Bypass the ac compressor pulley?

You might be able to do that if you use a shorter belt and bypass the AC and the larger idler. As for the size, not really able to say as you would need the exact length that your are bypassing and subtract that from the current belt, then add in the length of the new belt location. To get a close number you could use a flexible tape and measure the path without the idler and AC. You will also need to look at the actual routing to make sure that the different run will clear the other items. What is the reason for the bypass?