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2Addicts | BMW 2-Series forum Technical Topics N55 (M235i) Engine, Transmission, Exhaust, Tuning High Pitched Whistle Under WOT

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      03-07-2018, 06:00 PM   #1
CJ_M240
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High Pitched Whistle Under WOT

I’ve had my M235 for a couple months now and I have been noticing a high pitched whistle/rattle during hard acceleration. It’s not normal turbo sounds but almost like an intake leak or something. It sounds like it’s originating from the driver side and I cannot hear it during normal acceleration.

Question is is the whistle/rattle normal? If it’s not has anyone had it diagnosed and repaired?
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      03-08-2018, 03:45 PM   #2
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Maybe charge pipe is cracked? Stock intake?
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      03-08-2018, 03:53 PM   #3
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I was also thinking you should examine the charge pipe carefully....
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      03-08-2018, 07:03 PM   #4
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Quote:
Originally Posted by frenchfry675 View Post
Maybe charge pipe is cracked? Stock intake?
Yes, stock intake. The car only has 15k miles so I’d be surprised if the charge pipe is cracked but I will take a look.

If it is cracked it looks like the charge pipe install is a big PITA, right?
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      03-08-2018, 07:45 PM   #5
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I haven’t installed my Er charge pipe yet but I don’t think it’s that bad. Your car is out of warranty I’m assuming?
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      03-09-2018, 07:07 AM   #6
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Grab FTP Charge-pipe if you planning to keep the car for another 15k miles you'll save yourself the WHAT ifs
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      03-09-2018, 05:21 PM   #7
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Quote:
Originally Posted by frenchfry675 View Post
I haven’t installed my Er charge pipe yet but I don’t think it’s that bad. Your car is out of warranty I’m assuming?
It’s still under warranty but if it’s the charge pipe then I will likely upgrade it.
I am not completely sold that it’s the pipe though because it’s only makes the noise for a second and then it’s gone.
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      03-09-2018, 06:04 PM   #8
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Quote:
Originally Posted by CJ_M235i View Post
It’s still under warranty but if it’s the charge pipe then I will likely upgrade it.
I am not completely sold that it’s the pipe though because it’s only makes the noise for a second and then it’s gone.
If it does it all the time take to the dealer and have them ride with you. Is your car stock?
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      03-13-2018, 09:36 AM   #9
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It's a boost leak for sure. If you have any aftermarket parts such as an intercooler or charge pipe I would check and tighten those connections first as they are likely the culprit.

If you're bone stock under warranty, let the dealer figure it out haha.
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      03-13-2018, 11:24 AM   #10
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Quote:
Originally Posted by CJ_M235i View Post
I’ve had my M235 for a couple months now and I have been noticing a high pitched whistle/rattle during hard acceleration. It’s not normal turbo sounds but almost like an intake leak or something. It sounds like it’s originating from the driver side and I cannot hear it during normal acceleration.

Question is is the whistle/rattle normal? If it’s not has anyone had it diagnosed and repaired?
Do you have the M Performance exhaust? I've got it and the rest of my car is stock. The MPE can make a pretty loud high pitch whistle under hard acceleration, especially in more humid temps. It's the sound of the wastegate managing boost and the air going supersonic around the wastegate.

I have the stock intake and occasionally can hear a fairly pronounced intake whistle under certain acceleration. No rattles though. I've got the Torque app and can monitor boost. Nothing wonky is going on. It shows expected boost of 9 to 11 psi depending on gear, density altitude, load, rpm, etc.
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      03-14-2018, 06:07 PM   #11
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Quote:
Originally Posted by XutvJet View Post
Do you have the M Performance exhaust? I've got it and the rest of my car is stock. The MPE can make a pretty loud high pitch whistle under hard acceleration, especially in more humid temps. It's the sound of the wastegate managing boost and the air going supersonic around the wastegate.

I have the stock intake and occasionally can hear a fairly pronounced intake whistle under certain acceleration. No rattles though. I've got the Torque app and can monitor boost. Nothing wonky is going on. It shows expected boost of 9 to 11 psi depending on gear, density altitude, load, rpm, etc.
I do indeed have the MPE exhaust with the stock intake. I think you are onto something with the air whistling past the wastegate.
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      03-15-2018, 08:20 AM   #12
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Quote:
Originally Posted by XutvJet View Post
Do you have the M Performance exhaust? I've got it and the rest of my car is stock. The MPE can make a pretty loud high pitch whistle under hard acceleration, especially in more humid temps. It's the sound of the wastegate managing boost and the air going supersonic around the wastegate.

I have the stock intake and occasionally can hear a fairly pronounced intake whistle under certain acceleration. No rattles though. I've got the Torque app and can monitor boost. Nothing wonky is going on. It shows expected boost of 9 to 11 psi depending on gear, density altitude, load, rpm, etc.

I have a MPE and it does the same... Pretty sure it's normal.
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      09-03-2019, 03:26 AM   #13
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Hi all, just came across this post. I know it has been a bit outdated, but I am experiencing the same with my BMW F36 435i with MPE exhaust.

Just to verify, i've added a soundclip:
https://gofile.io/?c=LwqiHw

Is this the noise we are talking about? Many thanks for the help
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      09-03-2019, 03:16 PM   #14
NateDog07V
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Dealership trip may be in order
https://www.2addicts.com/forums/show....php?t=1630733
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      09-07-2019, 10:59 AM   #15
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It's hard to believe this is from the transmission to be honest. It's not always present, not even always under full throttle. It seems to go more into the area of the turbo/cats or exhaust system. What do the other guys had as an outcome with this noise?
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      02-05-2020, 03:36 AM   #16
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I coincidentally started noticing this 2 weeks after getting the MPE. So this is ... normal right?
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