I think the title completely says what I need. I use FSX (Flight Simulator X) to simulate flights and while flying the B738 I saw that it consumes much more fuel than the estimated amount, which is calculated by the software. By doing some research in the airplane folder I figured out that the problem is because the wrong Specific Fuel Consumption (SFC) is entered there. And by some research on the net I also found the type of engine that B738 uses. So, right now, I need to know the SFC of the CFM56-7B24/26/27 engine so that I can enter the correct value in FSX.