Engine and Transmission Tech

Graham has the long and short of it. Money, money money.

However, brass is a good bit heavier so if weight is any concern at all it can make a significant difference. Also I think the brass radiators actually use the thinner walls because the material is stronger. There are in fact countless analysis of why one or the other is better but with current refinements to each type their real life performance seems to be extremely similar. Meaning that you might as well choose on the basis of weight and, yes, money.

Now there is a very good reason for using a cross-flow radiator instead of downflow in these cars particularly, and that is because the radiator typically sits so low in relation to the engine. The issue is air in the system, and a crossflow tends to make plumbing designed to remove air simpler. Other than that I'm not sure there is an advantage. But if you look at well engineered conversions such as Graham's SBF based one you'll see that the size of the radiator does not necessarily mean the frame rails have to be cut. I, OTOH tend towards overkill and use the largest radiator I can get cheap from Summit, and move the bumper mounts outward so that any collision damage does not automatically kill the radiator. Since I've been known to bump things that is a valid concern, as is a reinforcement below the radiator to prevent curb damage.

YMMV.

Jim

"Also I think the brass radiators actually use the thinner walls because the material is stronger."

The opposite is true. Aluminum is much stronger. Copper/brass radiators have tubes 1/2 the size because of their weakness. That's why they have 4 - 5 rows compared to aluminum rads. 2 row cores.
I could have probably gotten by with a narrower rad. than 22" but horsepower creates heat and like you, I prefer to go overkill and do it only once.

During my working years, part of my job entailed dealings with radiator suppliers.
Generally speaking, an aluminum rad supplier is going to rave about the performance of his product and the copper/brass rad supplier is going to do likewise. ie a supplier, like Griffin, is not going to extol the performance of Cu/brass rads. Here's some typical examples
Article from Hot Rod magazine with input from Griffin Aluminum rads
[www.hotrod.com]

Article from Copper Development
[www.copper.org]

And some general discussion on both.
[www.customlineclub.org.au]

So there you have it – depending on who you listen to either rad is superior. One comment that I remember from one of our rad suppliers (who manufactured both products) was that: “rad for rad, the Cu/brass will cool better”, but by their very construction they can't be identical.
Unless copper comes down in value and weight, aluminum rads are here to stay!

Here we have it "MONEY" Don't expect any Brass beverage cans any time soon, aluminum is here to stay. :-)

Sorry for opening a can of worms. All I wanted to do was offer my real world experience on cooling a high HP engine in a confined space.There are plenty of ways to do it and this was the way I did mine and it worked extremely well. Nothing more, nothing less. See ya.

JWD,

Thanks for you input!
Copper, Alloy, Down vs Cross flow, all work and in fact I have done all of them now, except copper down flow.
What I can figure out is lots of guys are running the Fast Cars Inc rad, am I the only one to have developed a leak. Yes it's a few years old but no mileage, no stray current (no top rad cap to fully know), yes it's solid mounted but that how it's designed.

Dan Masters, Rob F, Terry S any comments here?

Hey JD,

No worries, Everyone has their own experiences.
I genuinely appreciate a success story. It makes me feel good to know that someone has a working solution to such a controversial problem.
The rest of us are actually probably kinda jealous.

Cheers
Fred

I seem to remember Dan's radiator being changed out once. Can't speak for Rob. Doubt Terry S. checks in here much, if at all. I'm betting his conversion has very few miles on it.

Not sure where Fast Cars sources their radiators. Likely has them custom made just for them.

Jim D, as much as I'd like to go along with you I just can't but it occurs to me that we are probably talking about different things. As a bit of a materials specialist though I can assure you that for a given amount of material brass is stronger. Now there are some pretty darn strong aluminum alloys but they aren't used to make radiators. In fact I was told that the reason aluminum radiators use a larger tube size is that the metal isn't as strong, odd as that sounds. It's the wall thickness that you have to look at. The walls of a 1/2' or 3/8" tube are very thin compared to the walls of a 1" tube. If you made a brass radiator using the same construction methods used for an aluminum radiator it'd be 2-3 times heavier. Which tells you something about how much lighter aluminum is as a material.

Anyway, there are countless examples available to compare the metals, from bolts to hammers to swords. No wait, they don't make aluminum swords ;)

Jim

FWIW...I heard, one major reason the 917 Porsches' were so fast, they used Magnesium in their cooling systems ! Jus' sayin.