That also makes sense, on my parents 05 f150, when the alternator went out, they were like an hour from home, at night. When the head lights started to dim, he would have to put it in neutral rev it up some and it would then charge the battery. Then he would pop it back into gear and get a couple more miles.

Although you said the ALTERNATOR was good, how about the wires coming/going to the alternator, possible problem there.

 

Maybe I'm being dumb after a long day at work... but when you go UD crank pulley, don't you go SMALLER Alt pulley to spin it faster - not bigger?

 

Well the problem was present before and after the alternator swap.. The new alternator is the PA performance 130amp alternator.. We also changed out the battery for a known good battery.. I also had installed the PA performance power wire kit which uses a better quality and thicker power wire.. He said he checked all the power and ground cables and everything was hooked up right and looked clean and good... I am going to have to look into the underdrive pulley and see if thats a possibility..

 

Ive had the same thing rolling through my head all day actually...lol. I think if it went to a bigger pulley it would spend faster at the spindle. Because the belt moves at a constant speed, so therefore the farther it is from the spindle, the faster it will be spinning at the spindle. Similar to say car tires, a mustang, with say 19" rims, will read higher speed than a car with say 16" rims. assuming you dont get it calibrated. I think this is right, its made sense in my head :P

 

Smaller drive pulley needs larger accessory pulley. Just picture the gears on a bike.

 

Smaller stuff spins faster at the same road speed.

 

Then why do I put a smaller blower pulley on to spin it faster?

 

Smaller = faster

 

Ok the UDP is a smaller Diameter. Theirfore it has less circumference.

That means, when at the same rpm as before, the the pulley will make more revolutions per minute then the stock pulley, but its turning the belt at a lower rpm due to the less curcumference. So now since the belt isn't going as far, the alternator isn't turning as fast. So if you need the alternator to turn faster, you make the distance it has to turn to make a complete circle smaller. How ? Smaller Pulley.

Same concept with the SC pulley. If you want to turn the supercharger faster, you make the distance it takes to make a complete revolution shorter (circumference).




So if you have 2 Pulleys the same exact size turning at 600rpm. They are both turning at 600rpm. If you half the circumference of 1 pulley. It will turn 2 times to the 1 turn of the other. So one will be at 600 rpm, and the smaller one will be at 1,200 rpm.

In that case, your crank pulley is the 600rpm, and a new smaller pulley on the supercharger is the one half the circumference that turns twice as fast.

 

Get it ?