1st Gen R53 Cooper S Supercharger Screaming Problem

So I developed a weird problem today while I was driving around. I ran a few errands today. I took my girlfriend to get her eyebrows done after we ran some errands. My R53 was off and sitting for like 15 mins or so, about the same time my R53 had been sitting at our other stops. It wasn't running while I was waiting for her either. So we left and started driving and I gave it some medium throttle and heard a very weird sound. It literally sounded like some little kid screaming so I looked around and didn't see anyone, and then I turned the corner and gave it a medium throttle and I heard the sound again. I was like what the hell is making that sound. So I started playing with the throttle and noticed it was only when the TPS was reading above about 30. I have 2 videos of it. One is me driving showing the ScanGauge2 with the TPS sensor. The other is in the engine bay so you can hear the sound. The first video isn't as loud but the 2nd one is easily noticeable.

[ame=http://www.youtube.com/watch?v=Z6tEPTY9HII]MINI Cooper supercharger screaming issue 1 - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=dpRzXhmZNkY]MINI Cooper supercharger screaming issue 2 - YouTube[/ame]

I also attached a photo of the intake horn on the driver's side that had slipped a little bit. I did move this back to the correct that but that didn't seem to be causing the issue as it was still making this sound. I will have some time tomorrow to mess with it. It doesn't appear to be coming from the supercharger itself or the pulleys. I also replaced the tensioner pulley about 2 years ago, and the by-pass valve just this past summer. I have never heard this problem before, just seeing if anyone else has seen this, and maybe get some ideas of what to check.

 

That's what I was thinking. I don't know what the boost pressure was at full throttle as I didn't want to rev it out that far just in case something else was wrong. I'll be taking it apart tomorrow to see what's going on exactly. Just trying to get some ideas on what everyone else thinks. Might as well get all the info before hand so I can check everything and spend less time going back and forth.

I didn't think about the intercooler being bad, I'll have to check it out as well. Thanks for confirming what you think it could be and for the additional info!

 

Yup, the boot needs to be replaced. I also found that the horn was loose. The back nut actually fell off and luckily it was just sitting there so I lucked out by not losing it!



So I retightened the horn and torqued it down this time. I must not have torqued it when I replaced the by-pass valve in the summer.

I also retightened the boot clamps and tested it again. Definitely sounded normal again but the boot was still sliding, so I'll be ordering some new ones. Until then though, I jerry-rigged a way to keep the boot from moving on me until the new ones get here. I tested it with it set up like this and it appears to be holding fine now and it's not moving on me. A temporary fix until I get the replacement boots.

 

Yeah I am planning to replace the motor mounts in the spring. They aren't completely shot but they don't look too healthy. My MINI has almost 150k and the factory bushings and mounts, so I'm going to be overhauling them in the spring when I have more time and money.