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Underdrive Pulley

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  • Underdrive Pulley

    I'm looking at the VAC underdrive pulley set... are these ok to use for Daily driver? Can I install this without any other mods? Is this worth bolt on mod for HP and Torque?

    I only have Chip and Evo intake for engine mods.

    Pls help... need info...


  • #2
    I don't have any experience with them, but I think I wouldn't wanna underdrive the waterpump and the alternator for just a few extra horses, power steering on the other hand would be ok.

    - Tire is the other control arm bushing.


    • #3
      These are absolutely fine for the street.



      • #4
        Will this really add HP and torque? Low, Mid or High RPM?


        • #5
          I was hoping for 3 - 5hp at/near redline. Even tried to do a comparrison on the dyno but I was missing a spacer for the alt pulley so I couildn't swap back to find out. Sold the car since then.

          Don't buy these for a power increase. On its own whatever they add is probably negligable. There will be something in it, but I don't think its noticable. With that said however, I still recommend them. They are high quality pulleys that will help to some extent.



          • #6
            I spoke to VAC about these before the Group Buy was organized on here. They never did any dyno runs to calculate their listed figures but they do "free up" HP. Its not so much that your adding any vs cutting back on the stuff that takes it away. Similar to adding a light weight flywheel.

            on the track there is no need to over work the alternator and water pump for so long at high RPM's as the waterpump.

            I wouldn't mess iwth it for a street driven car as the amount of time you spend in the high rpm range is limited. while on the track it's ok to bring down the rpm of those items.

            skip it
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            • #7
              I am surprised that someone has not come up with a poly rib style belt system for the S14

              I can't remember who had did once but I know I have seen it.
              Who knows where I'll be, changes from day to Continent.


              • #8
                The groupe A pulleys are ribbed. Hard to come by but there are sources. Also they underdrive as well.

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