What are the pros and cons of Aluminum ratiators versus brass radiators?

The effectiveness of the radiator is complicated and dependent on many parameters. Basically heat must transfer from the coolant to the pipes to the fins to the air. I think that you will find that the conductivity of the solder between the pipes and fins in a brass -copper radiator is much less than in an al radiator. This is why Al radiators are more effective; and not the relative thermal conductivities of the two materials.

the pro's of al radiators lie in lower weight and nowadays lower production costs when produced in large quantities. another consideration might be that when you have an al-engine you don't have a potential between radiator and engine that could promote corrosion due to different materials. these pro's are mainly of concern to the carbuilder. as chumley remarked: they are somewhat more critical to the use of the correct coolant. modern low-silicate coolants are preferred nowadays. these coolants are actually corrosive themselves - the idea is that they coat all aluminum parts with a thin layer of aluminiumoxide and so create a stable environment where no further corrosion takes place - and so a lifetime coolant is born that does not create a waste problem as long as the car is onthe road.

I would also like to update & an earlier posting you made regarding the CuproBraze Process & correct a number of your statements. (Please don't take offence, but I would like to set the record straight on a number of technical issues).

1. >>Quote: “CuproBraze is the name of a new manufacturing process for copper-and-brass automotive radiators.  The process uses fluxless lead-free brazing..."

Answer: The CuproBraze Process is NOT a fluxless process, as a small amount of flux additives have to be included in the tube-to-header slurry/paste to prevent the 'de-wetting' phenomenon, & porous joints. In addition, the binders which burn off during the brazing process contribute to environmental load.

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2.  >>Quote: "to produce new thin-walled radiators that perform better than thicker-walled aluminum products."

Answer: In general, the CuproBraze radiator can only perform better than a 'poorly designed' Aluminium Radiator... despite all the marketing hype to the contrary...

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3.  >>Quote: "The new radiator was developed by the International Copper Association and produced initially by the Universal Auto Radiator Manufacturing Company.  They are typically 30% to 40% lighter than traditional copper and brass models, can be made smaller than their aluminum counterparts, and can provide up to 30% less air-side pressure drop.  The CuproBraze process also shortens manufacturing time and reduces production costs.”

Answer: Most of this information is from ICA marketing literature from a few years ago (1998/1999/ball valve)... In practice, these original claims were never upheld in the real world. 'Universal Auto Radiator' is now bankrupt & no longer operates.

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4.  Quote: “Cost-Efficient CuproBraze® Radiators Show Superior Durability in Road Tests..."

Answer: This claim is, in general, unsubstantiated in practice...

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5.  Quote: "…In addition, CuproBraze radiators can be made smaller in size, or with significantly higher heat transfer efficiency than aluminum models.  The CuproBraze process offers further advantages over standard aluminum radiators, such as greater fuel economy, lower air side pressure drop, lower cooling module costs and weight, and less parasitic engine losses….”

Answer: Again, these claims are, in general, unsubstantiated in practice...

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6.  Quote: “Commercial Production of CuproBraze® Radiators Begins Over 90 different models to be offered in 2000
The CuproBraze® revolution in automotive radiators has begun.  Universal Auto Radiator Manufacturing Co. in Pittsburgh, Pennsylvania, USA, became the first company in the world to begin full production of the new CuproBraze radiator."

Answer:  Again, UAR is out of buiness (for almost 1 year, now)

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6.  Quote: "...the CuproBraze® alloy can be HF (high frequency) welded; ultrasonic weldability had been mentioned as an advantage for Al by Peter7307.  See
“Berry Radiateurs Adopts CuproBraze Process and Begins Production”

Answer: HF welding of 85/15 CuproBraze Brass has a lower thickness of around 0.110mm. In many cases, this is not thin enough to save cost over an equivalent Aluminium tube.

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7.  Quote: "It appears that CuproBraze® has given Cu the competitive edge over Al in the radiator & HXer market."

Answer: This was the marketing hype we (me included) used to market CuproBraze in the early days. In practice, the expected results have, unfortunately not been achieved...

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