Maybe, I haven't seen details on how the stock NPP system works. Is it simply a vacuum line from intake to muffler or is there a controller?

For those of us adding NPP to a non-NPP car, OP's method is one of several ways to skin the cat. With the standalone vac pump you can start in quiet mode (big plus for me), and switch between the two at will. I can also keep it in quiet mode and rip on it without the valves opening.

 

There is a controller that won’t allow it to open until 3500 rpm. But with direct vacuum, it just depends on how hard you press the gas. Simple, no electrics. Like a vacuum secondary on old four barrel carburetors.

 

Turns out I had the wrong hose size for the MAC solenoid and that was causing my vacuum leak. The correct ID hose is 3/16" - (AutoZone Link). Below is a short vid of a cold start in mild mode, idle in mild, switch to wild briefly, and switch back to mild. I'll post some pics of how I mount the pump and solenoid in the trunk. To start in mild mode I switch ignition to "on" without starting the car, the pump closes the valves in a few seconds, and then I start the car.... exactly what I wanted for early morning starts.

"new video to come" sorry alll

 

I realize this is an old thread but with fairly recent comments, I wanted to ask how the folks who used this DIY method over standard NPP in a box liked it. Any issues?

I have been reading all sorts of posts about the NPP function and M2W. I think I understand the main differences between stock bi-mode/NPP vs removing the NPP fuse for those that had NPP option from factory vs adding M2W for those who had stock NPP vs NPP in a box for those who added NPP exhausts to cars that did.not come with NPP from factory, and finally vs the DIY method in this post.

I actually think I would prefer the stock NPP which only opens the valves when load is at level where vacuum from motor decreases (around 3500 rpm generally). That avoids drone in highway at low rpm for those who choose to remove the fuse and/or have not installed a manual controller.

Since I did not have NPP from factory, but now have bi mode exhausts, the only way to remove highway low rpm drone is to install NPP in a box or this DIY method which uses an external vacuum pump. I think NPP in a box is simpler since all parts and instructions are included. But this DIY method is appealing since it avoids vacuum tapping at rear of intake manifold and the required routing vacuum lines through length of car to the back.

Can someone explain how the manual switch is connected? I presume it is attached to the solenoid but the write up does not explain. The NPP in a box uses the vacuum from motor so I assume that control box is just the solenoid and remote control parts all rolled into one. The M2W option for OEM NPP also uses the fuse box to control the OEM solenoid.

So does this DIY method also require the manual switch to be connected at the fuse box? If so, how? Would the switch not be able to be connected directly to the solenoid in trunk and only serve to complete the circuit in either on or off position without the need for power source?

Thanks.

 

Hopefully the pics below will clarify the wiring. The switch is wired inline on the positive leg. I used 14awg sheathed speaker wire. For simplicity the leg going to the switch uses black and red wires, but it is POSITIVE.

My car did not have NPP from the factory. I like the functionality of this system and being able to keep it in stealth mode at WOT. I am planning to relocate the switch to the ashtray area when I get around to it.

I didnt want to mess with tapping into engine vacuum and running vacuum lines under the car. I found it easier to run the electric wires through the cabin and install the pump/solenoid in the rear.. that's my opinion and preference.

 

Thank you. Exactly what I needed. I agree with everything you said.

I will set up with regular switch first. But one idea I am.playing with is whether there is a way to code a switch that can be run using the BT button on the steering wheel. I am picking up a steering wheel that has those buttons.

Preliminary research found a few posts about retro fitting BT to 2008 and older cars. Since mine has the onstar option, I just need to make sure the onstar module is version 8 or 9 and the radio is 2009 or newer. But I do not care for BT and would rather use that button for M2W. There is something called arduino device that may allow signal to be used. Have more research to do.

 

Awesome, glad i could help. I bought a 50’ reel of 7/64 hose and a multi pack of the tap a fuse items. Happy to ship you enough of each to do your project if you cover the shipping. May also have some of the vacuum T’s leftover. PM me if interested.

 

Is 7/64” the size of hose that attaches to the vacuum tap on the intake manifold?

 

I don't know, I didn't use the intake manifold vacuum tap, I built the standalone vacuum pump system.

