Metallic raspy rattling sound when accelerating hard above 4000k rpm

[mavisky]

Spent a couple hours in the mountains yesterday. Car got up to temps in the low 200's for engine oil, coolant. And trans and diff pills were in the high 100's.

Immediately began noticing a noise above 3500 to 4000 echoing off the mountain walls at partial throttle. At full throttle the exhaust would drown it out. Sounded exactly like someone else described. A plastic bag out on the wind at 100mph. Curious what part number my car has on it as it's one of the first 10 built for 2018.

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[mavisky]

If it truly is a resonance issue and not something coming loose, I wonder if something like lead tape would help add mass to the unit and change it's harmonics due to the added mass. May even be something that could be added without R&R of the transmission. I may try and pick some up locally and at least give it a shot before turning it over to the dealership for what sounds like a long journey there.

 

[NoXiDe]

Kyle, when are we doing a mountain ride? Let's get these 2 GT350's around helen or something. I'd be curious to also hear what your hearing.

 

[mavisky]

I was just up there yesterday and ran into another GT350. Just PM me and we'll work something out. I've never really heard the noise commuting into work and back but yesterday it sounded like the paper bag description or an exhaust leak. Found some lead foil tape that you use for golf clubs to try and attached to the plate from underneath the car to see if that serves as any assistance whatsoever.

 

[Zeromaz]

This is NOT something lose.

 

[DCShelby]

Mine’s doing it now too. Some dynamatt might dampen it out

 

[Shelby Nick]

My car also had a rattle. Sounded like a heat shield or something like that. I decided to crawl under the car and found that donut shaped sound dampening device was loose. Tighten it up and was good to go! Another 350 also had the same issue!

 

[DCShelby]

My car also had a rattle. Sounded like a heat shield or something like that. I decided to crawl under the car and found that donut shaped sound dampening device was loose. Tighten it up and was good to go! Another 350 also had the same issue!

What size socket did you use? I assume you raised the car some? To get access??

 

[Shelby Nick]

I just jacked up one side of the car and used jackstands. I got some light under the car and luckily was able to find it. The other side was fine, just one side was loose. Sorry, but I forget what size socket I used. Good luck, I hope it’s that simple fix!

 

[DCShelby]

I'll take mine in for it, I park in my condo garage and the retired people who are the condo police force (they have nothing better to do) would get pissy if I had the car up on stands. But thanks, I will show my service writer the picture. I get that metallic plastic bag in the wind sound at 4k rpm or so.....as other have said, if I'm next to barrier or something..you really hear it.

 

[s550_dav]

This is the rattle from the underneath that I’m having. Anyone knows if this thing is normal? Or is the the bell housing plate as well? It’s kinda driving me nuts lol

 

[NoXiDe]

Is that with the valve closed?

 

[s550_dav]

Is that with the valve closed?

The footage is actually the valves are off and on

 

[Mjc1241]

I heard it yesterday on my car when I got next to another car or median. Happened to pull this thread up. If nothing is loose and it is a common resonance issue, unless it gets worse I am not going to have the dealership try to poke around under the car. I will mention it to my friend who is a tech at a local dealership and see what he says and if others have complained.

 

[mavisky]

Jacked the car up tonight and put an entire roll of lead tape onto the panel between the engine and the transmission. There's a decent sized portion of it directly exposed near the oil drain. Will be curious to see if this has any effect whatsoever.

Lead tape cost me $10 from Dick's sporting goods in the golf department. It would be awesome if a fix was this easy.

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