tedrasor

anyone buying this model corvette should expect considerable noise coming from the muffler system when traveling at steady speeds above 77mph. this is a loud fluttering sound heard in the cabin of the car, not exhaust sound. this sound is caused by the valves that open and close the exhaust system. At present GM is not interested in solving the problem...Buyers beware!

Oh4GTO

I don't hear my exhaust valves or AFM valves

MMD

Avanti

" Troll post. " Well, maybe, but who knows? Give him/her a break perhaps?

Pelee4me

I have a 2019 GS with this issue. I took it to the dealer and they kept it for 3 weeks and put over 300 miles on it test driving it. They replaced the muffler twice. Never found the problem. A week ago they told me that the GM technical specialist has to take a look at it. I'm waiting for them to call back to set an appointment but it's been a week with no news so far. In my case it's only when the car in is in V4 mode. The noise is incredibly loud. From my perspective this is a real issue not a troll post.

tedrasor

My dealership found the problem was with the valve in the muffler as I stated earlier and also tested two other grand sports in their inventory and found the same problem. Again as you said only in V-4 mode. This a 2019 problem only as they tested an earlier model with no problem. The dealership also tested a 2019 Stingray and again no problem. Thank you Ted Rasor

tedrasor

Again I am back Pelee4me . What I did not include in my agreement with your comments is that My dealership is Jessup Cad.- Chev in Cathedral City, Cal. They spent hours diagnosing the problem. As you know the only way to get rid of the noise is to shift into M or V-8 mode. In V-4 mode the valve closes to provide back pressure so the V-4 will run properly. However at 1500 to 1800 RPM the valve flutters causing the noise we love to hate. For more information you or your dealership can contact service manager Jeff Bachant at 760-328-9999. They have provided GM with this info but as of now there is no fix available

KenHorse

Funny, neither my '14 Z51 did it nor my current '19 GS do this...

mracer14

Who uses V4 mode on a Grand Sport.

Pelee4me

This is the sort of response I'm sure we all hope for when looking for information or possible solutions to problems. To answer your question, I do.

Oh4GTO

I do all the time. 140 mile round trip to work.

KenHorse

Only time I ever heard a noise under the floor was when my neighbor's dog "disappeared"

DALE#3

Another WIN for the Range Device.Keeping those Corvettes from tear downs
What is a Range Device your wondering? Hmm
https://www.corvetteforum.com/forums...er-butter.html

V1lla1nous

I've never heard this sound, but I also have my valves open 100% due to M2W switch.... Problem solved.

Deweyox

Mine is quiet as a mouse at 80MPH VROOOOOOOMMMM!~

mountainears

Talking about different set of valves. M2W does the NPP valves. This is talking about the AFM.

V1lla1nous

Parker Corvette

Interesting issue. I am taking my 2019 stingray into the dealer today for a test drive because of a similar noise. Have had the car for 6 weeks. Driving in touring mode so possibly was in 4 cyl operation at 75 mph on I-25.