7/64ths is the correct size for the NPP Actuators and the Dorman pump listed above.

The M2W kit comes with vacuum hose for the intake manifold and the actuators... but they may be different size hoses.

These instructions were helpful for my install even though I didnt use M2W.
https://nakidparts.com/pub/media/pro...ild-2-wild.pdf

Pic of the M2W kit, my guess is the hose pictured is larger than 7/64th.
https://nakidparts.com/c6-corvette-n...etrofit-system

Maybe someone with M2W could answer you.

 

I have been very happy with my set-up. Reversible and completely reliable. I rarely use the pump-I like the sound with the open valves. You won't regret the vacuum pump arrangement.

 

Agree with this. I close the valves in ACC mode for start ups at home... cam + tune + headers = some extra noise. I enjoy being able to open the exhaust at will, and being able to close it at will. I would love to have this same system on my daily 392 Charger... whenever I cold start it's like gun shots reverberating in our small neighborhood.

 

Neighbor just bought a 392 Challenger Scatpack. Beautiful car but it is pretty loud at start up. My son asked why he doesn't use the quiet mode and I said I don't think ithas one. The NPP option for Vettes has been around since 2008 but this 2022 Challenger does not have that option. Good job Chevy.

 

What size is this filter? I see them in the 1/8, 1/4, 1/2 NPT sizes. Thinking 1/4 but can anyone confirm? Thanks.

 

I’m not sure the size, but it was included with the solenoid I got on a ma zon. Buy this one and you won’t have to source it separately



3 Port Mac Valve, DC12V 5.4W 3 Port Boost Control Solenoid Valve for Boost Controller 35A-AAA-DDBA-1BA https://a.co/d/fPYHOWK

 

This is the one I ordered. Few days ago. I guess it should have the filter as well. Looks the same as the one in your link but a little cheaper. Hope I got the right one. It arrives today. Thanks.

 

I look at all these posts about an alternate vacuum source. Just want you make sure that you all know that it's really easy to take off an LS intake manifold and open up the QEM vacuum port

Dave

 

Amen, that's the way I did it and had the intake manifold ported and rod modded while it was off. Also running just a vacuum line from that port directly to the mufflers. A few bucks in vacuum line and a few minutes of time to route them. Nothing to break. Plus my Vette is way too loud to run around with the flaps open. They open when they need to be open....as in under hard acceleration.

 

Yea, I was leaning that way initially and all the comments about how hard it was to get to that vacuum port behind the intake pushed me to alternate ways. I did not even want to try the EZ tap since running vacuum lines down the length of the car, either via tunnel tube or rocker panel seemed like a lot of effort if I ever had to track down a vacuum leak.

I know i will still need to run wires from trunk to passenger footwell but wires just seemed easier than a vacuum line since I can just tuck wires along the inside of the trim. Also, the notion of doing this project was attractive and offered the same level of control as stock NPP with M2W.

I am going to try to set it up with remote control option which only cost $16. If I can get that to work, the next evolution I want to attempt is to see I can modify the blue tooth controls on the steering wheel. Not sure how successful that will be. I picked up a 2013 steering wheel and started opening up the control. I have a 2008 so BT is not possible unless I get a newer stock radio and a newer onstar module. The BT control on the steering wheel has 4 wires which I presume are: power (green), ground (black) and two other wires (blue and yellow) that I have to figure out.

Does anyone know if that BT control is just a switch to turn on and turn off the BT? From what I read. The BT module is actually part of the Onstar module which is not in the steering wheel. So if it is just a switch, I was thinking that I can draw the power and ground from the harness but instead of attaching the blue and yellow wires to the switch, there may be a way to connect the switch to the remote control board which should be small enough to attach inside the steering wheel switch area.

At least that is my novel idea. However, since I am not an electronics guy, I have no clue if this is even remotely possible. Any experts out there want to share their knowledge and tell me that this is do-able or impossible? Thanks.

 

I just found this thread and this seems to be a great way to add NPP. I like the simple open or close at the flip of a switch. I will do a dead peddle switch if I end up doing this.

 

You can do the same thing with "NPP in a BOX" , comes with everything you need to control NPP mufflers including remotes that you can slave to your homelink buttons if u like

Dave