DeTomaso Mailing List: February 00, Message #275

Hack,

Thanks for the info. Those numbers do indicate much lower cooling 
perfrormance. However, there seem to be advantages in spite of them, 
although they may not apply to our cars. I found this rather 
interesting discussion about NPG on a stock car racing site: 
http://www.stockcarracing.com/tech/coolerhds.html  . Most of the 
problems they're talking about there have nothing to do with street 
driven cars. And perhaps the cooling systems are designed to 
accommodate the NPG characteristics.

In the Evans' info it was the zero cororosion, longer component life, 
etc. that caught my eye. My application, in case you haven't noticed, 
will be in ZONKEY's new 4.6L, which will have more that enough 
cooling from the Pantera's system. 
http://home.earthlink.net/~rbarkley/Pantera .

Thanks again,

Richard

"Hack D. Carsom" <wallroose@hotmail.com> wrote:
>Subject: Re: Anyone heard of Evans NPG coolant? It sounds fantastic.
>Date: Thu, 10 Feb 2000 12:58:57 -0500
>
>Sounds fantastic, but is it.  If you wanted to experiment with 100%
>inhibited propylene glycol you could try the "Seirra" environmentally safe
>stuff available everywhere.  But is it better, or is it marketing.
>
>Lets use some data to cloud the issue.(ASHRAE Fundamentals,Sec 18.7-9)
>
>@ 200 F       Water        Ehtylene Glycol       Propylene Glycol
>
>heat cap
>btu/lb-F       1.0              0.63                   0.69
>(more is better)
>
>Viscosity
>cp             0.3              2.5                    3.0
>(less is better)
>
>Boiling point
>Point F        212              388                    369
>(more is better)
>
>Max contact
>temp F         n/a              300                    300
>
>Thermal
>Conductivity   0.38             0.13                   0.10
>
>1.  So,  With the reduced heat capacity, you would have to pump 30-35% more
>glycol (more mass) to transfer the same energy as water, or raise the
>temperature of the glycol (heat=mass x heat cap x temp rise).
>
>2.  And as the viscosity of the fluid increases the pumping frictional
>losses increase, thus moving less fluid for the same speed.  This increases
>the temperature (see 1).
>
>3.  A little temp increase that should be ok, right? The boiling point is
>much higher for the glycols.  But what about caburization temp?  At 300 F
>the glycols start to thermally decompose (scorch).  Is this a problem?
>
>4.  And finally, the thermal conductivity (a measure of how fast the fluid
>adsorbes or gives up heat) is a third of that of water.  This again tends to
>raise the temp.
>
>I'm guessing if you ran pure antifreeze or the sierra product or the Evans
>NPG in your Pantera it would run VERY warm.  You would have to get a new
>guage to read that warm, 260-300.  It wouldn't boil over, but would it cook
>the glycol to cylinders walls in the water jacket.
>
>Corrosion inhibited water is probably better for a stock pantera cooling
>system.
>
>FWIW
>4130