Crossflow Radiator

[XCRN]

I'm still trying to figure out how the flow direction makes it possible to run a lower PSI radiator cap.

I have no idea, just various articles I read on the subject mention this detail. But I do not believe it is the flow that allows running a lower pressure cap, it’s physically where the rad cap can go. On a down flow, the cap can only reasonably go on the top of the radiator, the hot side. On a crossflow, the rad cap can be positioned on either side but it typically seems to be on the cooled side of the rad.

 

[freedom_in_4low]

I'm still trying to figure out how the flow direction makes it possible to run a lower PSI radiator cap.

If the radiator has a 1 psi drop and the cap is on the outlet side of the radiator then I guess you could run a 17 psi cap instead of 18 and the overall system pressure would end up about the same but again...what is the benefit???

 

[Wildman]

Does anyone know of a crossflow radiator that has the auto trans cooler provisions and puts the coolant inlets and outlets in roughly the same spot as a factory radiator? This is specifically for a GM engine swap, and I have had great success with maintaining temps with an LS swap specific crossflow radiators with the cammed LS and I keep hearing about issues of people using factory style downflow rads having issues. I want to use what I know works, but the twist on this swap is I want to be able to swap in a factory style radiator from the local parts store in case I am far away from home and the main radiator leaks (which has happened twice now on the LS swap rad, so this is not some theoretical worry). I have found one source for a rad that is cross flow and has the ports close enough that appears to be for Ford V8 swaps, but it does not have the trans cooler provisions which I will probably run an aux cooler, I just like the idea of being able to use the one in the radiator as well to warm the trans up to temp quicker during the cold season.

Anyone know of a radiator that matches these requirements?

https://www.ebay.com/itm/1636387728...pid=5337789113&customid=&toolid=10001&mkevt=1

Wizard Cooling used to offer one.

https://wizardcooling.com/i-3050095...minum-radiator-ls-engine-swap-1014-210ls.html

 

[GoldenGorilla]

I don't understand how the cooling system has a high-side or low-side since the fluid is common.

Why wouldn’t the pressure be the same throughout the system?

If you think about how a bulb thermometer works, as it warms the liquid expands. If it had no gas filled space to expand in to, the pressure would increase. As it cooled the pressure would go down. There aren't exact equivalents to the ideal gas law (PV = nRT) for liquids as compressibility is nominal but there is a similar formula.

Fluids expand and contract with heating or cooling. In a crossflow, the cap is on cool side. So if you're able to run an 18psi cap on the cool side there will be a bit of a pressure drop across from the high side as the coolant becomes more dense. And with that the engine will be able to run a slightly higher psi like 20psi, which in turn increases the boiling temp of the coolant mixture. That means fewer pockets of boiling in the head and better overall cooling.

I'm sure there are variants off the Darcy-Weisbach equation to express a radiator system. These express pressure drop over distance in a flowing fluid, which also applies to a vehicle cooling system, but there are more dynamics at play and it's not quite that simple. If you just ran a long closed loop of pipe around a pump, you would see a pressure drop as measured at different points in that loop.

 

[GoldenGorilla]

Does anyone know of a crossflow radiator that has the auto trans cooler provisions and puts the coolant inlets and outlets in roughly the same spot as a factory radiator? This is specifically for a GM engine swap,

https://www.ebay.com/itm/1636387728...pid=5337789113&customid=&toolid=10001&mkevt=1

I'm not sure if you mean auto trans coolers on the bottom like stock TJ or on the side with the cool side tank, but assuming the latter, Champion has this one.
https://shop.championcooling.com/Sh...02-2003-2004-2005-2006-Jeep-Wrangler-SKU-8102