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From: neal@weitek.UUCP (Neal Bedard)
Newsgroups: net.auto.tech
Subject: Re: Gas Mileage
Message-ID: <373@weitek.UUCP>
Date: Mon, 27-Jan-86 16:13:29 EST
Article-I.D.: weitek.373
Posted: Mon Jan 27 16:13:29 1986
Date-Received: Wed, 29-Jan-86 04:10:24 EST
References: <576@adelie.UUCP> <103@dg_rtp.UUCP> <372@watmum.UUCP>
Organization: Weitek Corporation, Sunnyvale
Lines: 45
Summary: Particularly nasty weather...

In article <372@watmum.UUCP>, gvcormack@watmum.UUCP (Gordon V. Cormack) writes:
> 
>    (1)  Until the engine is completely warm it must run with the
>         mixture enriched (choke on) in order to get enough vaporized
>         gas to the cylinder to burn.  This extra gas is wasted.
>           
>    (2)  The tires, bearings, and transmission are stiffer in cold
>         weather.  However, this effect is much less significant than
>         (1).
> 
>    (3)  Many people let their cars warm up in cold weather, wasting
>         gas.  Also, many people take more short trips in cold 
>         weather.

Three more:

	(4)	In snow: wheelspin decreases mileage (the original question
		was from MA, no?)

	(5)	In rain: additional rolling resistance due to water being
		pushed aside by the tires decreases mileage (applies to
		fresh snow as well.)

	(6)	In any foul weather: spending more time driving in lower
		gears (since safe speeds are reduced) decreases mileage. Also,
		spending more time coping with dense traffic has a like effect 
		(alludes to (3) above.)

The higher air density/ water content arguments are insignificant (in any
event, both would *increase* mileage) unless one is discussing the effects
of turbochargers with and without intercooling and/or water injection.

[Anyone remember that snake-oil ad for the `water injector' that J.C. Whitney
used to sell? They used to say "Ever notice how much better your car runs in
a dense fog... etc.?"]

The crux of the biscuit is that wintertime driving habits (including engine
warm-up) are the only significant reasons for lower winter mileage. Notice
that some people seem not to encounter this. I suspect that members of this
group live in places where the winters aren't so severe.

-Neal
-- 
"If I owned half of that dog, I'd shoot my half." -Pudd'nhead Wilson 
UUCP: 		{turtlevax, resonex, cae780}!weitek!neal