Huhu,
This script was eigendlich integrated into my Fliegl transporter Pack as a global mod. But popular request I made of it an extra mod. As long as the aaa_IncreaseRPMWhileTipping.zip in modfolder is, the script for the speed increase from the Transportation Fliegl pack is no longer loaded. But it is important that loads the aaa_IncreaseRPMWhileTipping.zip previously, therefore NOT rename this please. This mod makes sure that the speed of vehicles increases, if you emptied a trailer. Even the IT Runner DLC is now supported. So now the speed increases even when taking a container or lowers.

Reviewing the xml entry:
You can now adjust the values ??in 2 ways. Either globally via the modDesc the aaa_IncreaseRPMWhileTipping.zip, or local in Fzg.xml.
Entry looks like this:

Once this entry is included in the Fzg.xml, the entry is no longer valid in the modDesc for the associated vehicle.
First day:
maxRpm="2000"
This value determines how high the speed when tilting it.

Second day:
exhaustColor="0 0 0 6"
This value determines the color of the exhaust gases. If the black should not be so strong visible simply the '6' decrease.