lightweight alt pulley?

whiterider00 · 07-25-2008, 05:19 PM

been looking into getting some better pulleys for the Ho, and ive seen multiple places that offer a lightweight stock size, and underdrive crank pulley, and a lightweight underdrive alt. pulley. does anyone know if there is a lightweight stock size alt pulley available? thanks in advance.

jackal2000 · 07-25-2008, 05:27 PM

http://www.z-spec.com/catalog

whiterider00 · 07-26-2008, 01:00 AM

actually looked on there many times, and under the alero, they only have a crank pulley...but under the cavalier theres a alt pulley...my mistake, i should have been more thorough. thank you jackal.

01silveralero · 07-26-2008, 01:05 AM

http://www.pfyc.com/pc/GA3016/ALUNDE...or+Pulley.html

whiterider00 · 07-26-2008, 01:08 AM

that ones underdrive...looking for stock size. thanks tho

since we r on the subject, how much of a difference would i notice if i were to go with an underdrive crank or alt pulley, over stock size?

01silveralero · 07-26-2008, 01:15 AM

like 5hp maybe if that

whiterider00 · 07-26-2008, 01:26 AM

well for a mod under $100, 5HP is pretty damn good. and youre saying i would get that much more with an underdrive, lightened pulley, over stock size lightened pulley?

01silveralero · 07-26-2008, 01:30 AM

yes overdrive is mainly over good for supercharged engine when they are using smaller pulleys so the overdrive help to compensate for the smaller pulley and make more boost.
to my knowledge there really is not much use for overdrive pulleys.

whiterider00 · 07-26-2008, 01:34 AM

well, that sort of answers my question...ill probly just stick with stock size, lightened alt and crank pulleys, that way i can still use the same belt, and all that. ive heard that with these pulleys the main increase in power comes from the weight lost in the pulley much more than from smaller diameter. if anyone else has any opinions, i would be glad to hear them. thanks.

alerored04 · 07-26-2008, 05:02 AM

I have an underdrive crank pulley. It did not do much except let the car rev faster, not much gain on the butt dyno.

Vinalero · 07-26-2008, 10:56 AM

an underdrive crank pulley is a smaller size crank pulley. With a smalle diameter crank pulley that turns at same speed as before with the stock, you have to think the belt will turn slower because it takes more revolution of the pulley to have the belt do a full cycle. therefore all other pulleys will turn slower. It takes some load off of the engine.

An overdrive pulley does the opposite, it makes every other pulleys turn faster (including the supercharger pulley) therefore making more boost from the supercharger.

When talking of lightweight, its only that the less rotating mass there is, the less power lost making those pulley turn.

So if you are going to get some pulleys, your best bet if you are staying NA is a lightweight underdrive crank pulley and a stock size lightweight alt pulley.

And Red is right, it will rev faster, but not much gains in term of hp. But quick revs = quick throttle response. Its not a loss for the price.

whiterider00 · 07-26-2008, 12:17 PM

Quote:

Originally Posted by Vinalero

an underdrive crank pulley is a smaller size crank pulley. With a smalle diameter crank pulley that turns at same speed as before with the stock, you have to think the belt will turn slower because it takes more revolution of the pulley to have the belt do a full cycle. therefore all other pulleys will turn slower. It takes some load off of the engine.

An overdrive pulley does the opposite, it makes every other pulleys turn faster (including the supercharger pulley) therefore making more boost from the supercharger.

When talking of lightweight, its only that the less rotating mass there is, the less power lost making those pulley turn.

So if you are going to get some pulleys, your best bet if you are staying NA is a lightweight underdrive crank pulley and a stock size lightweight alt pulley.

And Red is right, it will rev faster, but not much gains in term of hp. But quick revs = quick throttle response. Its not a loss for the price.

that has pretty much been my thoughts since the beginning. i do plan on getting what you recommend, especially for the price they are. if i do get the underdrive crank and stock size alt pulley, does anybody know what size or part number for the belt to get? thanks again guys.

01silveralero · 07-26-2008, 12:57 PM

Quote:

Originally Posted by whiterider00

that has pretty much been my thoughts since the beginning. i do plan on getting what you recommend, especially for the price they are. if i do get the underdrive crank and stock size alt pulley, does anybody know what size or part number for the belt to get? thanks again guys.

usually on the site (depending on where u get it) they will have belts for people who switch to underdrive pulleys.

whiterider00 · 07-26-2008, 01:45 PM

checked the few places that sell the pulleys, and none seem to sell the belts, or even list what size it is. im sure its listed somewhere on this site , or someone with that setup knows...

Vinalero · 07-26-2008, 01:52 PM

Quote:

Originally Posted by whiterider00

checked the few places that sell the pulleys, and none seem to sell the belts, or even list what size it is. im sure its listed somewhere on this site , or someone with that setup knows...

when I was checking for pulleys on ebay, some said that with the pulley would come the correct size for the belt, and others just said it on the page.

Anyways, with the belt tentionner you should have some gap in the length of the belt. I'd take the factory belt off and only get a shorter belt of same width,

whiterider00 · 07-26-2008, 11:24 PM

thats what ill probly have to do. now can anyone tell me how dificult this is going to be? something i can bang out in an hour or so with some hand tools, or should i try and find somewhere to do it and save myself the aggrivation?

Vinalero · 07-27-2008, 12:47 PM

For the crank pulley, Its not hard, but I guess its only time consuming. Best way is to raise the car, take passenger side wheel off as well as fender liner and then you have the pulley.

for the alt pulley, I dont know so I cant really say. Maybe its only to unscrew the bolt and put the other pulley back on.

alerored04 · 07-27-2008, 02:39 PM

For the crank pulley you will want air tools as it is a huge pain without them and maybe not even possible since you need to crank the puller on very tight to pop the stocker off. For the alt pulley make sure to loosen the nut on it while the belt is still on the pulley holding it stationary. No one wil install a UD pulley for you, before I knew what I was doing I tried to find someone to do it for me and they won't since it is not a stock style dampener pulley, they do not want to be liable for engine damage that will never happen.

whiterider00 · 07-27-2008, 04:26 PM

great...looks like ive gotta do it myself then. thats ok, thats what beer and friends are for. thanks again for all your help everyone. try to get some pics and results up when i get it done.