Major cleaning (edit: HIGHLY Recommened)
09-18-2004, 03:35 AM
#34
Burning Brakes
Well, there is a simple idea, which surely others have already tried and/or posted. This is a synthesis of various cooling ducts on race cars, airplanes, etc. so I can't claim any particular originality:
Cut a ~1" slot out of the trailing edge of the metal nose piece that covers the IC. Ram air comes in via its existing IC duct at the nose, which is at or near the stagnation point of airflow in front of the car, so air pressure is high there. The air travels through the IC and then up and out the slot, over the leading edge of the hood. Such internal ducting should be faired, for smooth and efficient internal flow. While stopped in traffic, air can still move through because hot air rises naturally, no longer trapped under the hood. When the car is moving, the slot is a venturi that draws cooling air through, up, and out, including the exhausted cooling air from the radiator, AC condensor, and engine bay. In other words, air flowing over the hood is much faster than air jammed in front of the car, causing low pressure and therefore lift. Such lift already exists, but now is used to draw air through the slot, up and out. The result is cooler IC, AC, radiator, and engine compartment. With cooler running temps, the water pump would not work as hard to pump coolant through the radiator, so gas mileage would improve slightly. On wet or cold days, this heated air flowing over the hood would slightly help to keep the windshield dry and ice-free. Combined with exhaust wrap or blankets over the headers and turbocharger, undherhood temps would be much lower, making for better performance and longevity of rubber hoses, etc. which degrade in a high heat environment.
This idea boils down to making a better exit path for cooling air. Our cars have good inlets for cooling air, but lack any decent outlet. Therefore, cutting more inlet holes in the IC nose cover seems less efficient than making a simple outlet. This is, in effect, a simple device like fishes have, where high dynamic pressure at the nose combines synergistically with low pressure over the body to generate efficient flow through the gills.
Cut a ~1" slot out of the trailing edge of the metal nose piece that covers the IC. Ram air comes in via its existing IC duct at the nose, which is at or near the stagnation point of airflow in front of the car, so air pressure is high there. The air travels through the IC and then up and out the slot, over the leading edge of the hood. Such internal ducting should be faired, for smooth and efficient internal flow. While stopped in traffic, air can still move through because hot air rises naturally, no longer trapped under the hood. When the car is moving, the slot is a venturi that draws cooling air through, up, and out, including the exhausted cooling air from the radiator, AC condensor, and engine bay. In other words, air flowing over the hood is much faster than air jammed in front of the car, causing low pressure and therefore lift. Such lift already exists, but now is used to draw air through the slot, up and out. The result is cooler IC, AC, radiator, and engine compartment. With cooler running temps, the water pump would not work as hard to pump coolant through the radiator, so gas mileage would improve slightly. On wet or cold days, this heated air flowing over the hood would slightly help to keep the windshield dry and ice-free. Combined with exhaust wrap or blankets over the headers and turbocharger, undherhood temps would be much lower, making for better performance and longevity of rubber hoses, etc. which degrade in a high heat environment.
This idea boils down to making a better exit path for cooling air. Our cars have good inlets for cooling air, but lack any decent outlet. Therefore, cutting more inlet holes in the IC nose cover seems less efficient than making a simple outlet. This is, in effect, a simple device like fishes have, where high dynamic pressure at the nose combines synergistically with low pressure over the body to generate efficient flow through the gills.