Classic industries radiator finally gave out

72bluNblu said
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.

I agree, there is engineering that goes into it. If the OP is short on room two 1 inch tubes is LESS thick that your .75 3 core and it will flow more coolant at the same pressure and pump speed.

Two 1 inch tubes will cool way more that what the OP has IF he has thought out the rest of the cooling system. That means a quality high volume water pump, over drive pulleys and a decent fan. If anyone has that, two 1 inch cores will cool way more than what is claimed.

Fins per inch has its limits as well. Get too many fins per inch and you can’t get enough air through the radiator to cool anything. Too few fins and you can’t dissipate the heat quick enough.

I forgot to mention you also need a quality high flow thermostat. The only thermostat I’ve found that is always fully open by it’s rated temperature is the Robert Shaw/Stewart Components thermostats.

I just had a Pontiac guy call me on Monday and his engine runs at 192-195 a 180 thermostat. So I had him pull it out and verify when it opened. And sure enough it was starting to open at 180, when it should have been fully open by then.

A new thermostat is on the way.

There is certainly more to it than the number of cores and the size of the cores. You can run a 4 core radiator too, but what do you get? A total of 2 inches of tube. Same as a 2 core with 1 inch tubes and the two 1 inch cores will flow more coolant than the 4 cores at .5 inch each.

Fit the biggest radiator with the biggest, fewest cores you can get and use the thermostat to set your minimum operating temperature. Build in some safety margin so a few years down the road you won’t need to buy another radiator when you increase the power.