OCJeff

During a recent drive on an open straight road, I was accelerating and started to hear something that sounded like exhaust rattle, or metal on metal noise at around 115 MPH. The car was not affected (nothing changed with drive or acceleration), and the noise didn't scare me, just sounded like something that might be a common issue.

Anyone else with some sort of exhaust (or something else) rattle at high speeds? Any ideas?

This is a stocker, so no mods have been done (except the AVIC-Z1 of course).

-Jeff

SilverBulletAMG

Mine has a rattle that will start around 80mph but my rattle seems to be coming from the drivers side vent or somewhere up in that area. I mentioned it during my sevice B and the guy took it out for a test drive (I wasn't along) and said it didnt do anything when he was driving. I'm sure the idiot never took it past 80 though because it does it EVERY time...and if it's windy it will start at a slower speed. Of course I read his comment on the paperwork at the end when I was picking up my car and they were closing for the day or I would have had him jump in a go for a ride. Next time I'm in I'm going to take a mech along for a ride.
I'm convinced mine is something up front rattling in the wind though. From your explanation it sounds like yours is coming from the back?

OCJeff

To me it sounds like more under the car. The car is quiet at that speed, and then this noise emminates from, what sounds like, below the car.

SilverBulletAMG

Thats different than my rattle then. Well, anyone know what either of us are talkin about?lol

Fifth Ring

I'd suspect a plastic panel flapping. It could be the belly pan, or any of the many little panels around the car.

Here's what you do. Get up to 115MPH, open the door, and lean out and look under the car for flapping. Have someone else in the car to videotape the whole thing. The video could end up being worth a fortune, although you may not be around to enjoy the money.

amgmark

I have a similar issue. One of the metal strips on the roof has come loose and when I drive over 90mph it flaps.. I thought it was coming from under the car until my buddy put his hand out and felt the metal trim flapping on the roof. I have resecured it for now, but it needs to be held down better. The dealer actually fixed this before and it came loose again.

You should probably check all your trim pieces..

GDawgC220

I would take the tech/advisor for a ride instead. They are not suppose to go that fast when testing your vehicle...what if they got a speeding ticket while doing that. Its just to cover their end for liability and such.