Thread: Aluminum radiator question

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66.............a double and or triple pass radiator has dividers inside the radiator. The coolant goes thru the top half of the rad then it drops down and flows over the spacer to a hole where it starts again the flow. The problem is the time it takes. I guess I didn't quite explain it as well as I should.
It all comes down to flow and you want the flow not interrupted in a cooling system. A double or triple pass has interruptions in them.
Double and triple pass radiators work well in an all out race car. And yes, I have seen and talked to some guys who do run them on the street. But I have always heard them complain on how much hotter there motor runs as well.

Double tripple pass are for constant high RPM stuff like NASCA or SCCA kind of stuff.
Tube size mostly depends on radiator style. Top flow works best with smaller tubes. The cross flows work better with larger 1' to 1 1/2" tubes.
The main reason is the top flow radiators need a restriction to help prevent coolant at higher RPMs frome running a path of least restance from the inlet to the outlet and basicly bypassing a majority of the radiators cooling area.
The cross flows dont have the same issue it has to flow from side to side. So the flow restriction isnt needed. Increase in flow allows more water to be exposed to the cooling area and sent back into the engine.