CravenSpeed has developed a lightened crank pulley for the MINI R53 Cooper S & JCW to replace the OEM component without altering the configuration of the original belt layout. Constructed from 6061 aircraft aluminium you will benefit from extensive weight savings and, as a result, will benefit from power gains of up to 10% depending on how your MINI is set up. CravenSpeed crank pulleys come fully balanced and counter-weighted, and feature anodising for superb wear resistance & strength. If you are looking to release yet further power from your MINI’s engine, it’s possible to buy a 2% enlarged and lightened crank.
CravenSpeed states that each US pound saved in weight from the engine’s rotating assembly is worth roughly 2.7 horespower. The concept is that the crank is a parasite; it does not put power to the drivetrain but still requires the energy produced by the engine to rotate. When you reduce this parasitic weight, you release power that was previously used only for spinning the supercharger and alternator. You have effectively released power previously unable to harness.
This pulley is safe to use even though you are swapping from a ‘damped’ pulley to a single mass, solid pulley. The elastomer (rubber ring that looks similar to a harmonic damper) in the OEM pulley acts as an isolator to suppress natural vibration and noise from the engine itself. A traditional harmonic damping pulley would have been designed to protect against crank failure from torsional movement but CravenSpeed has researched the need for this and found it to be unnecessary in the MINI engine because of advances in engine design and materials. You can fit this part with confidence.