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Engine underdrive pulleys

Discussion in 'Powertrain' started by Dreadon, Aug 1, 2007.

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    Dreadon Guest

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    my bad i ment has anyone put them on to their car and are they worth it
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    Dreadon Guest

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    underdrive pulleys

    has anyone got either the alternator pulley or teh crank pulley from aem or unorthodox racing or obx i see them on ebay and i would think they help some
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    GSE21tuner Formerly rollatuner110. Representing AZLexus.club

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    Please use the search option or check the for sale section before you post in here asking us to do it for you. C'mon now. Not trying to be rude but it's just common sense. There was someone selling a set in the for sale section. Check it out and see if it's still for sale.
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    JspeXAE102 Well-Known Member

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    I don't see how a alternator pully is unsafe since the alternator would effectively be spinning slower.
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    GSE21tuner Formerly rollatuner110. Representing AZLexus.club

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    It would eventually kill the alternator.
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    Vibe New Member

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    i thought there werent any real detriments to AEM's power pulley set? its just replacing the alt pulley with a lighter one, no?

    compared to the other pulley sets that require you to remove the harmonic dampener
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    JspeXAE102 Well-Known Member

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    It's lighter and a larger diameter so it'll spin the altenator slower thereby minmizing parasitic drag. The ampage output would be reduced because it would be spinning slower but that's all.
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    rainbow_star New Member

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    alternator pulley will kill your alternator and the crank pulley will kill your engine. :D :D :D
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    Vibe New Member

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    how much less? im asking because im putting in a sound system
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    MovieSTAR i hurd u liek?

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    ive heard it helps..but your parts wear out faster...alot faster
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    GSE21tuner Formerly rollatuner110. Representing AZLexus.club

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    If you're putting in a sound system, underdrive pulleys are a bad idea. It would be better for you to get overdrive pulleys.
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    jcrwzr Member

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    don't do it. all i've heard is bad news for your electrical components
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    GSE21tuner Formerly rollatuner110. Representing AZLexus.club

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    You only gain 2-3 hp or less. It's not cost effective or safe.
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    JspeXAE102 Well-Known Member

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    .. because the alternator is spinning at a slower RPM?
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    nocpan New Member

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    All engine tuning essentially shortens the life of the components, so there is no such thing as getting 50HP more and still having the same engine life, I had the ASP underdrive pulley and unlike air intakes and mufflers ect... i did feel little increase in power, on 4-speed auto I could very nicely chirp the tires, I didn't notice problems with power steering or AC to which this was connected.

    As to the alternator pulley it will cause your alternator to pump less juice when idle, because at idle it will spin slower then designed, and so the battery will not get charged and any electronics like stereos amps lcds ect will not function properly, to remedy that you basically need to upgrade your alternator.
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    JspeXAE102 Well-Known Member

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    Thank you for a logical explantion Nocpan.

    I can see how an underdrive crank pulley would potentially cause engine damage because of the removal of the harmonic dampener but IMO an alternator underdrive pulley is safe. Reason being the pulley is designed to underdrive by no-more than 15-20%. The reduced ampage generation is not of major concern if you are building the car for performance as opposed to audio competitions or light shows. If anyone cared to look up the history of the underdrive pulley; it was invented to extend the life of accessories in race cars which engines routinely run at higher RPMs by running them slower thereby causing less wear and burnout.

    Please understand that performance and ICE does not go hand in hand. Infact it's like night and day. People who race their cars remove sound deadening, audiophiles install dynamat. Same goes for pulleys.

    BTW I know of a lot of people who run underdrive crank and alternator pulleys from Unorthodox with no problems. Just make sure you stick with a reputable brand.
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    GSE21tuner Formerly rollatuner110. Representing AZLexus.club

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    For me, I just don't think its cost effective. 200-300 for underdrive pulleys for approx 3 hp just doesn't cut it for me.
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    HINcorolla05S Guest

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    Well, they may wear stuff out sooner, but i have the OBX Underdrive Crank pulley and the lightweight Alternator pulley with Gatorback belts and can tell a slight difference, i mean it's nothing crazy, but it does do some good. I got a really good deal in a set of silver with the belt for $150. I have for sale though the 15% underdrive for a 1ZZ motor, just the pulley though. NO alt pulley. Wasn't too hard to install, and the ALT pulley is not SMALLER OR BIGGER, just lighter. Check out my auction on ebay if you want: You can have it for as cheap as $25 or buy it now for $65. Auction ends soon. BTW i'm Mystique72torinoman.

    http://cgi.ebay.com/ebaymotors/ws/e...em=110164274180
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    GSE21tuner Formerly rollatuner110. Representing AZLexus.club

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    I'll pass. My plugs give me more power.
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    Vibe New Member

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    shouldnt it work on 8th gen 1zzfe? no?
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    JspeXAE102 Well-Known Member

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    The 2-3HP gain is per pulley and it comes from only the reduced rotational mass. If the pulley is underdrive then you can expect 5-7. Last I checked you can get a alternator pulley for ~$80.
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    GSE21tuner Formerly rollatuner110. Representing AZLexus.club

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    Well unless I came upon some free ones, I wouldn't spend money to buy them. I have more important upgrades to do. I need Ksports!
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    HINcorolla05S Guest

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    I'm sorry, but i'm not 100% sure if it would. I'm told that it does, but i'm not going to back that up because I cannot be certain. I don't wanna give you incorrect information. It should though if they are the same size and fitting. Mine states that it's for a 03-07, so, i would ask a toyota technician. You will need a slightly smaller belt though, or atleast i did and this is a replica of mine. <br />
    <br />
    Looking at pictures of both motors, i would say it'll fit, but check first.
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    HINcorolla05S Guest

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    I need a SUPERCHARGER!!! LOL
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    Vibe New Member

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    2-3hp per pulley or 5-7 if underdrive is pretty good. if only i can find ones that are certain to fit my 8th
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    GSE21tuner Formerly rollatuner110. Representing AZLexus.club

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