| The efficiency is defined as the ratio of the temperature removed from the air charge by the intercooler relative to how much temperature is put into the charge by the turbo/supercharger. For example: If the turbo/supercharger puts 150 degrees F into the charge when compressing the air, and the intercooler removes 110 of those degrees, then the efficiency is:
Eff = 110 / 150 = .733, or 73.3% You can define it how you want. All I'm interested in is the temperatures so I can convert them to absolute temps and see the percent change in air mass if flow and pressure stay constant. This way I know the hp differences. Based on the numbers I ran years ago, intercooler efficiency may make a 20% difference in hp... this is 80% efficiency vs. heat soaked intercoolers. With fan placement, you can probably vary the hp by 10% or so without hardly trying. This is probably why you see throttle body dynos that don't make sense. The hp improvement is better at lower rpms than at top end. In this case the fans were probably placed to make the intercoolers more efficient, and the better numbers were made. Then at the higher rpms the intercooler efficiency drops out due to intercooler short circuit, or the air shooting across the core.
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