Barrel 4 x 6 Intercooler 2.25 inch Outlets. The Liquid to Air Barrel Intercooler is a world first exclusive in its design for the industry. The radical cylindrical shape was designed for race, drag and street applications, providing maximum cooling, airflow and performance efficiencies. A 12- volt pump circulates water throughout the barrel providing a stable outlet temperature and the unique internal baffle system and cooling fins ensures an even amount of cooling is provided within the barrel itself. The Barrel Intercooler requires no ambient (external) airflow and is used in conjunction with a supporting high performance radiator and thermo fan assembly. This enables the Intercooler unit to be mounted as close to the manifold as possible, reducing turbo lag and providing maximum performance.