technoman007

I bought my first Corvette four weeks ago and it is my daily driver.
I am super excited to be part of the Corvette family .

It is a 2009 A6 Base ( Victory Red ) and had 31k on it when i got it.
I added Android auto to it after i got it and have already put around 2000 miles on it. The car runs perfect and puts a smile on my face every time .

There is only one thing which slightly bothers me. After the car is all warmed up and I stop at a traffic light, i hear something resonating. My guess is that it is the exhaust. When it resonates the car is in drive and a hairline over 500RPM and i have my foot on the brake pedal. The resonation ceases immediately as i drive away. The resonating sound at idle is a discomfort for the ear.
If i put the car in neutral the rpm goes slightly over 550 and sound reduces drastically.

I am going to check the exhaust hangers(and springs) this weekend to see if anything is loose.

Has anyone faced a similar issue and if you were able to resolve it?

Thank you.

ByByBMW

I have been here a while and have never heard of the specific circumstances you are describing. First thought is maybe somebody put aftermarket mufflers on the car. Other than that hopefully somebody else has some ideas for you.

Turbo6TA

Although I have not had this problem myself, I am close to 100% that it's exhaust related.

Like you suggested that your going to do, is check for any part of the exhaust system vibrating against something else on the car.

Another possibility is a loose baffle inside one of the mufflers.

Are your mufflers OEM or aftermarket? ... If they are OEM, are they the standard mufflers or the NPP option mufflers (that have the valves / actuators attached to the muffler tips?

ben dover

I think your diagnostics are the best approach. I've never heard of such low rpm rumble before, but at 500 rpm there is probably a fair amount of vibration. That idle seems too low. Most complain of drone at around 1600 rpm.

ben z

If your planned inpsection doesn't turn up anything obvious, I would warm her up and get someone to hold her in D while you take a listen around outside. (Of course be really careful, you don't want to get run over!) Something like that which only occurs under very specific conditions you pretty much have to duplicate the same conditions to find. And cabin acoustics give you that ventriloquist effect, hard to always spot where it's coming from when you're inside.

Typical exhaust drone comes on between 1500-1800 rpm range from what everyone has experienced. The previous owner of mine put on aftermarket mufflers, which I will soon be reverting to stock on account of drone.

technoman007

Thanks for the response Turbo6TA. Its OEM mufflers and they are standard.

Turbo6TA

Well, I think it's pretty well obvious that your stock exhaust is vibrating up against something.

As far as "drone" is concerned, what you have is nothing like drone ... and the OEM standard mufflers don't drone at any rpm / vehicle speed.

Your going to have to somehow put it in "drive" and let it idle (emergency brake on), and then get under the car the best you can and track down where the noise is coming from.

Good luck ... in your situation, at least it's not the End of the World!

ByByBMW

Dutch08

As others have said drone is ~1200 - 1600 rpm. So just a data point (this is probably not your problem), I once used a piece of steel to hold up my muffler because the rubber hanger broke. The low speed resonance was awful. Get under the car and track the noise was good advice, IMHO.

buckmeister2

You are calling it resonation, but you are describing vibration...which do you think it is?

If resonation, does it have aftermarket exhaust parts, anywhere?

nick14003

not sure what you mean by "resonating" do you mean a rattle?

I drive mine every day without mufflers and it doesn't bother me, with mufflers this car is so quiet it may as well be a prius

something is probably loosey goosey under there

JMills

Not exactly sure what your you're describing, but I'd checked differential