I had my JCW SC on my '03 S for about 20K miles, recently the max psi has droped significantlyt from 17.5 psi to 14. (17% pulley)
I have tons of mods on my car, but nothing big before this happen, and I change gear @ 4 to 5K nomally, see red sometimes but not often.
I ask the tech to check any leakage of SC or related piping problem, he told me everything seem normal, and he would like to judge this is the problem of SC aging .
I was so shocked of such short life of JCW SC, do you guy has similar experience or any info of the normal life span of "special coated" JCW M45?

 

Check your bypass valve. It is a weak link on the mini and sometimes they don't fail all at once. But that would be the 1st thought. It's a lot less expensive than replacing the supercharger. There quite a few threads about this. Peace

 

Especially with what the JCS parts cost. Eaton claims the SCs are good for over 100K....

You can try the VGS mod, it uses the post SC vaccum as a control, and boost helps hold the bp valve closed.

Another quick test is to wire tie the BP valve shut, and see if you recover your boost. (this is called the RyePhix to us mid-time NAMers).

Matt