I know that there are several kits out there for a retro-fit NPP system, but I wondered if anyone of you has done a DIY for the vacuum control system. I was thinking about wiring a three way rocker switch, such that Position 1 - Quite Mode (Valves closed all the time), Position 2 - Semi-Quiet Mode (Valves close on start and partially open during times of hard acceleration when the manifold vacuum reduces), and Position 3 - Sport Mode (Valves alway open - no vacuum). There are several inexpensive air solenoid valves available. My thoughts are when the solenoid is closed then that is Position 3. Would you need at least a 3 way solenoid to bypass any stored vacuum to the atmosphere if you were in either of two other positions prior to switching to Position 3? When the Solenoid is open then in the path for Mode 2 is an unimpeded vacuum source from the manifold. With high vacuum the valves would be closed and low vacuum would be open to some degree. For Position 1 however, it appears you would need a one way check valve to ensure that the vacuum you had would not bleed away or decrease due to engine acceleration. May you need a 4 way vacuum solenoid to accomplish this. Anyway, I have just received my NPP mufflers and trying to work through the pneumatic portion in my head. Any suggestions would be appreciated from the group.

 

Sounds like you have it thought out correctly, I was going to do the same thing except just the 2 modes open and closed, but decided against making my own when I saw the factory system uses vacuum canisters and what not. So I bought the npp in a box and opened it up and it was actually really simple I believe it was just the one 3 way solenoid with the wireless circuit board controlling it. Not really much to it I suggest you go for it!

 

Did it also have a check valve to prevent the varying manifold pressure allowing the valves to open under acceleration?

 

You can get a vacuum reservoir ball on the cheap.
http://www.carid.com/dorman/vacuum-r...FQuMaQodOXwApQ

Back of the intake manifold has the port to pull the vacuum to begin with.

So all you need to do is install a 12v pneumatic solenoid ($12) shortly after the intake manifold vacuum line to control the vacuum line after it.
http://www.ebay.com/itm/Keurig-12V-P...-/281663800609

The 12v pneumatic solenoid is what you are controlling with a switch, or controller box.

At the back of the car, vacuum reserve ball in line with the T of the vacuum lines out to hit the two NPP solenoids on the mufflers.

At wide open throttle, you will lose some of the vacuum off the back of the intake manifold if you stay in the throttle long enough, and the reserve ball will maintain that needed amount of vacuum during such time at the back of the car to keep the NPP valves closes.

So to add in your second toggle position, then just add in another vacuum solenoid to the reserve ball to take it out of play for your second position.

Postion 1 would have both solenoid valves open to keep the NPP's closed

Postion 2 would have the solenoid right off the manifold open, but the solenoid to the vacuum ball closed. At WOT, the vacuum pressure in the manifold is going to drop, and since there is not enough vacuum or reserve to keep them closed if you stay WOT long enough, the NPP valves will loose vacuum to allow them to open.

Postion 3 would just have solenoid right off the manifold closed instead and it does not matter what the reserve ball solenoid is doing, since there is no vacuum getting past the first solenoid to send any vacuum on the lines to the NPP solenoids .

 

Dana523, thanks very much for the input. I drew out what you described and had a couple of questions. It looks like the solenoid from the manifold would have to be a three position vacuum solenoid. For the case of the manifold solenoid, the output will either go to the ball or directly to the NPP tee with two separate paths. I would think the best route would be a 3 way at the manifold and the ball solenoid inserted between the ball and the NPP tee. Than way you wouldn't have to drain off the stored vacuum from the ball. If it was prior to the ball you would have to let the vacuum escape or it would still hold in the NPP in the closed position. Am I missing something in my thinking? Jerry

 

I'm not 100% but i think it was just the 3 way solenoid in the npp in a box. But the check valve may have been incorporated into the valve. There is no vacuum canister, I believe that there is probably a check valve in the solenoid so once the solenoid is open, lets vacuum close the actuators and even at wot or 0 engine vacuum the check valve holds the vacuum on the actuators.

 

No, single tube off the intake manifold for vacuum, through the 12v pneumatic solenoid at the front of the car close to the intake manifold, tubed to the back of the car.

The single vacuum line at the back of the car gets split to three lines, with two of the lines to the mufflers valve controls, and the third line goes to another 12v pneumatic solenoid before it ends at the reserve ball.
Note, tube length from the front of the car and to the back of the car will slow down the vacuum response time for a buffer to allow the ball reserve to work fine.

Both 12v pneumatic solenoid in the open position to allow a vacuum through them, you have a vacuum to both mufflers to hold them closed when the motor is running.

When you go WOT on the throttle, there will be a dip in vacuum pressure in the intake manifold, but since the reserve ball is holding a reserve vacuum when needed, it will be enough to hold the muffler valves closed when the manifold dips it vacuum pressure to the vacuum line.

When the 12v pneumatic solenoid is closes to the reserve ball only Still a vacuum going to the mufflers, but when the intake vacuum pressure dips during WOT, no vacuum reserve in play to over come this short vacuum pressure dip, so the vacuum to the mufflers valves dips down, and the muffler valves will open up.

Close the 12v pneumatic solenoid in the engine bay, and no vacuum is going to the back of the car on the vacuum tube, and the muffler valves stay wide open.

So lets say that the 12v pneumatic solenoid are normally open and will allow air flow through them without power (12 volt power to them closes them, so prevent a air flow through them).

Your quiet toggle position will do nothing/not send power to either of the 12v pneumatic solenoid.

The next toggle position on the switch, muffler roar when you go full throttle (WOT). So 12 power to only the 12v pneumatic solenoid to the reserve ball, to close the the vacuum line to it.

Last toggle position, being the muffler loud position, hence muffler valve open, just need to send power to the 12v pneumatic solenoid right off the intake manifold in the engine back to block the vacuum after it down the line to the back.


OEM system, and you can see that the vacuum reserve ball is just T's in line with the muffler lines; to supply a short reserve to the muffler valves when the intake vacuum dips at WOT. Also, just a single 12v pneumatic solenoid to control if mufflers see a vacuum or not to close the muffler valves to start with.


So with a second 12v pneumatic solenoid in line just before the reserve ball, when the vacuum pressure dips during WOT and ball reserve out of play (12v pneumatic solenoid closed), the vacuum pressure to the muffles dips down far enough to allow them to open.

 

Thanks. That was very helpful. Appreciate it. Jerry

 

No worries, and if you want to add in a remote type system for control (at least on and off) then here you go.