The Challenger 650 does not have FADEC, but there are engine controls and mechanical systems in place that affect how your lever position controls the engine.  The most common issue seen reported with the simulation is the engines are not making "full power", or rather not achieving the rating on the N1 EICAS display. The reason for this is the engine has an N2 limit which varies based on total air temperature, which depends on aircraft speed and temperature. The TAT is shown on the PFD lef