[x6er]

Hi all,
A wiered thing I just noticed on my 2011 335i e92. the car has less than 7k Kms and is a manual. when I accelerate and once I lift my foot off the gas pedal, I hear this faint short whistle, like a wheeze..!! the whistle can be heared on all speeds if the window is closed.... so every time I shift...I hear it. I can also here a longer version of the whistle when accelerating sometiomes especially on low speeds (second to third for example).
I need to really focus to hear the sound, but now since I know its there, I hear it all the time.
Does anybody have or had the same thing? any opinions are greatly appreciated as I am taking it to the dealer next week and am anticipating the "I can't hear a thing" or "its normal".... kind of responses.
Thanks

[reaper335]

possibly the turbo's spooling?

[PeteW84]

I belive the stock diverter valve on the N55 is much louder than the DV's on the N54. I remember reading about it in the performance section. Sounds normal to me, especially since you hear it while shifting, or lifting off the gas pedal. Turbocharged cars make all sorts of whistling and hissing sounds. Unless the car feels slow, or loosing boost you shouldn't worry much about it.

[x6er]

Thanks for the replies. the car does not lose power, it just hisses when delivering it, lol.
It might be the DV, but why it only happens under load? I mean, when not driving, revving the engine and liftinbg off the gas does not produce the same whistle!
Keep em coming and I will update you when I see the dealer. Thanks again.

[Elie335]

check for boost leak?

[YianniM3]

I just bought a 2011 last week and it was doing this and it drove me insane. I had pulled out the tube aka the golf tee mod and I never clamped it I just left it lose and it was making that sound so today I plugged the tube and it stopped whistling. Maybe the previous own removed the little hose from the left exhaust check that out.

[x6er]

Originally Posted by nixta325

I just bought a 2011 last week and it was doing this and it drove me insane. I had pulled out the tube aka the golf tee mod and I never clamped it I just left it lose and it was making that sound so today I plugged the tube and it stopped whistling. Maybe the previous own removed the little hose from the left exhaust check that out.

I am the original owner and the car is 100% stock.

[tibra1]

The N55 doesnt use the same DVs as the n54...the n55's is located in the throttle body..n i believe its elctronically controlled
My guess is that is the sound of the turbo..keep in mind the n55 uses a single bigger turbo..which means u would prolly hear more spool up sound

[MaximusJ]

[2M]

i have the same problem, it goes a lil something like this

[x6er]

sorry could not play the clip to comment

[PeteW84]

Originally Posted by Alpine3

i have the same problem, it goes a lil something like this

Doesn't work for me as well...

[tibra1]

[PeteW84]

[Wild Squid]

It is normal. Its just the turbo telling you it means business.

[x6er]

Originally Posted by Wild Squid

It is normal. Its just the turbo telling you it means business.

but why I only hear it under load, i.e. only when the car in gear and moving. at idle I can rev the engine to the red line and no sound!?

[ChasVS]

Because it doesn't know the words?

[TheStigsTwin]

I immediatly thought of the whistling at the beginning of the Andy Griffith show. (Ha, showing my age there). But seriously, it's a normal engine noise, don't worry about it.

[07GraphiteXI]

do you have x-drive? could it be differential whine?

[syncro]

maybe compressor surge? When you come off the throttle the turbines spin the other way and it makes a weird noise, my friends grand nash does it, just a thought.

[tibra1]

Originally Posted by x6er

but why I only hear it under load, i.e. only when the car in gear and moving. at idle I can rev the engine to the red line and no sound!?

LOL..b/c under load is when ur making boost..

[tibra1]

Originally Posted by syncro

maybe compressor surge? When you come off the throttle the turbines spin the other way and it makes a weird noise, my friends grand nash does it, just a thought.

No