Pulley Question...noise? alum vs steel?

[91LX_5L]

Ok I deffently am going to be getting some pulleys.

Are aluminum that much better then steel? i can pick up a used pair of standard underdrives (mac) for cheap, is it worth it to pay 3x the amount for aluminum?

i've heard people say that they sometimes whine and sound cool are there certain ones that do this more or is this not true?

Thanks

 

[AznStanger3v]

using aluminum means less rotational mass. It really wont matter for underdrives though. IMO, its not a weight difference that can make a difference. just get the ebay ones.

 

[squall9393]

i've heard people say that they sometimes whine and sound cool are there certain ones that do this more or is this not true?

Thanks

Sound cool? Whining isn't good. Prolly means the belt is rubbing.

 

[Black95GTS]

using aluminum means less rotational mass. It really wont matter for underdrives though. IMO, its not a weight difference that can make a difference. just get the ebay ones.

I disagree. We're talking abotu something that spins thousands of times when you're driving. Say the combined weight of the aluminum vs. steel is 3 oz difference. Say each pulley spins 2000 times each. I know they all are different sizes and spin differently but bare with me. Thats 6000 rotations, pulling a difference of 18000 oz total. Convert oz to lbs and your engine just had to pull 1,125 pounds less weight over the course of your drive.

This is the reason people switch the aluminum drive shaft and also why drag rims are small and you can fling a skinny like a frisbee. Lowering rotational inertia and mass is huge. So for the extra 30 bucks, get the aluminum.

 

[91LX_5L]

ok ignore the noise question.

I can find used steel pulleys for about $40 where as aluminum ones will run me about $100 is it worth it?

 

[mattkimsey]

I think the aluminum ones are 8lbs lighter.

 

[91LX_5L]

yes but how does 8lbs make a diff?

 

[mattkimsey]

8 lbs. doesnt make a big difference. But it does take 8lbs off the front of your car and every little bit adds up. Pulleys are also sprung weight.