Octane requirement increase (ORI) was determined for eighty-six 1981 model cars operated on unleaded gasoline. All ORI values were determined from the increase in maximum octane requirements irrespective of whether requirements were obtained at full- or part-throttle. At 15,000 miles, the mean ORI for all cars with full-boiling range unleaded (FBRU) fuels was 5.1 Research octane numbers, 3.3 Motor octane numbers, and 4.2 (R+M)/2 numbers. At 15,000 miles, the mean ORI for seventy-four cars with full-boiling range high sensitivity unleaded (FBRSU) fuels was 5.2 Research octane numbers, 3.6 Motor octane numbers, and 4.4 (R+M)/2 numbers. At 15,000 miles, the mean ORI for seventy-four cars with primary reference fuels (PRF) was 4.1 octane numbers. Compared with 1980 models (120 cars), the mean ORI for all cars in the 1981 program with FBRU fules was the same on a RON basis, and 0.1 MON higher. In general, the mean ORI with FBRU fuels has not changed appreciably for the 1975 through 1981 model cars. ORI decreases about 0.2 to 0.3 octane number per octane number increase of initial octane requirements; this relationship is statistically significant.

  • Supplemental Notes:
    • Prepared by the 1981 Octane Requirement Increase Analysis Panel of the CRC Light-Duty Octane Technology and Test Procedures Group. CRC Project No. CM-124-81.
  • Corporate Authors:

    Coordinating Research Council, Incorporated

    219 Perimeter Center Parkway
    Atlanta, GA  United States  30346
  • Publication Date: 1983

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: v.p.

Subject/Index Terms

Filing Info

  • Accession Number: 00387835
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: CRC 535, HS-036 540
  • Files: HSL, TRIS, USDOT
  • Created Date: Aug 30 1984 12:00AM