[firefly1241]

looking to pick up an underdrive pulle kit for my 1992 gt havent looked to hard to find one yer was wondering wat are some good sites you guys use for parts also what a grood brand of pulleys would be ?

[1slo5.0]

Summit. March or BBK underdrive pulleys are good. There are alot of other good ones out there too.

[firefly1241]

srry for the serious masacre in my last post lol. but anyways i was looking at some bbk steel underdrive pulleys, I was going to get there steel kind since they should be built stronger but idk for sure. Aluminum is light and may give me a better take off even if it is a hair of a second what are your guys ideas?

[TENGRAM]

the difference in weight is so minimal i don't think it would make a difference either way. for something as simple as underdrive pulleys, just buy the cheapest ones you can find. mine were made by CAT...never heard of them? me neither, but they were $40 and do the job as well as any

[Tony_90fox]

i got my pullies at a UPR table at a swap meet for the NMRA. I dont think they make pullies though, or at least i havent been able to find them if they do. anyway, whatever brand they were, they cost $80.

[82GT]

You can usualy find a cheap set on Ebay

[cobraetti]

I got the BBK steel from CJPONYPARTS.COM($80.00), the only thing I might be aware of was that when I used the alt. pulley it greatly reduced the output of my alt.. So I went back with the stock Alt. pulley :sleep

[firefly1241]

so if i go with them keep the stock alt pulley ??? or was that just in your case 89 ragtop ?

[Tony_90fox]

some people have had problems so they go with a 130 amp alternator....that should keep it charging well. Get one off a taurus or buy it new.

[firefly1241]

how much off a taurus u think and what year ???

[cobraetti]

Yes in my case it benefited me to reinstall the factory ALT. pulley(lights were going dim at idle). you can see if this is the case with yours

[shurb125]

Just put a set ot BBK on my 93 covert Wednesday, haven't had any problems thus far, and as far as the alt pulley the new BBK was actually slightly bigger than the original but I still put it on anyways.

[turbong]

Well personally I would like to see a test done to see if there is a difference. In theory rotating mass weighs more then stationary mass. For example 1lb weights 1lb, but a 1lb pulley rotating at X speed then it now weighs 1.3 lbs. Not 100% sure on formula. So you would be gaining on loss of weight but how much is the real question. I do say the billet pulleys are better since they would never rust or need painted. And the cost isn’t that big of difference 50 compared to 80….

[TENGRAM]

Originally Posted by turbong Well personally I would like to see a test done to see if there is a difference. In theory rotating mass weighs more then stationary mass. For example 1lb weights 1lb, but a 1lb pulley rotating at X speed then it now weighs 1.3 lbs. Not 100% sure on formula. So you would be gaining on loss of weight but how much is the real question. I do say the billet pulleys are better since they would never rust or need painted. And the cost isn’t that big of difference 50 compared to 80….

i'd like to see that test too, even if it only uncovers a 1 or 2 hp difference. when i bought my pulleys from Dallas Mustang, they actually tried to tell me that the aluminum pulleys, with their lighter rotational weight, would cause a loss of engine momentum between shifts, and thusly slightly less performance...sounded like some BS at the time, but seems worth noting in this discussion

[turbong]

Yes and no at the same time! The rotating mass (weight) helps you only when launching the car from a slow roll or a complete stop. For example pick up a bucket of water and throw it as far as you can with out spinning it around first. Then using the same amount of water in the same bucket twirl the bucket around and around like a helicopter and then release it. The second throw will travel much further. I had an AWD Eclipse and with the stock fly wheel I could launch the car at 3k RPMs but when I put on an aluminum flywheel I lost the ability to launch the car at 3k, I had to at 5-6k RPMs.
(So you loose little launching ability with lighter pulleys and flywheels but gain lighter weight car and more HP) But with RWD not many are worried about gaining or loosing launching power!

[1slo5.0]

1 pound of rotating mass is equal to 8 lbs of dead weight. However in the case of underdrive pullies the difference is so minimal that you will never notice it.

[firefly1241]

thats alot of helpful info not really for the get up in go i want it in the long run

[Tony_90fox]

do you have gears? you will get up and go with some 4:10s for sure!

[turbong]

--------------------------------------------------------------------------------
"1 pound of rotating mass is equal to 8 lbs of dead weight. However in the case of underdrive pullies the difference is so minimal that you will never notice it. "

Are you sure it's not 1.8lbs rotating to 1lbs dead weight? I don't think it's that much of a differance. If a steel pully weighs 5lbs then that would be 40lbs rotating. I think the ratio is 1.8 for ever 1lb, if i'm wrong then please corect me. I'm looking for it online but with no luck.... LOL

every100lbs is a .10 in the quarter mile

[TENGRAM]

Originally Posted by turbong -------------------------------------------------------------------------------- "1 pound of rotating mass is equal to 8 lbs of dead weight. However in the case of underdrive pullies the difference is so minimal that you will never notice it. " Are you sure it's not 1.8lbs rotating to 1lbs dead weight? I don't think it's that much of a differance. If a steel pully weighs 5lbs then that would be 40lbs rotating. I think the ratio is 1.8 for ever 1lb, if i'm wrong then please corect me. I'm looking for it online but with no luck.... LOL every100lbs is a .10 in the quarter mile

you may be right about the rotating mass, i really don't know, but a pulley doesn't weigh 5lbs...its much less, probably 1 maybe 2 pounds.

also its important to point out that, although 100lbs is about a tenth in the quarter, normal street driving is where weight reduction really pays off. consider driving and never shifting later than 2000rpm. at 2000rpm our 5ohs only have about 100hp. at 100hp, weight plays a much larger role in performance.