I've created the circuit, but I had some confusion about the NPN terminals. I've never done this before so I was really unsure of how the symbol corresponds with the transistor. I think I have it figured out. Would you mind taking a look at the schematic and make sure it's all kosher? I found a company that can print some circuit boards for a couple bucks each. I tried my hand at using the double sided PCB boards and I just made some ugly connections trying to route things. This seems pretty clean and fairly cheap to do. I think I have to order 5 so I'll make a few extra if anyone else wants one.
https://1drv.ms/b/s!AoVwbfZXGuTDhcdN...aeefw?e=FG6Ql0
https://1drv.ms/b/s!AoVwbfZXGuTDhcdO...Aqk3A?e=XzifVr
Also, I edited the code through a bunch of educated guess at what should be cut and added. Still not a code junky but I think this code does what I need it to. Any suggestions on the code or does it look right based on not using any memory and more analog switching?
#include <PWM.h> // pwm-frequency-library


const int _pwmPin = 9; //pin9 on arduino board
const int _buttonPin = 8; // pin8 on board
bool _isRunning = true;

bool ReadValveState()
{


{

}

{

}
}

void DoOpenValves()//sends a pwm signal to valves causing them to open
{
pwmWrite(_pwmPin, 203);
}

void DoCloseValves()//sends a pwm signal to valves causing them to close
{
pwmWrite(_pwmPin, 51);
}

void setup() {
InitTimersSafe();
SetPinFrequencySafe(_pwmPin, 200); //sets the pwm pin frequency to 200 Hz
pinMode(_pwmPin, OUTPUT); // sets the pwm pin as an output pin
pinMode(_buttonPin, INPUT_PULLUP); //sets the input pin for the button
pinMode(LED_BUILTIN, OUTPUT);


}

void loop() //the main body of our arduino code, this is run over and over as long as there is power
{


if (digitalRead(_buttonPin) == HIGH) //check the state of the button if it's pressed
{

DoOpenValves();
}
else // Any state other than High
{

DoCloseValves();
}


}

I appreciate your help.
-Stroke

 

If it worked as it was, what did you change and why?

 

His original code and circuitry worked exactly as he designed. I prefer to have additional functionality that relies on analog circuitry instead of a memory bank for position. Making it a manual on/off and then an auto open feature based on engine load/throttle blades. So at cruise and light throttle it stays closed and quiet, but if I get down on the pedal, vacuum drops, and triggers the ground connection of the adjustable vacuum switch and opens automatically. Then closes again when I let of the throttle. An adjustable vacuum switch makes it extremely versatile and adaptable to any engine combo.

It requires the modifications that I have made to the circuitry and code to work properly since I’ve done away with the momentary switch.

This is just all so new to me, but my code tested out to work properly. Just not sure if it’s problematic in some way for the Arduino. Also, I’m going to print some PCB’s since I’m saving so much money on the controller and I want to make sure the PCB design came out right.
-Stroke

 

I know of no vacuum switch on a C7, and would not want to use same on a mod.

Its enough to run a wire harness to do this on a car like C7 that did not have this stock from the factory.

 

The C6 and the C7 both uses a combination of sensors to know when to tell the valves to open. RPM and TPS, I believe. Probably a few more that I’m unaware of.

 

Its a lot more simple - two valves and a switch.
4 valve system may use other inputs but that is cutting back an already restricted 2-3/4 exhaust system before it enters the mufflers, why you'd want to cut those back never made sense

 

C6 had vacuum to open and close the NPP. C7s are electronic.

Elmer

 

correct. But even the C6 still had an actuator that worked off of sensors to allow vacuum to the valve.

 

Dat is true. I ran a vacuum line off my Edelbrock SC to the rear and hooked up a M2W box on it and had a seriously good sounding C6. Long tubes, NPP, and !CATs made a good exhaust system.

Elmer

 

I think there is confusion about what strokemyaxe is trying to accomplish. He's trying to take the electronic valves from a c7 and drive them with an Arduino and a simple circuit that is controlled by a vacuum actuated switch. Plus if I remember correctly you are going to out them in a c3. I looked over your code, it looks okay to me. When you have code that looks like this:
bool readvalvestate
{
}
And there's nothing between the { } you can delete the entire entire thing. It's a "method" that does nothing and only confuses your code. Aside from some things like that I think what you have will work.

Keen in mind the c7 muffler butterflies have springs in them so that they are normally open and your own signal actually closes them when it's at 80% duty cycle which might just be bad naming on my part, but you get the point. 80% duty cycle is 203 and 20% is 51 when you are calling pwmWrite, so once you have your system put together you might find it necessary to switch the 203 with the 51 depending on whether your vacuum actuated switch is normally open or normally closed. You'll know if that's your issue because it will work opposite of what you want

 

All done with it. Took a long break from the car mid install. Made PCBs, housings, wired second standalone fuse box, made the harness and have enough stuff left over to make 4 more units except the Arduino controller. Giving a couple away to some buddies down here in Texas that did the conversion to NPP as well.

 

Congrats on getting it working!

 

Will this retro work on C8s? Has the code changed? I have purchased all components and ready to assemble.