1980 320i (E21) Custom Radiator Solves Over Heating Problem

Even since the car was new, on hot summer days my 1980 BMW 320i would run hot, especially with the air conditioning running.
I have the 1.8L 4-cyl with manual 5-speed transmission, which
only produces 105HP. As underpowered as it is, it still ran too hot, even at highway speeds on hot summer days with or without the air conditioning on.
Air Conditioning systems were all add-on that year, as there was no factory air for that model. The OEM radiator was not adequately sized to be cascaded behind the add-on A/C condenser, and still keep the engine cool on hottest summer days.
Hard wiring ON the electric auxilary cooling fan for the condenser side and the addition of plastic fan shroud on the engine side had little or no cooling effect.
I searched high and low for an oversized radiator for the E21 body, but to no avail.
So, I designed one myself.
I made a template (sketch) for a custom down-flow radiator with the same inlet and outlet configuration as the OEM, except maximizing radiator core dimensions to the limits of the E21 body. The result was a design that requires only one 5 minute modification lower radiator mounts.
I got estimates for the project from two custom radiator companies: Griffin Radiators/Anderson, SC and Ron Davis Racing Products/Phoenix, AZ.
I went with the Ron Davis estimate and 6 weeks later had the radiator delivered to my doorstep for $638 (including shipping).
Its an all aluminum design (no epoxy), with nearly twice the core area as the OEM at that same core thickness.
Performance is amazing. With the oversized custom design, I've yet to see the operating temperature reach the half way mark on the gauge.
The gauge half-way point use to be the lower limit temp with the OEM radiator. The OEM radiator allowed the temperature to travel to full scale on hot days, on the verge of boil over. Having to run the cabin heat on hot summer days on beach trips just to keep the engine from overheating got to be a real drag.
Pictures of the OEM vs Custom, and installation can be seen at www.bmwboard.com in the 3-Series FORUMS area. Just look for the post from: Z4madehere and titled: "1980 320i Runs Hot"
http://www.bmwboard.com/forum/showthread.php?t "361
Hopefully posting here will gives future folks with a similar condition at least one valid search result.
JoshIII Mechanical Engineer Greenville, SC snipped-for-privacy@hotmail.com
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