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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Here is some of what Bell says about intercoolers:


Does one style core cool better than another?
No, almost no difference. With three decades of testing intercoolerís, we have found no appreciable difference between any core style or manufacturer. Keep in mind, that the merit of a core is itís efficiency versus its internal drag characteristics. When sized for a tolerable flow loss, virtually all cores will produce essentially the same efficiency results. Perhaps a core with slightly less flow area per linear inch, or one with longer tubes, will need perhaps 5% more tubes to equal the best of intercoolerís with regard to flow loss and efficiency. Not a very important difference.

What are the differences between short tubes and long tubes?
The longer the tube the greater the pressure loss accompanied by a slight increase in efficiency.

Does the length of the tube affect efficiency?
Very little. The most heat comes out of the tube where the temperature difference between the inside and the outside is the greatest. That exists in the first couple inches of the tube. The last inch of the tube, wherein the charge temperature is rapidly approaching the cooling media temperature, will transfer very little heat, thus being of minor use.

What factors affect efficiency of an Air-to-Air Intercooler?
Frontal area: This is a rapidly decreasing function. If the proper core size is used, then doubling it will definitely not double the efficiency. More likely, doubling the core would raise the efficiency about 5% and cost twice the necessary amount and add substantially to the weight.

Plate area: Plate Area (the sum of the Core-Plate Area which is exposed to the Atmosphere) is directly proportional to the frontal area and the thickness. Thickness, however, is a double-edged sword. With the greater thickness, the plate area increases but less ambient air can penetrate the thicker core to offer cooling.

Ambient air quantity: It is very important to insure that air coming in the snout of the car will actually go through the intercooler.

Are there any improvements that can be made to the system for improved efficiency?
Yes, several small factors influence the efficiency. A proper duct is probably the single most beneficial thing that can be done to an existing intercooler. Positioning in the main stream of ambient air is crucial. By comparison, a taped up intercooler with no ambient air flow will offer only about 20% efficiency.

Last edited by 911st; 02-11-2010 at 07:34 AM..
Old 02-11-2010, 06:39 AM
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