[da28fan]

Hi. Have a 2003 Cobra. Current pulleys are stock. Want to change 2 idlers to 100 mm (90 mm is stock I think) and change the blower pulley to a 2.75 but not sure what size belt to use. (No auxiliary idler). I'm guessing a 74 (same as stock) because reduction from smaller blower pulley would be offset by going to larger idlers (90 to 100mm). But strictly a guess. Anyone have a more scientific way or a chart to guage for sure? Thank you.

[dakine858]

Originally Posted by da28fan

Hi. Have a 2003 Cobra. Current pulleys are stock. Want to change 2 idlers to 100 mm (90 mm is stock I think) and change the blower pulley to a 2.75 but not sure what size belt to use. (No auxiliary idler). I'm guessing a 74 (same as stock) because reduction from smaller blower pulley would be offset by going to larger idlers (90 to 100mm). But strictly a guess. Anyone have a more scientific way or a chart to guage for sure? Thank you.

If you get an under-drive pulley set then you can reuse your current belt