I had been thinkin about underpullies & remembered something about the stock alternator possibly being problematic. Then, last night. while minding my own business, my Battery light came on & I began discharging!

So, are under pulleys worth it?

Do I get a higher output unit or mod it in some other way (pully size)?

How aggressive on the pulleys? Lookin for a little bump. Nothing that could prove problematic?

There's an auto electric shop I've been going to for over 30 years, back when I had a fleet of trucks. They could rebuild mine to special specs. if need be.

 

i had underdrive pulleys but took the alt pulley back off and put the stock one back on and never had any problems

 

My under drive pullies didn't mess with my charging hardly at all. The only time the volt gauge drops is at an idle, as soon as it gets to about 900 rpm, the gauge goes right back to where it normally is. I didn't put the alternator pulley on because it was the same exact size as the one in the kit. I only installed the water pump and crank pullies. I had to get a belt that was 2" shorter too. I didn't notice a huge difference but, it was noticable. I bought the March Performance Steel set. I've heard the aluminum sets can be noisy (sqeaky). Plus, the March set was the least expensive and provided the most (supposed) HP gains. They claim 8-15 HP! Shoot, for $50 it was worth it, to me.

 

mine were the bbk billit aluminum ones,,,never had a problem with sqeaking,,ever

 

That's why you'll notice I wrote "can be" noisy. I never stated that they were for fact because I don't know that to be true. Thank you though for pointing out the BBK set were o.k., those are the ones I almost bought thinking the aluminum would be better, less rotational weight and all....

 

the BBK I used were also Aluminum but I didnt like tham as they were heavier than the stock units they replaced...

I dont like the added weight...

 

...and so I stand corrected yet again. Damn, twice in one thread. I suck.

 

Hmm. a side bar to the my thread> Hack! When my Alt went out. My curb idle went to exactly 1K. I did not waver at all. So what tell's it to do that . The ECU? If you want to pooch an ECU or most electronic stuff. Underpowering is worse than a little overpowering. Maybe the ECU monitors & tries to compensate by adding RPM?

You and dr_bowtie have underpully's. Both have Slightly higher curb idles. Compensation for the slight drop in Voltage output at the lower RPM w/ the underpully's? My 302 has always been 650 RPM warm curb idle/ hell or high water, Except the moment the battery light came on & the alternator failed! then idle went to exactly 1K. Is it possible your underpully's are to blame for your slight high Idle? we've pretty much covered all other possibilities.

 

I would've probably agreed with that, except my idle is rock solid at 700 rpm since I changed the ACT Sensor and I still have my underdrive pulleys on.....

 

I have the factory pullies on my truck...I merely stated pullies i've installed...they were on customers vehicle...

I wont install under drive pullies on my own vehicles...