5.0 Under Drive Pulleys. Anyone running them?

[Dan Whitaker]

I'm thinking of putting a set of under drive pulleys on my Mounty. Is anybody running them? If so have you notived a difference.

I assume(Yes I know what happens when you assume ) the set for 5.0 Mustangs will work.

 

[boominXplorer]

I was wondering this too. Theres a set from a 94-95 stang on CL for $20 :woot:

 

['97 V8]

What exactly do underdrive pulleys do?

 

[CougarX]

I don't know if they will work or not. All the accessories are different on Explorers and the crank pulley is a one off piece that is nothing like a Stang. You might get lucky and get a couple accessory pulleys to fit but they probably won't align with the rest of the pulleys. Explorer has all the front pulleys/accessories mounted closer to the block then a Stang for radiator clearance.

 

[chriswells78]

I tried the FRPP 94-95 pulleys, they won't work. The Waterpump pulley on the kit is too big, it would rub the idler pulley that is located above and to the right of the WP pulley.

I have been considering a lightweight harmonic balancer/crank pulley though.

I have a set on my mustang and they have preformed great, no issues. Some people have made mention that after installing underdrive pullies, they experienced charging issues, espeically on pre-1994 Mustang 5.0 engines. My neighbor being one of them. He replaced the alternator pulley with the factory pulley and has no farther issues.

FYI on underdrive pulleys...They work in 2 ways

1) replace steel pulleys with lighter weigh aluminum, the biggest advantage to this is in the crankshaft pulley/harmonic balancer. The lower weigh means less resistance to the motor from idle to top end.

2) In making the crank pulley lighter, they usually make it smaller in diameter. This means that the belt doesn't spin as fast. (think of it as a gear reduction) In turn, you must put a larger pulley on your alternator so that it is driven at the same rate. The bigger pulley on the water pump, slows it back down to normal operating speed and helps pick up some of the slack so that you can use the same belt.

 

[dreamr]

I run underdrive pulleys on my 5.0 Mustang. Performance wise, they gave me a bit in the responsiveness depatment, though not a lot of overall power. I did experience charging issues as well. I would pull up to a stop light and the amp gauge would fall way way way way down. I had to keep the car over 1k -1500 RPM at all times to keep the battery charging. I upgraded to a 130 amp alternator and the problem is gone.

 

[Dan Whitaker]

Thank you everyone for your replies. I'll find something else to spend my money on Which is not too hard of a thing to do.