stainless ?

[DaveEFI]

Yes, I've seen that (the ally one). But isn't copper a better conductor of heat?
The ally is probably to save weight.

Copper is a good conductor of heat but ali is used in high performance rads because it is stronger, the weight of the rad is mainly due to the coolant in it rather than what the rad is made from. The strength means that the tubes that carry the coolant can be thin walled and be oval in cross section. The large flat sides of the oval tubes have more contact area with the fins than round tubes so the heat is pulled out of the coolant more efficiently.

In fact many so called 3 row ali rads do not actually have 3 vertical rows of tubes they have one "very ovalized" set of tubes!

BTW, I'm not a "brain box"....I read all of the above in my 4 stroke tuning book!

Pete

I'm amazed ally is stronger - I can remember ally house mains cable being used during a copper shortage and it was so easy to break. Even although it was larger to carry the same current.

[sidecar]

I'm amazed ally is stronger - I can remember ally house mains cable being used during a copper shortage and it was so easy to break. Even although it was larger to carry the same current.

I guess it might depend on the exact composition of the ali, like I said its only what I've read!

Although I have seen ali rads with the large tubes as described. Copper rads sometimes have oval tubes but the ones that I've seen only have a long side of maybe 10mm.