Used when supercharging the GXE10 Lexus IS200/Altezza AS200 1G-FE engine.This kit increases the total belt system grip by up to 50%, helping to eliminate the dreaded belt slip often experienced when supercharging the 1G-FE engine. It's usually more pronounced at larger drive pulley sizes / higher boost levels.Our supercharging kits (and the TTE kit for that matter) use the water pump to drive the supercharger. The water pump is driven by both the power steering pump and alternator belts, but they have very little contact surface with the water pump pulley, often resulting in it slipping under load.Our upgraded system adds an additional idler pulley on a custom bracket with CNC milled mount (for perfect alignment), which routes the 4PK alternator belt around the pulleys, so it can grip on more surface area both on the water pump pulley and the crankshaft pulley. This results in a massive increase in total belt system grip, eliminating slip in most cases (or helping a lot with reducing it).Tensioning of the alternator belt is still done via the alternator tensioning system, no change is necessary. A longer belt is required, which is provided with this kit.Main benefits:Up to 50% more total belt system gripEliminating or massively reducing the belt slip under loadDesigned to be used on supercharged 1G-FE enginesRetains the OEM belt tensioning systemWhat's included:1x Custom idler pulley bracket (CNC milled mounting points, CNC machined pulley mount)1x INA 531089110 pulley, normally used on the 1ZZ-FE engine2x countersunk bolts to mount the bracket to the engine1x M10 bolt to mount the pulley to the bracket1x Custom washer to secure the pulley to the bracket1x 4PK1488 belt to replace the alternator belt