I fly with two in series
and have more than adquate cooling for most regimes of flight. A steep
full power climbout on a hot day will push the system to its limits, but
otherwise they work just fine for the power an NA 13B is likely to produce.
Ed;
I certainly wouldn’t argue with
what works. What size lines and connectors are you using?
I tend to try to err on the side of too
much cooling; and may have in my setup. There are a number of variables
we don’t really have a good handle on until we go fly, and it’s not
a limitation I want to have to deal with.
Al