(Discussion)Most effient voltage??

[MetalMan]

Perhaps you'll find this useful:
http://img.diytrade.com/cdimg/85838/...1082223033.jpg
I'm pretty sure the amp draw listed is where the motors are most efficient (they mean nothing for RC cars, though).

As the kv goes down, the resistance goes up, which means lower amp draw (indicated in the chart). As kv goes down, voltage should also go up. All of the XL motors are capable of producing the same power, but the 12XL would heat up less if it is spinning at the same RPM as an 8XL.