a couple weeks ago I got an upgraded pulley and spark plugs on my 03 cooper S with just over 100,000 miles on it. at the same time I had motor mounts replaced. immediately after driving away there was a much louder noise coming from the supercharger. So, I had the supercharger rebuilt and it is still making the same loud noise with still no added performance. This is getting very expensive does anyone have any information on a possible reason? Or any ideas would be much appreciated.

 

Did you go with aftermarket motor-mounts? Some add a-lot of added NVH...noise, vibration, and harshness. Since the probem began at the same time as the motor mounts...are they installed right?
And can you expand upon "loud noise". It is not very desriptive.....

 

I am assuming "your" SC was rebuilt, and it was not swapped right? Did you check the tourqe on the bolts for the new pulley too...you did use a tourque wrench right?!
Like insaid above...decribe the noise...is it whirring? Clanking, rattling, grinding, rymthamic, music like, mono-toned, multi toned....
Have you isolated the sound to the SC...put a long handled screwdriver up against a metal surface on the item you suspect is making the noise...then put the other-end against your ear...or buy a mechanics stethscope..and listen, and sense the vibration if you will...
Was the rebuild shop well known? Comptent? Warrentied?
A SC with a pulley is a bit louder...it has more of a "whir" to it since it is running faster....

 

With the motor running, take a long prybar or rod and carefully (so that you don't touch moving parts) place the prybar tip in various places around the engine bay while placing your ear on the other end. You'll get a feel for where the noise is coming from. Place it on the nose of the supercharger, the tail of the supercharger, the water pump, and on the face of the tensioner bracket, listen for differences in sound intensity.

 

With a cold motor, remove the belt, start the car, if the noise remains, it is not from the supercharger or belt tensioner. Without the supercharger racket it is easier to locate other noise sources.

 

I had a very competent mechanic install the motor mounts, pulley and plugs. The motor mounts are called the half moon and acorn. As far as the noise goes, it is more of a whirring noise that is harmonic as the rpm's increase. The more the RPM's increase the louder the noise gets. It is much louder than just a whir noise that you would hear from the supercharger. It is a harsher, vibrating type sound. My mechanic noticed the noise immediately and so he recommended I have the supercharger replaced or rebuilt. So I got the supercharger rebuilt and reinstalled w/ a 1 yr warranty...the same noise after the rebuilt supercharger was installed is still prominent and I feel no performance, or pull from the pulley that was originally installed. Any ideas? Your help is much appreciated.

 

Could be the crank pulley..... Harmonic balancer - the rubber center fails, but, not always instantly

 

Check the stuff you touched first:

You sure the spark plugs are all nice and tight to the right torque?
And the pulley, bolts torqued correctly?

 

Check to make sure the pulley isn't spinning on the shaft. Also I've seen several "rebuilt" superchargers that were very noisey.
Also not a bad idea to check the crank pulley. But if this started right after the pulley install I'd go back and check all that was done with that. Noise after the pulley install isn't normal.

 

Run your car WITHOUT the belt on; this WILL tell you what is what~~~~~~~ OBEY

 

This will isolate the issue...good idea, really, just don't let the run for more than a one or two minutes....and from a cold start. If you stll hear the noise, then it is internal to the motor....
but like Way said, check the pulley....it is strange to have it start after a pulley install...the pulley may be on too loosely, or miss alighned. I would hope most SC rebuilders functionly test the SC after assembaly for noise/function by attatching a belt to the pulley, and giving it a spin at speed.....

 

Removing the belt is more work than necessary. A well-placed prybar will reveal the source in 30 seconds.

 

+1 With the mileage you have, I would start with the crank pulley.

 

+1 With the mileage you have, I would start with the crank pulley.