I don't know why there is so much misinformation about aluminum radiators on the forums.
some helpful reading.
I believe a good aluminum radiator is better than copper/brass. Look at Ron Davis Radiators, etc.
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The maximum size of brass tubes is 5/8" because of the physical properties of brass. If the tubes were made larger, they would not be able to withstand the pressure and would "balloon" and eventually rupture. The number of rows is determined by the core thickness. Cramming extra rows into a particular core thickness has no advantage and actually decreases efficiency as the surface area of the fins would be reduced.
Aluminum radiators are now being used in 99% of today’s new vehicles. The copper/brass radiator is on the verge of extinction.
Because of the strength of aluminum, larger and wider tubes are now possible, allowing a higher volume of coolant to come in contact with the fins. A 1 inch aluminum tube can carry more coolant than two 5/8 inch brass tubes. Another property of aluminum, because of its strength over copper, is that the fins can be thinner and more fins can fit in a given space.
In conclusion, when determining how efficient a radiator is, only be guided by core thickness and fin density (fins per square inch).
The obvious advantage of an aluminum radiator versus a copper/brass version has a lot to do with weight savings, but there are actual cooling benefits as well. Even though traditional brass and copper materials are better conductors than aluminum, the extra strength of the aluminum allows for larger tubes with more surface area. Even an aluminum radiator with fewer tubes than its traditional counterpart can potentially offer improved cooling, as the larger tubes make more efficient use of available core space.
Aluminum is much stronger, allowing the use of considerably wider tubes. Wider tubes allow more direct contact between the fins and the tube, increasing the radiator's capacity to dissipate heat away from the engine.
An aluminum radiator built with 1" wide tubes with a .016" tube wall turned out to be approximately 60% lighter than the same copper brass radiator. The 1" tube increased direct tube-to-fin contact and cooling capacity by roughly 25%. Therefore, a 2 row aluminum radiator with 1" tubes is equivalent to a 5 row copper brass radiator with 1/2" tubes.
Today all vehicle manufacturers incorporate aluminum radiators with wide tubes in their designs. GM, for instance, offers an aluminum radiator with 1-1/4" tubes. Mercedes Benz uses 1-1/2" tubes.
Copper is a good heat conductor, but solder required to bond the tubes to fin creates an insulation point that prevents some heat transfer. Aluminum tubes are welded rather than soldered to the aluminum tanks, providing a more efficient conductor for cooling efficiency.
Most aluminum radiators are manufactured with plastic tanks. To take it one step further, some are manufactured with aluminum tanks. The advantage of the aluminum tanks over plastic is the obvious added strength and the elimination of the insulating epoxies between the core and tank as well as the added heat dissipation properties of the aluminum tanks themselves.
In conclusion, an all aluminum radiator will have an overall efficiency rating 20-30% higher than the traditional copper/brass version with the same core thickness, regardless of the number of rows. Some of the increase in efficiency is directly attributable to the use of aluminum tanks in place of the plastic tanks in the majority of modern radiators.
