HEY! WHAT ABOUT ME? haha jfwy. so whats the differences between getting an overdrive or underdrive alternator pulley? advantages or disadvantages. wouldnt the overdrive pulley cause the alternator to spin slower, and wouldnt that be BAD if i had a system? wouldnt that be bad regardless. help me out!

 

The underdrive pulley will be for the crank pulley. Installing it by itself will cause the alternator to spin slower...equals lower output....dim lights.....possible low battery. Installing an overdrive alternator pulley will cause the alternator to spin as fast (or about) as stock with U/D crank pulley....equals normal operation assuming no e-fans or monster sound system.

If you have one or both of those upgrades then you might also look at a 145amp alternator. I had the U/D crank & O/D alt. pulley with 130 amp alternator and got slightly dimmed lights when the e-fans came on.

Spinning the alternator faster or slower won't hurt it or electrical system since it has a built in voltage regulator on the output.

 

i have factory electric fans since its an 06 do you think this will affect it in the same way? and how much does one of those alternators cost, and who makes/sells them? thanks

 

Depends on what alternator you have....105amp, 130amp or 145amp? The output should be cast/stamped on the housing.....IIRC. You should be able to go from there. Git r done!!!

 

Since it's my daily driver for now I want to get the best gas milage i can out of it but still have the power too. All of my mods so far have been to add both power and mpg. I'm about to buy a little gas saver 91 Nissan though and then it will just be a weekend driver, strictly for play. I want to keep it street legal but I want it to be one of the fastest little 4.8's around all motor.

Future mods: Corvette Servo (if not a completely race ready built tranny), Cam springs and hardened pushrods, Underdrive pulleys, 3.90 gears, exc. I'll probably own this truck till my 2 year old is old enough and responcable enough to drive it. So I have plenty of time to make it faster. just need to know what the best options for the money are.