[Mark114]

I think I read someplace that the valves sit open when the car shuts down to prevent them from sticking closed while the car sits due to rust or corrosion from moisture in the exhaust system.

[squish72]

sounds about right. when you pull the fuse for the npp the valves are already open so they stay open

[DarkSSide]

Originally Posted by KingLT1

All you have to do is turn the ignition on(press start with foot off the brake) and set the drive mode to snow/ice and it sets the exhaust to stealth mode.

I thought the car had to be started to access drive mode....perhaps that’s exhaust mode. Anyway, the 5 second pushing start with foot off the brake worked. Now I’m wondering, after looking through optional exhaust and drive modes, what happens if you’re in Track Mode with Stealth Mode on exhaust? Does the steering and suspension just change to track but quieter? I’m also curious as to why NPP is good for 5 hp on Corvettes but GM claims no change when equipped on our cars....

[KingLT1]

Originally Posted by DarkSSide

I thought the car had to be started to access drive mode....perhaps that’s exhaust mode. Anyway, the 5 second pushing start with foot off the brake worked. Now I’m wondering, after looking through optional exhaust and drive modes, what happens if you’re in Track Mode with Stealth Mode on exhaust? Does the steering and suspension just change to track but quieter? I’m also curious as to why NPP is good for 5 hp on Corvettes but GM claims no change when equipped on our cars....

Nope it don't...drive mode effects both the steering and NPP.

Marketing. Just like back in the 90's and early 2k GM gave the LS1 Vette 350hp and the Camaro 305-325hp, when in reality they were all within a few hp of eachother. If you give the lesser model the same HP rating performance enthusiasts will be more inclined to go that route instead of buying the higher model.

[SuperSound]

Originally Posted by KingLT1

Marketing. Just like back in the 90's and early 2k GM gave the LS1 Vette 350hp and the Camaro 305-325hp, when in reality they were all within a few hp of eachother. If you give the lesser model the same HP rating performance enthusiasts will be more inclined to go that route instead of buying the higher model.

Not really the right example. There was no SAE testing at that time, remember the SVT Cobra debacle in that timeframe. The C6 and C7 both got a separate SAE rating for NPP. The best guess is GM paid for a separate certification for NPP for the Vette, but didn't for the Camaro for the same reason you mentioned....marketing the Vette at the top.

[Lemosine]

In my M6 SS if i hold start for 5 seconds it will not let me change the mode and tells me car has to be started.

[KingLT1]

Originally Posted by Lemosine

In my M6 SS if i hold start for 5 seconds it will not let me change the mode and tells me car has to be started.

The you are not holding the start button long enough.

[DarkSSide]

So follow up question(s): Did I read somewhere in the owner manual that it is advised not to run in stealth mode for prolonged periods of time? And does stealth mode reduce horsepower (I’m guessing yes but a negligible amount). And even when (cold) starting it in Stealth mode, she’s still pretty loud....lol.

[crosive]

starting the vehicle in stealth mode is the only way to have a (semi) quiet startup. any other mode opens the valves for a few seconds at least.

the manual does state not to leave it in stealth mode with spirited driving for too long. In stealth mode the valves never open. In touring mode, the valves will open under hard acceleration, but the car still starts loud. In sport and track mode, the valves stay open most of the time, but will close after some amount of cruising. I can't remember if they close all the way however. In all modes but stealth, the valves open if you go wot

[Lemosine]

Originally Posted by KingLT1

The you are not holding the start button long enough.

Just tried it again held it for 30 seconds for the heck of it. Maybe an A8 thing?!

[SuperSound]

Originally Posted by Lemosine

Just tried it again held it for 30 seconds for the heck of it. Maybe an A8 thing?!

Try in neutral with the parking brake on. Might be a safety programming thing.

Sent from my SM-G950U using Tapatalk

[KingLT1]

Originally Posted by Lemosine

Just tried it again held it for 30 seconds for the heck of it. Maybe an A8 thing?!

No it shouldn't matter...all you are doing is putting the car in accessory mode which allows you to access the drive modes. Perhaps you have to put the car in neutral with the parking brake on for m6 as mentioned above.

[MR-02]

I read somewhere that if you do this.....
1. Press and hold start for about 5-8 sec, without brake or clutch, wait for green light, it "pressurizes the fuel lines/system" ???
2. Release and Then press start again to actually start the car the right way,
3. It minimizes that first 40 sec of loud clacking that is trying to heat up the cats.

I've tried it on some cold mornings but not sure if I can tell the difference from inside the car. Combine that with stealth start up, and it is quieter on cold start. Any one know about this ??

[MR-02]

here it is , post number 35
https://www.camaro6.com/forums/showt...46#post9435846