i was talking to a friend today and this topic came up about what do they do to increase HP and i couldnt give an answer, what is it with under drive pullies that give the increase over the stock pullies?

 

they slow down the accessories so the motor doesnt work as hard, thus freeing up a few horsepower.

 

....yup

 

uh huh they are rite the crank pulley is smaller and water pulley is bigger the crank is what spins on its own and drives everythign else... so lets just say you old crabk pulley was 10 inchs in curcumrance every time it spends u move 10inchs worth of belt which moves all the other accessories and energy doesnt come from no were so it takes it from the hp you engine creates.... no when u step down in size lets say 7 in in curcumferance u only move 7 inchs of belt which in turn is less work.... so u save more hp.... no u can explain it to your friend.... they my numbers were just made up tho... but if gives u the idea does it not.. if u want curcimfrance of a circle is 3.14 time the diameter... not that is matters the kits have already had all the engineering done so u dont really have to think about it just throw them on... its onyl a little xtra hp tho

 

even though the HP gained is hardly worth the price of those damn things.... especially when your alternator dies because the thing isnt spinning fast enough, and you burn out the voltage regulator

 

I know people have diff. opinions of pulleys, i agree with adder they are not worth the problems. You can do it and keep the original alt. pulley and you wont have as many charging problems.

 

I dont like them.. Mine overheated with them on.. That was even with the Lincoln Mark electric fan..

 

yup, had the same problem with the overheating AND the charging problem. I put the stockers back on and didn't notice a difference.

 

my charging is a little low so I bumped the idle up slightly as it said to and its fine. The temp has never been an issue, I live in phoenix and watch it like a hawk.....

 

yea i understand you agruement adder... i mean the 5hp isnt worth that kinda **** to deal with... i didnt have either problem with mine but i an still selling them... cuz well they dont get along with a s/c i wouldnt run them on a t/c either cuz of the possible cooling problems... turbos are hot.... i ran my when a h/c/i and bolt ons and had no problems but i dunno how they would do on a s/c.... and u know the cobra comes stock with a uderdrive pulley dont ya... just one... the crank pulley on a cobra is a little smaller than a gt... no much tho.. and water pump is the same so i dont think it does to much... for more boost on my s/c i might get a gt crank pulley and some methenal injector to go with it... but thats after suspension i wont be able to hook 500rwhp so ya