Change car performance (edit files)

Hello,
I want to play around with some files related to the performance of cars but I cannot get the results I want.
I have copied the files I want to change in the Documents\BeamNG.drive\vehicles folder (sub-folder with vehicle name) and I can change for example the name of the engine and it changes in-game too so everything should work.
The problems I have are:
How can I change gear ratios? Adding gears works but I cannot find the right settings for gear ratios.
How can I add more rpm? If I set maxrpm of the engine to a higher value nothing happens in-game at the speedometer.

 

You need to change revLimiterRPM...