99kamarokid

iTrader: (5)

i was looking up pulleys and there are a few different types, but i dont know what the difference between them are .. there was a harmonic balancer crank pulley, a underdrive crank pulley... then there was a underdrive and a overdrive alternator pulley... what is the diffrerences between these??

blkZ28spt

The net power gain comes from an underdrive crank pulley. The harmonic balancer pulley is the same item as an underdrive crank pulley.

I would levae the alternator pulley alone. Chances are if you need an overdrive pulley for the alt you already know this because it is to support things such as aftermarket stereo equipment that takes more electricity.

I have the 'SLP' underdrive crank pulley. Had it for a year and a half, I think. Works well, no problems. Pulleys typically net around 0.1 ET reduction/1 mph gain in the 1/4....or close....well worth the relatively minor expense.

Tainted

iTrader: (9)

its a decent mod if you can get one cheap. but there are better things to do before a pulley

00slowredz

i've heard mixed reviews....arent they a pain in the *** to install???

Tainted

iTrader: (9)

sometimes. fi you have the right equipment then they arent

99kamarokid

iTrader: (5)

well if ur doin what it says ur doing in ur sig, than u have to take off ur pulley anyways... and tainted..its not a lumkin, its a Blumkin..hahahahaa,

Tainted

iTrader: (9)

i hate blumkin so i go with lumpkin plus lump sound so much more appropriate. as in a lump of ****

TheBlurLS1

iTrader: (8)

Our cars don't have a "harmonic balancer" like old school motors due. However, you still see it because that's what most people identify as "the crank pulley".

In older motors, the crank pulley served more of a purpose than to just turn the belt, it actually helped balance the motor. LS1's are internally balanced. An "underdrive pulley" for an LS1 refers to a smaller crank pulley, which turns the accessories slower, and helps to free some power that the car would have to waste on accelerating the water pump/alternator/power steering.

You can also take it a step further and run an "underdrive alternator pulley", which will spin the alternator even SLOWER. This frees up even more power, but you begin to run the risk of your car not recieving enough charge to the battery. If you have a big stereo or something, and want to run an "underdrive pulley" (crankshaft), you can put on an OVERDRIVE alternator pulley, which turns it faster. You don't free up quite as much HP as if you just stuck on a crank pulley, but you'll avoid charging problems.


That being said, 90% of the people on this site just swap out the crank pulley for an underdrive unit.

99kamarokid

iTrader: (5)

thats what i wanted to hear....thanks

TheBlurLS1

iTrader: (8)

NP.

That's what we get paid so much for........... NOT!

/Borat voice

Urban Legend

iTrader: (5)

Leave it alone. What are the gains? 7 hp?

blkZ28spt

Leave what alone?

If you get anywhere near 0.1/1mph it is well, well worth the money. Try doing an et/mph/hp per dollar calculation on most other mods and see how it compares to a pulley.

Urban Legend

iTrader: (5)

Tremendous gain there. I need to switch mine out to an underdrive type then.

Ripper415

iTrader: (6)

i agree that they are a bit overpriced for the gains they show but when youve done all the other boltons and this is the last one, might as well go for it.

blkZ28spt

Again, why don't you guys calculate a power per dollar ration of the pulleys vs some other mods...

Ripper415

iTrader: (6)

well off the top of my head as far as better hp/dollar....lid, ported tb, ram air kits....but when you get to thinking they arent that bad. i mean how many people will gladly pay more than double what a pulley costs for an electric water pump showing the same gain. everyone out there should go research some ewp's and check the pricing. suddenly a pulley wont seem so bad lol

blkZ28spt

Ported throttle body? I doubt it...

Why don't you figure the hp/$ for things like a cam, heads, blowers, etc...

Ripper415

iTrader: (6)

yeah, a ported tb is one of the first & best things to do. if you do it yourself its free (cant beat that hp/$ ratio) and you can gain around 5hp. if you send it to someone who actually knows what they're doing itl cost you under $100 and you can gain even more. i've heard of and seen dyno gains of 7 rwhp from just a hand ported tb. thats about the same as a pulley but for half the price.