The 1.3l Motor in an Rx-8 is a 'Rotary'. For one complete 'stroke', the crank moves 720degrees for our cars (intake, compression in 360 degrees and combustion and exhaust in the other 360 degrees). The Rotary however does the whole in half the movement. That is only 360 degrees.Therefore in a sense when comparing the rotary to a standard 4-stroke cylinder internal combustion engine, you should take the rotary as 2600cc. Which eventually means that the fuel consumption of a 1.3l Mazda Rx-8 will be higher.