I have a 2003 mini cooper s. it has 74000 miles on currently. i recently had a 15% pulley put on and it was super quick. but over the past couple of weeks it feels like its boost is gone. the whine of the supercharger is also quieter. i had a friend (a mini tech) hook it up to the vacuum and it was getting the correct amount of boost(10lbs which is 2 more over the factory 8). has anyone had this problem before or have any ideas of what it could be?

 

this is a ....ummmmm....2nd Generation MINI forum.....ummmmmm....... I have no idea why your 2003 mcs has lost power. Sorry.

 

I need a moderator to move this.....
and its likely that your supercharger or some other seal has failed cause your missing about 5 pounds of boost from what i understand.
so check that bad boy out.....
and hes right this is the second gen forum.
Read carefully Welcome to Nam son.

 

Silva:
Welcome to NAM - check for vacuum leaks. Do you have any warning lights on?

 

Could be bypass valve.

 

Could also be a slipping belt - does the ribbed side of the belt look glazed at all?

 

Agreed, boost does not seem normal.

Typical culprits (already mentioned):

Slipping Belt, could be caused by old or wrong sized belt, or tensioner issue.

Bypass Valve, could be loosing seal.

Internal Supercharger issue, vanes could be abused, but considering mileage and use of normal pulley, not likely use - should be the last thing checked IMO.

Vaccum Leak - would probably cause rough idling, cel or similar issue on top of under performance. Hard to diagnose without smoke test. Could be a possibility depending on method of pulley installation.

Another possibility is that the pulley might be slipping on the supercharger shaft at high rpm from not enough torque on the bolts. Would be IMO the next to last thing to check.

That's initially what comes to mind.

 

The only warning light that i had come on was the check engine. that reset itself. i checked the pulley belt and it seems to look fine. i guess i'll have the bypass valve checked first.

 

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