The max RPM limit of aftermarket alternators can bearound the 18000 alternator RPM mark. This works great formost factory applications until you start building engines that exceed factory RPM. Once the alternator reaches its max RPM it stops charging and your voltage drops, as well as potentially reducing the life of the alternator with the higher RPM. This oversized pulley from Aeroflow Performance willsolve this issue.

Specifically designed to suit OE Toyota 1JZ/2JZ alternators. This oversized alternator pulley isalso required in high-RPM engines (7500 + Engine RPM) toslow down the RPM of the alternator to prevent it from prematurely failing. This is aquick and easy install by removing the pulley and installing this directly on.