Exhaust
Thread Starter
5th Gear
Joined: Jan 2021
Posts: 5
Likes: 0
Exhaust
Rookie here and asking opinions from the veterans . Purchased 14 stingray with long tube headers and straight pipe npp disabled . Like muscle car sound but feel like it’s got bit of drone . Best after market muffler to add , or find used NPP system ? Worried the NPP possibly to quiet ? Anyone have any experience with this and have some advice ? Will be adding a cam as well Gwatney stage 3 I believe .
Tech Contributor
Joined: Oct 1999
Posts: 41,066
Likes: 9,835
From: Charlotte, NC (formerly Endicott, NY)
Stock mufflers can be fairly loud when in open mode which is basically a straight pipe. The noise level depends on what is dampening noise in front of the mufflers. I think the difference between the stock mufflers and aftermarket muffles is more a matter of tone than loudness. The problem with adding NPP mufflers to a car that didn't originally have them is the lack of control software/hardware to control the muffler valves.
If your car had NPP before the mods were made I assume the system was tuned to eliminate AFM so you don't get errors from the AFM valves that are on the inlet of the mufflers used for the Stingray and Z51 cars. The GS and Z06 mufflers don't have the AFM valves on the inlet.
Bill
If your car had NPP before the mods were made I assume the system was tuned to eliminate AFM so you don't get errors from the AFM valves that are on the inlet of the mufflers used for the Stingray and Z51 cars. The GS and Z06 mufflers don't have the AFM valves on the inlet.
Bill
Thread Starter
5th Gear
Joined: Jan 2021
Posts: 5
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First off thank you for anyone responding . Again first time owner and don’t know to much about these newer cars ha prob shows my age bit more . This car originally had the NPP and yes it has been tuned recently . The only mods are the long tube headers and a halitech cold air . Nothing compared to what I read on here! It was tuned right around 512 crank and I believe 440 rw. I’m not racing or anything this just personal like for me . I’m def doing a cam , thought maybe with the cam , (straight pipe , headers ) it may just be to much for the wife when we take out . So what would I need as far as the borla mentioned with the NPP option ?
Supporting Vendor
Joined: Jan 2016
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From: Orange County, CA
We can get you setup with the right one, feel free to text us.
-Josh
-Josh
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Your One Stop Aftermarket Shop!
Borla / Corsa / AWE Tuning / Kooks / Morimoto / BC Forged / Vossen / Soul Performance + More!
Orange County, CA
Email: info@merakiautoworks.com
Text/Call: 213 394 2886
Website: www.MerakiAutoworks.com
Last edited by MerakiAutoworks; Jan 1, 2021 at 07:54 PM.
Melting Slicks
Joined: Aug 2014
Posts: 2,746
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I’d put stock NPP back on it so that you can quiet it down when you want and still have the option to go loud when you want. It gives you the best of both worlds. Plus a used set of OEM NPP is going to be much cheaper than a good aftermarket muffler with NPP functionality.
Last edited by lakemg; Jan 3, 2021 at 03:31 PM.
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Instructor
Joined: Mar 2018
Posts: 222
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From: Fountain Hills, AZ
LT headers and catless xpipe with the Mild 2 Wild NPP controller give the options of REALLY LOUD (locked open) or really quite (controlled by the driving mode selection) whenever you want. I have the M2W On and Off programmed into the garage door buttons on the visor so it is extra convenient.
Last edited by ricmalaz; Jan 4, 2021 at 08:10 AM.
Thread Starter
5th Gear
Joined: Jan 2021
Posts: 5
Likes: 0
I sure appreciate all the advice and hearing what has worked for y’all . Think makes most sense on my end (or maybe the misses preference ha ) to try and locate a used oem set of npp for reasonable price. Since doing a cam few other things hopefully makes best financial sense if I can get reasonable used pair and with headers and open be great for me and closed wife enjoy few cruises . Thanks for all input , anyone hear of any npp for sale please pass on ! Great forum great help , appreciated . I’ll try to do before after video maybe help someone else down the road .
Burning Brakes
Joined: Aug 2001
Posts: 837
Likes: 388
From: Olathe KS
Do you know how the NPP was "disabled?" If they just pulled the fuse to keep the flaps open all the time it's really simple to re-enable it by replacing the fuse, no need to purchase anything. They could've also disconnected the connector at the NPP valves just above the tail pipes. I've seen folks who have welded the valve so it won't open which would be a bit more difficult though so that's why I ask. You may want to go with an axle-back if that's the case or get a used NPP axle-back from the market here.
There is a really good writeup of what fuses do what and where they are at the thread here: https://www.corvetteforum.com/forums...ck-result.html
The Borla is going to be louder than the NPP when in touring mode but it will give you a deeper rumble which is nice with the headers. Sound is such a personal preference, I'd try to find some youtube videos of that combo if I were you. Good luck!
There is a really good writeup of what fuses do what and where they are at the thread here: https://www.corvetteforum.com/forums...ck-result.html
The Borla is going to be louder than the NPP when in touring mode but it will give you a deeper rumble which is nice with the headers. Sound is such a personal preference, I'd try to find some youtube videos of that combo if I were you. Good luck!
Instructor
Joined: Mar 2017
Posts: 239
Likes: 30
From: Columbus, GA
I bought my 2014 Stingray with a Borla S-type which retained the NPP option and I can tell you that in comparison to stock exhaust Stingrays it’s got a deeper rumble (not drone) when you give it gas but at idle it’s ever so slightly louder than a stock exhaust. All in all it’s a good exhaust if you want quiet at idle but rumble on throttle.
