Is it changeable?

 

I don't know, off the top of my head, what the size of the stock pulley is. It can be changed to increase boost. Most people go with a 15% size reduction.

I suggest you do a search of this forum for "pulley" and then spend some time
reading.

 

It's somewhere about 2.75"-3". For some reason the MINI crowd deceided to use a 'percent smaller' nomenclature rather than the 'certain size' as most other groups do. So you won't see any refferences to the actual pulley sizes.

 

According to jlm https://www.northamericanmotoring.co...ghlight=pulley

"The stock Mini S blower pulley measures 2.583" dia.
as far as the P&D line of pulleys:
"15%" is 2.200 dia;
"17%" is 2.148 dia;
"19%" is 2.070 dia."

 

philvia,

Aloha and welcome to NAM.
Yes the pulley for the supercharger is changeable usually to a smaller diameter size between 15% and 19%.

Another way to look at the supercharger is that in stock form it makes about 11.5 psi boost and with the 15% reduction pulley it improves to about 14.9 psi.

If the pulley size is reduced, the supercharger turns at a higher RPM for the same engine RPM which increases boost. The amount of boost increase is directly proportional to the reduction of the pulley size. But at the same time more heat can be generated.

If you are not a risk taker then consider the 15% pulley-
http://www.webbmotorsports.com/faq.php

Best results can be had from matching a pulley upgrade with an ECU software upgrade.

In addition to Webbmotorsports.com, good places to contact for info would be NAM sponsors-
http://www.detroittuned.com/products...20050219173709
or Eric at
Helix13.com