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Jerry. I have mine set to sport only, sounds good at take off, but they do close at some point/rpms when cruising. However, I kinda like it that way. As I've grown more mature (re: old ) I've found that cruising without a roar from the exhaust is right up my ally.
Yep, on my C6 I installed a simple toggle switch I put in the front cup holder so I could control when the NPP butterflies were open. In the C6 it was easy as the fuse panel was in the front of the passenger seat. Had to shut them on the Interstate or the drone was objectionable. Could do the same with the C7 but would have to run long wires.
The C7 even NPP set at "Always Track,"which I use, they are closed when on the Interstate at 78 mph in 7th gear in my Grand Sport. To reach ~1700 when they open would be traveling at ~81 mph. The times I do reach that speed are to quickly pass an 18 wheeler to limit the time exposed to the tires throwing rocks! I do that very quickly by downshifting to 4th and the engine, low restriction air cleaner and open NPP sound fine!
When I got my 2014 that happened the first month and the rock hit the windshield. Fortunately is was a small chip below the raised passenger side wiper. I filled it with a windshield repair kit. I don't like driving on the Interstate for several reasons. But 18 wheelers throwing rocks and their tires tread in the road are two key ones! You also sit low and SUV's and pick-ups just go over tire treads giving little time to avoid them.
It's an option you don't want to pass up Max. Plus, it's actually cheaper than the brand name aftermarket exhaust. It has different settings, stealth, normal, sport, and track. You won't be disappointed in the system.
Sorry newbie questions , just started looking at a stingray !!
What does NPP stand for? I assume its the performance exhaust
Can it be programmed to start at normal settings so the cold start doesnt wake up neighbours
Does the exhaust become louder at sport and track mode, does the valves open?
NPP is the RPO (Regular Production Option - or order code) for the Performance Exhaust (described in the Order Guide as "Exhaust, performance, increases to 460 horsepower, aggressive exhaust sound, with 4" polished stainless-steel tips")
Sorry newbie questions , just started looking at a stingray !!
Can it be programmed to start at normal settings so the cold start doesnt wake up neighbours
Does the exhaust become louder at sport and track mode, does the valves open?
In all drive modes it starts with the NPP valves open so it "essentially" bypasses the muffle and it's loud for ~30 seconds.
The butterflies that open and "essentially" bypass the muffler are either fully open or closed- no in-between position. The sound does not vary other than the rpm that the valves are open and than it goes from than fairly quiet to fairly loud.
You can remove a fuse that controls the electric motors so the valves can be "always open" in loud mode.
You can buy a device called Mild to Wild that does the same thing as "pulling the fuse" but on command of a remote that actiaves a remote rely. However when it is set to off it's like putting the fuse back so it will operate depending on the drive mode. It cannot make them always closed!
Set at Touring mode they open at ~2500 rpm. Set at Track ~1700 rpm from my observation. In either mode when accelerating in lower gears they will be open and be in loud mode. The only change in volume is the rpm and exhaust volume flow.
In all drive modes it starts with the NPP valves open so it "essentially" bypasses the muffle and it's loud for ~30 seconds.
The butterflies that open and "essentially" bypass the muffler are either fully open or closed- no in-between position. The sound does not vary other than the rpm that the valves are open and than it goes from than fairly quiet to fairly loud.
You can remove a fuse that controls the electric motors so the valves can be "always open" in loud mode.
You can buy a device called Mild to Wild that does the same thing as "pulling the fuse" but on command of a remote that actiaves a remote rely. However when it is set to off it's like putting the fuse back so it will operate depending on the drive mode. It cannot make them always closed!
Set at Touring mode they open at ~2500 rpm. Set at Track ~1700 rpm from my observation. In either mode when accelerating in lower gears they will be open and be in loud mode. The only change in volume is the rpm and exhaust volume flow.
thanks for the explanation, so you can set the exhaust noise to various level like sport, touring and track, my concern is cold starts and any way to have a quieter cold start. After that I am good with exhaust noise depending on the mode and rpm you are driving
ALL C7s are dual exhaust. Not just the NPP. ALL C7s are loud at startup. Even the non-NPPs are louder at startup. But, they both quiet down. The valves on the NPP, don't open fully at less a certain RPM, is reached. 2,700==full open, IIRC. Then, they all quiet down. You can pull a fuse to leave em open, but the drone is miserable at steady highway speed inside the cabin. Esp. the hatchbacks decibel level. Buy aftermarket exhaust systems to capitalize on your noisemaking tastes.
