Maxima Hi Test fuel additive (473 ml)

Maxima Hi-Test is a concentrated octane booster. It raises the mixture's resistance to auto-ignition, which eliminates engine knock. It contains no metals or phosphorus and mixes with all fuels. The manufacturer states an effect from about 1 oz per gallon, roughly 8 ml per litre. It makes sense for higher-compression engines and tuned two-strokes when race fuel is not at hand.