Force overwrite must be disabled to edit the scripts, otherwise all changes will be overwritten with the official version.
Connect to FTP
First the FTP access must be set up:
After this has been set up, you can now connect and open the server folder.
Here we open the following path:
In the config.lua, to disable the speedometer we can edit the following line:
cfg.speedometer = true
Here we simply set "true" to "false" and save the file.
After a server restart the Speedometer Ingame will be disabled.