The "PLUS" is for an extra additive package above and beyond a normal 20/50 racing oil. This formula was developed and perfected through three years of track testing to specifically reduce heat and subsequent wear in short track NASCAR racing. The 1996 season proved it to also be the oil of choice by many crew chiefs in the TOP ALCOHOL divistion of NHRA and IHRA. The user can expect high lubricity, lower oil temperature (up to 40 F) and a stronger protective additive film that stands up to racing fuel dilution at least 50% longer than other racing oils. Excellent of course, for normal highway usage.