Yep, inlet/outlets on rads are very, very restrictive. 7/64x1/2" (0.05 sqin or 1/4" diameter hole equivalent)) at best. I was aware of it when I JB-welded 5/8" and 3/4" over existing tubes and "just wanted to see how it would work"
and then forgot about it.
Drilling holes in tank end plates I also found a small tube inside one tank and baffles in both tanks. Now removed.
As for airflow, when I get new elbows welded onto the rads I'll collect new data. I think the large delta is due to the very slow coolant flow -- stays in rads way too long (and thus not circulating through the engine fast enough).
Finn
On 2/27/2021 9:32 PM, Steven W. Boese
SBoese@uwyo.edu wrote:
Finn,
If the "WTeng" sensor location is somewhere in the engine block and not at the coolant outlet and the "WTout" sensor is in the coolant exiting the engine, then the coolant flow rate through the system may need to be increased
by enlarging the radiator connections.� Typically, it seems that at normal operating temps, the delta-T across the engine and across the radiators is about 15 deg F.
It also would appear that the mass air flow through the radiators may need to be increased since the air delta T is quite large and the temp of the air exiting the radiators is close to temp of the coolant exiting the
radiators.� If your OAT were increased to 100 deg F, you could see "WTout" of ~250 deg F with the setup as it is now.
The attached plots show the effect of changing only the air inlet and outlet areas of my system which has ~0.9" id plumbing to the single radiator.��
FWIW
Steve Boese
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