PDA

View Full Version : Aluminum Vs Copper Radiators



temperacerguy
09-21-2011, 01:46 AM
OK, since there is a group buy on Aluminum radiators, and one person didn't want to buy because "copper cool better than aluminum" I wanted to address the issue.

Yes, it is true that Copper is a better heat transfer medium than aluminum. There is no question about it, and that is where the "copper radiators are better" debate comes from. However. That is only one small aspect of the radiators.

However here's the problem. Up untill the mid/late 90s, all copper radiators were brass tubes and copper fins/headers, however the fins were connected to the tubes with tin solder (poor heat transfer medium), and the tubes were connected to the end plates with tin solder.

This caused two problems. First of all, the tin is a poor heat transfer medium, and the heat had problems transfering through tin to the fins from the tubes. The 2nd is that the dissimilar metals would cause a condition called "Solder bloom" which is a chemical reaction between the 3 different metals.

The other problem is that copper radiators are not that dense.. Thus there is not much surface area where the tubes meet the coolant. They tried to solve this problem by adding additional cores, to get more surface area.


Aluminum radiators on the other hand are 100% aluminum. There are no chemical reactions between metals.

And while aluminum is not as good of a heat transfer medium as copper, they are not held together with tin solder which inhibits heat transfer. They are welded or alumabrazed together with alluminum. The cores also are far denser as such a single core of alluminum has roughly the same tube density and heat transfer as a full copper/copper brazed dual core. a Dual core aluminum radiator has roughly the same heat transfer as a copper/copper brazed

You will note that I stated those as "copper/copper brazed". In the mid 90s, many manufacturers changed to a more expensive procedure called "copubraze" where the tubes/fins/header tanks were brazed together without tin solder. This eliminated many of the problems with copper radiators.
So. If your copper radiator was designed after the 90s. If your copper radiator was built after the 90s, and if your copper radiator was built by one of the good manufacturers, then your 4 core copper radiator will cool as well as a dual core alluminum radiator.

To me, that's alot of "If"s. So I just stick with an alluminum if available and be done with it.

85gtsblackman
09-21-2011, 06:05 AM
the was a thread about this but im curious about this as well. though i will be replacing my single big copper radiator in my gts with a 3 row aluminum one

temperacerguy
09-21-2011, 06:53 AM
Where are you finding a 3 row alluminum? That's pretty damn thick. the 56mm thick are dual core alluminum.

85gtsblackman
09-23-2011, 03:05 AM
its for my 3rd gen, im using a 240sx megan radiator

cklamp
09-30-2011, 08:58 AM
Anothing thing to think about, Copper will "spread" the heat out better, but Aluminum will shed the heat quicker. That's the reason most Computer heat sinks have a copper base with Aluminum fins. It's also why Copper bottomed pans are better than aluminum for cooking as the heat from the burner will be more uniform on the copper pan than the Aluminum ones.

Later
C