Larger pulley (what impact will it have)

[Trueoo7]

Bought a set of serpentine aluminum pulleys but they did not make one for the a/c eliminator pulley. Finally found one and sent away for it but its 4 1/4" compared to the stock 3" one. What if any effect will this have on the water pump and alternator. Will I need to worry about overheating or undercharging?
Thanks
True

[427sharpe]

A larger pulley slows the rotation of the part it is on...a lg alt pulley will spin an alt slower, producing less charge at high rpm. On a street car, I would keep the stock pulleys unless you are going to rev pretty high all the time. Esp on the h2o.

[Bruce Edwards]

First off the ac eliminator will have no effect on engine drag as it is just another idler pulley.
The thing to remember about pulleys is that on an engine it is the relationship between the crank pulley size, (drive pulley), and the driven pulleys.
Think of it as a 10 speed bike. The closer the pulleys get to each other the slower the driven pulleys turn.

[zipzip]

the ac eliminator will have no effect

Pay attention to what Bruce said... Unless the pulley is actually connected to something, it does nothing but increase the belt length needed to wrap around everything.

The ratio between the driving pulley (crank) and driven pulley (alt or pump) is the ratio you should be concerned with.