If you have you have a supercharged W Body you've almost certainly been tempted to swap your stock pulley for a smaller unit.  After all, this is the easiest way to make power on the supercharged cars.  Unfortunately it's also the easiest way to blow your engine if proper pre-cautions are not taken.  

 

This brief article will discuss what it takes to run each specific pulley.  This article should be used as a reference only.  You should always scan for knock after switching to a smaller supercharger pulley.  Click here for more information on knock.

 

Your vehicle is equipped with a 3.8" supercharger pulley stock.  The one exception to this rule is a limited amount of SLP branded Grand Prix GTXs and Regal GSXs which were equipped with a 3.5 pulley as an option.  Your vehicle will make about 6lbs of boost with the stock pulley depending on weather conditions.  

 

This guide makes the following assumptions:

 

For each .10" in pulley size you go down you will generally pickup 1lb of boost. 

 

Core Modifications (3.5" - 3.4") - The following modifications should be present when any pulley smaller than stock is being used.  They will also allow most vehicles to run a 3.5 - 3.4" pulley with no knock.:

 

3.3" - 3.2" - In addition to the modifications above:

3.1" - 3.0" - In addition to the Core Modifications:

2.9" - 2.6" - In addition to the Core Modifications:

We take no responsibility for any engine failures as a result of advice garnered through this article.  A responsible owner will always scan for knock after changing his supercharger pulley.

 

Happy modding!