Without a doubt one of the most widely and frequently used RC car motors is Tamiya’s stock 540 Motor.
The motor is produced by Mabuchi Motor Co. LTD, based in Japan. If you would like to know Voltage, Speed, Efficiency, Watt etc. to calculate your R/C cars speed and performance then this official 540 Motor product spec PDF might just what you are looking for.
You may need Adobe Reader to view the file.
Not sure what to make out of these numbers and how to calculate how fast your R/C car, buggy, truck should go? Look here.