NPP Drone
Thread Starter
Race Director
Joined: Nov 2009
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From: Dallas Texas
NPP Drone
I have a 2013 GS with NPP. When all the pipes are open there is a pretty good drone which many have complained about and I did a search first.
I like the change with ultimate sound of the open exhaust but is there a single modification step to eliminate some of the drone? X pipe, other?
I like the NPP ability to switch back and fourth.
Thx ahead. I'll take the flaming too.
I like the change with ultimate sound of the open exhaust but is there a single modification step to eliminate some of the drone? X pipe, other?
I like the NPP ability to switch back and fourth.
Thx ahead. I'll take the flaming too.
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Unless you've modified the pipes more than stock, "all the pipes open" for NPP means only two of the four (the inner two)---correct? I don't know if X pipe, etc. will do what you wish but what I wanted was a little more sound, no drone and not the on-off (full open or full closed) of most add ons.
So, I added the little stainless collars that keep the flaps slightly open. What that did was for me to select the amount of opening which correlated to how much sound I wanted at idle as well as escalating sound as I accelerated. It also allowed me to have no drone (but more sound than closed--less sound than full open) at highway speeds. It also meant that at full throttle or starting at about 2900 rpm, the flaps would begin to open as they normally would to full-open. It works well for me.
So, I added the little stainless collars that keep the flaps slightly open. What that did was for me to select the amount of opening which correlated to how much sound I wanted at idle as well as escalating sound as I accelerated. It also allowed me to have no drone (but more sound than closed--less sound than full open) at highway speeds. It also meant that at full throttle or starting at about 2900 rpm, the flaps would begin to open as they normally would to full-open. It works well for me.
Melting Slicks
Joined: Oct 2004
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From: Woodland CA
Off the top of my head, maybe adding a resonator at the mid-pipe might help reduce some drone. I can’t tell you how much though. But if you already have the switch, I would just set it back to MILD when the drone gets too bad. That’s what I do. I would say 99% of the time I have it on WILD and set it on MILD for those rare times when I need to quiet it down.
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From: Daytona Beach FL
I have a 2013 GS with NPP. When all the pipes are open there is a pretty good drone which many have complained about and I did a search first.
I like the change with ultimate sound of the open exhaust but is there a single modification step to eliminate some of the drone? X pipe, other?
I like the NPP ability to switch back and fourth.
Thx ahead. I'll take the flaming too.
I like the change with ultimate sound of the open exhaust but is there a single modification step to eliminate some of the drone? X pipe, other?
I like the NPP ability to switch back and fourth.
Thx ahead. I'll take the flaming too.
I believe for your GS it's greater than 3500 RPM and 25% throttle.
If you don't like the sound with the NPP valves open, just let off the throttle.
If you're cruising at 65 or 70 mph and more than 3500 RPM then you're still in 3rd gear - shift to 6th and enjoy a nice quiet ride down the highway!!!!!
Le Mans Master
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I assumed he had the Mild to Wild, and had it opened. If it has drone without that, then he IS running high RPM's, or something is wrong.
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I too have the M2W. I also have the collars and they can be set to have the valves partialy open in an infinite number of positions. I bought mine from nakkidparts dot com (not sure if they're a forum sponsor - google them) I think I paid around $25 for the pair
Thread Starter
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Joined: Nov 2009
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From: Dallas Texas
Unless you've modified the pipes more than stock, "all the pipes open" for NPP means only two of the four (the inner two)---correct? I don't know if X pipe, etc. will do what you wish but what I wanted was a little more sound, no drone and not the on-off (full open or full closed) of most add ons.
So, I added the little stainless collars that keep the flaps slightly open. What that did was for me to select the amount of opening which correlated to how much sound I wanted at idle as well as escalating sound as I accelerated. It also allowed me to have no drone (but more sound than closed--less sound than full open) at highway speeds. It also meant that at full throttle or starting at about 2900 rpm, the flaps would begin to open as they normally would to full-open. It works well for me.
So, I added the little stainless collars that keep the flaps slightly open. What that did was for me to select the amount of opening which correlated to how much sound I wanted at idle as well as escalating sound as I accelerated. It also allowed me to have no drone (but more sound than closed--less sound than full open) at highway speeds. It also meant that at full throttle or starting at about 2900 rpm, the flaps would begin to open as they normally would to full-open. It works well for me.
