As far as the ATR unit, the fin or cooling surface is VERY small inside the "box". Small and restrictive end tanks do not help either.
When you look into spearco's ratings the liquid IC's have a VERY low pressure drop across them around 0.18 psi @ 700 cfm. The large air to air front mount cores are usually closer to the 1.0 to 1.5psi @ 700 cfm. Yes front mounts are bigger, but the air has to flow through those long tubes.
The liquids are small because they can be. They are so superior at removing heat that a large one would be pointless.
The inlet air temp remains steady from the start to finish with a small increase only off the line.
What kind of charged air temps where you seeing with the air to air and at what boost level. Thats what I'm the most curious about. I would have a better understanding of the potential gain if I knew those temps.
Thanks: Jason