Hi, it will depend how big is or are brakes you use ,it will heats more or less, depend of the time you are pulling cars, how many hp has the car you are testing, how many seconds you are holding at 100% Thottle ,etc.

i dont think all dynos using eddy brakes controll these, just dynapack or another dynos that use hydraulic brakes. first time when i was building my dyno , i was thinking to add an external temperature ultrasonic sensors for log these but didnt find a ultrasonic sensors for good price then i left it as it, never had problems with these, i meansm didnt noticed problems with brakes , for example, as you will know, eddy brakes torque are affected by temperature..maybe if you use small brake and for tune a car, i means tune a car but take it stationary mode for some hours, +30 pulls etc, as i do normally, you could notice your brakes need more % of braking.