This 100mm billet idler pulley is designed to replace the factory idler pulley located directly beneath and to the left of the supercharger pulley.
In CTS-V or ZL1 applications using a smaller than stock supercharger pulley, belt slippage at higher engine speeds can reduce both boost and power. The larger diameter of this pulley serves to increase belt wrap at the supercharger pulley, as well as increase tension on the supercharger belt. This pulley is an easy bolt-on solution to troublesome belt slippage.
Use with 2.40", 2.50" or 2.85" Supercharger Pulley This pulley is approximately 4" in diameter and 1.75" wide at the belt surface. It is compatible with the original 8-rib belt used in the GM LSA application as well as custom applications using a 10-rib belt.
Note: In rare instances, this idler pulley may interfere slightly with the accessory drive pulley located directly behind it. In these applications, a 16mm flat washer may be used between the provided rear pulley spacer and the rear of the pulley. We use Fastenal part number 1140361, which measures 16mm x 30mm.