The difference between an 8 wrap and a 10 wrap coil tattoo machine lies in the number of turns of wire in the coils. An 8 wrap configuration has two coils, each with eight turns of wire, while a 10 wrap configuration has two coils, each with 10 turns of wire. The number of wraps affects the machine's voltage, with more wraps resulting in a higher voltage. Higher voltage machines tend to be faster and more powerful, while lower voltage machines are slower and better suited for fine details and delicate lines.