TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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Pulleys don't have bearings - so if you have a bearing issue, this won't help. ie the power steering pump - the pulley is pressed on the shaft - if you're having power steering "bearing" problems, then you need to replace the pump. Same with the smog pump, and A/C and the alternator - nothing goes wrong with the pullies, it's the parts themselves that go bad.
Not completly on topic and I know this isnt exactly what he is talking about but,Pulleys can break.My Power steering pump was making a weird noise on my tbi truck.I thought it was the pump itself.About a week later I cranked it and bang!the pulley broke off the shaft going into the pump.You may want to take a close look at the pulley just to be sure it doesnt have any stress cracks in it.
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5.7,Stock TPI,LT4 production cam w/1.6 R.R.
ZZ4 heads,Hooker 2460 headers w/full 3" exhaust
2500 stall,3.42 gear,suspension mods.Full list of mods in VB garage.
i was also doin it for cosmetic appearance as well.
If you want to spend $150 on a cosmetic upgrade, that's your call.
Don't get me wrong here, lightening the rotating assembly will help. It just has to be a large enough percentage of the total rotating mass to help. Light weight pulleys on a 9000 rpm Honda 4 banger, ok, that might work. Light weight pulleys on a 5500 rpm Chevy V8, not so much.
Thanks for the input. I never wanted to do the upgrade for hp gains. I originally wanted to do it to spice up the look of my engine. I didn't even know about a possible hp increase until I done a bit of reading about the pulleys.
well there seems to also be an underdrive ratio with these, so it's not only the lightweight that will help with performance. there's no info about the ratio though.. and there are many different opinions about underdrive pulleys (udp) for our cars on our board with arguments of too high cost/hp, not enough coolant flow or low alternator output with UDPs.
__________________ '84 T/A HO 5speed, freshly rebuilt L69
'89 Formula, somewhat modded L03 and soon T56+3.73
do not confuse a lack of traction with an excess of torque
Me either,until then.It appears a small stress fracture started and eventually mad its way far enough around the pulley about a 1/2 " from the shaft.Luckily I was at idle.It was an easy fix though.
The UDP debate has been covered here 10,000 times.I think its a personal choice depending on the use of the car and mods
.Just dont expect any real power gains.Its something I may do for looks and when I run out of other mods.
not looking for power gains to tell you the truth, just the cosmetic aspect ot spruce up my engine bay. I didn't know anything about the hp gain until doing a little research.
underdrive pulleys = less revolutions for the alternator = less electrical power output of the charging system, same goes for the water pump. as said, you'd prolly want to do some research about this. you can also get sets with crank underdrive and alt overdrive so all belt accessories will spin slower except the alternator
__________________ '84 T/A HO 5speed, freshly rebuilt L69
'89 Formula, somewhat modded L03 and soon T56+3.73
do not confuse a lack of traction with an excess of torque
Never seen that happen before! 
