rF's timing scheme is limited to those 3 sectors per lap. BUT there is nothing stopping you from using multiple laps per loop. If it takes 3 laps to get through one physical loop you would just need to adjust the race length x3. The problem is then comparing sector times, S1,lap1 should not be compared to S1, lap 2... Use my same instancing method as is used for point to point timing.
If you just want to see where you are losing time get Motec, it will break a lap down into turns and straights making it a ton easier to see where you are losing time.