Classic industries radiator finally gave out
What is the downside to two 1.25 inch tubes? Th answer is nothing. I’d ditch the clutch fan long before i skimped on tube size. There is no downside to bigger tubes.
Uh, we're already talking about a very important downside to bigger tubes. Namely, if the core is too thick you may not have enough clearance for a decent fan set up. The OP seems to have a 1/4" to give, which is great. But on my car, if I went to a radiator a 1/4" thicker than the one I've got I'd be out of luck for fan clearance on my current set up.
The other thing is that the size of the tubes is only one of a whole bunch of factors that go into determining how much heat a radiator can dissipate. Tube spacing, fin spacing and density, water flow and air flow all have a big effect too. So running larger tubes but less of them (tube spacing) could mean you have larger tubes and less cooling capability.
Just saying your radiator has the biggest tubes is an advertising gimmick, same as saying your radiator has the most number of rows. The radiator with the biggest tubes may not have the highest cooling capacity, just like the radiator with the most rows might not. And you don't see radiator manufacturers listing the actual amount of heat energy their radiator can dissipate, and you won't. They'll say stuff like "cools 450hp!!!" but they won't publish the data behind that calculation. And those kind of calculations use a lot of assumptions, so you can get different numbers by playing with the data and parameters.
I love my cheap old Champion 3 core, and I wouldn't trade it for a fancy 2 core 1.25" tube radiator that costs 3x as much.
