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Active Autowerke Underpulley Kit (E9x M3)
Active Autowerke Underpulley Kit (E9x M3)
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Active Autowerke Underpulley Kit (E9x M3)

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The BMW S65 V8 engine as used in the BMW E9X M3 does not make available all of the horsepower that the engine actually produces. This Power Pulley KIT through a redesign of the crankshaft outer pulley, actually releases this developed and available horsepower.

This performance product is designed to not only to make available horsepower but to still retain all the inherent qualities of your BMW E9X M3 without sacrificing reliability. Another key element in the launching of this under-drive pulley system was the task of manufacturing a DPK, a double side belt for the air conditioner. Whenever you alter the crankshaft main pulley size, it will also influence the size of the A/C belt. As of late production 2007, BMW change over the belt configuration to a double sided groove belt on the E9X M3. Active Autowerke philosophy is always to try and maintain components like a BMW fashion, as if BMW would have done. This would be a first in the BMW performance industry to have an aftermarket DPK belt produced.

To further enhance the system, Active Autowerke will provide an extra spare DPK belt with the kit. This would be for emergency circumstances if the need ever arises. Tested and ran on the in-house Mustang dyno here at Active Autowerke quantifies a true measurable 12 + horsepower gain on a completely stock BMW M3.

Anodized in a hard finish as revealed by the almost jet black color also makes this BMW performance product seem obscure within the engine bay. This performance upgrade is easy to install and can be fully reversible if the need arises. It is packaged to be simple with a crank pulley and correct matching belts in an all inclusive KIT.


  • BMW HP gains: 10 RWHP ~ 12+ HP over stock
  • Complete Bolt on System and is easily reversible
  • Aircraft Grade Billet 6061 Hard Coat Anodized Aluminum
  • Simple and easy to install
  • Includes Replacement Drive and A/C Belts
  • Extra spare DPK belt provided where applicable
  • Designed for use on DCT and Manual models
  • Reduces Rotational Mass
  • Does not cause overheating found in smaller pulley designs
  • Pair with AA Software for Additional Gains
  • Available for all production dates (Single sided & DPK belts)

Vehicle Fitment:

  • 2008 Bmw E9X M3
  • 2009 Bmw E9X M3
  • 2010 Bmw E9X M3
  • 2011 Bmw E9X M3
  • 2012 Bmw E9X M3
  • 2013 Bmw E9X M3