The ice box gets filled with ice, then water. The iced water then gets pumped forward through my neck-mounted water/air intercooler (pump on before engine start) and recirculated. The reason dry ice is not used in IW/Air intercoolers is it will freeze the moisture out of your intake air, forming frost on the inside of your intercooler... causing major intake blockage. A peek inside my intercooler reveals the fine air passageways:
A straight-through, ice water/air intercooler is INCREDIBLY efficient... less than 1/10% pressure drop. I'll keep you informed on Maxton runs... bring a bag of ice.