does anyone know where i can get an overdrive pulley just for the alternator. i need to spin it a little faster(u/d pullies did not come with one). thinking of upgrading to a high output, but kinda stupid if its noting going to spin no faster. so i decided to just spin this one back up to normal. my problem is only at idle with everything on drops to 12.6v. which every meaning, 4000watts of system, a/c on high max, e fans(20-25amps, not troyer setup) and of course all the headlights ect, which has all been changed to leds, or hids. and i have two yellow top batteries.

any help would be a great help lol...

just mainly want to know if i can get an overdrive for the alt, and where?

 

I'm not an electrical expert by any means but I don't believe you can increase the output of an alternator by changing the pulley size. There really wouldn't be a reason to make high output alternators if all you needed to do was change pulley sizes on a standard one would there? If I were you I'd go for the high output alternator and save yourself a lot of hassle.

 

Sure You , but it really only affects charge output at idle and other low rpms where the alternator won't be making full output. The issue is whether our not it's that important to you to have higher charge for the time that you spend at idle?

 

i never had a problem with the factory 110 till i installed the u/d pulleys. now i only have the problem at idle, with everything on. if im heading down the road or at anything over 900rpms im fine. if i was to put my factory crankshaft back on and take off the u/d pulleys, i would be fine. all i was doing is trying to get my idle amps back up, by using a smaller pulley.

if i was to install a high amp alternator in atemp to slove this problem i think i would be in the same place i am now, sure the one im look at putting out 110 at idle but the was at the normal idle not with the u/d's.

so if the alternator is only spinning at 600rpms, my factory 110 isnt putting out much, if i get 110 at idle(800rpms) spinning at the 600rpm is it going to put out any more then my factory one is now?

im trying to firgure out if i just want to get a high amp, but if i just change the pulley size and that fixes my issue do i really need a high amp?

see my issue.

 

Get the high output. The second battery is good if you listen to your stereo or use equipment (lights, etc) with the engine off; while the truck is running the stock alternator is trying to maintain a charge on that second battery as well.
I'm curious how you're pulling 4,000 watts out of a 110A alternator? 1,400 RMS watts would pull around 180A of current, and that isn't even taking into account "peak" power demands from the amplifiers. Just saying.
Bottom line...you need as big an alternator as you can get....

J.
2004 XLT 2WD Scab flareside, 220A, k&n cai, banks monster, edge evo

 

I think people are missing the point that with the UD pulleys installed you are not turning the alternator at high enough RPM to create necessary output. If you are creating enough power at speed when the alternator is at proper RPM then you can get by with decreasing pulley diameter to increase alternator RPM. It sounds like you are on the top edge of power demand/output though and going to a HO alternator would probably be better and not require the pulley change.

 

Its basically like a pulley change on a supercharger. The smaller the pulley the more boost and the faster boost is aquired. Correct me if im wrong

 

Some HO altenators do come with the overdrive pulley.....reason in part to achieve the higher output....