Converting SS exhaust to NPP Exhaust

[wane713]

Can you convert to the NPP exhaust if your car has regular SS exhaust? I was told you need a computer control to do it by dealer and my car doesn't have it because it wasn't built with the NPP exhaust! I know there is vacuum controls but I guess computer controls it also that why there is a fuse people pull to keep valves open all the time? Just wondering if anyone successful went from regular exhaust to NPP not from factory? I really would like to do this!

[dentnshell]

Several people have done it... Several options:
Simply hook up vacuum - should operate very much like factory
or
NPP in a Box - allows you to add the mild to wild option to a non factory NPP
or
build your own. - Any combination in between

I have posted a few threads and "feel" like I have a grasp on it, but will know a ton more tomorrow... Waiting on O2 sensors after they broke on my header install. Took the down time to actually run the vacuum lines for my NPP. I have a eBay solenoid $15 that I think will partially control it.
more research shows you need two solenoids or a single 3-way solenoid. A 3 way should make it work more like NPP in a box.
Without a three way or a second solenoid the system cannot vent to air keeping it from going back to "wild" until the vacuum leaks down.

Plenty of information out there and don't forget most all of the corvette information applies as well

[Homeless Man]

Why don't u just buy another exhaust. Many sound better and will be easier to install.

[wane713]

Thanks I didn't think about corvette also. My question doesn't the NPP also work in conjunction with the vacuum and the ECM? I know where I can get the NPP mufflers as well as the all the vacuum lines and solenoids from a ZL1 pretty good price just want to be sure I can make it work without being controlled by the computer. Are you converting yours or did it have the NPP exhaust. Thanks for the help I appreciate it, I bought my 1LE weeks ago now.

[wane713]

I like the option of being able to quiet it when I have to and open it when I want to

[dentnshell]

Originally Posted by wane713

My question doesn't the NPP also work in conjunction with the vacuum and the ECM?

Yes, with the factory option the ECU will control when the valve opens and closes based on RPM. I understand it to be around the 1500 and 3000 RPM Range.

Originally Posted by wane713

Are you converting yours or did it have the NPP exhaust. Thanks for the help I appreciate it, I bought my 1LE weeks ago now.

Yes, I am converting mine. The way I understand it... simply hooking up vacuum will get you close... As at startup there is not initial vacuum, so it is "wild" I would assume that vacuum will build fairly quickly and close the system at an idle where the factory system would keep it open until you got rolling. I also understand that when you accelerate the system will will loose vacuum and open things up. The factory option is, " I would assume" better tuned on the control of this vacuum.

Most people with factory NPP simply pull the fuse which takes away control. It seems that many of us that are adding it want the control... Mine (wife daily driver) sounds great with just the NPP bolted on. Actually the wife is not inclined for it to be any quieter. Which is why most people say why add it... simply get the exhaust you want and bolt it on. I would tend to agree as we purchased a Borla ATAK to install.... But before we could get it, found a great deal on an NPP take off. So before opening the box on the ATAK I bolted on the NPP. It does sound good.
Now it is time for Long Tubes and CAI. This is where I think the NPP will shine (Don't know as the car is not done yet) I think it will sound great with the NPP and headers in constant "Wild" mode. But I think I would prefer on long highway trips the option of "Mild" mode.

I have done a great deal of research on single / double solenoid controls... As well as NPP in a box and 3 way solenoids. But honestly it is all speculation until I can actually get the car of the Jack Stands! I do believe I am more interested in "Control" than the actual finished product.

