread Starter
Racer
Joined: Jan 2014
Posts: 318
Likes: 81
Modded NPP
I got Z06 NPP mufflers (after welding on 2.5 stock pipe) and installed them on my car. After install I noticed the exhaust is still a little quiet and want the exhaust louder but worried if I do the stock mod add the pipe over the perforated section internally that it would be too loud. Has anyone heard of someone covering half or greater portion… but less than full closure of the internal perforated pipe and what the results were?
Le Mans Master
Joined: Dec 2005
Posts: 6,999
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From: Southeast TX
Racer
Joined: Apr 2024
Posts: 485
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From: SoFlo
2024 C6 of the Year Finalist - Unmodified
I have a question, if you cover the perforated pipe will you still be able to put it in quiet mode? When the NPP baffles close the exhaust goes through the perforation into the muffler and out the other 2 tips. That won't happen if you cover the perforated pipe and the exhaust will have nowhere to go.
Burning Brakes
Joined: Apr 2023
Posts: 1,087
Likes: 392
From: Florida
2025 C6 of the Year Finalist - Unmodified
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Burning Brakes
Joined: Jul 2002
Posts: 1,136
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From: Nova Scotia
You didn't say what kind of car you have, but since the z06 mufflers were welded to 2.5" pipes I assume it's an LS2 or LS3. The npp on LS3 cars don't have perforated pipe inside, so a modded Z06 muffler would basically sound like a stock LS3 npp muffler. When my LS3 car was stock, I pulled the fuse and left it out, sounded awesome. But after adding headers I found it too loud. And doing the mod has a negligible affect on quiet mode
Burning Brakes
Joined: Jul 2002
Posts: 1,136
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From: Nova Scotia