Good work, to be perfect, need change gear ratios.
I made some tests, to begin...:
(Requires adjust at final drive for each track)
gear_1st 3.6
gear_1st_downshift_multiple 0.675
gear_2nd 2.41
gear_3rd 2.21
gear_4th 2.01
gear_5th 1.88
gear_6th 1.64
gear_7th 1.46
gear_8th 1.28
gear_all_downshift_multiple 0.86
gear_change_throttle_off_time 0.05
gear_change_throttle_on_time 0.05