Cars don't need easystart of 5 degree timing, this is only for us to start the engine easy.
Cars have enough power out of the batterij and use a powerfull start engine to spin the engine around.
Modelengine have also low pressure, so the petrol don't burn very easy as do by high pressure engine.
BTW, race engines have a hole differend ignitioncurve then jigsaw / weedeaters have.
Most of the people don't use a start engine but start the engine by hand, thats why we need easystart.