i just found out somehting. and i am not sure if this is already known.
if i hit turbo/nitro every 3 or 4 seconds, the speed remains as high as if i am holding turbo key, yet the nitro fuel is barely used. as a result you can do most tracks with full speed (250 i believe) with hardly any nitro used. the onyl thing stopping you is the bouncy ball, but in time race even that one is not there.
i believe it might be better if turbo was handled like that speed up power up - i.e. one time burst of energy.
otherwise great game! looking forward to any improvements. wish someone made SuperKarts (the old DOS game) mod.