Seems to me that the radiator could cause a big pressure drop. Have as

big a

radiator volume as you can and as big a return line as possible- up to

the 1

3/4 " that the  pump inlet is.

 I just ordered and am anxiously awaiting delivery of  a C&R Racing rad.

It's

plenty big- 27 x 18 x ~2 1/4, with  AN 16 fittings.

As far as  friction loss, it goes up with the square of the volume of

flow.

You can have a smaller radiator that drops the coolant temp less than a

large

rad, and you then have to run the fluid through the system faster.  If on

the

other hand, you use a bigger, more effective radiator, with the coolant
returning from the rad much cooler, it seems that you could run the

coolant

through the engine much slower.

Al Gietzen wrote:

Basically true, Bryon; but one criteria in an airplane is light weight (and
minimal space). So we like to keep the radiator small.  This is the same
reason we don't necessarily like Lynn's approach of putting in the 5/8"
restrictor at the pump outlet.  It is a solution with a penalty; a larger
radiator.

Al

 
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