ok so i was thinking about putting new underdrive pulleys on my 1996 3.8l but a few people have told me thaat it is a bad idea because it might blow my alternator if anyone could help me out on what i should do that would be great.
it will cause a slight drag on the alternator and will cause a slight jump in voltage. What i did is keeped the stock pulley on the alt. and changed the other ones.
yea i was thinking that too especially because i have to amps going in my car but i have only been able to find the crank shaft and alternator pulley kit for my engine so would it even be worth it
i put the motoblue 42% UDP on mine, and if i idled my car with the A/C on, all my lights would dim and if i shut off my car it wouldnt start up again, but just last month i changed my battery and i dont have any problems anymore, and the new battery is holding up well, so i figure that problem was cuased by my weak battery. if your charging system is in good shape, you ought to be ok, im sure there are a few people who have had problems with them though.
PS. i'll let you know if i get any future problems with the UDP
im a little confused, some of you are saying that the underdrive pullies will ADD load on alternator/ water pump and INCREASE votage, when i put the UDP on my it slowed down every accessory on my belt, i would think the only way to increase voltage would be to put an overdrive pulley on any of the accessories, since one overdrive pulley would speed the whole belt up. am i far off?
im a little confused, some of you are saying that the underdrive pullies will ADD load on alternator/ water pump and INCREASE votage, when i put the UDP on my it slowed down every accessory on my belt, i would think the only way to increase voltage would be to put an overdrive pulley on any of the accessories, since one overdrive pulley would speed the whole belt up. am i far off?
That is correct. A UDP slows down your accessories to free up lost hp due to parasitic losses. I know the 94-98 kits come with an alternator overdriver so you won't lose charging capacity......
Do pulleys effect The Alternator ? 
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