The 2nd gen RX8 is weird.
   The last one looks more like a
 RX7 2nd
   gen

   Paul


 Paul,
 If we think of impeller leading edge as
 a wing gently entering the water
 stream... and then the trailing edge
 mimicking a extended wing flap...
 directing as much water as possible
 into the pump housing scroll.
 The computer model helps us not stall
 the "wing" or congest the flow at
 any point on it's surface (or between
 adjacent surfaces).  We would like
 to have each section do equal work.
 Then Mazda's new design makes more
 sense.
 Barry Bordes

 The water must make a sharp right
 angle. It comes in on the same axis as
 the pump shaft.
   Then it must turn 90 degrees and
 flow outward towards the housing scroll.

 The device that does this well, using
 air, is a turbo charger compressor
 wheel.

 I suspect a good water pump would work
 the same way. I could be wrong of
 course
 but I would like to see some comparison
 data and a CFD before I would be
 convinced.

 Turbo charger compressors are hard to
 make. They are probably machined
 on a 4 or 5 axis
 NC mill. Too costly for a car.

 High pressure die casting  them
 would be very hard to do I suspect. The
 mold must be
 made in perhaps multiple parts to get
 the finished product out of the
 mold. Very expensive.

 In the case of a water pump It may be
 necessary to make them in iron or
 steel for long life.
 That prevents high pressure die
 casting.

 In the case of the 2nd gen RX8 that
 could be done in a simple iron or
 steel sand or ceramic casting.
 There are no 3D double curved surfaces.
 It is probably better than the
 stamped steel
 first gen RX8 or 3rd gen RX7
 impellers.

 It remains to be seen if the aluminum
 after market NC Mill  impeller
 will hold up for long periods.

 We are using the KSE water pump on the
 time to climb. How that is made I
 know not.

 Paul Lamar

I would like to see some quantitative data back to back with the first gen RX8 impeller.
Should be easy to do with a 2 HP AC electric motor and a fixed orifice say 3/8th of an inch
to simulate the restrictions in the engine block. Measure the pressure just before the restriction.
This will give us data at one RPM unless you have a stepped puley on the 2 HP AC motor.

Paul Lamar

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