Under drive Pulleys
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Joined: Sep 2009
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From: Utah
Under drive Pulleys I bought March Performance alternator pulley and a crank pulley and i was told my engine would blow within a month from the local shop when i was getting some welding done. so my question is it safe to install them if i still drive my car daily??
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Depends, did you put the stock damper back on OVER the useless underdrive pulleys??
The stock pulley serves as pulley and harmonic damper. A number of people put on the UD pulley and leave off the stocker when you are supposed to put the stocker on over it. If you left it off the shop is right that you are doing damage.
UD pullies are of little value on most LT1s because they can not slow our waterpump, on applications where they slow the waterpump they are a nice simple upgrade.
Pulling the belt entirely on an LT1 is worth about .1 at the track, so it stands to reason that a 34% UD pulley would only gain you .034 at the track, a street car will vary more than that pass to pass.
IMO don't bother with underdriving the accessoruies till you do a good damper and then get one that is undersized.
The stock pulley serves as pulley and harmonic damper. A number of people put on the UD pulley and leave off the stocker when you are supposed to put the stocker on over it. If you left it off the shop is right that you are doing damage.
UD pullies are of little value on most LT1s because they can not slow our waterpump, on applications where they slow the waterpump they are a nice simple upgrade.
Pulling the belt entirely on an LT1 is worth about .1 at the track, so it stands to reason that a 34% UD pulley would only gain you .034 at the track, a street car will vary more than that pass to pass.
IMO don't bother with underdriving the accessoruies till you do a good damper and then get one that is undersized.
