NPP Drone
Drifting
Joined: Mar 2003
Posts: 1,771
Likes: 141
From: Kaukauna WI
Depends on your mods. On a stock car, the drone will be minimal. On my Z06 with heads, cam, intake and x-pipe, the drone is AWFUL right at 1450-1650 RPM. So, 6th gear at 70-75 is a no-no with the system open. My Corsa's droned with these mods too. With NPP closed, it's nice and quiet.
Le Mans Master
Joined: Nov 2014
Posts: 6,252
Likes: 113
From: Texas
The PO pulled the fuse. The noise was dreadful. I purchased about $250 of sound insulation from a vendor here which helped. What really helped was replacing the fuse with a M2W.
Drifting
Joined: Mar 2013
Posts: 1,705
Likes: 539
From: Hampton VA
I pulled the fuse on my NPP and the drone at around 55-60 was terrible. I like a louder sound from the exhaust but I couldnt deal with that, I had a corsa cat back on my previous Vette and there wast any drone might be an option for you
Burning Brakes
Joined: Apr 2016
Posts: 1,120
Likes: 110
From: Chattanooga TN
After going from painfully quiet stock muffler to painful drone of louder system and back to stock I went to 2006 NPP mufflers on my 2005 and the results are perfect. When closed it is still too quiet and when open it sounds more like a Corvette should but with no drone. By the way, complete sound mats throughout made just a slight reduction in the drone. I used the nakidparts.com mild to wild switching system which works great and has included remotes but I used one of the garage door opener buttons that also works well for switching. I recommend this change if you want better sound but no drone. I use it open most of the time with no problems and am certain it will work well without switching (which was not an option in 2005). I got my practically new mufflers off Ebay and a local shop had no problem with the install of the inlet pipes being slightly different size.
Drifting
Joined: Mar 2016
Posts: 1,665
Likes: 128
From: Wilson, TX
St. Jude Donor '17
When I bought my '08, it had BB Bullets. Great sound in town but the drone on the road drove me to going back to NPP (that it originally had). Love the NPP. Sounds nice in town and with the mild to wild, I can make it quiet on the road.
I highly recommend it
I highly recommend it
Instructor
Joined: Feb 2015
Posts: 178
Likes: 10
From: Fort Worth Texas
Idk but my opinion seems to be completely different from the majority here. I can not stand the Highway drone one bit. It over powers the radio and definitely cant talk over it. I installed a switch where the ash tray was and installed some sound dampening that helped the drone but still nvr like to keep it open on HW with windows up. (for whats its worth - 25 yr old ears)
Racer
Joined: Dec 2016
Posts: 381
Likes: 40
From: CT
Race Director
Joined: May 2012
Posts: 15,762
Likes: 3,281
From: Phoenix area, AZ
I'm very well aware of what drone is, having experienced it in the past. I just don't hear any on my car. As I said, drone is relative.
Intermediate
Joined: Sep 2013
Posts: 41
Likes: 7
From: Palm Coast Florida
Open NPP Drone?
The highway drone is real and drove me and my wife crazy. And at low speeds, it pops like mad on decel. If that's not acceptable you can add the M2W, or as I did add some spacers to the vacuum butterfly shafts to keep the straight pipes slightly open full time. I added (or subtracted) spacers until I was satisfied with the sound at idle, at low around town speeds and 70+ on the highway. Sounds really great. Pipes open up fully as designed at 3,500 rpm.
Drifting
Joined: Oct 2004
Posts: 1,756
Likes: 267
'Open' gets kinda annoying on the highway. 'Mild' is way too tame. I installed a dead pedal foot switch to control the NPP, but opted to place clips (like speed nuts) on the butterflies to prevent them from closing completely. They are still adjustable but easier than the collar method. And the huummmm in 'mild' is absolutely perfect. So around town I switch between the two positions, but leave it in 'mild' when on the freeway. No drone with the modified 'mild'.
Here's a pic of the cllip (speed nut) that I mentioned before. Just slide it over the butterflies to hold them open slightly. You can adjust to your own taste. Mild is more lively and NO drone on the highway.
Pro
Joined: Nov 2016
Posts: 577
Likes: 93
From: North Alabama
I had NPP and ran it wild all the time. On mild it just didn't sound like a vette should. At highway/interstate speeds in 6th gear there was a lot of drone. Worse when you hit an incline. It drove me to put on a Borla S Type II axle back and drone is gone. I can't even make it drone if I try. And since I've put on Kooks long tubes and off road 3 inch X pipe with the Borla and still no drone. If you don't want drone spend the $$ and get a Borla.
Plus the Borla has 4 inch tips.
Plus the Borla has 4 inch tips.
Last edited by ONEBADZ; Nov 14, 2017 at 08:47 PM.
Drifting
Joined: Sep 2016
Posts: 1,260
Likes: 324
From: Florida
I just got my car with NPP, and the previous owner installed mild to wild. Open, it sounds great driving around at lower speeds in town, but getting up to highway speeds, it seems to quiet down with lower rpms, but there is an annoying drone. What I'm trying to say is that it's nice to have the option to turn it off.
Thread Starter
Pro
Joined: Sep 2013
Posts: 536
Likes: 62
From: New York
I just got my car with NPP, and the previous owner installed mild to wild. Open, it sounds great driving around at lower speeds in town, but getting up to highway speeds, it seems to quiet down with lower rpms, but there is an annoying drone. What I'm trying to say is that it's nice to have the option to turn it off.