Cheaper than a UDP.
The drag on the engine is SIGNIFICANTLY less when the A/C clutch is disengaged and when the alternator has no load.unclesam099 said:esc, that's the underdrive pulley working for you.
WD, do you have some before/after timeslips? i personally ran my car without power steering for about 3 weeks and didn't notice any gain in power at all. i highly doubt that you will lose .3 without a belt, which is very important to make your car run right!! i'm surprised that your car didn't die on you when you were running on the battery!!
oh, and just because the electrical power to the alternator is disconnected, the belt is still turning the alternator and the A/C pump!!!