OEM dual mode performance exhaust

[Nate76]

I was wondering how much it would be to add the factory quad tips exhaust after the fact. It's a 940 dollar option when the car is being built, but wondering what it would cost to do it after. Or if there was a better option. I love the quad tip look, and not sure how the difference in sound is on the factory option but I would imagine its a little louder. Appreciate anyone's 2 cents.

[Dynamite]

The dual mode exhaust isn't just the tips. It is a whole catback system, and will cost more to add it on after the fact.

You can make any exhaust system have quad tips.

[Sickness91Z28]

I bought a used NPP system and had them cut and send just the mufflers back. Cost me around $500 for that and $60 to have it welded up. Sounds great

[Anaconda]

You can find used NPP catbacks or axlebacks for cheaper than what it would cost new on the GM parts sites. I myself got the axle back for around 500 as well but the flaps are always open. I haven't put a Mild2Wild switch on it or run vacuum. The sound is an improvement over the stock, however the volume of in cabin noise to me personally is a little too loud, especially on the highway. Of course it's subjective and people's tolerance of noise level in the cabin is up to them, but for me it does get annoying. Sounds great outside though when wide open throttle.

[Nate76]

What's NPP? Could someone also please explain the dual mode and how is sounds. Also is it available on non OEM exhaust? What I'm looking for quad tips, a nice low rumbling sound and not too much cabin noise except when I'm really giving her gas. Any ideas/comments?

[Allstar_2SS_14]

I have the dual exhaust OEM and its the best choice over any aftermarket I think. Its nice and quite on the highway and great sound on low gears. Just like any other parts I would choose OEM over aftermarket anytime.

Sent from my Nexus 5 using Tapatalk

[ST1LE]

Originally Posted by Nate76

What's NPP? Could someone also please explain the dual mode and how is sounds. Also is it available on non OEM exhaust? What I'm looking for quad tips, a nice low rumbling sound and not too much cabin noise except when I'm really giving her gas. Any ideas/comments?

NPP is the factory code for the OEM dual mode exhaust. The dual mode uses the ECM and vaccum lines running to the engine to open and close flaps on the exhaust..one side is straight through and the other is through a muffler. This is NOT easy to do after the fact. I think Billy Boat has a dual mode exhaust, but I am not sure and cant think of how that works after the fact either.

[ChocoTaco369]

Originally Posted by Nate76

I was wondering how much it would be to add the factory quad tips exhaust after the fact. It's a 940 dollar option when the car is being built, but wondering what it would cost to do it after. Or if there was a better option. I love the quad tip look, and not sure how the difference in sound is on the factory option but I would imagine its a little louder. Appreciate anyone's 2 cents.

I absolutely love the NPP exhaust. I think it's awesome because of its versatility. IMO, you can have the ultimate setup with the NPP, which would be:

1.) NPP exhaust
2.) Mild-to-Wild controller
3.) NOWEEDS diverters
4.) Solo cats if you want your warranty, LT's+HFC's+tune if you don't care about your warranty.

This would essentially give you three "modes:"

1.) Ridiculously loud with open diverters.
2.) Moderately loud with diverters closed through just the NPP with the valves fully open. It should be fun cruising around town, loud at WOT but may have some drone when cruising.
3.) Close NOWEEDS and NPP valves for no drone when cruising.

Truly the best of all worlds, but if you're building your car, this would be a $2,500+ exhaust if you do the install yourself and a $3,000 exhaust if you're paying for install. (~$900 for NPP, $950 for diverters, $575 for Solo cats or $700-1500 for LT's+HFC's, $80 for Mild-2-Wild + install and misc gaskets, extensions, etc.)

I am fortunate because I purchased my car with 5,000 miles on the clock well under MSRP and KBB value with an NPP. However, if I were building the car from scratch, I'm not so sure I'd go that route due to the expense. I'd probably not purchase the NPP and simply buy a ZL1 or 1LE rear diffuser and get the Stainless Works Retro Chambered catback with the quad tips instead. It isn't as versatile, though.

Just my thoughts.

[Trunz150]

Absolutely love the NPP exhaust, the sound is seriously music to my ears everytime I drive, I have gotten many compliments in it as well

[Todd in Vancouver]

NPP is one of my favourite things and I get a ton of positive feedback on how cool it sounds. I'd never own one now without it.

[Scott@Bjorn3D]

Originally Posted by Sickness91Z28

I bought a used NPP system and had them cut and send just the mufflers back. Cost me around $500 for that and $60 to have it welded up. Sounds great

Problem with that is you still do not have NPP sound. Standard exhaust systems have resonators on them. The NPP has no resonators in the exhaust at all.

[MLAZ1990]

Don't know much about dual mode other than it sounds amazing!

[slick rick]

Originally Posted by Scott@Bjorn3D

Problem with that is you still do not have NPP sound. Standard exhaust systems have resonators on them. The NPP has no resonators in the exhaust at all.

[Sickness91Z28]

Originally Posted by Scott@Bjorn3D

Problem with that is you still do not have NPP sound. Standard exhaust systems have resonators on them. The NPP has no resonators in the exhaust at all.

The LS3 has 2 straight through resonators...not much of a resonator at all. The L99 has the massive multi chamber resonators. Huge difference