Paul,
Do you know if anyone has tried a better water pump? By that I
mean a separate engine driven after market pump. I have found at least 2
examples Mazarre (sic) makes a engine driven pump intended to replace a
standard pump on a V-8 chevy. They have a performance chart for the pump
on their site explaining that the pump requires about 4.8 HP to
move 60gpm "with normal engine back pressure." They do sell the
electric water pumps, but only claim they are good for drag racing, NOT
for road use. As we have told people forever it seems. 5 HP sounds about
right on their engine driven pump if they are moving that much water
without cavitation. The Wisconsin powersport guys said they had tested
the standard second gen pump and it was topped out at 53 gpm at the
verge of cavitation. I wonder if we could move more water and solve that
problem? I also like the original PowerSport efforts into center feed
cooling. That seems like a better idea over all if you are going to run
at those power levels. Perhaps Steve might tell us if that was ever
followed up on?
Bill Jepson

Cooling with a 2nd gen pump is just not a problem for aircraft use.
Mark Steitle with the installed thermo couples is not reporting
any problems so far. Mazda data at 7000 RPM has the "cylinder head" temperature
100 F lower than a water cooled Continental aircraft engine like the one
that went around the world in the Voyager.

There is an after market pump that Jim Mederer used on one of his
1200 HP turbo 3 rotors. It is used on 800 HP sprint cars and it is made by KSE
as I recall.

Changing the cooling system from series to parallel As P.S. attempted and NSU
used  would be a worth while thing to do but it is near impossible without a
complete redesign of the engine. The fact of the matter is nobody, unless they
are building a Reno racer, are going to demand much over 300 HP as they don't
want to burn the fuel.

Paul Lamar