mattstang2007

one of my buddies from class has a 2002 gt and he wants to put underdrive pulleys on, but he asked me if i had heard that doing this might render the a/c useless and lose powersteering i told him i havent heard that but i also have a newer stang, so has anyone heard you can lose a/c or powersteering with underdrive pullys... honestly to me it doesnt make sence to lose any of it since you should just be replacing the stock ones with lighter/smaller pulles right?so it should all connect right back up, but i wanna make sure, because i am gonna help him put them on.

texas_stang02

technically you will lose some power steering, but it's so small an amount you'll never notice it. when you put underdrive pulleys on, you're just slowing down the belt-drive accessories (a/c, p/s, water pump, alternator) because they use up some of the engine's power. by under-driving them you can free up some power, and most of the underdrive pulley kits that are on the market don't reduce them enough that you will feel any lost power steering or see the car overheating or anything like that. i'm not sure what kind of power gains there are (probably no more than 10 hp), but if he's got the money and the time to put em on, then i'd say go for it. another positive is that he might see a slight increase in fuel economy, because the engine is having to work less than it would with the standard pulleys.

tcuallstar

if he is planning on going Forced induction dont do it bc you will just have to take them off and put the stockers back on, i have them on my car, i wouldnt go with anything else besides steeda, thier crank pulley is SFI approved. stay away from the piggy back systems. The ac blows just as cold, no charging issues and power steering isnt even noticeable

mattstang2007

thanks for the help guys.

2002silvergt

def. go with steedas...tell him ive got a set i bought a month ago for $185 and are in mint condition...im going supercharged and have o get rid of them....tell him ill take $100 for them...

oxfordgt

You will not lose any p/s or a/c function. Underdrives have nothing to do with those 2. The underdrive pullies slow the water pump and the altanator by using bigger pulleys. The belt speed would stay the same if you didnt change the crank pulley but the crank pulley is changed to a smaller pulley which speeds the belt up and keeps the altanator and water pump at the same stock speed. So really underdrives do nothing for you.The only gain you get is from the lighter crank pulley.

Chopper

The smaller crank pulley drives everything slower.The water pump and alternator pullies are bigger to slow them down even more than with just a crank pulley change alone.

The smaller the diameter of a circle,the shorter the circumference will be.
The bigger a wheel is,the farther it will roll for each revolution.The same holds true for UDP's.

As far as performance increases,they won't really show up until you get into the higher RPM ranges.Since they turn the accessories slower the bearings and seals should last longer also.

99BlackPonyGT

UDPs are sounding like a worthless mod.....glad i didnt give in and buy them while i was looking at them during my timing chain job

1999 GT

go with steedas....if you buy a cheap brand the pullies aren't designed right and over time the alternator pulley will fry your computer

StylinM6s

I'm going to get steedas. Despite what people may think it is a bolt-on power mod. It's already dyno proven to gain 11whp to a 96-98 cobra