I have stripped my engine and have removed my charger but would like to know what % ruduction it is ,where and how do i measure to work it out?

 

Most of the reduction pullies are marked with the percentage. Do you know for certain there's a reduction pulley installed, or are you trying to find out? Most (but not all) of the aftermarket reduction pullies are held on with bolts, while the factory pulley is pressed on.

Could you post a picture of the pulley?

 

yes will do but send me your email as i dont know how to put pics on here