This pulley replaces the standard pulley on the alternator, which will allow you modify your standard alternator from single groove to four grooves. It has a 17mm spindle

This part is also available with a 15mm spindle PLY-MVA1-49

Multi-vee pulley for 2.0L - PLY-MV1

The standard single groove style alternator belts have a tendency to be thrown off the engine when used in fast road, competition or track day use. We recommend the replacement of the single groove pulley with our multi-groove pulley (this can only be used on cars where the pulley only drives the alternator with this belt). The smaller crank drive pulley also reduces the speed of the alternator because of its reduced diameter (diameter is 110mm); this has the added advantage of increased clearance when using a dry sump system.

Multi-vee pulley for 1.6 & 1.4L - PLY-MV2TW-58-EX1

On the 1.4/1.6L engines they already run a multi-groove pulley in most applications, but due to fact that the pulley in standard form is quite heavy & large in diameter, it is not ideal for use with highly tuned versions. We would recommend the use of PLY-MV2TW-58-EX1, which includes our trigger wheel & you will need our small sensor CRK-SEN-5. If you are using our dry sump system there is already a mounting on the system to accept our sensor, if you are using wet sump you will need to fabricate your own mounting bracket.