NPP Fuse Pull
Pro
Joined: Jul 2021
Posts: 694
Likes: 617
From: Crosslake, MN
The valves are very active normal driving in sport and track. Bad video but this is pretty normal driving. Understandy how they function now I probably could keep them closed all the time with throttle control in sport or track.
Pro
Joined: Sep 2011
Posts: 712
Likes: 502
From: Round Rock, TX
2024 C8 of the Year Finalist - Unmodified
The second part of your post had made me feel stupid for a few days now. I didn't realize that was part of the problem; the fact that there's so much metal makes me unable to hear my own car. I hung out of the car with the door open and revved and yeah, it's louder than I thought because it's so muffled by the firewall, glass, and engine/trans being between me and the pipes. Sigh, more things I'm unhappy about and writing on a list of "reasons why I'm selling my C8". I appreciate you pointing this out so I know there's a fundamental problem with mid-engine cars.
Race Director
Joined: Mar 2007
Posts: 11,254
Likes: 8,388
The valves are very active normal driving in sport and track. Bad video but this is pretty normal driving. Understandy how they function now I probably could keep them closed all the time with throttle control in sport or track. https://youtube.com/shorts/mGRulZs2r...RNcrSipwXJhYm2
Is around 2K RPM regardless of gear and speed? I was, and have been, well aware that they close under certain conditions in Track or Sport. But, in my HTC, with the top down, I tried to detect the conditions where they close. It just seemed to me that the conditions where they close are benign, very little throttle angle, and steady cruise (and maybe you can confirm) lower speeds. To me it was conditions where the exhaust is not going to be so loud even if the valves were not closed. If I'm right, it means that forcing them open all the time is going result in little perceived difference in exhaust sound - wrt Track or Sport - which is what one person concluded after trying it.
Last edited by Andybump; Jun 19, 2024 at 01:05 PM.
Pro
Joined: Jul 2021
Posts: 694
Likes: 617
From: Crosslake, MN
You are pretty accurate. They seem to close on light throttle for the most part. I agree when they close or start closing the engine sound isn't changing much.
Last edited by mortelec; Jun 26, 2024 at 05:02 PM.
Thread Starter
Racer
Joined: Apr 2024
Posts: 320
Likes: 95
From: Annapolis, MD
There's more to it than that that I am keeping track of... but I didn't spend $70k (and have to be about to put out another ~$3300 for a protection plan if I decide to get it) to be unhappy with the exhaust note. My $5000 99 Mustang GT sounded better than this car. For this kind of money and $750/mo payments w/$100 insurance per month on top, I really don't appreciate having any doubts or dislikes whatsoever with this car. If I keep it, I'll throw an AFM/NPP delete catback at it for $2000 and probably be happier with it. If not, I'll see about sport cats or just sell it.
Race Director
Joined: Aug 2016
Posts: 12,710
Likes: 10,140
From: Garden Valley CA
There's more to it than that that I am keeping track of... but I didn't spend $70k (and have to be about to put out another ~$3300 for a protection plan if I decide to get it) to be unhappy with the exhaust note. My $5000 99 Mustang GT sounded better than this car. For this kind of money and $750/mo payments w/$100 insurance per month on top, I really don't appreciate having any doubts or dislikes whatsoever with this car. If I keep it, I'll throw an AFM/NPP delete catback at it for $2000 and probably be happier with it. If not, I'll see about sport cats or just sell it.
Thread Starter
Racer
Joined: Apr 2024
Posts: 320
Likes: 95
From: Annapolis, MD
After a few weeks of research after getting the car, I believe it is the only purpose yes. People report an unpleasant exhaust note and droning with loud catbacks/catless pipes in V4 mode. However, without simulators, you will get a MIL despite it just being for sound purposes - guess if they were to fail closed the V8 might have a hard time getting exhaust gases out of the system as a whole, or GM just likes having any and everything on this car throw a MIL...
Race Director
Joined: Mar 2007
Posts: 11,254
Likes: 8,388
After a few weeks of research after getting the car, I believe it is the only purpose yes. People report an unpleasant exhaust note and droning with loud catbacks/catless pipes in V4 mode. However, without simulators, you will get a MIL despite it just being for sound purposes - guess if they were to fail closed the V8 might have a hard time getting exhaust gases out of the system as a whole, or GM just likes having any and everything on this car throw a MIL...
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Burning Brakes
Joined: Mar 2013
Posts: 1,174
Likes: 226
From: Colorado
There's more to it than that that I am keeping track of... but I didn't spend $70k (and have to be about to put out another ~$3300 for a protection plan if I decide to get it) to be unhappy with the exhaust note. My $5000 99 Mustang GT sounded better than this car. For this kind of money and $750/mo payments w/$100 insurance per month on top, I really don't appreciate having any doubts or dislikes whatsoever with this car. If I keep it, I'll throw an AFM/NPP delete catback at it for $2000 and probably be happier with it. If not, I'll see about sport cats or just sell it.