CADbrian

So I've read a lot of threads about people pulling their fuse to effectively leave open the exhaust valves. I've looked in my owners manual and found mine (for my year and model) to be fuse # 42. Since it's such an easy thing to do (pull/replace the fuse), I'd like to see / hear the difference, but my silly/dumb question has more to do with *when* to pull the fuse (when the car is running or when the car is turned off and not running)? Or does it matter? Thanks.

Superstar555

It's best not to pull or add fuses while the car is running.

bsterling9

I don't know for sure, but I was under the impression you can change your default exhaust status under the settings on your info screen. No need to pull any fuses. I haven't taken delivery of my car yet, so I can't guarantee this.

dvilin

By pulling the fuse the valves stay open 100% of the time no matter what mode you are in. That is the only way to keep the valves open all the time in any mode.

Bill Dearborn

True. However, there is no need to pull the fuse to get the valves to stay open all the time. With Engine Sound Management set in track mode the valves are open all the time without pulling the fuse. If you turn off Engine Sound Management it also puts the exhaust in track mode and the valves stay open all the time as well.

I leave my Z06 engine sound management set in track mode all the time unless I want to hear the radio or am on a long trip. Then I set it to Stealth.

All you have to do is push the settings icon on the center display and go to Engine Sound Management and choose track. Voila, Noise.

OP: if you want to pull the fuse only do it when the vehicle is turned off. That is the standard way of doing things involving electronics.

Bill

dvilin

Not so on on my 2015 in track mode they stay open longer than other modes but will close at certain rpms.

bsterling9

That was my understanding as well. I believe I saw a Youtube video on this.

kenownr

My 15 A8 is the same. Fuse out: open all the time. Fuse in Track mode: cycle at certain RPMs.

Ed'sC7

Pull the fuse with engine off....Valves are spring loaded and always open when powered off.

CADbrian

I think I'll try it using the Engine Sound Management set in track mode and see what happens. Then, if I determine that I'm not hearing what I want and when I want it I'll consider pulling the fuse.

I've read enough threads to presume there are some differences across the C7 model with regards to how to effectively leave open the exhaust valves, so I'll share my results for those whose model mirrors mine.

Thanks to all.

redman76

I've played around with my fuse #42 a little. Even in Track mode you can hear the valves open at a lower RPM than Sport mode. To me it was a little annoying, so right now I'm running with it pulled. It's a subtle difference, but I like it better now. I do like being able to control through the exhaust sound management and mode select, but it's something fun to play around with (pulling fuse). I may put it back in when taking long road trips, but right now it sounds just right.

And yes, as already advised, pull with engine off. Oh . . . '17 GS here.

CADbrian

Redman76, forgive me for parsing the above paragraph but I want to be sure that I understand you correctly...

You said, Are you saying [that with the fuse in], even in track mode you can hear the valves open at a lower RPM than Sport mode?


You said, Are you saying that it was a little annoying to hear the valves open at all? Meaning you prefer NOT to hear the valves open and prefer to have them open all the time regardless of which mode you're in?


You said, This is with the fuse in place, correct?


You said, You may put the fuse back in place when taking long road trips so the louder sound doesn't become too much to take?


Sorry for the ridiculously parsed questions, but knowing exactly what you mean helps me to figure out what I'd like to do. Thanks.

joemessman

Remove fuse 42 and exhaust open at all times. With fuse in, and using driving modes in Sound Management such as Track, the flaps will close under 1,800 RPMs. And actually if in Sport with the fuse in flaps will close at about 2,000 RPM. Noise ordinance is the issue in regard to this. As I stated, remove 42 and open at all times regardless of RPM.

jmmoh

On my last road trip I put the fuse back in. Got a bit annoying after 800 miles. Just run in sport works fine for me

Boiler_81

They do close, even in track mode in order to meet federal drive by noise standards.

See this thread for a more detailed explanation: https://www.corvetteforum.com/forums...ck-result.html

I pulled mine and am happy with the sound. If I were going on a long road trip, I would reinstall it and have control.

JGarland

If the car is running and the valves are closed and you pull the fuse, they will open. You will hear the difference.

If they are already open (sport or track mode) and you pull the fuse, nothing changes because they are already open. You wont hear any difference.

Pulling the fuse just prevents the valves from closing under low pressure/load conditions such as letting off the throttle or "coasting".

If you want the valves open 100% of the time, pull the fuse or get a mild2wild switch.

CADbrian

Has anyone experienced adverse consequences of pulling this fuse? For example, this guy on YouTube lays out a pretty compelling case NOT to pull the fuse.

Pulling Fuse 42 (in his case) generated the following issues on his diagnostic report:

• loss of communication with steering wheel module: measure position angle and rate of turn
• loss of communication differential control module: locks axles to differential, change the gear ratio applied to axles, amount of torque applied to the drive line
• loss of communication electric brake control module: controls brake system, activates ABS and traction control

Yikes, sounds scary to me.

I may just decide to control the sound via the Engine Sound Management and live with the valves being closed at the lower RPM's. If what this guys is reporting is true, the risks are not worth the rewards to me.

Are there any of you out there good with electronics that know if what he is reporting is true?

JGarland

Never heard of such a thing. I've had multiple vettes with NPP (pulled fuse) over 10 years with no issues like that.

dbaker

Bought mine,drove home & pulled fuse.

That was over a yr and 3,500 miles ago.NO probs.

\db2

Kevin A Jones

I'm wondering if there's anything else the U-tuber may have altered in the C7 that caused the issues on the report and he's only assuming it was removal of fuse #42?