Underdrive Pulley Killing Alternator?

[lilem14]

I have a 99MTX cougar. I am on my 4th alternator with 112,000 miles on the engine. I was wondering if my underdrive pulley could be contributing to the problem. Doesn't it cause the alternator pulley to spin faster, resulting in it being overworked? I have a small system in my car with a 450watt rms amp and the lights dimm now. The car is also bucking and drives insanely slow if the ac is on, but I think that this has to do more with a possible IMRC problem.

Anyway. I don't really care about performance anymore. Would replacing my UD pulley with a normal crank pulley help out the longevity of my alternator and help the lights, which never dimmed before I got the UD pulley and threw a system in the car?

[freednighthawk]

Actualy, the underdrive pulley is designed to make the accessories spin slower, not faster. Yes, replacing the UD pulley with the stock type can make the lights stop dimming, or at least decrease it, because the alternator will be spinning at the speed it was designed for. However, I don't think it will help the longevity of it any.

[brapple]

are you using rebuild alternators from autozone, etc? if so those rebuilds have a 100% failure rate ... get a ford reman and you should be all set ...or go to the junk yard ...

[lilem14]

I really don't remember which alternator I have. I remember asking for ford parts(or motorcraft) the last two times but who knows if they actually gave me them

[lilem14]

What is the best way to provide longevity for my alternator?

[Redlineracer12]

Buy a good one from a Ford Dealer as Brapple suggested. You shouldn't have problems with the UD pulley or the stock crank pulley, if anything the UD would extend the life of the alternator because it would spin less.