need help
question is....
does overdrive always mean bigger pulley, and underdrive always mean smaller pulley?
or does overdrive mean more speed, and underdrive mean less speed?
a smaller pulley on the crank (typically known as underdrive pulley), spins the accessories slower.....including the alt
so in order to get the alt spinning back up to stock speed you need to overdrive it, which in this case means a smaller alt pulley.
confusing
some math:
6" crank, 2" alt = 1:3 rotation
4" crank, 2" alt = 1:2 rotation....alt spinning slower, what we call underdriven generally
4" crank, 1.5" alt = 1:2.7 rotation so the alt is spinning faster, overdriven
4" crank, 2.5" alt = 1:1.6 rotation, so the alt is spinning slower, underdriven
does overdrive always mean bigger pulley, and underdrive always mean smaller pulley?
or does overdrive mean more speed, and underdrive mean less speed?
a smaller pulley on the crank (typically known as underdrive pulley), spins the accessories slower.....including the alt
so in order to get the alt spinning back up to stock speed you need to overdrive it, which in this case means a smaller alt pulley.
confusing
some math:
6" crank, 2" alt = 1:3 rotation
4" crank, 2" alt = 1:2 rotation....alt spinning slower, what we call underdriven generally
4" crank, 1.5" alt = 1:2.7 rotation so the alt is spinning faster, overdriven
4" crank, 2.5" alt = 1:1.6 rotation, so the alt is spinning slower, underdriven
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Joined: Jun 2008
Posts: 2,585
Likes: 3
From: Edmond, OK
swapping the alt pulley to overdrive or underdrive isnt gonna have a change in power all that much. wont even be noticeable
conan, im confused now haha. on ASP website, why is the underdrive alt pulley smaller than the stock alt pulley in the pic if it spins faster?
conan, im confused now haha. on ASP website, why is the underdrive alt pulley smaller than the stock alt pulley in the pic if it spins faster?
thats why
i think it boils down to what they call underdrive and overdrive....
I'm confused too, I think (teke) is on the right track... what do they concider a under drive and over drive. My thoughts would be to call a small pully a overdrive, because you spin it faster, and a bigger pulley, a underdrive because its spinning slower.
won't affect hp...
but it will help the charging system...particularly if you run a sound system.
that's the reason for overdriving the Alt with an underdrive crank pulley.