[dentnshell]

My research essentially went like:

Hey what is NPP and how does it work?
What is the Fuse pull mod?
Thinking to myself... Why would people pull the fuse? Hooking that wire to a toggle switch would make morse sense!
What does the M2W kit do?
Hey the M2W kit is essentially a toggle switch in wireless form! Cool!
Holly crap the M2W kit looks identical to cheap 12 volt wireless switches that are all over eBay and amazon
No really they are the same! Check out the remotes...
Wait a minute I don't have factory NPP how am I going to hook it up?
What is this NPP in a box kit?
It appears to be a vacuum solenoid that is operated by a M2W switch. I can make that.
Did more research...
It appears that if you simply hook up vacuum to the NPP mufflers you are "Close" to factory
I want more!
It appears that if I purchase a normally closed solenoid that I can hook it up to vacuum and to the mufflers and the kit will stay wild unless I supply power via my cheap wireless switch then it will allow the vacuum through and quiet things down... If I turn the thing off it will get wild again.

I ordered a bunch of stuff!
Decided to order Headers
Decided Headers and NPP are a marriage made in heaven! ( in my mind anyway)
installed headers and broke the O2 sensors.. Car is on blocks waiting on Amazon.
went ahead and ran the NPP vacuum line, but have been too lazy to hook up the solenoid.
Instead spending hours thinking about how it should / could work

I then thought to myself... Self, if the valve shuts off when under full vacuum where does the vacuum go? Dummy it stays under vacuum and the NPP won't get loud again until the system bleeds off.
Hey I can add a second solenoid that is normally open and when you hook them both up to power the system will work... ( much like GM 5 wire door locks)
Wait a minute this is getting complicated... Maybe I should have gotten a 3 way solenoid.
Research...
Yes, a 3 way solenoid would have solved the problem!
Wait a minute, If I I hooked my 2 solenoid design up to two switches I could essentially keep the system quiet even under acceleration! Almost full control ( still limited by vacuum supply at startup)
More control that is what I want!
Do I really want more control? I mean this is not the space shuttle.
Hey dummy, hook up what you have and find out if you really need two solenoids or if the system holds vacuum and for how long.

[Jasper]

But the NPP isn't going to be any louder than a muff delete. That's essentially what it is right?

And muff delete isn't that loud at all (I know, I have it). So if you really like the Jeckyl and Hyde thing, you should just go with the no weeds.

[dentnshell]

Originally Posted by Jasper

But the NPP isn't going to be any louder than a muff delete. That's essentially what it is right?

And muff delete isn't that loud at all (I know, I have it). So if you really like the Jeckyl and Hyde thing, you should just go with the no weeds.

tell that to the poor soles that live in CA!

http://www.camaro5.com/forums/showthread.php?t=388767

[2012LS3VERT]

Originally Posted by dentnshell

My research essentially went like:

Hey what is NPP and how does it work?
What is the Fuse pull mod?
Thinking to myself... Why would people pull the fuse? Hooking that wire to a toggle switch would make morse sense!
What does the M2W kit do?
Hey the M2W kit is essentially a toggle switch in wireless form! Cool!
Holly crap the M2W kit looks identical to cheap 12 volt wireless switches that are all over eBay and amazon
No really they are the same! Check out the remotes...
Wait a minute I don't have factory NPP how am I going to hook it up?
What is this NPP in a box kit?
It appears to be a vacuum solenoid that is operated by a M2W switch. I can make that.
Did more research...
It appears that if you simply hook up vacuum to the NPP mufflers you are "Close" to factory
I want more!
It appears that if I purchase a normally closed solenoid that I can hook it up to vacuum and to the mufflers and the kit will stay wild unless I supply power via my cheap wireless switch then it will allow the vacuum through and quiet things down... If I turn the thing off it will get wild again.

