Whistle noise @ 70mph

[15xdrive35i]

Hi everyone,

I have a 2015 X1 xdrive35i, only modification is a dinan tune. For the past several weeks I have noticed a whistling noise when cruising @ about 70mph, significantly louder when the foot is on the accelerator. When I let my foot off the accelerator, the noise improves by a substantial amount. I took it to my local dealer who could find anything wrong. Looking for any thoughts on what it could be? I don't hear the sound at lower speeds.

[thestimp]

Originally Posted by 15xdrive35i

Hi everyone,

I have a 2015 X1 xdrive35i, only modification is a dinan tune. For the past several weeks I have noticed a whistling noise when cruising @ about 70mph, significantly louder when the foot is on the accelerator. When I let my foot off the accelerator, the noise improves by a substantial amount. I took it to my local dealer who could find anything wrong. Looking for any thoughts on what it could be? I don't hear the sound at lower speeds.

Any chance you can describe the whistle or get a passenger to figure out where its coming from? A little while back in the forums, a sideview mirror and a bad windsheild mold caused stuff like this. Check all your trimmings and under car mudguards, whistles are damn near impossible to diagnose.

[15xdrive35i]

Thanks for the reply!! It is hard to describe....I think it's coming from the engine area...the unique thing about it is that it tends to worsen when accelerating as opposed to coasting. But it is localized the 70-75mph range, over that speed and it seems the wind noise seems to overcome it.

[Xdrive35i2014]

Intake noise? U are running a tune so maybe during acceleration, the engine is sucking up more than before hence the whistle noise?

It might be easier if u capture the noise in a video.

[Turbod]

Are you sure it is not rpm based and that it is just the mph? My X1 makes a flutter type whistle at 35 mph and at about 77 mph both of which happen to line up at 2,500 rpm. I notice that when I am on the accelerator slightly it will make the noise louder vs when I am just maintaining speed.

The point I am making is if it is at that speed regardless of which gear you're in I would look for exterior aerodynamic interferences. If it is dependent on, lets say 6th gear, then it could be rpm based and coming from the engine.

[15xdrive35i]

Thanks for the replies guys. Tried to get a video but too subtle to pick up over road noise. Next time I drive I'm doing to drop it a gear when I hear the noise to see if it changes with the RPMs.