After installing the Borla exhaust today, I went for spin around the neighborhood. Everything sounded fine during the drive. But at one stop light, I felt and center pipe right below the car started to rattle for a little bit. But as soon as I hit the gas again, the rattling stopped. Is this normal for a new install and the strange rattling will go away? I've checked all the Accuseal clamps to make sure they're tightened before I started the car.

 

Try re-checking each bolt again. They shouldn't loosen up, but you never know. If things are all tight, then you may have a defective muffler/resonator. In any event, if things are all tight, a phone call to the vendor is in order. Cat-back exhausts don't normally need a break-in period.

 

If its rattling then a part is loose or a there is some sort of defect. As far as break in periods though...exhausts will break in a lot as you get some miles on them. At least thats how it has been in my experiences. The Eisenmann exhaust that I had on my Audi was quieter than stock until almost 500-1000 miles after install, then it really came alive. I have BMW friends that have all experienced the same thing as far as exhausts breaking in...they will sound better and usually get louder as more miles are put on them. Sometimes new exhausts will smoke a little bit too, until all the coating on the inside is burned out.

 

Louder is one thing; rattling is another. I think you are on point with your original statement about a part being loose or defective.

 

thanks for the info. I will go under the car again today and take a look.

 

I hope it is just a bolt that needs tightening. Removing a cat-back that you just installed is a real b**ch!

 

It may be one of the hangers rattling against the heatshield along the exhaust channel. My magnaflow rattles when the engine is cold. I just haven't had a chane to cut about 1cm off the end of the hanger.

The way I figured it out was I put the car up on stands and started her up. Be very careful doing this though!

 

When I had a Borla race on my '02 MCS, I noticed that when the car was fully warmed up (i.e. after a good bit of driving) the tips extended from the bumper about an inch more than when it was cold. I assume that other components of the exhaust were also expanding and contracting with the heat.

You might make sure there is plenty of room around everything, especially the bolts on the clamps - If I remember correctly, they were pretty long and stuck out a bit.

 

Check the exhaust tips,my borla sport tips would grow together after car warmed up.It would start buzzing and rattling after a warm up.I checked all clamps and interference of parts and found nothing a- miss.Jacked up car and started it and heard ringing which turned into buzzing at idle.Put flat end screw driver protected with rag and pryed tips apart,no more buzz or rattle.My next Mini we got the Invidia exhaust instead.

 

thanks for all the response. I went back under the car today and found nothing out of the ordinary. I give it a few more days to see if the rattling comes back. Like I mentioned earlier, the noticeable rattling occurred just once during idle at a stop light. I thought the center pipe fell apart!

Those of you still driving w/ the Borla exhaust, can you hear the sound of air moving through center pipe as you're driving? I think I can hear the exhaust sound running through the center pipe below me when I'm in the car. It's not a loud sound, but a steady rumble. Is that the way an aftermarket exhaust supposed to sound?

 

I've noticed with different exhausts that they often need several hundred miles to "break-in" or to get the sound they will have for the duration. I do occasionally get noises that come and go too. I installed an exhaust from MyMini and after a week I autocrossed the car with it and a day later I got a few rattles and buzzes which have either greatly diminished in volume or disappeared completely in the week since I first heard them. I will be going under the car in the week sometime to retighten everything and make sure everything is still good.

-Keith

 

Mineon: thanks for the info. That will certainly put my mind at ease. I just don't want the entire exhaust system to fall off on me one day