Hey @Rangerr, the engine size is generally the volume of fuel and air that can be pushed through a car engine's cylinders and is measured in cc. On that line, the size of the Maruti Suzuki Celerio Engine Size would be 998 cc and in terms of liters would be 1 Liter. What you are asking Is the dimensions of the CNG engine. While I do not know the dimensions, I know that the tank size will be relatively smaller than a petrol engine. And roughly the CNG engine would take up about half your boot space.