Perhaps this chart from Tekin can be of some help, also assuming you are asking about 1/8 electric. My personal experience-opinion is even the low side of these recommendations are plenty for racing. An under powered 1/8 electric is nearly unheard of.
Tekin T8 Voltage Recommendations Chart
Last edited by Dave H; 07-14-2013 at 04:13 PM.
Reason: 1/8 class assumption