Query:

Is there any way to start the C8 with NPP in STEALTH MODE ?

I could do this with my C7Z.

I have not been able to achieve this yet with the C8 (1LT, MAG RIDE, NPP )

Thanks !!
Happy Thanksgiving !!

 

Others have also asked this - I have not seen anyone post a way to do that. While I do not want to do that myself, the question prompted me to experiment to see if I could get the car exhaust sound to be in stealth mode by setting the exhaust sound to stealth while in the accessory mode, and then starting the car. That did not work for me. Below is what the shop manual says about the start-up "bark". It does say something about "during specific modes of operation" - but there is no other detail that would suggest a way to cause the valves to be closed at start up. That is, assuming you want the valves to function normally at all other times.

 

When I shut fown the C7 Z in STEALTH MODE, it would startup in STEALTH several hours or even a day later.
I have yet to replicate it in the C8. 😟

 

Likely an emissions reason for not allowing that option. Just a thought, based on no knowledge whatsoever.

 

Others have suggested that. And in another thread, debated the point. But the shop manual specifically says the purpose is to achieve a more aggressive exhaust note on start up. There is also quite a bit in the manual about control of emissions on start up, and heating of the cats, including adjusting the timing, and the air fuel mixture that I posted in another thread. It never says that having the valves full open at start up is for emissions. Having said that, what you say could still be true - I just could not find any evidence. I must admit I was actually surprised to find in the shop manual that the open valves at start up was to produce a more aggressive exhaust note. I was expecting it to say it was for emissions - but it didn't.

 

Somewhere (but not found in my 2017 Z51 Stingray owners' manual--so far) I recall reading that the exhaust setting of STEALTH should NOT be used for extended periods of time, as there would be a possibility of overheating the engine due to the restriction on the exhaust system. The Stealth setting is to be used only temporarily to get out of your neighborhood quietly on Sunday mornings, and then the exhaust setting should revert to normal driving conditions.

Old guys have heard of exhaust "backpressure" forever in their talks with car guys. A restricted exhaust system (which causes higher backpressure) results in a restriction on horsepower but also results in a quieter car (considering all things equal with the mufflers, etc.). Conversely, Unrestricted exhaust pressure allows the engine to "breathe" easier and make more power, but it's loud and noisy. (Note the top fuel dragsters' lack of an exhaust "system" and mufflers.)

So think about the idea of starting your car-- you want the engine to "breathe" its best on startup so that there would be minimum initial "backpressure", and so perhaps the engineers thought the noisy, less restricted exhaust setting would be the best initial setting on a car with variable control of the exhaust system and sound. The high compression ratio in modern Corvettes requires a stout starter, but that would seem to have little to do with the exhaust system once engine starting is accomplished. The desirability of an initial "Open" exhaust system at startup seems contradictory to me, because a more restrictive exhaust might cause quicker engine warmups to light-off the catalytic converters to lessen emissions.

Our late model Corvettes like to "breathe" easily and therefore it seems that the Tour setting or the less restrictive Sport or Track settings should be the normal modes. So use the Stealth setting sparingly, and enjoy the raspy bark of your C8 on startup!
Just a thought, but I would welcome the comments of a C8 engineer on this issue.

 

There are two cautions for stealth mode in the 2021 Owners Manual. The first is in the section specifically about "Track and Competitive Events". And it says don't use it at all. The second is more general and says don't use it for spirited driving, auto-cross driving, or driving on high speed tracks. I attached them below. There is nothing about "extended periods of time" in the manual other than under those specific conditions mentioned in the caution statements. Also, the exhaust is in stealth mode when using the Weather Mode - and there is no caution about using Weather Mode for extended periods of time, as long as you are not doing any of those things mentioned in the caution statements. I don't know anything about what might have been true for the C7.



This is in the section on competitive track events - and specific to that condition.

This is a more general caution, but again its specific to spirited driving, auto-crossing, or high speed tracks. Nothing about extended use under normal street driving.

 

I recently received a survey from GM asking about various features and whether I'd be willing to pay a monthly subscription for, or a one-time fee for, different features. One of them was the ability to start the car in quiet mode (I think that's what the survey called it.) I told them if that feature can be added, it should be done for free for anyone who wants it.

So GM clearly COULD program the car to start in quiet mode if they want to. They just chose not to, probably figuring that Corvette owners like the noise. Which is probably true, most of the time, but not always.

 

I agree, I do like the spirited exhaust sound when driving, but not when I start it and pull out of my garage in my townhouse complex where the sound reverberates like a canyon.

 

Wish there was an OVER THE AIR update they could create to make the STEALTH start up happen.

 

I totally agree and would love to have that happen if possible.

And since we're wishing, I wish that it could be easily activated before startup (somehow!), and not required to be activated at the end of the previous drive cycle when you're not thinking about the next start up.

 

I also received the survey mentioned above. Based on those questions, it looks like GM is gearing its future options/add-ons towards high-profit apps and subscription fees. I recall one of the questions regarding a possible audio system download feature giving the driver more system flexibility and enhanced audio quality. Sounds like they might offer sound stage options with a more robust equalizer. Then they wanted to know how much I'd be willing to pay for it upfront or by monthly subscription.

 

But, could we avoid making start up a two step process? Perhaps when starting, it could be accomplished by just holding the start button down a little longer to enable the quiet start feature (since the GM survey implies its possible to have that feature). Quick push - normal aggressive bark. But, hold the button down-stealth start mode. The bark doesn't bother me, Ilike it, but since we are discussing it, that would be my suggestion.

 

Exactly. Make it easy, and NOT a seven-step process with the damn infoannoyance screen, setup, setup, setup, setup....give us a damn button to quiet those barking dogs in the wee hours. It's a high class car. Why make it a 69 Camaro with side pipes?