http://www.fluidyne.com/pl_theoc.html 

 Really liked the DB 30517 (3.75" thick double pass model)  Will probably use this one on my -8.   

 Tracy   

Perhaps you mean use “two” instead of “this one”.  I looked closely (longingly) at the fluidyne when I was in the market for a cooler; but they just don’t make on with the capacity for the 20B.  One DB 30517 would handle neither the flow nor heat rejection needed; however 2 in parallel would do it.  At least that’s what my analysis says.

Al