What is the difference between Sport and Track exhaust mode? I thought in Sport the valves are open all the time, what does Track mode offer over that?

 

The difference, at least with my 2015 manual trans Z, is that in Sport the exhaust goes into quiet mode in fifth, sixth, and seventh gear, when low throttle cruising. Track is in loud mode all the time.

 

No it is not, in regards to Track mode. The NPP exhaust valves will still close in Track mode under light throttle cruising just like they do in Sport mode. Track mode allows the valves to stay open more during aggressive driving, but once you get into steady state cruising the valves will close.

 

We have other choices rather than just LOUD... lol...

 

When the valves are open, there is no difference in sound volume between Sport and Track. Track mode, the valves will be open more often and at wider RPM and Throttle ranges than Sport.

 

Seems pointless. I don't think I've ever wanted anything besides loud all the time or quiet. Should've just been an open/close valve switch.

 

Your wish has been granted...

https://www.corvetteforum.com/forums...ob-how-to.html

 

With the M7 transmission use Settings to set the Exhaust in Track Mode. Set Drive Mode to any other mode than Eco. Once those settings are chosen the exhaust valves are open all the time except in 5th gear when the engine is running less than 1500 rpm. I have run this test multiple times over the last 5 years and they stay open as I have indicated. If you are driving in 5th gear with engine rpm below 1500 and then accelerate hard you will hear a POP when the engine reaches 1500 rpm and the valves open.

If you set the Drive Mode to Eco the valves will close every time the engine switches to 4 cylinder operation. As you drive along you will hear the exhaust get quiet and then loud. Try doing this in 4th gear at 40 mph using light throttle and as engine load changes you will hear the sound get quieter and louder. This is all explained in the Factory Service Manual.

If you have an A8 transmission the reason the valves close and open all the time is the engine runs in Eco Mode all of the time except when the transmission is operated in manual mode. Use Settings to set the Exhaust to Track Mode and then drive around with the transmission set in Manual mode and the valves will stay open. You might have a gear like the M7 5th gear where they will close at less than 1500 rpm.

With light throttle openings and low load, the stock exhaust system doesn't make a lot of noise compared to some aftermarket systems when the valves are open but you can tell the difference between open and closed. When the throttle is close to wide open or at wide open and the engine load is high the exhaust screams. Just ask anybody who has been passed by a stock Z while on track.

Bill

 

That is NOT how my car operates. If I put the exhaust in track mode it sets the valves open all the time. In Sport it closes them under light throttle in fifth gear and above.

 

With unit some of us made as the link I provided above , you can keep them open all the time and with the click of a Homelink switch you can go stealth. I set my exhaust in the computer to stealth and I control the NPP valve. Open full 99% of the time.

 

That seems to be a lot of effort to accomplish something that is very simple on the C7. Since I don't need to control the exhaust when I am outside of the car I just use the center dash screen to control whether it is in Stealth Mode or Track Mode. Instead of fumbling for a remote I just touch the screen 3 times. Plus, I get two more selections if I want them. Sure the M7 is less complicated than the A8 due to GM's decision to have the A8 run in Eco Mode all the time except when the transmission is switched to Manual Operation. Yes, when in 5th gear the valves will close when the engine is running less than 1500 rpm (which is a little above 35 mph) but the driver doesn't need to choose that gear and they will be open in 4th and 6th at that speed.

Bill

 

I ran with the fuse pulled for a few days, so full open 100% of the time. While it sounded great, it was just too loud and was too much for my liking.
I keep mine in Track and enjoy the breaks when the flaps close at cruising speeds. I do like when I get back on the gas and they reopen though!

Ron

Edited: I didn't pull and cap the vacuum lines in this car. I tried that in my Ghibli and put it back to stock also as it too was too loud too much.

 

Funny, mine is 1400 rpm's in 5th, but otherwise this is it^
They NEVER close in track mode except below 1400 (or 1500) in 5th. Throttle level has no affect on it

 

I have the Corsa catless Xpipe and WeaponX lid on mine. Track is nice for a while, but sport is perfect as in higher gears I can hear my SC whine as opposed to all exhaust, all the time.

 

I came from a manual vehicle that had OEM NPP and now to my 19 C7Z A8, I can tell you 100% for sure that the C7Z A8 does not run in Eco mode at all unless you select that mode, with that the modes dictate the valve behavior unless you override the mode in the Infotainment system by forcing them into Auto/Stealth/Sport/Track. I spent 17 hours in my car testing the modes in my 19 C7Z versus my 2017 M6 car testing the NPP modes. It is very apparent when the vehicle switches with the exhaust system in either Sport or Track from open to closed. Both of my vehicles I used for the testing had secondary cat deletes on them so the exhaust tone was louder than stock and made it easier to tell when the exhaust tone changed from the valves opening/closing. I also emailed Al O. and Tadge several years ago in regards to the GM logic on the NPP system, both of them advised that on the Auto and Manual cars the valves will close even in Track mode under light throttle cruising. GM is required to do this in order to pass the EPA drive by noise certifications otherwise they can possibly exceed the noise dB limits when driving by the road side testing locations.

Personally I just pulled the use myself, even with the valves open 100% of the time the NPP system isnt all that loud. One of my previous vehicles was a 17 Camaro SS 1LE with a Procharger, catless ARH headers and a AWE Touring system. Even now, my 19 C7Z with a catless x-pipe and the stock NPP system is very tame compared to how aggressive my Camaro was sound wise.

 

^exactly why not everything Tadge says is gospel.
The valves do NOT close under any throttle or cruising conditions in the manuals while in Track mode OTHER than 5th gear 1400 rpm's or less.
I'm not guaranteeing they didn't change the logic after 2015 because obviously that could be done at any time, but the 2015's operate this way

 

So what you are confirming and saying is this, when someone says that the valves dont close in Track mode the statement is not accurate, as they do. So if a person drives on the highway in even yes a Manual M7 C7 Z06 and they go into 5th gear and start cruising along at 1500rpm or less, the valves will close. This includes 6th gear and 7th gear as well. So Tadge and Al O both answered the question accurately that yes even in Track mode the NPP valves can and do close. So if a person wants the valves to stay open they need to look into one of the known options to keep the valves open.

 

Yes, they close in 5th below 1400 rpm's
This does NOT include 6th and 7th gear in any way.
Just like Bill confirmed about his 2015 which is all I'm speaking to, there is ONE time they close, in 5th below 1400 rpm's regardless of throttle position or anything else for that matter

 

Pull the fuse and find out how loud your car is, the valves are not truly 100% open unless the fuse is out, makes a world of difference. Then your only option is loud until you put your fuse back in aha

 

You do know that this isn't what this thread is about, right?
Whether the valves have positions other than open or closed is a different question.