How to positionne exhauss smoke pls help?

Hi all
How to position correcly the default fx_engstrt effect on the aircraft.cfg :-/
or if i made my how fx_engstrt_pl8 for example how i position it whit the aircraft.cfg file
How to position correcly the default fx_engstrt effect on the aircraft.cfg :-/
or if i made my how fx_engstrt_pl8 for example how i position it whit the aircraft.cfg file