Paul Lamar wrote:

BTW I had a talk with Jim Mederer on the subject of water pumps and he agrees
with me. A restrictor is not a good idea and you want as much water flow through
the block as you can get.

Paul,
I agree with you, but it occurs to me that there are two moderating factors: erosion
and diminishing returns.  Higher flows will contribute to higher erosion rates.  I
don't think that is likely to be a problem for us, but a good engineer should at
least acknowledge that it has been considered.

As for diminishing returns, remember that the HP consumed is a (linear? quadratic?
exponential?) function of the flow rate, but the heat transferred is an asymptotic
function (i.e. approaches a maximum).   So one needs to pick a point that is
adequate for the cooling expected, as higher flows eat more HP than the additional
cooling is worth.

Russell Kent

In a perfect world but there are hot spots in the engine that the flow
may or may not be optimized for. Mazda's design focus of course is on the 
automotive duty cycle. Jim Mederer's experience is from another world where
three hundred or more HP is being asked from each rotor.

IMHO we are beyond the optimum at the 100 HP per rotor level as I see 
no damage from excess heat on the rotor housings during normal operations. 
The rotor housings are not cracking around the spark plugs and 
the steel liner is not separating from the aluminum die casting. 
The apex seals are not wearing very fast for whatever reason let 
alone excess housing temperatures. As long as we use an apex seal 
lube oil that can tolerate the heat long enough to be effective 
we seem to be OK. Two cycle oil mixed with the fuel seems to be 
doing a good job.

When more turbo engines begin to be used the situation may change.

Our main problem right now is preventing the coolant from
boiling.

Paul Lamar
 
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