I have the underdrive pulley currently installed on my TL and am currently looking at getting a system for my car.

12" Sub:

# 4-ohm total impedance
# power handling: 50-150 watts RMS (300 watts peak power)
# frequency response: 26-250 Hz
# sensitivity: 86 dB

and most likely a 600W amp (I will not utilize all of this power obviously).

Will my underdrive pulley / alternator have problems powering this stuff with a smaller pulley?

 

PM Excellerate. I think UR limited it to 650 Watts.

 

Same question I have. Does the regular size OEM diameter UR pulley really help?

I have a 500wrms @ 4 ohms mono sub amp with a 1.5 farad Cap. Would the underdrive pulley be OK with this sub amp? Also must consider that the 1.5 farad cap is like a small battery, it helps alot.

What should I get?

Thanks and sorry for a simple question, and yes I have been searching/reading on this.

WOW 180 ft/lbs.

 

its on with 181 foot pounds torque ~

And yes the underdrive can handle up to 600 watts
Beyond that---- the problem is the alternator is turning slower, so less output at idle.
You may have noticed the ac not as good at idle but everything is fine once moving.

The standard alt doesnt make enough power to run the cars electrical needs and the stereo at full draw.

Make sure you have a good battery and enjoy!

 

The stock diameter UR pulley was still like 7 lbs lighter and a difference of 1 hp (or freed hp) than the underdrive. I wasn't hot on the idle effects on the alternator and with the stock one theres no need to replace the belt.

there was a place around town that would add windings to your alternator so it would handle a bigger load. it was cheap, too

 

600 watts RMS is the limit for the underdrive pulley.