i have a 2006 jcw and was wondering if anyone out there has put on a pulley,if so any performance changes,what size,what make etc

 

I have a 15%pulley i love it its from alta its the v1 works great dosent slip
very noticible power increse
i would do that and the jcw intake plus a tune and you should be set for a while
i realy have no need to go over 5 k around town at all its so tourquey
love it

 

You can upgrade your pulley but you would loose your JCW warranty on the supercharger. Since the JCW kit already has a reduction pulley compared to stock you should leave it alone.

You might consider an RMW ECU tune to get the most out of your hardware but that would affect your JCW ECU warranty.

If you don't care about your warranty then you can add any of the reduction pulleys for a little more HP.

Most JCW owners would keep the warranty intact until enough time passes for the warranty to expire. Otherwise you could have bought a basic Cooper S and spared the expense of the JCW upgrade.

 

I have MCS JCW 06'. I decide to change the pulley and tune the ECU after that I talked to Jan and he told me don't change the pulley only put camshaft and tune the ECU .