[Bigrich45]

First thing I want to get out of the way is I'm in Florida and it is not cold whatsoever. And there has not been any crazy temperatures changes. Now that's out of the way. I left work today and got in my car and was shocked at how much louder it was. Out of now where ! I have had muffler delete on my car for about a year now. Which really doesn't make it much louder. But I mean it's now like twice as loud. Blown Catalytic converter? Blown resonator maybe? Honestly I'm not even complaining cause I think it sounds really cool now haha. Burbles like crazy. I'm not sure at all what caused this.

[Vivek.]

....did someone steal your cats?

[E92William]

^this right here

You live in Florida, home of the scam and theft! Just like I do. People here will literally chase you on offer up and marketplace when you're selling something like say a floormat, asking if you have catalytic converters for sale, they're obviously worth good money and they could have perfectly taken the secondaries. Go check maybe your exhaust came off at the manifolds though

[Bigrich45]

Originally Posted by E92William

^this right here

You live in Florida, home of the scam and theft! Just like I do. People here will literally chase you on offer up and marketplace when you're selling something like say a floormat, asking if you have catalytic converters for sale, they're obviously worth good money and they could have perfectly taken the secondaries. Go check maybe your exhaust came off at the manifolds though

Haha I'm in Ponte Vedra my brotha near Jax. I'm not sure any PV guy are stealing 08 bmw cats lol.

[ttthai]

Could it be an exhaust leak?

[LemansE90335xi]

Originally Posted by ttthai

Could it be an exhaust leak?

I guess possible missing cats would qualify as an exhaust leak.

[E92William]

Hopefully not lol. I work by the MIA airport and I'm sure a lot of guys around that area would

[CTinline-six]

Did you look under the car to see if something is loose/disconnected?

[Boston4]

I had this happen this past weekend on a trip with my E90 - the weather was cold, but I think that I've isolated the issue to a different factor: water.

Was it raining when this happened to you? I'm thinking I have some kind of exhaust leak that presents itself when driving in moderate-heavy rain. The issue was definitely present through an hour of back roads to get to my destination in the rain. I parked for about 20 minutes and it disappeared when I started it back up, until I got back on the main road - at that point, water and loud exhaust returned.

I drove home 3.5 hours in dry conditions with normal volume levels in similarly cold temperatures. Not quite sure what to make of it.

[Boston4]

Originally Posted by Boston4

I had this happen this past weekend on a trip with my E90 - the weather was cold, but I think that I've isolated the issue to a different factor: water.

Was it raining when this happened to you? I'm thinking I have some kind of exhaust leak that presents itself when driving in moderate-heavy rain. The issue was definitely present through an hour of back roads to get to my destination in the rain. I parked for about 20 minutes and it disappeared when I started it back up, until I got back on the main road - at that point, water and loud exhaust returned.

I drove home 3.5 hours in dry conditions with normal volume levels in similarly cold temperatures. Not quite sure what to make of it.

Update: This issue is caused by a very minor exhaust gasket leak. The bolts are just rusted out and it won't hold a seal - the issue is exacerbated by water causing the metal to contract and lose the seal. Interestingly, it doesn't sound bad even during cold starts - only happens when driving in the wet.

[Bigrich45]

Forgot to tell ya what happened, I found the cause. I did my own muffler delete and I have 2.5 inch pipe where the muffler is suppose to be. It's held in by a exhaust clamp, the exhaust clamped popped off. So basically the exhaust fumes were just coming straight out the resonator and not a extra 2-3 feet of piping.
You wouldn't think this would make that big of a difference but it really does.

[E92William]

Lol if you had said you did your own muffler delete I think everyone would have automatically gravitated towards that. Pretty wild such a change in length could make it thag much louder

[2one3E90]

Does a exhaust leak make performance worse or even noticeable? Isnt it a good thing LOL less back pressure?