Keep Your Cool Mishimoto offers a bolt-in, high-efficiency radiator for the Focus ST By Steve Turner Photos courtesy of Mishimoto Right off the dealer lot the Focus ST is one of the most fun cars Ford has ever offered. It offers a balanced package of power and handling that makes it a blast to drive on an autocross or road course. If you really beat on the car hard, however, temps will rise and the PCM will put things into limp mode and spoil the fun. The solution is to bolster the car’s cooling system and the team at Mishimoto have developed a direct-replacement radiator upgrade (PN MMRAD-FOST-13;$660) that increases the cooling system capacity and efficiency. “Our engineering team often tackles complex problems to provide ideal solutions for customers. This is true for all our product lines, across a broad range of vehicle makes and models. We are not strangers to Ford’s lineup of EcoBoost models, and our team is quite familiar with the issues that exist for each,” John Marsteller. Market Research Specialist at Mishimoto, explained. “In general, we’ve found that the stock liquid cooling systems are not handling the abuse from heavy-footed ST (Fiesta, Focus) and Mustang owners. Each model shows deficiencies in coolant heat transfer, rising oil temperatures, and power-crippling heat-soak.” In developing its larger, direct-replacement radiator for the Focus ST, Mishimoto overcame the complexities replicating the factory endtanks with its own tig-welded tanks. They bookend a 34mm, two-row core that offers a significant increase in coolant capacity and surface area. It accepts factory or aftermarket hoses and the stock cooling fan, plus the front of the endtanks have the proper mounting points for the active grille-shutter system, air conditioning condenser and intercooler. “… Heat transfer is greatly affected by the surface area of the fins within the core. Fins work to transfer heat from the internal coolant tubes to the air passing through the core,” John said. “By increasing the density of the fins, shorter fin with decreased pitch, we can make a huge impact on the overall surface area, which should result in a more efficient heat exchanger.” For more on the benefits of this unit, the company put together this comprehensive video… [video=youtube;1hDFfqVUd-Y]https://www.youtube.com/watch?v=1hDFfqVUd-Y[/video] If the radiator sounds like the cure for what ails your track-rat ST, you might want to know how to install it. Fortunately, Mishimoto put together an installation video as well… [video=youtube;J0UYEaPkId8]https://www.youtube.com/watch?v=J0UYEaPkId8[/video] Now you know how to cool off your ST so it will handle extreme situations, but Mishimoto doesn’t just have a radiator for the Focus ST. If you are really hammering hard, the company also offers an ST oil cooler upgrade. Mishimoto’s high-efficiency Focus ST radiator (PN MMRAD-FOST-13;$660) features a 34mm-thick, two-row core that offers a 16.6-percent increase in cooling surface area and a 10.7-percent increase in air surface area. The stock core is only 27mm while the Mishimoto core clocks in at 34mm thick. The increase in thickness allows for a 25-percent increase in coolant capacity.