Just the nature of the beast. Had to have all that oil for lubrication and cooling and they (R-2800s & R-3350s, etc.) were not tight-fitting engines. That's why the oil tanks were so huge. 56 gallons as I remember. The 'G' Connie I flew could not carry a full load of fuel because the oil capacity was not large enough. A limitation (fuel/oil ratio) that may no longer exist; I don't know. It only burned about 5 gallons a hour!