Yep. sorry guys. I have M2W and I thought all four opened in the wild phase. And yes the drone is when the wild is on. I do like it and can obviously switch it off. I guess I would would like a little less drone and more pipe or exhaust sound when it is open. Thanks for the replies. I'll keep reading also.
Last edited by vet55; Apr 30, 2014 at 10:04 PM.
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Thread Starter
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Joined: Nov 2009
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From: Dallas Texas
I'm assuming the same for my reply.
I too have the M2W. I also have the collars and they can be set to have the valves partialy open in an infinite number of positions. I bought mine from nakkidparts dot com (not sure if they're a forum sponsor - google them) I think I paid around $25 for the pair
I too have the M2W. I also have the collars and they can be set to have the valves partialy open in an infinite number of positions. I bought mine from nakkidparts dot com (not sure if they're a forum sponsor - google them) I think I paid around $25 for the pair
Unless you've modified the pipes more than stock, "all the pipes open" for NPP means only two of the four (the inner two)---correct? I don't know if X pipe, etc. will do what you wish but what I wanted was a little more sound, no drone and not the on-off (full open or full closed) of most add ons.
So, I added the little stainless collars that keep the flaps slightly open. What that did was for me to select the amount of opening which correlated to how much sound I wanted at idle as well as escalating sound as I accelerated. It also allowed me to have no drone (but more sound than closed--less sound than full open) at highway speeds. It also meant that at full throttle or starting at about 2900 rpm, the flaps would begin to open as they normally would to full-open. It works well for me.
So, I added the little stainless collars that keep the flaps slightly open. What that did was for me to select the amount of opening which correlated to how much sound I wanted at idle as well as escalating sound as I accelerated. It also allowed me to have no drone (but more sound than closed--less sound than full open) at highway speeds. It also meant that at full throttle or starting at about 2900 rpm, the flaps would begin to open as they normally would to full-open. It works well for me.
Thx. I will check it out.
Thx!
Last edited by vet55; Apr 30, 2014 at 10:02 PM.
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Joined: Jan 2005
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From: Daytona Beach FL
Yep. sorry guys. I have M2W and I thought all four opened in the wild phase. And yes the drone is when the wild is on. I do like it and can obviously switch it off. I guess I would would like a little less drone and more pipe or exhaust sound when it is open. Thanks for the replies. I'll keep reading also.
If you have a M2W switch, you can close them up, but I think what you want is what AORoads mentions - the collars that hold the valves open slightly, i.e., they never fully close.
The valves are in the two inner exhaust outlets. It takes engine vacuum to close them, so if you look in the exhaust when the engine is shut down they will be open.
When you start the engine and vacuum builds, the valves will close - at least until you reach the RPM/throttle required to open them, or open them with your M2W switch.
Generally they are either fully closed or fully open. Fully open will give you drone when cruising, but if you have the collars to restrict hem from closing completely that may give you an increase in sound without so much drone when you close them.
Good luck with it, and let us know what works for you.
Last edited by BEZ06; Apr 30, 2014 at 10:30 PM.
Thread Starter
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Joined: Nov 2009
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From: Dallas Texas
Aha!! Now I understand what you're talking about!!
If you have a M2W switch, you can close them up, but I think what you want is what AORoads mentions - the collars that hold the valves open slightly, i.e., they never fully close.
The valves are in the two inner exhaust outlets. It takes engine vacuum to close them, so if you look in the exhaust when the engine is shut down they will be open.
When you start the engine and vacuum builds, the valves will close - at least until you reach the RPM/throttle required to open them, or open them with your M2W switch.
Generally they are either fully closed or fully open. Fully open will give you drone when cruising, but if you have the collars to restrict hem from closing completely that may give you an increase in sound without so much drone when you close them.
Good luck with it, and let us know what works for you.
If you have a M2W switch, you can close them up, but I think what you want is what AORoads mentions - the collars that hold the valves open slightly, i.e., they never fully close.
The valves are in the two inner exhaust outlets. It takes engine vacuum to close them, so if you look in the exhaust when the engine is shut down they will be open.
When you start the engine and vacuum builds, the valves will close - at least until you reach the RPM/throttle required to open them, or open them with your M2W switch.
Generally they are either fully closed or fully open. Fully open will give you drone when cruising, but if you have the collars to restrict hem from closing completely that may give you an increase in sound without so much drone when you close them.
