Modifying Radiator Flow
In my first round of measuring pressures across radiators , I found that small amounts of grill blocking can significantly reduce cooling airflow through heat exchangers, and that the optimization of engine bay flow in more modern cars can have a major effect on the flow through radiators. My older truck had less than half the pressure differential across its radiator than my Prius had through two stacked radiators (one in front of the other), and the instantaneous pressure readings in the truck jumped around a lot while in the Prius they were stable. Recently, I went out again to test radiator pressures on the Prius after making a modification to the airflow under the car. In stock form, the large central exhaust tunnel is open: One change from stock here is the addition of a catalytic converter shield, visible just at the back of the engine undertray. Generally, cars benefit from having smooth floors, which tend to reduce both lift and drag. With the EV transition under way, more a