I have a 2012 5.0 Mustang and had Borla S-type cat back exhaust put on about a month ago and ever since I get some wicked vibration and rattles coming from my rear mostly around 1000 rpm in 4th gear or when accelerating hard but only at the beginning of the pull. I brought it back to the shop of install and they checked everything said all was good ...and of course it wouldn't make the noise that day?
Then I took everything out of my trunk including spare , took my license plate off and it is still making the noise.
Then I brought it to a different exhaust shop a few days ago and they couldn't find anything out of place either?
Could it be that the tone is so low it is vibrating like a subwoofer at 1000 rpm?
another thing when it is rattling and I down shift it goes away?????
anyone else have this problem or a solution?
Thanks for any advice in advanced

 

Sound vibrations unless its rubbing or hitting. I put dynomat in my trunk and its good now

 

Has to be something with the install..... But not the quality of the borla components themselves. You're 100% positive there was no rattle prior to your exhaust install? I'd let another reputable exhaust shop look at it, to make sure everything is lined up and tightened down. Next option would be to contact Borla customer service themselves. They are top notch and can help answer any questions and will back up any warranty or quality issues. Ask me how I know

 

I sent Borla an email under the advice of the original installer about a month ago asking for help and they never got back to me.....
And yeah the noise was never there before I was previously running outlaws on it and only unwanted noise from those was drone

 

Running at 1k rpms in 4th may produce a certain tone/resonance from the Borlas that vibrates something back there. Considering that lugging the engine like that isn't the smartest thing to do for the engine, I'd cruise in 3rd or drive a bit faster in 4th. Problem solved.

I have S-Types as well, next time I drive it, I'll see if mine does the same thing.

 

get in the trunk and have someone drive the car.. jk
try putting the rear seats down and see if you can locate the noise.

a friend of mine had a similar problem, but it turned out to be his spare tire nut/holder, which was loose and rattled. in your case that can't be the problem since you removed it.

do you get the vibration when you rev when at rest?

 

Check and see if the over axle pipes are really close to contacting the panhard bar brace. That was the problem causing crazy rattles when I had a catback on my 09 GT. I verified by sticking a towel between the brace and exhaust pipe and the rattling stopped until it destroyed the towel lol.

 

at 1k I wouldn't suspect drone if you said 2k almost certainly the drone of the exhaust at 1k I would say probably one of the hangers isn't on exactly right and is either A: bouncing a round at bit or B: is rubbing against something else... just my two cents

 

This. Not sure which exhaust I was on with my 05 but I had a pretty bad rattle when the pipes got warm. Got under the rear and wrapped whatever parts were close enough to the exhaust pipes to cause a rattle with header wrap. Problem solved...I feel your pain. Made driving annoying at times..

 

If you don't install the over axle pipes correctly it will hit the panhard bar. I had a rattle I couldn't figure out until I laid under the back of the car and had my wife slowly rev it to 2000 rpm and hold it. Come to find out it was one of the bolts on the passenger side hanger not on tight. So that would be my advice. Lay down under the rear bumper and have someone slowly rev it to pinpoint the issue.

 

Thanks fort he advice so far
I just got home from work and drove the whole way "30miles" with the trunk mat out and the rear seats down and it was a very loud metalic rattle/Buzz whenever I accelerate now no matter what the rpm ? can goodyear and a actual exhaust shop both be that in incompetent

 

any other mods? I find that now and again one of the jam nuts for my BMR panhard bar comes loose. I'll be locktiting it next time I'm under there.

 

No other mods the the rear of the car
Here is a clip from inside my car, trunk mat is out as the rattle is more noticeable without it, rattling starts at 2min40sec in and you can hear it best at 4-5min
I am about to send the clip to borla to see if they can tell if it is a internal problem with a muffler as 2 different shops cannot find anything rubbing


here are pics of the rear hangers that most say would be the cause of rattles

 

It doesn't sound like rubbing or something lose in the muffler. Something is lose on the rear of the car. A visual check doesn't always work. Take your hand and shake everything around in the back.

 

The exhaust expands at least 3/8in from cold to hot.

Bend those two brackets back to clear at least another 1/4in. Bend the bracket to clear and bend then hangers back down flat/straight.

I had this issue when I installed mine, it made no noise until it was warm, and then sounded like it was coming apart.

The hanger pictured was rubbing the metal.

 

Someone from Borla listened to my clip today 8/12 and they are sending me out a whole new rear section of my S-Type cat back since they couldn't tell which side it is coming from in the clip. So they must of come across this before if so quick to replace? So two for Borla customer service

 

I listened to the clip, IMO its the hangers. The should be no deeper then the rubber ring. 3 of the 4 hangers pictured and pushing the rubber mount and deforming it.

I had that same sound almost when I installed mine. I bent the hangers out of the way and it fixed it. It took about 5 attempts to figure out what it was.

Before you go thru the trouble of removal and reinstall, bend the hangers back away from the mounts.

Based on the pictures I bet your sound is from the right side of the car.

When the exhaust gets hot it expands back and takes up that hanger space and rubs on the metal.

 

Show sig dang it!

 

Yet another example of borla customer service. It's been my experience with them as well. Too notch.

 

I drove my car 30 miles to work and checked the drivers side hangers as soon as I pulled into the ramp and they were pushed right up against the bracket metal on metal.... never thought of checking them when hot so I am sure you are right about this one .....thanks, hopefully the new set borla is sending me will fit properly right out of the box , how did you bend them while still on the car?