DRAG RACING WITH AIR-TO-LIQUID INTERCOOLERS

There are diverse opinions about the advantage of air/liquid intercoolers versus air/air intercoolers in drag racing applications. Some say there is no advantage over air/air and they also say if there is an advantage it is offset by the added weight.

The real facts are that other than a small additional weight factor, a proper application of an air/liquid intercooler will increase power more than enough to offset any additional weight, and will
always yield superior performance over an air/air unit. Furthermore, the additional weight is sometimes needed for ballast, eliminating this disadvantage. To understand why air/liquid intercoolers are superior for drag racing, consider that the cooling medium in an air/air intercooler is the ambient temperature of the outside air at any given time. If we have an engine running at 30 psi of boost pressure, with an ambient temperature of 90º F, depending on compressor efficiency, the discharge temperature will be approximately 400º F.

Assume that you have an air/air intercooler that can give 90% effectiveness at over 100mph and less at lower vehicle speeds. 90% at the above condition will give a temperature out of the intercooler of approximately 120º F, and higher temperature out at lower speeds due to lower cooling and velocity across the surface of the core. Additionally, you are leaving the line with a hot intercooler caused by heating during burn out.