Pulleys

[blacksnapon]

Wow, my debate started a big time storm. Listen, to stop the arguing, if i can afford the pulleys, il buy them. If i like them they stay, if not then il say wow i should've listened and im a huge moron. Then re sell them... I talked to my buddy who i help do engine performance work and he says it would probably be a bit better, but not much. Il be the judge of that. My money. Thanks for everyones .02 cents, sorry it had to get so angry.. Mike

All accessories rob horsepower because they take power from the crank to turn them (ever been in an escort when the a/c kicks on?). The underdrive pulleys use "gear reduction" to reduce the parasitic draw. If the crank pulley is smaller, and the accessory pulley is larger, less power is needed to get the accessory turning. The downside is, the accessory isn't as efficient. The alternator doesnt turn as fast, the a/c wont cool as well, and the p/s is closer to "armstrong". Most generally, you'll gain about 2-5 horsepower.

 

[Mr. Stroker]

im hoping for a tad bit better mileage. I know when my compresser turns on in my bronco the idle will go down..

 

[eco]

im hoping for a tad bit better mileage. I know when my compresser turns on in my bronco the idle will go down..

Isn't there a sensor that kicks the RPM up a tad when the AC kicks on? I know the power steering pump has something like this. Once pressure reaches a certain point, the RPM goes up.

My solution for reducing parasitic load is to GET RID of the accessories all together. I have no PS pump, AC, air pump and mechancal fan.

 

[frederic]

Eco,

When the AC kicks on the idle RPMs should increase by about 100 or so.

 

[Bob Ayers]

Isn't there a sensor that kicks the RPM up a tad when the AC kicks on? I know the power steering pump has something like this. Once pressure reaches a certain point, the RPM goes up.

My solution for reducing parasitic load is to GET RID of the accessories all together. I have no PS pump, AC, air pump and mechancal fan.

The PCM senses when the AC compressor kicks on, and opens up the IAC valve to keep the idle speed constant (or slightly higher depending on the compressor head pressure) with the additional load of the compressor.