[vtirocz]

I'm interested to see a non-NPP cutaway as well. I wish the exhaust was constructed of a high quality stainless steel instead of steel w/ aluminized coating. It doesn't seem like the $1200 axle back exhaust would have any performance advantage over the NPP.

[J-vette]

Thanks for posting the high quality pics. I guess that's why it has to be so big to reduce back pressure

[GMGP5X]

Originally Posted by J-vette

Thanks for posting the high quality pics. I guess that's why it has to be so big to reduce back pressure

NP. It is also 2 separate mufflers in one that also helps with aerodynamics.

[avalonandl]

TTT so people can see

[reeper]

Looking at this I don't know why I would do anything except cat-deletes

[Juliannnt]

Wait so there is no actual muffler in that giant suitcase?

[AndyUK]

Originally Posted by Juliannnt

Wait so there is no actual muffler in that giant suitcase?

the giant suitcase IS the muffler

[LSmith353]

Now, of course all of my speculation is based on experience with several different exhaust systems, as well as knowledge about fluid dynamics, so I could be completely wrong. And, if they were to fill the empty spaces in the muffler with rockwool or fiberglass (often used to increase sound dampening capabilities) my opinion might be a bit different.

Do you not think there may be some sort of sound dampening material in the center section?

[Marty McFlew]

There is no glass packing in this muffler which is why the sound is so blatty and raspy. Would sound more tuned deeper and smoother if it had glass packing in it.

[Danger731]

It does not have the low drone of a Loudmouth which can get brutal , definitely "pops""!

[MackSteelPrivateEye]

If those chambers were packed with fiber glass, you would get a deeper smoother sound with no rasp and pops.. May effect performance though a little.

[bowtie_thunder]

Originally Posted by MackSteelPrivateEye

If those chambers were packed with fiber glass, you would get a deeper smoother sound with no rasp and pops.. May effect performance though a little.

You can get the same effect by going with resonated axlebacks, like the ones I currently have. If I were to replace that crush piping (don't really need to) and my factory X-Pipe (also not really necessary), then it'd get pretty damn loud and raspy.

I get all the pops without all the rasps.

[cmitchell17]

Originally Posted by Marty McFlew

There is no glass packing in this muffler which is why the sound is so blatty and raspy. Would sound more tuned deeper and smoother if it had glass packing in it.

I think I remember seeing a Corvette NPP and the Corvette one actually has packing material. In my opinion the Corvette NPP sounds 1000 times better than the Camaro NPP. The Camaro NPP is extremely raspy and too loud. It does sound good at part throttle but when at WOT and high rpms the rasp comes on bad.

I want to go out and buy a stock NPP takeoff and try to open it up and modify it and try to add packing material.

I dropped a socket into my drivers side header when I put my heads and cam on, it ended up cracking my drivers side primary cat and eventually blew the entire drivers side primary cat out. So I gutted my passenger side. I am not kind of regretting it because it made the obnoxious, raspy sound even louder and more pronounced.

I have seen over on the other CTSV forums of someone adding a H pipe right after the collectors and it supposedly eliminates all rasp? I am skeptical but desperate to get rid of these awful sounds.

[bowtie_thunder]

Originally Posted by cmitchell17

I think I remember seeing a Corvette NPP and the Corvette one actually has packing material. In my opinion the Corvette NPP sounds 1000 times better than the Camaro NPP. The Camaro NPP is extremely raspy and too loud. It does sound good at part throttle but when at WOT and high rpms the rasp comes on bad.

I want to go out and buy a stock NPP takeoff and try to open it up and modify it and try to add packing material.

I dropped a socket into my drivers side header when I put my heads and cam on, it ended up cracking my drivers side primary cat and eventually blew the entire drivers side primary cat out. So I gutted my passenger side. I am not kind of regretting it because it made the obnoxious, raspy sound even louder and more pronounced.

I have seen over on the other CTSV forums of someone adding a H pipe right after the collectors and it supposedly eliminates all rasp? I am skeptical but desperate to get rid of these awful sounds.

If I remember correctly, yes, swapping the factory X-pipe with an H-Pipe does replace the raspiness with deep tone (like how the Mustangs do) and takes the noise down a decibel or two in the cabin.

The problem is that it doesn't quiet it nearly as much as the X, and in some cases, I've seen instances where it actually increases drone.