Quote from wark :

....

Also, my real car seems to know exactly how much fuel it's using (live MPG readout and "miles left in tank" display), and of course the tank capacity is no mystery, so I don't really see why you shouldn't be able to see how much fuel you have in the tank, digitally, more precisely than 1 litre increments.

I always thought the MPG gauge was essentially just a manifold pressure gauge that also took into account the car's speed.

Quote from amp88 :

Just reading an Ayrton Senna biography and there's a small, interesting quote on the teams calculating fuel consumption. In 1988 the McLaren Honda test driver Geoff Lees said that their fuel consumption could be calculated to within 200 metres over a Grand Prix distance. That's 200 metres out of over 300 kilometres (0.067%).

Eddie Irvine also said he lapped round Silverstone in a Formula Ford faster than Jim Clark in a Lotus 49 (apart from they raced on completely different layouts there was no way he could have been anywhere near the 49, especially not with Clark driving it). My point is I don't believe one quote by a test driver over everything else I've seen and heard over this issue. Maybe in testing it was possible to predict fairly accurately but in a race you ultimately have far more potentially unexpected events, problems or changes of conditions that all change your driving style and fuel consumption slightly.

Quote from tristancliffe :

Who cares whether it's 15lites or 15%, all you are looking at is the 15 bit.

I think it's more natural, using standard units like liters or kilograms than using a relative unit like % of the tank capacity.

It's a minor detail and I can live with it, but it makes sense.