Lubricating oil composition for engine equipped with supercharging mechanism, method for suppressing low-speed pre-ignition in engine equipped with supercharging mechanism using lubricating oil composition, and method for manufacturing lubricating oil composition

A method for producing a lubricating oil composition for engine equipped with a forced-induction mechanism, the method comprising a mixing step of mixing a base oil (A), a metal-containing surfactant (B) containing at least a calcium-containing surfactant (b1), and at least one basic compound (C) selected from the group consisting of a metal carbonate, a metal hydrogencarbonate, a metal hydroxide, and an amine-based compound, wherein the mixing step is performed so as to satisfy the following mixing conditions (1) to (3):

• <Mixing conditions>
• (1) The sulfur content contained in the metal-containing surfactant (B) is 0.2 mass % or more on the basis of the whole amount of the metal-containing surfactant (B);
• (2) The content of a calcium atom is from 0.08 to 0.20 mass % on the basis of the whole amount of the composition;
• and
• (3) A mass ratio of the content of the basic compound (C) and the content of a calcium atom derived from the calcium-containing surfactant (b1) [(content of (C))/(calcium content derived from (b1))] is 2.0 or more;
• wherein
• the amine-based compound included for selection as the at least one basic compound (C) is selected from the group consisting of ammonia, a metal-free dithiocarbamate and an aliphatic amine-based compound selected from the group consisting of an amine compound (c1) having one or more hydroxy groups and one or more amino groups represented by the following general formulae (C1), (C2), (C3) and (C4);
• an amine compound (c2) having two or more amino groups represented by the general formula (C3) or (C4);
• and an amine compound (c3) having only one amino group represented by the general formula (C5),
• wherein
• R1, R10, R11, R16, R29, and R47 are each a hydrocarbon group having a carbon number of 1 to 32, and R10 and R11 may be the same as or different from each other, such hydrocarbon group being saturated or unsaturated, aliphatic or aromatic, and straight-chained, branched, or cyclic,
• R2 to R9, R12 to R15, R17 to R28, R30 to R45, and R48 to R49 are each independently a hydrogen atom, a hydrocarbon group having a carbon number of 1 to 18, or an oxygen-containing hydrocarbon group containing an ether bond or an ester bond, the hydrocarbon group being saturated or unsaturated, aliphatic or aromatic, and being straight-chained, branched, or cyclic,
• a, b, c, e, f, g, j, k, w, and m each represent an integer of 0 to 20,
• d, h, and i each represent an integer of 1 to 6,
• (a+b) is 1 to 20, (e+f+g) is 0 to 20, and (j+k+w+m) is 0 to 20.