I ordered a bunch of stuff!
Decided to order Headers
Decided Headers and NPP are a marriage made in heaven! ( in my mind anyway)
installed headers and broke the O2 sensors.. Car is on blocks waiting on Amazon.
went ahead and ran the NPP vacuum line, but have been too lazy to hook up the solenoid.
Instead spending hours thinking about how it should / could work

I then thought to myself... Self, if the valve shuts off when under full vacuum where does the vacuum go? Dummy it stays under vacuum and the NPP won't get loud again until the system bleeds off.
Hey I can add a second solenoid that is normally open and when you hook them both up to power the system will work... ( much like GM 5 wire door locks)
Wait a minute this is getting complicated... Maybe I should have gotten a 3 way solenoid.
Research...
Yes, a 3 way solenoid would have solved the problem!
Wait a minute, If I I hooked my 2 solenoid design up to two switches I could essentially keep the system quiet even under acceleration! Almost full control ( still limited by vacuum supply at startup)
More control that is what I want!
Do I really want more control? I mean this is not the space shuttle.
Hey dummy, hook up what you have and find out if you really need two solenoids or if the system holds vacuum and for how long.

Here you go. Main NC solenoid is in line, on a on/off switch. The second one vents off the vacuum, on a momentary switch. Excuse the mess during testing.

[dentnshell]

Headers are hooked up NPP wild is not all that wild.... I am opting for a 3 way solenoid.. This will allow for the use of one single solenoid but will not allow for the system to be run in a permanent quiet mode....
If I really want that I can hook up the solenoid I already have.

basically a latched with makes it operate like: fuse in and fuse out.

My complaint vs real NPP is that it gets quiet FAST. Without the ECM to control the valving the vacuum build quickly and the valves operate much faster than I would like.... You can hear it during the transmission shifting... Also it switches to quiet virtually immediately on startup.

[wane713]

thank for the information guys sorry it took awhile to respond and communicate on this thread I started but I have been out of town . Really detailed, that what I need. I haven't done it yet but I believe I am going to go the NPP exhaust conversion route. I like you have the option of going open exhaust and quiet when I need to. I was being told by dealer couldn't be done which I didn't believe was true. This helps.

[dentnshell]

If you want true npp then you will need a few items...

I have put together some pricing from Amazon or ebay!
$55 - RPM window switch
$36 - ACDelco 214-474 GM Original Equipment Turbocharger Wastegate Solenoid ( this would not require special barbed fittings, price also includes a pigtail to hook it up. )
$17 - 50’ Gates vacuum hose
$15.35 - RM01 1 Channel Wireless Control On/Off ( basically the relay and wireless mild to wild control)
$8.39 - E Support 12v Car Add-a-circuit Fuse TAP Adapter Mini ATM APM Blade Fuse Holder Pack of 5
$7.99 - Dorman 47380 Vacuum Connector Value Pack, 65 Piece (Really only need a single vacuum Tee)

The wastegate solenoid is a three way solenoid. It will allow for vacuum to be pulled when on (quite) and it will vent to air when off (vent to air will allow for the valves to actually spring back)

An RPM window switch is not really needed unless you want it to operate like factory NPP and be controlled by RPM ebay has a RPM switch in the $45 -$55 range depending on how much control you want. This will allow you to have the NPP come on (quiet down) at a set RPM, say 1500. And go off again (get loud) at another RPM say 3500.

You can also add a second solenoid that will not allow the first to vent to air. This would keep the NPP engaged and keep it quiet at idle or at WOT. This would also require a three way switch. (probably instead of the wireless controller)


It all depends on how much control you want.

[wane713]

Originally Posted by dentnshell

Headers are hooked up NPP wild is not all that wild.... I am opting for a 3 way solenoid.. This will allow for the use of one single solenoid but will not allow for the system to be run in a permanent quiet mode....
If I really want that I can hook up the solenoid I already have.

basically a latched with makes it operate like: fuse in and fuse out.

My complaint vs real NPP is that it gets quiet FAST. Without the ECM to control the valving the vacuum build quickly and the valves operate much faster than I would like.... You can hear it during the transmission shifting... Also it switches to quiet virtually immediately on startup.

Are you saying here that the NPP in a box VS real NPP gets quiet fast compared to the real NPP? if I have NPP in a box system I should be able to control it to stay open or closed when I want correct?