Supercharger-like whine from engine? 2006 Z4M

[jontZ4M]

Hi guys

I've been increasingly noticing a supercharger-like whine from my car.

First I assumed transmission, but I pretty much ruled this out when:
A) realising that idle is present when car is static.
B) pressing/releasing clutch makes no difference to whine.

Next I assumed aux pulleys, so I removed aux belt and AC belt:
A) all pulleys feel fine
B) car still makes whine with belts removed

So as far as I'm aware that rules out transmission and aux area of engine.

Other things of note:
- whine is directly linked to RPM
- hard to locate but gut feeling is it's coming from front/top of engine. (I've had a listen around this area with stethoscope but can't confirm it).
- car is 51k miles. I'm the first "enthusiast" owner so I doubt it's had any kind of re-built work.
- no other problems or warnings etc.

What do you reckon guys?

Thanks

 

[bigwinn]

Can you grab a video

 

[Vanne]

Someone install a Vortec while you wernnt looking?

All BS aside, you removed the belts you said and still the whine? I'd prob look at the chain guide then?

 

[jontZ4M]

Can you grab a video

Will do, hopefully it will be audible over the other engine noise in the vid.

 

[jontZ4M]

Someone install a Vortec while you wernnt looking?

All BS aside, you removed the belts you said and still the whine? I'd prob look at the chain guide then?

Checked, and no massive supercharger added sadly. Will investigate chain guide thanks.