Fuel Effeciency

[Matra et Alpine]

Originally Posted by Misho

is that regardless of gearing ? lets say i go up the hill doing 60 on second gear with 3000 rpm. and then i go up the same hill again doing 60 but this time on third gear with 5000 rpm.
would the first case use less fuel because of the lower rpms ?

It depends on the torque and power efficiency of the engine.
If it's labouring then you'll have unspent fuel due to incomlete combustion - to counter that you need more throttle to get more air/fuel mixture in
For a given speed the accelerator position is a good first approximation