BLDC Outrunner Motor Windings
A Wye connected BLDC motor will have a \$K_t\$ that is \$\sqrt3\$ larger than a delta connected motor (assuming they are wound exactly the same.  This means that delta connected motors will run faster for a given voltage and produce less torque for a given current.  

The only issue you may run into with delta connected windings is that each phase needs to be identical in resistance or you can get circulating currents that don't produce useful power (making the motor less efficient).