C7 Muffler Delete
Thread Starter
2nd Gear
Joined: Nov 2024
Posts: 2
Likes: 1
C7 Muffler Delete
I recently got a 2016 z51 and want to make it louder. I have been told that if I remove the rear mufflers I can potentially mount the npp brackets back on so I don’t have to tune the sensor. I don’t really want to remove the front cats so I don’t have to tune out the o2 sensor as well. So it seems like the best option is to remove mufflers, mount bracket with the valves so it won’t throw a light and remove the rear cats so I don’t have to turn off the o2 sensor.
what is the best option that ya’ll have done? Is it best to just remove mufflers, both cats, and turn off both sensors? Or smarter to leave them?
what is the best option that ya’ll have done? Is it best to just remove mufflers, both cats, and turn off both sensors? Or smarter to leave them?
Racer
Joined: Mar 2020
Posts: 458
Likes: 104
From: Brentwood
This really depends upon how loud you want it to be and if you want to retain the npp option. Leave the front cats on remove the secondary ones with an x pipe (many options but if you go with awe mufflers use the Borla as Corsa x with awe has some reports of drone).
You can go straight pipe and remove the mufflers, I have done that but don’t recommend it.
I also can’t recommend a muffler unless you tell us if want it loud in cabin or just outside and if you want npp. If you don’t use the npp you just get adapter plates that bolt on to the actuators and zip tie them up. I have some I could sell you if you that route.
Personally I hate drone and would suggest the Corsa x and corsa extreme to retain the npp or the Borla x with the awe if you don’t care about npp. If you want it loud in the cabin and not just outside then you don’t want Corsa, go with awe. The extremes are loud but not inside.
there are plenty of other options but that’s my suggestion unless headers are legal where you’re located.
You can go straight pipe and remove the mufflers, I have done that but don’t recommend it.
I also can’t recommend a muffler unless you tell us if want it loud in cabin or just outside and if you want npp. If you don’t use the npp you just get adapter plates that bolt on to the actuators and zip tie them up. I have some I could sell you if you that route.
Personally I hate drone and would suggest the Corsa x and corsa extreme to retain the npp or the Borla x with the awe if you don’t care about npp. If you want it loud in the cabin and not just outside then you don’t want Corsa, go with awe. The extremes are loud but not inside.
there are plenty of other options but that’s my suggestion unless headers are legal where you’re located.
Instructor
Joined: Jun 2015
Posts: 102
Likes: 9
What I did with mine was get the Corsa catless X pipe and pull fuse 42 (I think that's the one for the NPP). No CEL will come on with the X pipe since the O2 sensors upstream of that and when I pulled the fuse, I just put my car in track mode so the valves are always open. Just have to make sure you pull the NPP not AFM fuse as the AFM one will throw a light.
These couple things made my car louder for sure. The pipe makes it sound more "open" and with the valves being open the car is probably 10% louder if I were to guess. Hope this helps.
These couple things made my car louder for sure. The pipe makes it sound more "open" and with the valves being open the car is probably 10% louder if I were to guess. Hope this helps.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
I recently got a 2016 z51 and want to make it louder. I have been told that if I remove the rear mufflers I can potentially mount the npp brackets back on so I don’t have to tune the sensor. I don’t really want to remove the front cats so I don’t have to tune out the o2 sensor as well. So it seems like the best option is to remove mufflers, mount bracket with the valves so it won’t throw a light and remove the rear cats so I don’t have to turn off the o2 sensor.
what is the best option that ya’ll have done? Is it best to just remove mufflers, both cats, and turn off both sensors? Or smarter to leave them?
what is the best option that ya’ll have done? Is it best to just remove mufflers, both cats, and turn off both sensors? Or smarter to leave them?
- There are four o2 sensors, not one
- Two o2 sensors....the fronts....are for fuel control
- Two o2 sensors....the aft sensors...monitor main cat efficiency, one per side.
- You can remove the secondary cats with Zero affect on the o2 sensors or the tuning since those cats are not monitored.
If you have the optional NPP mufflers, pull the fuse and the valves will be open all the time. Gives you about the same noise level as removing the mufflers without the hassle. Your hearing will thank me.
I have headers, bullet cats, and the factory NPP mufflers programmed to be open all the time in track mode. On the race track at WOT, it's fk'ing loud.
Thread Starter
2nd Gear
Joined: Nov 2024
Posts: 2
Likes: 1
Thank you guys! That helps a ton. Right now I have the range tech to disable the afm and have pulled the fuse so it’s in V8 with open valves 24/7. But it’s just not loud enough for me still. I’ve definitely heard about getting the corsa xpipe axle back but don’t have the money at this moment. So I was just going to remove the mufflers, just didn’t know what to do with the npp sensors or actuators because I didn’t want to disconnect them and throw a code. So essentially where is the best place to mount them if I remove the mufflers?
New Member
Joined: Mar 2025
Posts: 3
Likes: 1
So far so good for me!
I have completed the Muffler delete keeping everything else stock including the cats. I can say this was the best thing you can do in the exhaust honestly sounds 11 out of 10. The one other pro that people aren’t talking about is you don’t have to drive the car as hard. I feel like this is going to help a lot and protect your engine. Before you had to get too much higher RPMs to hear the sound stock.
