Drone Question

[GT40dreams]

I recently installed a Vibra Technics rear motor mount (fast road version) and torqued everything to spec. I also replaced the exhaust hangers with new rubber ones. All good for a while, but lately I’ve begun to hear a pretty loud drone at about 3000 rpm, which is loudest under deceleration. Since it had been a couple hundred miles since I installed the RMM, I checked it to verify that nothing was loose with it and retorqued. My exhaust is stock. I bought my 2015 ST new. It’s a garage queen with just 21,000 miles. Am I missing something, or is this drone just normal with after market rear motor mounts?

 

[M-Sport fan]

Is it an actual sonic drone, or just harsh(er) vibrations you are sensing?

 

[GT40dreams]

Is it an actual sonic drone, or just harsh(er) vibrations you are sensing?

It’s definitely a sound. It’s as if normal engine noise is amplified around 3000 rpm.

 

[foodtruck]

Maybe exhaust sprung a leak?

 

[Intuit]

As a test, try plugging the symPOSER.
https://www.fiestastforum.com/threads/intake-noise.17092/post-310311

I know you said it was stock, but check for intake alterations. Albeit rare, there are some dipsticks that like to remove air filters.

 

[GT40dreams]

As a test, try plugging the symPOSER.
https://www.fiestastforum.com/threads/intake-noise.17092/post-310311

I know you said it was stock, but check for intake alterations. Albeit rare, there are some dipsticks that like to remove air filters.

Thanks for your responses and ideas. Since I’ve owned the car since new, I’m spared any worries about what a previous owner might have done to it. As it happens, my first two mods on the car were a Mountune symposer delete plug and a Mountune induction kit with a K&N air filter. I’m pretty sure that the filter is still in place (I cleaned and re-oiled it a few months ago). As for the possibility of an exhaust leak, I will check that although the muffler shop tech that installed my new exhaust hangers in October said he checked for leaks and didn’t find any.

 

[Intuit]

Check to see if the plug is still in the firewall. Make sure the sound insulation is still attached to the cowl in the engine bay.

Across makes and models it has been common for exhaust header bolts to back off over the miles. Not sure if these are yet there. If you're in the rust belt, pushing the pipes around can result with delayed breaks at weld points and sometimes flex pipe.

 

[GT40dreams]

Check to see if the plug is still in the firewall. Make sure the sound insulation is still attached to the cowl in the engine bay.

Across makes and models it has been common for exhaust header bolts to back off over the miles. Not sure if these are yet there. If you're in the rust belt, pushing the pipes around can result with delayed breaks at weld points and sometimes flex pipe.

Thanks for your suggestions. I’ll check them out. I’m in Florida, so no rust belt snow or road salt! The downside is hurricanes!

 

[XR650R]

Thanks for your suggestions. I’ll check them out. I’m in Florida, so no rust belt snow or road salt! The downside is hurricanes!

I think you stiffened it up a lot. Drive it as is, and see if it doesn't quiet down over time. I bet it will.

 

[GT40dreams]

I think you stiffened it up a lot. Drive it as is, and see if it doesn't quiet down over time. I bet it will.

Here’s hoping…

 

[Sam4]

Here’s hoping…

If you're using the A/C with an upgraded motor mount - you've got NVH as a daily passenger...