Hi superman77m,
Let me go through an example. Here is a screenshot of the 2009 Turkish Grand Prix.
2009 was the last year F1 had refueling, and we had info about consumption available on broadcast. Based on this pitstop for Vettel, we know that 54 litres = 16 laps (these values are rounded, so we'd need to check multiple pitstops to get an average, but it's not relevant for this example), so 1 lap = 54/16 = 3.375 litres.
For magic data we need to know the mass of fuel. A good approximation is that 1 litre of fuel = 0.75 kg, so 3.375 litres/lap = 2.53125 kg/lap. We multiply this value by 2979 and the result is 7540.627, so the fuel value in magic data is 7541 (rounded to nearest integer).
Istanbul is a 5.338 km circuit, so by our calculations we get that average consumption is around 0.47 kg/km. That means your calculation of 2979 units of fuel per km is exaggerated, it should be 2979 per kg. It's important to pay attention to this distinction.
For modern F1 cars, we don't have refueling info but we have a limit of 110 kg on the fuel tank. Each race lasts at least 305 km, so can estimate fuel consumption as 110 kg/305 km = 0.36 kg/km. Using again Istanbul, we'd then multiply this value by the track length to get kg/lap, 0.36 kg/km * 5.338 km/lap = 1.92 kg/lap, then multiply this again by 2979 and the magic data value is approximately 5735 (in other words, modern cars use around 25% less fuel per lap than those of the V8 era).
Just for completeness I'll also talk about Monaco, which is the only race to run for 260 km. A quick Google search says that teams use just over 90 kg of fuel there, that would yield 0.35 kg/km, not that different from any other race.
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Now about "Fuel Consumption Player" (desc70) and "Fuel Consumption AI" (desc71). Both values are multipliers, with 16384 meaning 100%. "100% of what", you ask: I have no idea (maybe there's some "master consumption" hidden in GP4.exe, but again that's not relevant here). That does mean, however, that a fuel consumption value of 24576 will make cars spend fuel 50% faster, and a value of 8192 will make cars spend fuel 50% slower. To set these I have no better method than trial and error.
Let's say we initially set Fuel Consumption AI to 16384 (100%). Then run an AI-only race, so you can check their fuel level in the steering wheel. Let's say one of the cars starts the race with 28.0 laps of fuel. As this car completes lap number 10, let's say it has 16.2 laps of fuel. So it has spent 11.8 laps of fuel in 10 laps, which means it's burning fuel faster than expected and we need to reduce the Fuel Consumption value. It's good to repeat this process with at least two or three different cars to get a good average, or across different numbers of laps, since there's always some slight variation.
With this data in hand, you can adjust the Fuel Consumption value. We multiply the current value (in this case 16384) by the amount of fuel we expected to burn (in this case 10) and divide by the amount of fuel actually burned (in this case 11.8). The result is 13885, so this is the value we update in magic data. For player the process is the same, except you have to drive it yourself. And if you can get a friend to also drive and be your second opinion then better, since driving styles do influence fuel consumption.
Also refer to the table posted by Soutsen on the previous page for reference values for the original tracks. Fuel Consumption Player is always a little higher than Fuel Consumption AI.
And don't forget that all these calculations assume that fuel per lap (desc48) is correct, so be sure to set that value first.
My unfinished tracks: [
www.grandprixgames.org]
Send bug reports and track editing questions to
f1virtualblog@gmail.com