I wasn't sure because the most cars are up to 50L-60L. I guess older cars are less fuel efficient. Desregard my poor knowledge
Are you talking about regular cars? Lots of racing cars in R3E have a tank of that size - 100-120L - and generally you find smaller tanks in lighter cars. I suspect it has more to do with weight distribution/weight change during a race rather than fuel efficiency.
It also depends on the class regulations - typically endurance racing classes allow for around 100/120 litres or 1 hour of fuel, whereas sprint races with no refuelling will have less as there is no need for a bigger capacity and there is a greater fire risk.