| abstract |
A lubricating oil composition and method of operating a boosted internal combustion engine with reduced low-speed pre-ignition events and corrosion resistance. The oil composition includes a base oil, one or more overbased calcium sulfonate detergents, one or more overbased calcium phenate detergents, and one or more overbased magnesium-containing detergents. A ratio of ppm of calcium to TBN of the oil composition is less than 170; a ratio of ppm of magnesium to total soap content in wt. % is greater than 700; and there are limited amounts of boron and molybdenum, and all weight percentages and ppm values being based on the total weight of the oil composition. The compositions give low LSPI ratios and pass the Ball Rust test. |