[Chadi335is]

My 335is exhaust note has lost its raspiness, burble and become much quieter over a period of time. I hear more engine than exhaust inside and outside the car...
No fault codes appearing.... What could it be? Cats clogged? Vacuum lines? Or just used up mufflers?

Any help would be appreciated

[Rob09msport]

Used up mufflers would be louder most likely cats.

[Rob09msport]

Also vacuum line would leave exhaust flap open and if was waste gates you would probably be noticing more lag.

[Chadi335is]

Thank you for your reply.... My Indy can't figure it out nor the dealership... Both say no codes means no issues. surely something is either clogged or leaking so I think

[mxchris727]

Are you running any aftermarket tunes? Clogged up cats could be the cause. I'd run a exhaust system pressure check. They are quick, cheap, and easy to do.

[Chantz335i]

I had the same issues with my 335is. It felt as if my wastegates were stuck or the exhaust was clogged. Still never figured it out

[Chadi335is]

Originally Posted by mxchris727

Are you running any aftermarket tunes? Clogged up cats could be the cause. I'd run a exhaust system pressure check. They are quick, cheap, and easy to do.

Thanks - I'm thinking of picking up replacement cats... Do I have to it to an exhaust shop for the pressure test?

[Chadi335is]

Originally Posted by Chantz335i

I had the same issues with my 335is. It felt as if my wastegates were stuck or the exhaust was clogged. Still never figured it out

It sucks... Haven't enjoyed the awesome exhaust sound or burbles which are also gone

[E92_betty]

Hi all,

Having the same issue for the past few thousand miles.

Car sounds more “enginey” than normal and lost that growl that it had.

Car is running alright. Just got all vacuum lines replaced thru dealer and had them inspect everything. No codes, said everything was normal.

I don’t feel it sounds the way it should.

Am thinking either cats are getting old or muffler?

Any thoughts or anybody have success with fixing this?

[Chadi335is]

Originally Posted by E92_betty

Hi all,

Having the same issue for the past few thousand miles.

Car sounds more “enginey” than normal and lost that growl that it had.

Car is running alright. Just got all vacuum lines replaced thru dealer and had them inspect everything. No codes, said everything was normal.

I don’t feel it sounds the way it should.

Am thinking either cats are getting old or muffler?

Any thoughts or anybody have success with fixing this?

What software are you running? One thing I was told was that that the dealer may have updated my DME software which could have cause this.