I was wondering if I cold get a slightly larger crank pully to make the the alternator and water pump spin a little faster. Heres my reasoning for this. When I sit at a stoplight for about a minute or so my headlights will dim, my turn signals will slow down dramatically, the wipers will slow down and the voltage will drop off to about 11V sometimes less depending on what all I have running. I also noticed while sitting there the coolant temp will also go up a little higher. I want to make it so either I speed up the alternator a little bit with a smaler pully on it or speed everything up with a larger crank pully. Im just tired of sitting at stoplights on rainy nights with everything running and you can hardly tell I want to turn because my signals blink so slow and my headlights go dim which is rather annoying. I know that it lies in the speed of the alternator because if I rev up to about 1100rpm its fine but as soon as it hits back down at the 550 idle range it acts up like this.

 

You could just get a higher output alternator...and save the power for when you need it.

 

You can and it will work good, but i don't know if you will be able to find one.

 

maybe your belt is stretched or not tight enough and so it is a bit loose and slipping a little bit...? I'd try tightening your accessory belt in before you go buying a new alternator.

 

If it were loose, it would be slipping at upper RPMs. It would "grab" better at lower RPM's when there isn't much load on the engine.

Take the car to like Autozone. They test the charging system for free.

 

the alternator charges fine. I am a mechanic and have teseted it at the reccomeneded 2000 rpm with it loaded and it puts out 108 amps or so and stays over 12 volts like its supposed to do. The only time its a problem is at an idle so it tells me the alternator isnt spinning fast enough to keep up with the other stuff being ran like the lights wipers heater and the ac clutch when its on defrost. all I need to know really is if anyone knows where to get a smaller diameter pully for the alternator or a larger one for the crank. Ive checked for everything you guys have mentioned plus I put a new battery in it because I thought maybe it wasnt holding a charge very well under load but it still does the same thing.