Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
octane [ˈɔkteɪn] n окта́н
high-octane petrol or (US) gas бензи́н с высо́ким окта́новым число́м
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.