NPP disabled
Race Director
Joined: Aug 2002
Posts: 13,455
Likes: 76
From: Atlanta GA
I installed a Mild2Wild switch on my 19 C7 (ordered from the Corvette Musuem), have it linked to my HomeLink on my visor. I can press one button and have it go to Stealth Mode, press a different button and it goes to Track mode. The device in essence disables the NPP fuse at the press of a button.
Le Mans Master
Joined: Feb 2006
Posts: 5,979
Likes: 4,142
From: Kansas City, MO
This post covers lots of details of the NPP system:
https://www.corvetteforum.com/forums...ck-result.html
Due to noise laws even in Track mode the valves will close under certain conditions. Someone needs to put a GoPro down there and just film what happens along with a 2nd camera synced to the RPM.
https://www.corvetteforum.com/forums...ck-result.html
Due to noise laws even in Track mode the valves will close under certain conditions. Someone needs to put a GoPro down there and just film what happens along with a 2nd camera synced to the RPM.
Safety Car
Joined: Nov 2005
Posts: 4,364
Likes: 934
From: Huntsville Alabama
We'll learn something new every day. It did just it. 35MPH, still in 3rd, clutch & rev & NPP Vavles closed quiting the Rev... whats wierd is in 4th it already shuts them when you shift into 4th but if you clutch and rev they open up to make the Rev loud.. so backwards..
Last edited by mittens; Feb 4, 2022 at 09:14 AM.
Racer
Joined: Mar 2013
Posts: 327
Likes: 101
From: Houston
I think the engineers build in all these weird scenarios just to mess with us lol
Advanced
Joined: Jan 2022
Posts: 99
Likes: 17
From: Waaay Northeast Oklahoma
Mine are Loud all the time
Hey if any of you wants yours to be loud all the time, I have a deal for you. I have Flowmaster exhaust which, I understand, is louder than stock with the valves open. Not wake-the-dead but . . . . There IS no NPP valve. There are one pipe per muffler which Ys into two "bells" (Someone tell me the proper nomenclature for those - please). Everyone who hears them likes the sound. But I want it to be quiet on long trips with the wife, to be able to have a conversation or music. And on a long, traffic laden highway, I will use eco mode. SO I will trade someone, even trade, Stock NPPs for my Flowmasters. Everything from the muffler on back. Keep your AFMs. I'm not sure mine are working right. You pay your own labor and shipping and I do likewise. Think bout it . . . . I bought used OEM mufflers. A trade is out. But I will be selling the Flowmasters after I get the swap accomplished.
Last edited by ARAKNID; Feb 14, 2022 at 01:15 PM. Reason: additional information
Le Mans Master
Joined: Aug 2015
Posts: 6,884
Likes: 2,884
From: Toronto
Hey if any of you wants yours to be loud all the time, I have a deal for you. I have Flowmaster exhaust which, I understand, is louder than stock with the valves open. Not wake-the-dead but . . . . There IS no NPP valve. There are one pipe per muffler which Ys into two "bells" (Someone tell me the proper nomenclature for those - please). Everyone who hears them likes the sound. But I want it to be quiet on long trips with the wife, to be able to have a conversation or music. And on a long, traffic laden highway, I will use eco mode. SO I will trade someone, even trade, Stock NPPs for my Flowmasters. Everything from the muffler on back. Keep your AFMs. I'm not sure mine are working right. You pay your own labor and shipping and I do likewise. Think bout it . . . .
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Race Director
Joined: Apr 2017
Posts: 13,602
Likes: 12,864
From: Virginia
Advanced
Joined: Jan 2022
Posts: 99
Likes: 17
From: Waaay Northeast Oklahoma
Tech Contributor
Joined: Oct 1999
Posts: 41,037
Likes: 9,801
From: Charlotte, NC (formerly Endicott, NY)
If I put the drive mode into Eco and exhaust in Track Mode then I can hear the exhaust get louder every time the engine switches from 4 cylinder operation to 8 cylinder operation in 4th, 5th, 6th, and 7th. The engine doesn't switch to 4 cylinder mode in 1st, 2nd or 3rd.
This operation matches how the Factory Service Manual says it will operate when placed in Track Mode.
I have been living with the exhaust on this car for 6 years and have become very familiar with its operation. I made a PDR video that tried to demonstrate how it works but what I could hear in the car was many times drowned out by tire noise due to the placement of the PDR microphone.
Bill
@C7GSM7VERT
Joined: Mar 2014
Posts: 1,024
Likes: 935
From: S.F. Bay Area,CA
2025 C7 of the Year Finalist- Unmodified
2024 C7 of the Year Finalist - Unmodified
What the hell does NPP stand for anyway?!?
Could NOT find any definition in the OM. Regardless, after playing with the Mode Selector for about 1 year, the Club was going on a coastside cruise. It was time to pull fuse #87 (2019 GS, 2lt, M7, vert). Bottom line is it's awesome when fully open all the time. While the sound is much more satisfying for me, I do have to admit that if the trip involves some freeway cruising, the tone can be a bit monotonous when on the flat and level. I can now keep it in tour mode for a smoother feel of the road, with badass open exhaust all the time. Sold, but I do keep the fuse in a baggie in the trunk, just in case...
Race Director
Joined: Apr 2007
Posts: 16,023
Likes: 1,645
From: Toronto, Canada
C7 of the Year - Unmodified Finalist 2021
Could NOT find any definition in the OM. Regardless, after playing with the Mode Selector for about 1 year, the Club was going on a coastside cruise. It was time to pull fuse #87 (2019 GS, 2lt, M7, vert). Bottom line is it's awesome when fully open all the time. While the sound is much more satisfying for me, I do have to admit that if the trip involves some freeway cruising, the tone can be a bit monotonous when on the flat and level. I can now keep it in tour mode for a smoother feel of the road, with badass open exhaust all the time. Sold, but I do keep the fuse in a baggie in the trunk, just in case...
Safety Car
Joined: Jul 2018
Posts: 4,303
Likes: 2,055
From: Margate, FL
Sitting at traffic lights causes the average to drop like a rock because your going 0 MPH for many minutes. I average around 30 MPH on my commute despite 50% of it being at 75 MPH on the highway. The getting on and off the highway, around town, stop and go part is a killer. You have to take into account speeding up, slowing down and just sitting there not moving an inch. Even at track days my average speed will be in 40-60 MPH range just from idling in the pits despite doing 130+ on straights.
Advanced
Joined: Jan 2022
Posts: 99
Likes: 17
From: Waaay Northeast Oklahoma
Sitting at traffic lights causes the average to drop like a rock because your going 0 MPH for many minutes. I average around 30 MPH on my commute despite 50% of it being at 75 MPH on the highway. The getting on and off the highway, around town, stop and go part is a killer. You have to take into account speeding up, slowing down and just sitting there not moving an inch. Even at track days my average speed will be in 40-60 MPH range just from idling in the pits despite doing 130+ on straights.