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I am contemplating using a large tube single row radiator. Anyone done this? If so, what company or brand did you use?? feedback appreciated

I'm guessing you mean the same thickness, but wider front to back, inch or inch and a quarter? Many E28 radiators are like that, I think including the one in my '80 E12, which works great. No idea where to get an E 12 radiator like that, unless the all aluminum one that has been available at Amazon from time to time is like that. The E28 radiator is obviously not original, but is adaptable with modest modifications.

If you mean thicker tubes, top to bottom, I had a Bav with a radiator like that. It must have had great flow, but not enough tubes, it tended to get warm in very hot weather in town with the A/C on, but absolutely never budged at all on the highway, no matter what the conditions.

Mike

A large tube radiator, only has 1 row of tubes. The tubes are at least 1 inch wide, sometimes as large as 1.25. Thereby providing more "heat sink"
Many of the E24 guys are doing it and it is just another thing for me to think about. The radiator in my early E 24 is a triple row all copper unit. I haven't run my new motor yet and am sure what I have will let it run cool. The large tube is just a back up plan in case I have to go that way. Kind of like running a cross flow a/c condensor.

Lots of design parameters, but I wouldn't expect large tubes to generally be the right direction. Surface area for heat transfer is important and fewer larger tubes reduces that. There's obviously a balance between resistance to flow and surface area when selecting tube size and count.

I bet that's not copper, but brass, on the early radiator. Plenty of details in the cooling system FAQ I did years ago.

Coolant mixture makes a difference too. Just moved back to Texas and surprised how noticeable the difference was in moving from 50/50 back to a 1/3 antifreeze,2/3 water mixture to battle the heat.

I'm currently running an all aluminum (no plastic side tanks) version of the E28 radiator from Ron Davis (www.rondavisradiators.com) in the PHX area. IT's not cheap, but good quality. They've done the E12 radiator before too and seem to be ready to go with multiple BMW stock radiators in their portfolio.

Robert
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Bert Poliakoff wrote:Mike

A large tube radiator, only has 1 row of tubes. The tubes are at least 1 inch wide, sometimes as large as 1.25. Thereby providing more "heat sink"
Many of the E24 guys are doing it and it is just another thing for me to think about. The radiator in my early E 24 is a triple row all copper unit. I haven't run my new motor yet and am sure what I have will let it run cool. The large tube is just a back up plan in case I have to go that way. Kind of like running a cross flow a/c condensor.

Robert,

I am in Phoenix and have spoken with the Ron Davis people. I have also been in contact with several fellows here who are running his large tube radiator. All comments were very favorable.Ron Davis as well as more than several other companies insist there is more cooling surface with the large tubes. I was asking only for future reference should I need it as $500-Ron Davis's $900 is a hard pill to swallow. Right now I have a triple core brass radiator ready to use. My car is an 81 euro 635. So, longer story short, I will stay with my brass unit unless I have problems and then go in the other direction if needed

Thanks for your reply

Interesting. OK. When I purchased my radiator at Ron Davis 3 years ago, it seems like we were mostly talking about more tube rows than stock. Without some CAD images for reference, I wouldn't be surprised if we're somehow talking about the same thing.

Anyway, I've been really happy with my radiator purchase from them
for what it's worth.

Robert