Underdrive Pulleys
Thread Starter
On The Tree
Joined: Jul 2007
Posts: 107
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From: Southeastern Michigan
Underdrive Pulleys I had a set of underdrive pulleys on my '94 3.4L Camaro as did my friend on his GMC Sonoma. We definately noticed the power increase, however we both killed two batteries and my alternator died from constantly trying to charge. I have a 2000 SS Camaro now and need to know if this is a common problem with underdrive pulleys. Dimming lights and stereo drive me crazy, I won't spend the money if it is expected. -Eddie
Kinda a damned if you do, damned if you don't type of thing when you look at it from a performance standpoint. If you spin your motor much beyond the stock rev limiter with the stock pulleys in place, you'll end up spinning the alternator too fast and you'll kill it. But don't spin it fast enough, and you'll fry it that way too. My power steering pump liked to pee on my alternators, but I think I have that fixed now.
Some people have charging issues with underdrive pulleys, others don't. Those that do are typically cars with automatics because they idle lower than the manual trans cars, but other people have had issues with larger stereos.
Me? I run a stock diameter ATI superdamper with an underdrive alternator pulley. My power steering pump already puts out less fluid than a stock unit, I have an electric water pump already, so an underdrive pulley really doesn't do anything for me. But I still wanted to keep the upper RPM range of the alternator down so as to not fry it when I'm out driving my car hard, which is pretty much all I do anymore since it isn't my daily driver.
I don't think there is an easy answer to this one...I would personally never put an underdrive pulley on another car that I own. The ATI Superdamper on mine came after I had run a Powerbond UD pulley for about 2-3 years, and I never really noticed any difference with it.
Some people have charging issues with underdrive pulleys, others don't. Those that do are typically cars with automatics because they idle lower than the manual trans cars, but other people have had issues with larger stereos.
Me? I run a stock diameter ATI superdamper with an underdrive alternator pulley. My power steering pump already puts out less fluid than a stock unit, I have an electric water pump already, so an underdrive pulley really doesn't do anything for me. But I still wanted to keep the upper RPM range of the alternator down so as to not fry it when I'm out driving my car hard, which is pretty much all I do anymore since it isn't my daily driver.
I don't think there is an easy answer to this one...I would personally never put an underdrive pulley on another car that I own. The ATI Superdamper on mine came after I had run a Powerbond UD pulley for about 2-3 years, and I never really noticed any difference with it.
