RB26's move a lot of oil. RB26's move a lot of oil. Its said twice, just to reinforce the fact that RB26's move a lot of oil.
At 8,000 rpm under boost, oil wants to be pushed right out of the valve cover - or sucked into the inlet piping if the car is setup as delivered by the factory. PCV. Positive crankcase ventilation. Sucking all the oil fumes out of the valvecovers and into the inlet of the turbo. The turbo then attempting to compress and spread the oil all over the intercooler piping, the inside of the intercooler, and putting it into the combustion chamber, where it lowers the effective octane of the fuel.