With my 905 i made my first pit stop @ lap41. All i'd done to the car was to add a stage4 turbo and Super hard tyres. This was driving at 3 until lap 25 then 2 for the next 10 laps then 1 for the last 6 laps.
My next pit stop was at lap 83, but my tyres could hjave gone for longer... i was out of petrol becuase i didn't fill it to 80.... i stopped @ 71.
With a bit of work i'm sure the 905 could get more than 50laps without pitting
EDIT:
Tried again... Same settings as before, had to pit@lap 48 as the petrol run out. Am going to take the stage4 turbo off to see how that affects it..... be interesting to see if GT4 recognises that a smaller turbo (less flow and less boost) will use less fuel
EDIT:
Tried again... Took off the Stage4 turbo..... pitted @ lap 53. Ah, a nice 2 pit strategy. Unfortunately i finished 3rd by 26seconds. Hopefully a Stage3 turbo should sort that out.
EDIT:
Tried again... Left the Stage4 turbo off.... turned up the pace to 3, pitted on lap 50. I won by about 25seconds.