The API SP rated RP is almost a mirror image of Valvoline Advanced synthetic in terms of both ICP analysis and performance tests. Aside from the dye, they're essentially the same formula. HPS mirrors Valvoline VR1 synthetic. RP hasn't been a boutique brand the past decade. After the founder died and Calumet took over, things started going downhill. The dye is my biggest issue with them. Too many engines running RP end up with the engine internals looking like it purred Barney's corpse.
Ford Cyclone engine with ~80,000 miles total, ~60,000 miles on RP. All of that is from the dye.
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