Our ECOTEC Underdrive alternator pulley is larger than the factory alternator pulley by 20%.

Alternators will always take horsepower from your engine. By replacing the Holden factory sized pulley with a larger light-weight pulley, the alternator is slowed & takes less power, making more horsepower available to the rear wheels. 
An oversized alternator pulley is also required in high-RPM engines to slow down the RPM of the alternator to prevent it from failing.

Quick and easily to install. Simply remove the factory pulley and install our billet pulley. 

Material: Billet 6061 Aluminium
Finish: Anodized Black

To suit:
Holden Commodore VS VT VX VY models with 3.8L V6 Ecotec (1996-2003) L36 engines
Will NOT suit V8 models.