Walt- I think Ron is refering to an
oil to water heat exchanger as opposed to an
oil to air exchanger. The
oil to water exchanger can be built into the radiator or installed in line with the radiator hose. My oil runs 30 degrees more than the coolant temp on the track and about the same as the water on the street with it. The oil to air cooler kept the oil too cool on the street unless I blocked the air flow to it.
Scott