[ScaryFatKidGT]

So I have the NPP and I like it, but rather than go from "Tahoe" to legal Camaro/Corvette sound I'd rather have it go from "legal Camaro/Corvette sound" to "loud af and mean as hell scaring children loud". Even if the closed mode doesn't quite get as loud as the stock open mode as long as the loud mode is louder.


Power gains and weight savings are a + too.




My other option would be to leave the factory mufflers and do a full, x-pipe, crush pipe delete.



These seems to be pretty much the only bolt on I can do while keeping the warranty besides the Chevy intake correct?

[enzia35]

Lots of options out there. Borla is top notch, Flowmaster, Magnaflow, some here have had custom setups made.
Crush pipe has no effect on flow.

[ScaryFatKidGT]

Originally Posted by enzia35

Lots of options out there. Borla is top notch, Flowmaster, Magnaflow, some here have had custom setups made.
Crush pipe has no effect on flow.

The only ones I see that keep and use the NPP are 1 Borla system and 2 axle back and 2 cat back Hooker blackhearts, the catback blackhearts tho delete back cats which I will do eventually but don't want to just yet, then talk about an option that doesn't in the description but I haven't been able to find it.


Which system and piping diameter would be good for an otherwise stock car?




I have been looking on Phastek and Wildhammer, should I be looking anywhere else?

[enzia35]

Borla 60607 midpipe and then either the 11924 or 11925 axlebacks will keep the secondary cats. I believe those are 2.75" and that's fine for stock cars.

Juiced sent me a very juicy coupon code. They'll be the ones to get my money, once I get some!

[ScaryFatKidGT]

Originally Posted by enzia35

Borla 60607 midpipe and then either the 11924 or 11925 axlebacks will keep the secondary cats. I believe those are 2.75" and that's fine for stock cars.

Juiced sent me a very juicy coupon code. They'll be the ones to get my money, once I get some!

So I would probably want the 11925?



Is 3" to much? Is that kinda the cut off 2.75" or 3"? I see a lot of 3" stuff say for modded cars only.

[enzia35]

I'm personally going for the ATAK 11925. I think 2.75" is good for lightly modded cars. Someone will hopefully chime in on how much power you really need to be making for 3" exhausts.

[Aperretta]

Billy Boat does also, but they need to work on a minor issue with the valve flap size.

[MAGAUSA]

Is there a noticeable difference with the Borla Atak or S with the valves closed? Asking for a friend.

[enzia35]

Originally Posted by MAGAUSA

Is there a noticeable difference with the Borla Atak or S with the valves closed? Asking for a friend.

That's always been my question too. Here's an Amazon review, take it for what it's worth:

This is by far the best sounding exhaust I have ever owned on any GM muscle car. Installed on my 2016 2SS M6 with no other modifications to the exhaust system, and there is ZERO drone. Don't be scared of the ATAK being too loud; I'm very happy that I didn't go with the S-Type.

NPP valves open: it has a good mellow idle. Off-idle to 3k rpm sounds "throaty" (with a pleasant soft yet deep note combined with an enjoyable mid range note). Above 3k it comes to life and screams without an ounce of annoying rasp, nor does it have that 4wd truck exhaust tone. Never once does it let out an unenjoyable note. Every sound wave is perfection.

NPP valves closed: ATAK with NPP closed is the same volume level as the stock muffler with NPP open (below 3k rpm at least). The idle with NPP closed is barely quieter than with them open. Off-idle to 3k rpm is a little quieter than with NPP open. Above 3k rpm is where the real difference between open and closed is seen as it's very quiet above 3k rpm with NPP closed; it sounds like a radical rush of air without sounding bad, and is a little louder than stock muffler with NPP open. I drive with NPP closed in the morning.

It sounds like $1500 exhaust, and it's worth every penny.

[Steve 2016 SS]

Originally Posted by enzia35

That's always been my question too. Here's an Amazon review, take it for what it's worth:

I just bought that exact system and have the same car as you. Cant wait to put it on!!

[ScatPack]

Leave the NPP in place. and get some long tube headers and a tune. Or maybe some cat deletes and a tune. That will keep that signature sound, but amplify it and make it way more aggressive.

[Dvs510]

I originally wanted to do borla atak or secondary delete. For the same reason to keep npp.. but I couldn’t justify spending that much on exhaust just to make it sound better.. I finally said f it and bought the mbrp axle back.. installed it this weekend and I couldn’t b happier. Car sounds the same just deeper and louder.. not crazy loud but definately noticeable. I used a dB meter before and after and it shows about 10-11 dB difference. I live in California so I have the problem of can’t b too loud and emissions crap. Right now I think I’m right on the borderline as long as I don’t drive like an ass I should b good

[grampa_ss]

Originally Posted by Dvs510

I originally wanted to do borla atak or secondary delete. For the same reason to keep npp.. but I couldn’t justify spending that much on exhaust just to make it sound better.. I finally said f it and bought the mbrp axle back.. installed it this weekend and I couldn’t b happier. Car sounds the same just deeper and louder.. not crazy loud but definately noticeable. I used a dB meter before and after and it shows about 10-11 dB difference. I live in California so I have the problem of can’t b too loud and emissions crap. Right now I think I’m right on the borderline as long as I don’t drive like an ass I should b good

This is exactly what I did. Deeper and louder...but not too loud.

[ScaryFatKidGT]

Originally Posted by enzia35

I'm personally going for the ATAK 11925. I think 2.75" is good for lightly modded cars. Someone will hopefully chime in on how much power you really need to be making for 3" exhausts.

Looks like Borla is the only exhaust that is 2.75", all others are 3", however I was hopping for the open setting to be strait piped like on the Hooker and AFE products... Borla, Magnaflow, and BB exhausts looks like they rout the open side through the muffler although it might just be a strait pipe through there idk.

Originally Posted by MAGAUSA

Is there a noticeable difference with the Borla Atak or S with the valves closed? Asking for a friend.

Originally Posted by enzia35

That's always been my question too. Here's an Amazon review, take it for what it's worth:

Originally Posted by Steve 2016 SS

I just bought that exact system and have the same car as you. Cant wait to put it on!!

Go on Borla or the page on Jjegs and there is a very good video from them on it.


Closed they are all suppose to sound about the same. Open touring is mellow and deep what I assume most stock systems go for on muscle cars, S-type is similar to stock but louder, ATAK has a lot more low end and I'm assuming close to strait piped but maybe not.