[crbalch]

I have a 16 M235xi 8AT, and having just taken an 800 mile road trip I noticed something. When I am cruising at highway speed (~75mph), and I let off the gas, I hear a faint high pitched noise. When I get back on the gas it goes away, but then when I let off I hear it again.

Was wondering if anyone else has heard this as well, and if its anything to be concerned with. I am thinking it may have something to do with the whole efficient dynamics, but I am not too sure really.

Keep in mind, this is only when I have my music off, so its definitely something you have to try to hear. Anyone heard this?

[overcoil]

My guess is the Turbo.

[crbalch]

Originally Posted by ScottSinger

My guess is the Turbo.

Right but the noise is when I'm off the throttle, so I'm not sure it could be the turbo

[overcoil]

When u let off the throttle you create vacuum from the sudden reduction of exhaust force and the turbo slowing.
As much as a turbo makes noise when it's winding-up and blowing off excessive pressure it also creates high-pitch noise from reduction of pressure and flow.

[ohohoh123456]

very much like what I have w/ aftermarket intake. Except I hear this every time I let off the gas pedal.

[isthar]

heh. I get to hear a faint whine related to speed (NOT rpms NOT acceleration) starting at about 20mph... like a plane taking off ... I think... a whine... anyone hear that?

[808AWD325xi]

F2x and F3x cars have an issue with a high-pitched noise coming from the center A/C vents which can be difficult to duplicate. Ask your dealer to refer to SI B64 09 15. They need to install a parts kit.

[crbalch]

Originally Posted by 808AWD325xi

F2x and F3x cars have an issue with a high-pitched noise coming from the center A/C vents which can be difficult to duplicate. Ask your dealer to refer to SI B64 09 15. They need to install a parts kit.

Thanks! I will take it in soon

[808AWD325xi]

Originally Posted by crbalch

Thanks! I will take it in soon

You're welcome !!