speed passion reventon stock club race

[jake1*2011]

hi

i bought a reventon stock club race speedo and 8.5t motor combo a couple of days back, put it in the car and it worked fine but a bit a bit slow so i stuck a 5.5t motor on it, now it runs in reverse when i use the throttle, ive calibrated the transmitter and speedo but its still the same

it says in the spec "Max > 8.5t" does this mean nothing faster then 8.5t? if so why are they selling them with faster motors and the same speedo

how can i get this motor running the right way?

thanks