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Last edited by Skid Row Joe; 01-27-2019 at 12:56 AM.
For those interested, this is what is inside a C7 Muffler with NPP.
There is a sound chamber in the front that probably reduces some of the harshness. Exhaust enters the chamber that contains fiberglass and comes out the many holes in the baffle.
My understanding is that if you do not get NPP exhaust it won't have the cool looking outlets on the mufflers, but it has valves that open at 3000 rpm. My C6 does for what it is worth.
Nope, cars without NPP have NO valves after the muffler!
All C7's (perhaps not a resent Z06 and not on a ZR1) have what I show in post #29 pic as "V8 to 4 Valves." They have a different function! They operate from fully open when in V8 mode to "partially shut" when in 4 cylinder mode. That provides some back pressure so the car doesn't sound like a V8 with 4 cylinders miss firing and some performance issues when in that mode! Don't have a pic of a standard muffler internals but all pipes are flowing all the time though sound deadening. The standard muffler also doesn't have the black soot we NPP folks have to deal with on the outer pipes!
They would not charge $1195 for software that opened the valves at different rpm's! It's for the more complex muffler and NPP valves.
Had a C6 with NPP and checked out the issue with none NPP mufflers. Below are pics for mufflers for sale. Note the C6 without NPP has no valves. Since the C6 did not have V8 to 4 mode there were no valves before the mufflers. If your C6 has valves, someone may have installed them etc. Note the C6 used vacuum operated valves NOT the electric motor operated valves in the C7.
thanks for the explanation, so you can set the exhaust noise to various level like sport, touring and track, my concern is cold starts and any way to have a quieter cold start. After that I am good with exhaust noise depending on the mode and rpm you are driving
Boss, not to worry. They aren't obnoxiously loud at start up. And, as Jerry said they quiet down quickly.
My question is this. Will there be a fuse #42 if you don’t have n p p exhaust? I pulled the fuse, but I don’t notice a difference in sound. Although all four tips now become dirty after driving.
^^^
Hmm, if you have a fuse #42 but no NPP valves and no NPP special muffler it has nothing to do with the sound. It can’t as you have conventional mufflers with nothing to change sound.
You still have valves before the mufflers that only partially close when the car goes from V8 Mode to 4 cylinder. There is a fuse that is for those valves which does nothing for sound in 8 cylinder mode as the valves are fully open.
However unlike the NPP valves where the computer doesn’t care if you remove the fuse; for the 8 to 4 mode it does! It can detect that the motor control is not working and trips a. CEL with a check engine red light on the dash!
PS: See pic on my post #29. That is what is needed to change sound shown in Open and Closed Mode. If you don’t have those items you have a conventional muffler with no moving parts and nothing to change the sound but your right foot!
My question is this. Will there be a fuse #42 if you don’t have n p p exhaust? I pulled the fuse, but I don’t notice a difference in sound. Although all four tips now become dirty after driving.
Taevon, here's the easiest way to know if you have the NPP exhaust.
I’m in the minority, but if my Z06 wasn’t already equipped w/the NPP, I definitely wouldn’t have paid for the upgrade. The NPP is too quiet and I don’t like the gadgety actuators. I had my replacement exhaust (Corsa) delivered before the car.
FWIW and IIRC, M7 cars starting in 2017 don't have the V4/V8 valves. My 2017 GS doesn't, or if so I don't see them anywhere. My 2015 A8 did have them.
Yep guess my 2017 GS M7 doesn't have them either. Would not make a difference as in 2 years have never put it in ECO mode. Tested several times in my 2014 Z51 and even on the flat section of I95 around here could tell on the slightest grade when set at 77 mpg on cruise control could feel it change.
01-26-2019, 04:03 PM
Jerry. I have mine set to sport only, sounds good at take off, but they do close at some point/rpms when cruising. However, I kinda like it that way. As I've grown more mature (re: old 
) I've found that cruising without a roar from the exhaust is right up my ally. 
Buy aftermarket exhaust systems to capitalize on your noisemaking tastes. 
