[chewiechewie]

Now before you guys get on my backs because there's so many threads that talk about the turbos, this noise doesn't happen when you just flat out accelerate (at least I dont think )

I hear this noise from inside the cabin in my right ear when I'm driving at around 38-> 62. Whether it's coming from the engine or the diff or the vents, I'm not sure, but I turned off all my music and AC and it was still there.

This is a 2010 335xi. Any ideas?

[DimSum]

I have that on my car too, and I'm non-turbo.
I think the engine is just designed that way, people who sit in my car always say I have a whirling/mechanic sound...

[fdriller9]

Yea I've noticed that all the BMW's my family has had whine, including the E90 I drive currently.

Previous Models:
'04 745i
'03 X5 4.8

[DFW_MThree]

ive noticed this as well. but only after i put in the BMS PBX...maybe it added an invisible turbo? lol

[e90pilot]

I had a similar noise in my car. It sounded like I had a straightcut dogbox and got worse and worse. Took it to the shop and and the diff was fried. It's about $2000 installed and I wansn't the first to have this problem according to the shop.

[Gavin@MMW]

I get this sometimes, it sounds like a jet engine winding up (kind of)

And have never figured out what it was.

E90Pilot, Did the dealer cover it?

[e90pilot]

Car was out of warrenty. I had about 93k mi on it when it happened. In retrospect I should have coughed up the chash and put an LSD in it.

[AlanAZ]

ive noticed this as well. but only after i put in the BMS PBX

Me too, but RPM related, not MPH. If I turn off the tune, it goes away. I'm wondering what it is.

the diff was fried.. at 93K miles

Had you ever changed the diff oil?

[e90pilot]

Nope. Didn't think it needed it because it's an open diff and doesn't see much stress. I guess in was wrong. Or it could have leaked out. Either way looks like it should be changed with the tranny fluid. 60k mi miles is a good point to do it.

About the BMS PBX. I'm not sure how it works but if it changes the Vanos or Valvetronic that might make it whine or whistle. But the OP has a 335i and it looks like it's speed related. Might be a diff or tranny. Or it could be insulation. My friends 540i sounded like metal on metal but it turne out to be door insulation that had come apart. It sounded like turkeys caught in the door card after it got worse.

[jhb74]

I have had this in my car since it was new. My friends always laugh and tell me I have a jet engine (its a NA engine BTW) - I have noticed that when I shift hard (BTW shift has an important 'F' in it - glad I bother to check my spelling) the engine note of course drops instantly to the RPM that the cars at, but the jet engine noise spools down more slowly, which led me to believe that its pulleys or something under the hood.

[e90pilot]

Originally Posted by jhb74

I have had this in my car since it was new. My friends always laugh and tell me I have a jet engine (its a NA engine BTW) - I have noticed that when I shift hard (BTW shift has an important 'F' in it - glad I bother to check my spelling) the engine note of course drops instantly to the RPM that the cars at, but the jet engine noise spools down more slowly, which led me to believe that its pulleys or something under the hood.

Yea, it you shit hard and make turbo noises in your car, I would say maybe this is this the wrong subforum and you might wanna visit webmd or a hospital.

But, seriously now, that noise you're hearing is a cooling fan. It's clutch will disconnect after a certain rpm.