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From: bhs@siemens.UUCP
Newsgroups: net.auto
Subject: Re: What kind of gas to use?
Message-ID: <25300012@siemens.UUCP>
Date: Tue, 26-Feb-85 09:07:00 EST
Article-I.D.: siemens.25300012
Posted: Tue Feb 26 09:07:00 1985
Date-Received: Thu, 28-Feb-85 12:47:37 EST
References: <2120@pegasus.UUCP>
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Nf-ID: #R:pegasus:-212000:siemens:25300012:000:1610
Nf-From: siemens!bhs    Feb 26 09:07:00 1985



Mike:

I owned a 1970 Mercury Marquis for a while (429CID).
It also wanted 99 Octane. You must bear in mind that the octane measurement was
changed slightly, so that in fact with today's system, your car does not need
99 octane, but slightly less (could 95 be right?).

One trick I routinely did: mix, by volume, two parts unleaded premium with one
part leaded regular. While gas station attendants may give you funny looks, the
net effect is to increase the octane level of the resulting mixture above that
of the unleaded premium. Thus, try 10 Gal. premium and 5 Gal. Reg. You should
experiment a little, maybe the optimum ratio is 1:4. The real advantage of
increasing octane is really only noticed if you reset your timing accordingly.
This, however, will imply consistently using the mixture, or at least premium.
By advancing the ignition point of your ignition, you permit the engine to burn
the fuel mixture longer, ie. more efficiently. The way to do this: slowly
advance ignition until the engine starts to ping under heavy acceleration at
low RPM. Then, just retard slightly to make pinging go away.
I would carry this logic one step further: if I was going on alonger highway
cruise, I would overadvance the ignition, so that I was not able to use full
power without wrecking my valves, but while I could no longer rocket up hills
or make wild passes, I would get an honest 20 mpg at a constant 60 mph. Around
town, of course, my mixture would plummet to around 10-12, and with
overadvanced ignition, I always had to be easy on the accelerator.

			Bernard H. Schwab
			Siemens RTL, Princeton, NJ