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Can someone smarter than I am please enlighten me in layman’s terms on the operation of the NPP actuators?
First some brief background. I retired a few years ago after 49 years in the electrical supply/control panel business. I understand electricity and how it works but not so much electronic motor control (PLC’s, VFD’s etc)
I have a 2019 non-NPP Stingray and bought a set of Z06 mufflers for it.
I took one of the actuators apart and found that if you bypass the circuit board inside and feed the motor with 12VDC it will open and close the baffle. The problem is that the spring on the baffle is so strong that, when you remove voltage from the motor when the baffle is closed, the spring forces the baffle back open. I know enough to know that, if I supply constant voltage to a “locked rotor” motor, the current goes up and the motor will burn up.
My question is, does the GM setup constantly power the motor with 12VDC to keep the baffles closed (about 90% of the time) and, if they do, why doesn’t the motor burn up?
That is a great Q that I don't have an answer for. From what I have read the OEM signal going to the actuators is not plain old 12V power. It is some crazy thing that is near impossible to duplicate. I did the same as you and have ended up making some aluminum pieces to jam the valve at about 1/2 opened. They don't move and I wish they would but don't have the capability. One thing I have thought of is cutting the spring so the valve is easy to move and then getting something like the actuators used in radio controlled planes or robots. I would love to hide a rotating **** in the center console so I could adjust anywhere from open to closed.
The motors are controlled by a pulse width modulated (PWM) 12VDC, not a constant 12VDC. RC servos are controlled in a similar way with a lower supply voltage (but they can be put in any position, not just full open or full closed). A certain pulse width is full open, and another pulse width is full closed. I'd be careful internally jumpering them to a constant 12VDC. You could burn up the motor.
I uploaded the below image from another thread. Note the little pulse icons that the red arrows point to.
The motors are controlled by a pulse width modulated (PWM) 12VDC, not a constant 12VDC. RC servos are controlled in a similar way with a lower supply voltage (but they can be put in any position, not just full open or full closed). A certain pulse width is full open, and another pulse width is full closed. I'd be careful internally jumpering them to a constant 12VDC. You could burn up the motor.
I uploaded the below image from another thread. Note the little pulse icons that the red arrows point to.
Thank you for the explanation. That’s what I was afraid of.
Back to the drawing board. 😜
The Z06 just had the 2 NPP valves, was there not a second set of valves before the mufflers as well? You can do a search on here I know there have been many discussions on adding an NPP type system to Stingrays
The Z06 just had the 2 NPP valves, was there not a second set of valves before the mufflers as well? You can do a search on here I know there have been many discussions on adding an NPP type system to Stingrays
Correct, my standard mufflers have the AFM valves ahead of the mufflers and the Z06’s do not. I have a Range AFM disabler plugged in and will leave the AFM actuators plugged in and tied up under the car so I don’t get a CE light. 👍🏻
I cannot answer the O question as I just purchased my2015 3LT with the NPP option, and I heard that if you open them with the mild to wild, they were really loud. I found that my going to Settings>Driving mode>engine sound management I set them in track Mode, and they are open all the time I believe, at least that is what I was told. They don't seem that loud under normal driving, but with just a little gas they sound fine. It may not sound as loud seeing I came from a C6 with American long tubes and SLP Loud Mouths that I finally changed out to Borla Touring. So, these are not loud at all. Then again maybe mine are not open all the time even when I went through the steps above.
I cannot answer the O question as I just purchased my2015 3LT with the NPP option, and I heard that if you open them with the mild to wild, they were really loud. I found that my going to Settings>Driving mode>engine sound management I set them in track Mode, and they are open all the time I believe, at least that is what I was told. They don't seem that loud under normal driving, but with just a little gas they sound fine. It may not sound as loud seeing I came from a C6 with American long tubes and SLP Loud Mouths that I finally changed out to Borla Touring. So, these are not loud at all. Then again maybe mine are not open all the time even when I went through the steps above.
Since mine wasn’t equipped with the NPP exhaust from he factory, it doesn’t have the wiring for the NPP valves nor the computer programming to control them. Many have tried to figure out a way to control them in situations like mine and one or two have but not easily. Akrapovic makes a controller but I don’t want to spend $600 to $700.
I’ll probably end up installing the Z06 exhausts and running them open all the time or propping them partially shut like some others are doing. I’ve never heard the full open exhaust but, from what I gather from other forum postings, I don’t think they’re too loud or obnoxious. Just don’t want to rile up the neighbors. 🥴
NPP operation question
