Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site zehntel.UUCP Path: utzoo!watmath!clyde!floyd!vax135!houxz!houxm!ihnp4!zehntel!zinfandel!joe From: joe@zinfandel.UUCP Newsgroups: net.auto Subject: Re: Octane ratings, 1973 vs 1984 - (nf) Message-ID: <1541@zehntel.UUCP> Date: Tue, 19-Jun-84 04:21:17 EDT Article-I.D.: zehntel.1541 Posted: Tue Jun 19 04:21:17 1984 Date-Received: Thu, 21-Jun-84 07:13:07 EDT Sender: root@zehntel.UUCP Organization: Zehntel Inc., Walnut Creek, CA Lines: 23 #R:qubix:-119300:zinfandel:3200067:000:979 zinfandel!joe Jun 14 08:44:00 1984 Hi. What I know on the subject is that the motor method is the older of the two systems, and is still used. It involves a standard single cylinder engine run just hard enough to make the fuel tested detonate. This level of engine output is compared to the performance of pure octane, a relatively good performer. For exact percentages they find the percentage of octane in a mix of octane and pentane ( a very willing knocker ) that performs as well as the tested fuel. Fuels of other composition can perform better than pure octane so "150% octane" gas is possible. The other method "rational method" is a sophisticated chemically based formula for calculating the knocking potential, again as compared to pure octane. As the variables involved in knocking are many these are both guides but not absolute predictors. In practice they are consistant however, and usually don't vary for the same fuel by more than one or two points. Joe "I HEART MY DOG'S HEAD" Weinstein