[Memphis SS]

Originally Posted by bignaz

Perferated holes allow the gas to enter the muffler. If it was a bypass it could not be sold in most states let alone the state it is built in. Michigan. Michigan law prohibits the sale of card with exhaust bypass's from dealerships. So you will not see npp on a car lot in the state of Michigan if it was a bypass.


Npp does not meet the legal definition of bypass. The holes in the pipe inside the muffler are what makes it legal. Without the holes then npp would be a bypass and could not be sold on new cars from dealerships. You would have to buy the car then the dealership install it after the fact. Kinda like what Harley does on stuff.


If the inside pipe did not have the perferations on it inside the muffler then it would be a bypass. Since it does it is not a bypass. A bypass circumvents the muffler. Npp just makes the muffler less effective but still allows gasses to enter the main chamber through the perferations in the pipe.



If npp is a "bypass" what it's legally not it fails to meet the legal definition of bypass. Then every dealership selling cars with npp installed in states like Georgia, Michigan ets. Are breaking the law. And legally can not sell you a Camaro with npp unless you buy it without npp and then add it after you already own the car.


The perferations on those pipes inside the muffler are what makes it legal and not a bypass.

You're getting hung up on one word that is commonly used to describe the NPP system by online magazines, people on the forum, and Chevrolet reps I've met at show events. Give it rest...

As most here will say when the valves are open it allows the exhaust to take the least path of resistance and bypass the chambered area of the muffler.

[custommx3]

DUAL tips are not standard on an SS, at least not on a '16. A friend of mine has a '16 2SS, single tip, no NPP option.

[bignaz]

Originally Posted by Memphis SS

You're getting hung up on one word that is commonly used to describe the NPP system by online magazines, people on the forum, and Chevrolet reps I've met at show events. Give it rest...

As most here will say when the valves are open it allows the exhaust to take the least path of resistance and bypass the chambered area of the muffler.

Exhaust gasses still enter the first chamber of the muffler. Therefore not a bypass. Put a flow meter upto the inner tops with the npp vavles open. A very small but mesureble amount of airflow comes out.


Npp is a way to get around the law for exhust bypass's. That's why it's designed how it is. If not they would of saved a ton of money and just dumped it before the muffler.

[Memphis SS]

Originally Posted by bignaz

Exhaust gasses still enter the first chamber of the muffler. Therefore not a bypass. Put a flow meter upto the inner tops with the npp vavles open. A very small but mesureble amount of airflow comes out.


Npp is a way to get around the law for exhust bypass's. That's why it's designed how it is. If not they would of saved a ton of money and just dumped it before the muffler.

Let's just agree to disagree... you're hung up on one word that as stated is a common description..Here is one of the car sites that is using Bypass to describe the NPP system. (GM Authority)

You can ask for a retraction on misusing the word describing the NPP.

You will find that word you can't deal with in fifth paragraph

http://gmauthority.com/blog/2015/04/...-mode-exhaust/

Adding to the 2016 Camaro’s adjustable personality is the dual-mode exhaust. The system uses electronically controlled flaps to bypass the mufflers and provide a more spirited, aggressive sounding exhaust note under heavy acceleration. There’s also pre-set modes for further personalization, including a quiet ‘stealth’ mode and a louder ‘track’ setting.

[zx9rmal]

Originally Posted by bignaz

Perferated holes allow the gas to enter the muffler. If it was a bypass it could not be sold in most states let alone the state it is built in. Michigan. Michigan law prohibits the sale of card with exhaust bypass's from dealerships. So you will not see npp on a car lot in the state of Michigan if it was a bypass.


Npp does not meet the legal definition of bypass. The holes in the pipe inside the muffler are what makes it legal. Without the holes then npp would be a bypass and could not be sold on new cars from dealerships. You would have to buy the car then the dealership install it after the fact. Kinda like what Harley does on stuff.


If the inside pipe did not have the perferations on it inside the muffler then it would be a bypass. Since it does it is not a bypass. A bypass circumvents the muffler. Npp just makes the muffler less effective but still allows gasses to enter the main chamber through the perferations in the pipe.



If npp is a "bypass" what it's legally not it fails to meet the legal definition of bypass. Then every dealership selling cars with npp installed in states like Georgia, Michigan ets. Are breaking the law. And legally can not sell you a Camaro with npp unless you buy it without npp and then add it after you already own the car.


The perferations on those pipes inside the muffler are what makes it legal and not a bypass.

Gotcha and thanks for the explanation. I see your point, but I think for non-technical, practical purposes, it's basically a bypass since it would appear that, because of the pressure and restriction differences, very little of the exhaust gas would be passing through the perforations.

[rshelar]

I bought my 2017 SS used so I did not have a choice. It had the stock dual exhaust with no NPP and it sucked. I went with a Magnaflow axle back Competition system. $850 for the kit and $100 to install. Sounds great.