Maximize boost and unleash extra low-end torque with the ALTA 17% Supercharger Pulley, a precision-engineered upgrade for supercharged MINI Cooper S, JCW, and GP models. Designed to build boost earlier in the RPM range, this pulley delivers quicker acceleration and up to 1.5 psi more boost at redline, for reliable and responsive power gains.

Made from 6061-T6 billet aluminum, the Version 2.0 pulley weighs just 8.0 oz, reducing rotating mass compared to the 11.5 oz stock unit. Its stainless steel clamp-on coupler offers unmatched shaft grip—even on worn supercharger shafts—and eliminates the common issues with press-fit pulleys.

Cross-drilled grooves and oversized belt retainers ensure superior grip and prevent belt slippage, while the hub and pulley are precision-balanced to within 0.1g at 16,000 RPM, exceeding OEM standards for high-speed reliability.

Key Features:

• 17% Reduction Drive Ratio – Increases supercharger RPM for earlier boost and more power

• 6061-T6 Aluminum Body – Lightweight, anodized, and naturally balanced

• 303 Stainless Steel Clamp-On Hub – Secure fit, even on worn supercharger shafts

• Cross-Drilled Grooves – Improved belt grip under boost

• Oversized Belt Retainers – Reduces belt jumping and premature wear

• Open Aperture Design – Allows visual shaft alignment verification

• Precision-Balanced Assembly – Balanced to 0.1g at 16,000 RPM for smooth operation

• Compatible with ALTA Pulley Removal Tool (AMP-ENG-208)
  (Tool does not fit JCW or GP models for pulley removal)

Vehicle Fitment:

• 2002–2006 MINI Cooper S Hardtop (R53)

• 2004–2008 MINI Cooper S Cabrio (R52)

• MINI Cooper S JCW & GP*
  Pulley fits, but removal requires alternative method (not compatible with AMP-ENG-208 tool)

What’s Included:

• (1) ALTA Supercharger Pulley Body – 17% Reduction

• (1) ALTA Stainless Steel Pulley Hub

• (5) Grade 12.9 Bolts & (5) Grade 10.9 HI-Collar Lock Washers

• (1) Allen Wrench

• Installation Instructions

• ALTA Warranty Information

• ALTA Stickers