BBK Underdrive Pulleys

[Stonerboys]

Hi guys, Im thinking about getting a set of polished aluminum BBK under drive pulleys for my 92 5.0 AOD Lx. I was just wondering how hard are they to put on? Do you have to take the fan and radiator out to change them because if it is going to be a major project I dont want to to even bother with it then. I also heard that they really kill the voltage on your alternator is this true? I just replaced my alternator last year and I dont want to have to change to a bigger alternator to put these pulleys on. Also, do these pulleys make a noticable difference in the cars performance? Thanks in advance for your help!

 

[stangfanatic]

You will have to remove the fan (if you have the stock fan) to put the water pump pulley on and you can opt to not replace the alternator pulley to alleviate the charging issues you brought up. I did not see a noticable power improvement when I put mine on. It's kinda like putting a CAI on, if that's the only thing you do, you will not notice an improvement.

 

[Mustang5L5]

Asp makes overdrive alt pulleys to compensate for the under drives

I run the under drive crank and water pump pulleys. But the asp over drive alt pulley.

You will need an impact gun to change the alt pulley if you decide to.

I noticed a little improvement when I put my pullies on, but I also converted to an electric fan at the same time

 

[BYRDPE]

i would overdrive the alt and just install the u/d crank pulley.

 

[Stonerboys]

ok that's what I was thinking too about just keeping the alternator the way it is

 

[rjennings]

Look at the Steeda pulleys, they are a lil more expensive..but very nice. Dont have them yet, but plan on purchasing a set.

 

[BYRDPE]

ok that's what I was thinking too about just keeping the alternator the way it is

go ahead and get a smaller alt pulley (overdrive it) to go along with the ud crank pulley. by doing so you will make up for the ud crank pulley slowing down the alt rpms.

 

[93gtmustang]

Hi guys, Im thinking about getting a set of polished aluminum BBK under drive pulleys for my 92 5.0 AOD Lx. I was just wondering how hard are they to put on? Do you have to take the fan and radiator out to change them because if it is going to be a major project I dont want to to even bother with it then. I also heard that they really kill the voltage on your alternator is this true? I just replaced my alternator last year and I dont want to have to change to a bigger alternator to put these pulleys on. Also, do these pulleys make a noticable difference in the cars performance? Thanks in advance for your help!

I'd say don't do it, especially if it's a daily driver and you have an electric fan.
I have the full set of BBK underdrive pulleys on my 93, but the most of the street diving is highway miles back and forth to the strip.
If I do take it around town and get stuck in traffic on a hot day, the water pump get's underdriven, which starts the electric fan, which drains the battery, which is not getting charged from the underdriven altenator.
I guess you could overdrive the altenator pulley as mentioned. I don't think they're worth it personally, unless you're turning above 6000rpms, then they would save your belt driven accessaries.