This high latent heat of vaporization is desirable because it draws heat from localized hot spots that occur around the exhaust valves, exhaust ports and combustion chambers. It takes nearly 2.4 times as much energy to boil water as it does to boil antifreeze. Auto manufacturers compensate for this lower cooling capacity of water/glycol mixtures by increasing the volume of the cooling systems in production cars, but drag racers don’t want or need big, heavy radiators and pumps.Īnother important property of coolant is latent heat of vaporization, which is the energy required to change a liquid into a vapor. A 50/50 water/antifreeze mixture has a heat capacity that is almost 20 percent less than plain water. In the table shown here, pure ethylene glycol has a specific heat value that is only 57 percent of water. A liquid with a high specific heat has more capacity to absorb heat than a liquid with a lower specific heat. The specific heat capacity of a liquid is defined as the heat required to raise its temperature by one degree. These qualities are directly related to the cooling capacity, and it’s clear that water is an excellent coolant. If you’re going to store your race car in an unheated garage for the winter or transport it in freezing temperatures, simply drain the coolant.Ĭharacteristics that are much more important for racers are the coolant’s specific heat, latent heat of vaporization and thermal conductivity. But a racing engine doesn’t sit overnight in a subzero parking garage in Minnesota, and it isn’t driven across the Nevada desert with the air conditioning turned on. Obviously antifreeze protects an engine at extremely cold and extremely hot temperatures that’s why it is used in street-driven engines. Here is a comparison of the properties of water and ethylene glycol antifreeze: While these are important qualities for street-driven automobiles, they are irrelevant to a dedicated drag race car. Both of these alcohols have lower freezing points and higher boiling points than pure water.

Automotive antifreeze is typically ethylene glycol or its less toxic relative, propylene glycol. Science when it comes to chemistry, but the facts on antifreeze are readily available. In fact, the exact opposite is true: antifreeze reduces cooling capacity compared to plain water. I think that some racers have the mistaken belief that antifreeze improves cooling efficiency. I’m amazed that so many racers use antifreeze in their motors. But I’m going to make the recommendation that you should never use antifreeze in a drag race engine. Anyone who lives in the Snow Belt knows that antifreeze is an essential part of winter survival. With winter fast approaching, it’s the time of year when people start thinking about preparing their cars for cold weather.

“Some racers have the mistaken belief that antifreeze improves cooling efficiency.” By David Reher, Reher-Morrison Racing Engines

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