Proton has announced today that the Proton X50 will have a claimed fuel consumption of 6.4-litre/100 km for the 1.5 TGDI (177 PS/255 Nm) engine variant and 6.5-litre/100 km for the 1.5T MPI (150 PS/226 Nm) variant. The tests are done using the NEDC (New European Driving Cycle) method.
Yes you read that right. The more powerful engine is more fuel efficient. Why? Because the 1.5 TGDI engine uses direct injection while the 1.5T MPI engine uses port injection.
We also know that the Proton X50 has a 45-litre fuel tank, which means that the X50 has a theoretical maximum driving range of 700 km for the 1.5 TGDI and 690 km for the 1.5T MPI. Keyword: theoretical.
Realistically, you can expect to do no more than 600 km in real-world driving conditions.
Also, real-world fuel economy performance of turbocharged engines can differ very significantly from their laboratory test results, more so than naturally aspirated engines, even if you take into account the driver factor. The reasons behind it has been explained in this post.