The general rule Is 2 cubic inch of radiator core per cubic inch of engine. this Is really a starting point. A Subaru ea-81 is 1800cc or 100 cubic inches. we should aim for at least 220 to 280 cubic inch of radiator core. the VW rabbit diesel radiator Is often used with the Subaru ea-81. It Is 19 x 12 x 1 inch giving 228 ci of radiator. It is possible to make your rad smaller by making it twice as thick.
The second row of core looses effectiveness - it Is 60% as effective as the first row only. My rad is 15 x 10 = 150 ci adding the second row at 60% effectiveness is 150 x 60% = 90. Total becomes 240 ci which is more than the VW radiator. The problem i had was due to having a radiator too small for my engine And not knowing it. I found 4 places that would build my radiator to my spec but at différent prices. I retained TCP Performance to construct it. Do your homework have qoutes done And decide for yourself.
Need more info, dont hesitate.
Hi Bob, I'll be home friday let me post the data I got And you'll see it's not hard to find out what you need. Too bad I had to find out the hard Way. But with what I got you wont have to.
Norm used a EA81 Subaru engine. If you have not chosen an engine..wait until that choice is done and the other builders have figured out the parts that work with that installation. I have a friend working over a year trying to get a Subaru EA81 to run correctly in a CH701. Stu Duncan's CH701 with Rotax 912S has 265 hrs flying trouble free since March 2011. The engine you chose can make or break your enjoyment of the completed project.
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