|
I apologize for being late to this thread, but a few pages back there was discussion regarding location of front opening in a grille block and I remembered some things I had learned during powertrain development cooling tests for an off-highway vehicle.
To maximize effective cooling from a minimum of grille flow area the opening should be as close as possible to the radiator hose that delivers the hot coolant to the radiator. On most production vehicles this would be the "top" radiator hose. It will depend on your vehicle where exactly this hose is, in one of my trucks it is top and center and the other delivers to one end of the upper tank. In a cross-flow radiator it may be near the top of one side or the other. The reason you want your opening near this hose is that the coolant is hottest at this point. For a given mass air flow the most heat exchange will occur with the highest temperature delta between the coolant and the air.
Corvettes and similar GM vehicles switched years ago to a "reverse-flow" cooling system. These vehicles pull air from underneath the bumper via a set-back air dam to flow through the radiator without a "grille" opening. Since most of the air flow is at the bottom of the radiator they experienced more efficient cooling by delivering hotter coolant to the bottom of the radiator which is traditionally the "suction" hose in the system.
My personal experience revolved around a diesel application that could be overheated because it could be loaded to 100% power at low vehicle speeds for long periods of time. This vehicle underwent a body restyling without a change in powertrain. There was concern about the potential reduction in effective cooling area (went from about 6x10 unobstructed rectangle to a 5x18 perforated cover). Dyno tests showed lower coolant stable temps at full load (when corrected for ambient). The flow area on the old body was at the bottom center of the radiator and the new body placed the flow area at the top of the radiator where the hotter coolant entered.
__________________
|