Based on data from Mark's Handbook for Mechanical Engineers, I calculated the
following:
Ethylene glycol at 230F has a density of 62.8 lb/cu. ft. and a specific heat of
0.68 Btu/lb, or 5.71 Btu/gal.
Liquid water at 230F has a density of 59.6 lb/cu. ft. and a specific heat of
1.0 Btu/lb, or 7.97 Btu/gal.
Therefore, a 50/50 mix of glycol and water at 230F has a density of 61.2
lb/cu. ft. and a specific heat of 0.84 Btu/lb, or 6.87 Btu/gal. You can use
these numbers to calculate the specific heat of any of mix of glycol and water.
Both density and specific heat are temperature dependent.
So on a volumetric basis, which is what the pump deals in, the heat carrying
capacity of 50/50 mix is about 14% less than that of water alone. But I would
still use a mixture of commercial antifreeze and water, if just for the
lubricating and anti-corrosion additives, even if I didn't live in Michigan.
Are there any experienced racers out there who can tell us what they use?
Bill Weakley
weaklew@aa.wl.com
56 MGA & 65 Midget (neither on the road at this time) :-(
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