Colleague greybox - if we are talking about the nod Doupas 7.0 - is either good enough to not combine anything sys.txt (though for other skin's as well).
Most of the skins have a built-in options Speedometer - Doupas 7.0 is no exception.
Go to navigation menu / more / show on map / i:
you have 2 choices:
penultimate position - normally off (tap is on) - Speedometer,
somewhere in the middle - Optional large speedometer - a normally off.
Just turn on one or the other and you get what you wanted
If you want to have a velocity saver or HUD - you have maps Settings / Screen Saver Settings - and here !!! you set what you want to see.
Nothing in sys.txt and sequences because they do not need