NPP exhause question
Thread Starter
Instructor
Joined: Aug 2008
Posts: 169
Likes: 8
From: Suwanee Georgia
NPP exhause question
For those who have installed NPP exhaust. Seems to me that anytime you accelerate you will loose vacuum, since the vacuum source is directly from the intake, and the butterflies will open. Could you explain why this doesn’t occur or does it?
Drifting
Joined: Oct 2007
Posts: 1,565
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From: The Great Pacific Northwest...........I carry a gun cause a cops too heavy.
When you open the throttle on any engine the vacuum drops to O. With the NPP the vacuum keeps the valves closed except during acceleration, then the vacuum drops off and the valves open.
Hope this helps answer your question.
Hope this helps answer your question.
Last edited by CH-Z51; Dec 14, 2009 at 02:03 PM.
Burning Brakes
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From: Camdenton Missouri
Le Mans Master
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From: Milford NH
Drifting
Joined: Oct 2007
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From: Chino Hills CA
When you start a C6 with NPP the butterflies are open and then close as soon as there is enough vacuume to close them. At around 2800 rpm's an electric silenoid begins to kill off the vacuume as the butterflies open up. Pull the fuse on the system and the butterflies stay open all the time.
Thread Starter
Instructor
Joined: Aug 2008
Posts: 169
Likes: 8
From: Suwanee Georgia
NPP exhaust
Sorry guys, you didn't read the question very well. The question concerns NON FACTORY installed NPP. If you run the vacuum line dirrectly to the intake, when you accelarate and the vacuum drops the valves should open no matter what rpm the motor is at, isn't that correct, is that what is actually happening.
Melting Slicks
Joined: Oct 2003
Posts: 2,655
Likes: 5
From: Brea CA
Wow...
Sorry guys, you didn't read the question very well. The question concerns NON FACTORY installed NPP. If you run the vacuum line dirrectly to the intake, when you accelarate and the vacuum drops the valves should open no matter what rpm the motor is at, isn't that correct, is that what is actually happening.
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Michael S. Palmer
Safety Car
Joined: Jan 2007
Posts: 4,332
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From: Kuwait
I have it... installed on my 06, NON-FACTORY... what you do not understand is... it takes Vacuume to CLOSE the flaps... so if vacuume goes to Zero... they will be OPEN... You need a Retro-Fit NPP in a box... it is great...you can have open or closed ANY time you want. The NPP controls the vacuume. Vacuume does not fall to Zero, under hard acceleration, and they stay closed, if you set it to close... You open when you push the buton to allow vacuume... It is not hard to get used to
Burning Brakes
Joined: Apr 2001
Posts: 773
Likes: 107
From: NC
I have the B&B Fusion exhaust. It came with a vacuum reservoir that mounts in the space behind the passenger side rear tire. It holds enough vacuum to keep the exhaust in quiet mode even at full throttle. I would think the factory system would have some sort of reservoir as well.
Safety Car
Joined: Sep 2006
Posts: 4,075
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From: Wilmington NC
I have the B&B Fusion exhaust. It came with a vacuum reservoir that mounts in the space behind the passenger side rear tire. It holds enough vacuum to keep the exhaust in quiet mode even at full throttle. I would think the factory system would have some sort of reservoir as well.
The valves vacuum actuators must require a low amount of vacuum to stay closed and only crack open in certain instances that I described above. I guess a vacuum reservoir could always be added, if desired, if anyone finds it annoying.
Safety Car
Joined: Aug 2007
Posts: 4,836
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From: Rushsylvania Ohio
If you are going to add NPP to a non-NPP car, I think the best solution is to use the "NPP In A Box". This mounts in one of the rear storage bins and has its' own vacuum pump. You just need a 12 volt source and then run a short length of tubing over to the exhaust valves. No need to route a tube all the way up to the engine. Connected directly to the engine, the valves would be at the mercy of what the engine is doing. With the NPP In a Box, you can open and close the valves at will by just pressing the button on the included remote.
Melting Slicks
Joined: May 2004
Posts: 3,017
Likes: 2
I installed Z06 mufflers and ran the vacuum line to the intake manifold. You partially correct, in that when you get on it, the valves will open, but unless you stay WOT the entire time, the valves will start to close. So in a 1/4 mile run at the strip, yes they will stay open, but on the street as soon as you back off just a bit, they will close. Ed "Pipedreams" has some hard numbers as to the vacuum required to close the valves but I don't remember the numbers.
I used Sunset Orange's controller for two reasons. I did not want to drill holes in my car body, and two, I wanted the flaps to open at a preset RPM, much like the stock system.
I used Sunset Orange's controller for two reasons. I did not want to drill holes in my car body, and two, I wanted the flaps to open at a preset RPM, much like the stock system.
Team Owner
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Sorry guys, you didn't read the question very well. The question concerns NON FACTORY installed NPP. If you run the vacuum line directly to the intake, when you accelerate and the vacuum drops the valves should open no matter what rpm the motor is at, isn't that correct, is that what is actually happening.
The NPP in a box system available aftermarket, provides it's own vacuum source which eliminates the need to tap the manifold for a vacuum source and it allows that source to be controlled electronically from a supplied remote.
Racer
Joined: Aug 2006
Posts: 372
Likes: 0
From: L.I. NY
If you are going to add NPP to a non-NPP car, I think the best solution is to use the "NPP In A Box". This mounts in one of the rear storage bins and has its' own vacuum pump. You just need a 12 volt source and then run a short length of tubing over to the exhaust valves. No need to route a tube all the way up to the engine. Connected directly to the engine, the valves would be at the mercy of what the engine is doing. With the NPP In a Box, you can open and close the valves at will by just pressing the button on the included remote.
Melting Slicks
Joined: Oct 2003
Posts: 2,655
Likes: 5
From: Brea CA
Well...
To be honest... you can have all the theorys you want...
But, I like many, many others here, I have installed NPP on non-factory installed car... I used NPP In-A-Box, that connects to engine vacuume. THERE ARE NO ISSUES... It is BETTER on a Non-Factory car, than on a factory car... as I CAN keep the flaps closed above 3500 RPM, which a factory car can't do.... 
But, I like many, many others here, I have installed NPP on non-factory installed car... I used NPP In-A-Box, that connects to engine vacuume. THERE ARE NO ISSUES... It is BETTER on a Non-Factory car, than on a factory car... as I CAN keep the flaps closed above 3500 RPM, which a factory car can't do....
Racer
Joined: Aug 2006
Posts: 372
Likes: 0
From: L.I. NY
To be honest... you can have all the theorys you want...
But, I like many, many others here, I have installed NPP on non-factory installed car... I used NPP In-A-Box, that connects to engine vacuume. THERE ARE NO ISSUES... It is BETTER on a Non-Factory car, than on a factory car... as I CAN keep the flaps closed above 3500 RPM, which a factory car can't do....
But, I like many, many others here, I have installed NPP on non-factory installed car... I used NPP In-A-Box, that connects to engine vacuume. THERE ARE NO ISSUES... It is BETTER on a Non-Factory car, than on a factory car... as I CAN keep the flaps closed above 3500 RPM, which a factory car can't do....
...