Small, high power density turbocharged engines coupled to kinetic energy recovery systems are one of the key areas of development for both passenger and racing cars. In passenger cars, the KERS may reduce the amount of thermal energy needed to reaccelerate the car following a deceleration recovering part of the braking energy. This translates in a first, significant fuel energy saving. Also considering the KERS torque boost increasing the total torque available to accelerate the car, large engines working at very low brake mean effective pressures and efficiencies over driving cycles may also be replaced by small higher power density engines working at much higher brake mean effective pressures and therefore much higher part load efficiencies. In racing cars, the coupling of small engines to KERS may improve the perception of racing being more environmentally friendly. The KERS is more a performance boost than a fuel saving device, permitting about same lap times with smaller engines. The actual fuel saving is therefore only the one of the smaller thermal engine having less thermal power. New F1 2014 power train rules may pave the way for a fuel economy KERS development for racing that may also be beneficial to road applications. The paper presents 2014 F1 engine and KERS hypotheses and simulation of lap times.