Good luck with it, and let us know what works for you.
Thx to all!
Bought the nakidparts collars and will f/u. Thx.
Last edited by vet55; May 2, 2014 at 08:10 PM.
Advanced
Joined: Mar 2013
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I have a switch wired to the NPP fuse,but after adding the collars to the actuation rods-leaving the LOUD flaps barely open-now I rarely even use the switch. Just enough NOT to sound quiet and not loud enough to drone on the highway.
The collars were cheap,and they even come with a long t- handled allen wrech to install them. With the car off, its easy to override the spring to see how much you have actually opened the butterfly. Very little is all it takes.
The collars were cheap,and they even come with a long t- handled allen wrech to install them. With the car off, its easy to override the spring to see how much you have actually opened the butterfly. Very little is all it takes.
Racer
Joined: Apr 2012
Posts: 314
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From: Ontario
Exhaust systems that are poorly sound engineered can have an absolutely annoying drone. Some of the biggest name companies can be the worst. Driving a car with a drone can ruin an otherwise fun ride. Been there. I've never been a fan of loud exhaust anyway so I'm sticking with the stock system. It makes all the good sounds under acceleration and is quiet when it needs to be.
Drifting
Joined: Jan 2012
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From: Paris TN
I'm on my third muffler system and currently use NPP. I have a switch to open and close when I want. Drone is uncomfortable with the system fully open at cruise speeds and sometimes even with them closed, certain RPMs seem to produce more drone than I like. To be honest, I love the sound of Corsas on any LS engine but the cost is prohibitive for me. Drone is more noticeable in auto cars and Corsa fixes that with a resonator behind the X pipe or part of it. I had B&Bs and loved the sound when running it hard, but drone was unbearable. I feel your pain but not sure there's an easy fix. I'm guessing your's is a 6A as well.
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From: Dallas Texas
I'm on my third muffler system and currently use NPP. I have a switch to open and close when I want. Drone is uncomfortable with the system fully open at cruise speeds and sometimes even with them closed, certain RPMs seem to produce more drone than I like. To be honest, I love the sound of Corsas on any LS engine but the cost is prohibitive for me. Drone is more noticeable in auto cars and Corsa fixes that with a resonator behind the X pipe or part of it. I had B&Bs and loved the sound when running it hard, but drone was unbearable. I feel your pain but not sure there's an easy fix. I'm guessing your's is a 6A as well.
Exhaust systems that are poorly sound engineered can have an absolutely annoying drone. Some of the biggest name companies can be the worst. Driving a car with a drone can ruin an otherwise fun ride. Been there. I've never been a fan of loud exhaust anyway so I'm sticking with the stock system. It makes all the good sounds under acceleration and is quiet when it needs to be.
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From: Dallas Texas
So the idea of muffers resonating might be change by changing the frequency of one muffler only. I am thinking of trying the Kevler wrap in the Link and see how it goes. It's expensive but it is removable and will not void the warranty. Thoughts?
http://www.thermotec.com/products/16...ler-cover.html
http://www.thermotec.com/products/16...ler-cover.html
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I think drone is more a function of the plastic "trunk" floor material and the huge trumpet of a window channeling the sound directly to your head. Many have tried all combinations of pipes and mufflers and still claim some or even more drone.
If you ever hear a Z06 with its Bi-Mode fuse pulled you would think the coupe and GS are pretty quiet.
If you ever hear a Z06 with its Bi-Mode fuse pulled you would think the coupe and GS are pretty quiet.
Thread Starter
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Joined: Nov 2009
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From: Dallas Texas
I think drone is more a function of the plastic "trunk" floor material and the huge trumpet of a window channeling the sound directly to your head. Many have tried all combinations of pipes and mufflers and still claim some or even more drone.
If you ever hear a Z06 with its Bi-Mode fuse pulled you would think the coupe and GS are pretty quiet.
If you ever hear a Z06 with its Bi-Mode fuse pulled you would think the coupe and GS are pretty quiet.
Safety Car
Joined: Sep 2006
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From: Wilmington NC
Your are correct, the valves only open and close one side of the muffler which is unrestricted. The other side has no valves and is always open in either mode.
Last edited by j_digi454; Jun 13, 2014 at 10:13 AM.
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From: Austin Texas
You'll always have drone with the baffles open at low RPM regardless of what else you do with the rest of the exhaust, open exhaust at low RPM under load = drone.