Modded Mustang Forums banner
1 - 20 of 22 Posts

·
Banned
Joined
·
3,385 Posts
The only pulley change that gets you any power really is the crank pulley.. but when you change that to a smaller pulley for the hp gain you slow down the alt pulley.

Which means you'll have charge issues at idle.. to remedy this i've in the past had to install a smaller pulley on the alternator.. Right now on my 3g I have a 1.82" pulley I got off ebay for $16 shipped and it's worked great. I have a 4" crank pulley also.
 

·
Registered
Joined
·
3,101 Posts
They're all gonna slow it down, but i have Steeda's. I'm pretty sure they make em for your year model. I didnt have ne issues with over heating or undercharging, they work great!
 

·
Registered
Joined
·
3,101 Posts
I also see they have an overdrive pulleys for the alternator
yeah, but that would defeat the purpose. I Havnt had any problems with mine, they've been great! If you are really worried, you could leave the stock pulley on. You'd get a little gain and it'd slow ur alt pulley down a little bit, but not as bad as putting the bigger pulley on there. I hope this helps, i know i have a knew edge mustang, but its pretty much the same engine. My friend's 98 had them on it and it worked fine too. Do you do much sitting in large traffic jams?
 

·
Registered
Joined
·
1,182 Posts
I have had them on a couple cars and a truck and I personaly think they are a waste of money and time for no more then you get from them.
 

·
Banned
Joined
·
3,385 Posts
yeah, but that would defeat the purpose. I Havnt had any problems with mine, they've been great! If you are really worried, you could leave the stock pulley on. You'd get a little gain and it'd slow ur alt pulley down a little bit, but not as bad as putting the bigger pulley on there. I hope this helps, i know i have a knew edge mustang, but its pretty much the same engine. My friend's 98 had them on it and it worked fine too. Do you do much sitting in large traffic jams?
LOL

You've never put UD pulleys on a fox before obviously..

Like I said before if you want any power gains out of under drive pulleys without dealing with constant charging issues, just run the UD crank and wp pulleys and leave the stock alt pulley alone. You may depending on how healthly and what model alt you have need to go to an over driven alt pulley to get the same charging at idle that you did when you were stock.

If you don't believe me ask over on corral.net where people have played this game a billion times
 

·
Registered
Joined
·
4,424 Posts
I used a 3g alt, but swapped my fox pully for the one that came on the 3g (its way smaller). i had to sand a very thin amount of alu off the body of the alt, to get the pully not to touch the body tho.
 

·
Registered
Joined
·
3,101 Posts
LOL

You've never put UD pulleys on a fox before obviously..

Like I said before if you want any power gains out of under drive pulleys without dealing with constant charging issues, just run the UD crank and wp pulleys and leave the stock alt pulley alone. You may depending on how healthly and what model alt you have need to go to an over driven alt pulley to get the same charging at idle that you did when you were stock.

If you don't believe me ask over on corral.net where people have played this game a billion times
Ouch... fox's give you that much trouble with them? But +1 on getting a better alt...
 

·
Registered
Joined
·
3,101 Posts
yeah in most cases they are more trouble then what there worth
i've been through it too many times so i know for a fact now that you have to over drive the alt to get right charging back at idle with ud pulleys
And that kinda defeats the purpose then... that really sucks tho...
 

·
Banned
Joined
·
3,385 Posts
true but if your upgrading to a 3g alt for say an electric fan.. then you have the power but you won't have it at idle with ud pulleys so all you have to do is take that ud alt pulley from that three piece set and toss it in the trash and try your stock alt's pulley on your 3g and see if it's good enough for you or like me purchase a $14 over drive pulley off ebay and have no worries anymore.
 

·
Priest of the Car Gods
Joined
·
17,313 Posts
is there a 3 piece pulley that frees up horsepower and ?does not slow down the waterpump and undercharge an alternator? What brand?
Sounds like you don't understand how underdrive pulleys work. They free up power specifically by not using it to turn the accessories; the amount of power gained is directly related to how much slower you turn them (relative to the crankshaft).
 

·
Registered
Joined
·
3,101 Posts
true but if your upgrading to a 3g alt for say an electric fan.. then you have the power but you won't have it at idle with ud pulleys so all you have to do is take that ud alt pulley from that three piece set and toss it in the trash and try your stock alt's pulley on your 3g and see if it's good enough for you or like me purchase a $14 over drive pulley off ebay and have no worries anymore.
Yeah, thats what i told him in my first post... and u did as well, so thats probably what he's gonna do.
 

·
Registered
Joined
·
1,527 Posts
Discussion Starter · #16 ·
Sounds like you don't understand how underdrive pulleys work. They free up power specifically by not using it to turn the accessories; the amount of power gained is directly related to how much slower you turn them (relative to the crankshaft).
Yea I know that but what Im asking is there a brand that sells UD pullys that is driven at a reasonable rate were the alternator is under driven yet the ratio of the pully is reasonably rated to charge the alternator normally
 

·
Banned
Joined
·
3,385 Posts
Yea I know that but what Im asking is there a brand that sells UD pullys that is driven at a reasonable rate were the alternator is under driven yet the ratio of the pully is reasonably rated to charge the alternator normally
Can't have your cake and eat it too in most situations when talking about ud pullies but best bet would be ASP.. some claim that they can skate by with a set from ASP so you might want to look into there stuff
 

·
Priest of the Car Gods
Joined
·
17,313 Posts
ASP? never heard of them Ima check them out. I also heard that the waterpump pulley is also dangerous to underdrive
Depends on how you use the car. If it's a track car that's usually running at high rpm, you want to slow down the water pump so it doesn't cavitate. Of course, if it's a track monster, why not just swap to an electric water pump?

Personally, I'd never put UDPs on a daily driver for all the reasons you've mentioned. I'd rather find those 5hp somewhere else.
 

·
Registered
Joined
·
222 Posts
true but if your upgrading to a 3g alt for say an electric fan.. then you have the power but you won't have it at idle with ud pulleys so all you have to do is take that ud alt pulley from that three piece set and toss it in the trash and try your stock alt's pulley on your 3g and see if it's good enough for you or like me purchase a $14 over drive pulley off ebay and have no worries anymore.
It interesting how this came up. I was thinking the same thing. I have a set of pullies here I haven't installed yet, but also have a PA Perf 130amper... PA sez don't mess with their pully as you'll void your warranty. I've always voided my warranties... Is there any real gain? I was thinking of just leaving it be and just using the other 2...

Realistically, what would I gain by changing the alternator pully? 1 or 2 hp if that? Then on the flip side, I void the warranty and have 15 mins of labor... And a cool paper weight
 
1 - 20 of 22 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top