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Re: Coolant/Horsepower

To: rpalmer@ames.ucsd.edu
Subject: Re: Coolant/Horsepower
From: brockctella@juno.com
Date: Fri, 25 Sep 1998 07:24:28 -0700
Bob, obviously the manufacturers put antifreeze in for its freezing
propperties,

On Thu, 24 Sep 1998 20:43:52 -0700 Bob Palmer <rpalmer@ames.ucsd.edu>
writes:
>Dave, et Listers,
>
>I still stick by my previous story on this subject. One question you 
>can
>ask yourself is what do most auto manufacturers put in their new cars? 
>Most
>of these car manufacturers are not like Brad Parlee, "just looking for 
>a
>way to spend more money" when they fill their radiators. In fact, 
>these
>guys wouldn't part with a nickel they don't have to. If distilled 
>water,
>even with additives, actually worked as well as water/glycol mixtures 
>I'm
>pretty sure that's exactly what they would be using. BTW, does anyone
>happen to know the prescribed mixture for any standard production car? 
>From
>what I've seen, they must use at least a 50% glycol. Now certainly 
>factors
>included in the choice of coolant includes corrosion and, yes, maybe 
>they
>want to be able to sell you coolant at $5 a gallon instead of letting 
>you
>just fill it up with water. But the manufacturers have performance
>standards that have to be met, and using a less efficient coolant 
>would
>mean having to compensate with a larger (more expensive of course)
>radiator. Not a smart economic tradeoff I think. For most racers, the 
>use
>of glycol coolant is prohibited and straight water works quite well 
>enough.
>They usually use additives  like water wetter and higher pressure caps 
>to
>help compensate. Besides, if your engine gets over 245 degrees, it's
>probably time to pull over before you do some real damage anyway.
>
>Incidentally, I believe if memory serves me, that it is the heat 
>capacity
>of water that is 2.4 times that of glycol, not the thermal 
>conductivity. In
>any case, the thermal conductivity is a very minor parameter, much 
>less so
>than the heat capacity.
>
>Taking a sharp detour to another remotely related subject, I ran 
>across an
>empirical formula for calculating horsepower based on quarter mile 
>speed in
>a car magazine recently and thought, if you haven't seen it, you might 
>find
>it useful. Here it is:
>
>               h.p. = (q.m.speed/234)^3 * weight
>
>For example, if your car does 105 mph in the quarter mile and weighs 
>2600
>lbs, then:
>
>               h.p. = (105/234)^3 * 2600 = 235 horsepower
>
>They didn't say, but I assume from the answer that they mean net 
>horsepower
>at the rear wheels. So, save yourself the trouble and expense of a 
>chassis
>dyno and go run a quarter mile and not only get the answer, but have 
>more
>fun to boot!!
>
>Bye for now,
>
>Bob
>
>At 07:24 AM 9/24/98 -0700, Dave Binkley wrote:
>>Saw the following in the May 98 issue of Car Craft and have been 
>meaning to
>>post it.  The recent postings reminded me to go dig the mag out and 
>send
>>this along.  The article was entitled the "25 Lies Car Magazines Have 
>Told
>>For Years".
>>
>>"Lie Number 9: Glycol-based antifreeze is the best engine coolant.  
>The
>>Truth: Plain water is the best coolant.  Water has 2.4 times greater 
>thermal
>>conductivity than conventional ethylene-glycol-based coolants. Glycol 
>is
>>also much more viscous than water, and the more viscous the medium, 
>the less
>>the heat transfer rate.    Glycol has a higher boiling point than 
>water, but
>>even when using a 50/50 water/glycol mixture with a 15-psi radiator 
>cap,
>>glycol's boiling point is only 15 degrees more than plain water.  If 
>you
>>have a marginal cooling street car, try reducing the amount of glycol
>>antifreeze in the system and increasing the water content.  A  33 
>percent
>>glycol/water mix won't freeze until 0 degrees F.  On a race car or 
>street
>>car not subjected to freezing temperatures, consider running only 
>water as a
>>coolant."
>>
>>They go on to mention how ordinary tap water is extremely corrosive 
>and try
>>to use distilled water.
>>
>>Dave
>
>Robert L. Palmer
>Dept. of AMES, Univ. of Calif., San Diego
>rpalmer@ames.ucsd.edu
>rpalmer@cts.com
>


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