SR2 engines define fuel efficiency by "Fuelconsumption"??

@WNP78 I mean it shouldn't be so. Moreover fuel consumption should be mass, not volume.

@AnotherFireFox
fuelConsumption is the amount of fuel it consumes in some kind of unit per second (not sure what the unit is but it's the same one used to set fuel on fuel tanks, possible litres but I'm not too sure)
fuelConsumptionScale is the slider you get in the designer which affects not only the fuel consumption but the thrust.
thrust is literally the thrust given out by the engine at full throttle.
ISP is calculated based on the first and last value.

@WNP78 I mean it should be in physical values like isp or exhaust velocity.

Full list of engine xml options:

electricalConsumption type=float
fuelConsumption type=float
fuelConsumptionScale type=float
gimbalRange type=float
maxGimbalAngle type=float
maxTorque type=float
seaLevelEfficiency type=float
supportsWarpBurn type=bool
thrust type=float
vacuumEfficiency type=float