exhaust sounds muffled

[ivanuke]

Hey guys, I was cruising around today in my GT350 in sport mode, listening to the wonderful sound the engine makes. I would do sporadic acceleration and deceleration just to listen. Then after driving for about 15 minutes, the exhaust just went muffled, the car sounded like it was in normal mode and i checked and it wasnt, i still had it in sport. I pulled over and the baffles were still open, but it no longer had that loud exhaust sound.

I put the car in normal mode, and it nearly went silent, i was surprised at how quiet it was. I think my daily driver focus is louder. Has anyone had similar issues?

I wanted to add one more thing, the car sounded much raspier than it normally does when I started it up. And it would crackle and pop a lot louder than it normally does. I guess it may have something to do with it.

Update: 1/31/2016

Just an update, I did a db rating in normal and sport mode,

Normal was 87db, and sport mode was 89db at idle. Which I believe is normal, the issue is when im accelerating and getting up into the revs where it sounds like there is a a bunch of rags stuck in the exhaust (best way I can describe)

I revved the car a few times, and had it idle for about five minutes, and the car shut off. When trying to turn it back on it chugged for a sec and turned on. I called my dealer and im scheduling an appointment to get a diagnostic, its weird because I don't get any warning lights or anything. Its got a smooth idle, but every 15 sec or so, its like it hiccups and wants to shut off.

I think its worth noting, this all started happening after i came back from the track, and i hadn't driven the car since then until i made this post. I also didn't have an oil separator installed. The car did shut off on me after one session when sitting idle at the track, but i didnt think much of it. And a 2nd time when idling yesterday.

Also the car doesnt pull as hard as it used to.

The car has 1500 miles, with about 100 miles of actual track time.

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[kratty]

Sounds to me like your exhaust valves are malfunctioning. I've had that happen. In most instances, I get error messages on the dash, but not always. Are you sure you were able to switch between Sport and Normal? The icons actually changed when you toggled the switch?

 

[ivanuke]

Sounds to me like your exhaust valves are malfunctioning. I've had that happen. In most instances, I get error messages on the dash, but not always. Are you sure you were able to switch between Sport and Normal? The icons actually changed when you toggled the switch?

Yep. The icon changed, and i also got out to check and the valves were shut.

 

[ivanuke]

I would like to ask for a favor. Could someone who has their car please download a sound meter app (preferably on an iPhone 6 Plus) and record the db rating for normal and sport mode?

I would like to test how far off the sound db rating is from my car. Somethings up for sure and I can't figure it out.

Thanks guys!

 

[Higgs Boson]

Isn't that the job of the mufflers?

 

[ivanuke]

Isn't that the job of the mufflers?

Sure, but something has happened where the sound has been reduced so much that something is wrong.

 

[SchultzLT1]

I think it's just break in. I'm noticing it as well, but my exhaust valves are working.

And if that's the case. Choppy choppy for resonators

 

[Higgs Boson]

It is probably moving the Variable Cam Timing from a Warm-Up / Emissions Mode to normal driving mode and it has a different tone. The ECM retards the intake cam 30-40 crankshaft degrees from Emissions Reduction Mode to normal driving mode (called Fuel Economy Mode at lighter loads), this is going to take a lot of snap and pop out of the tone and smooth it out.

 

[ivanuke]

Thanks for the info.

Just an update, I did a db rating in normal and sport mode,

Normal was 87db, and sport mode was 89db at idle. Which I believe is normal, the issue is when im accelerating and getting up into the revs where it sounds like there is a a bunch of rags stuck in the exhaust (best way I can describe)

I revved the car a few times, and had it idle for about five minutes, and the car shut off. When trying to turn it back on it chugged for a sec and turned on. I called my dealer and im scheduling an appointment to get a diagnostic, its weird because I don't get any warning lights or anything. Its got a smooth idle, but every 15 sec or so, its like it hiccups and wants to shut off.

I think its worth noting, this all started happening after i came back from the track, and i hadn't driven the car since then until i made this post. I also didn't have an oil separator installed. The car did shut off on me after one session when sitting idle at the track, but i didnt think much of it. And a 2nd time when idling yesterday.

Also the car doesnt pull as hard as it used to.

The car has 1500 miles, with about 100 miles of actual track time.

 

[ronda]

Thanks for the info.

Just an update, I did a db rating in normal and sport mode,

Normal was 87db, and sport mode was 89db at idle. Which I believe is normal, the issue is when im accelerating and getting up into the revs where it sounds like there is a a bunch of rags stuck in the exhaust (best way I can describe)

I revved the car a few times, and had it idle for about five minutes, and the car shut off. When trying to turn it back on it chugged for a sec and turned on. I called my dealer and im scheduling an appointment to get a diagnostic, its weird because I don't get any warning lights or anything. Its got a smooth idle, but every 15 sec or so, its like it hiccups and wants to shut off.

I think its worth noting, this all started happening after i came back from the track, and i hadn't driven the car since then until i made this post. I also didn't have an oil separator installed. The car did shut off on me after one session when sitting idle at the track, but i didnt think much of it. And a 2nd time when idling yesterday.

Also the car doesnt pull as hard as it used to.

The car has 1500 miles, with about 100 miles of actual track time.

This doesn't sound right. Get it checked out.

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