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
Hi Paul,
These water pump and turbo impellers can be made these days by 3D
printing using laser powder technology. Even turbine wheels too, fault
free and very accurate.
Chris Hoskins.
Yes but 3D printing is too slow for production. It would cost a small
fortune in terms of corporate time.
When these are sand or ceramic cast ten or more are cast at the same time.
It only take a few minutes.
The same goes for rotors. Mazda recently updated their casting
techniques and now rotors are more accurate when they come out of the bold.
Paul Lamar
Hi Paul,
Yes you are right, 3D printing IS slower, but, it does NOT require
supervision, it will run ALL NIGHT LONG all by itself like our one here.
It depends on the volume required. If you need more production you use
more printers.
Chris Hoskins.
Way back in 2003 did did some 3D printed core boxes and casting patterns
for a Mazda intake
manifold. The local college had 3D printer that cost $30,000. I had to
take a course in order to use it.
My local pattern maker wanted to charge me $5000 for an intake manifold
pattern. Some of these
core boxes took over 24 hours to "print". After I did all this I decided
a p-port was better and much cheaper.
That was pre Obama when we still had an economy.
Paul Lamar
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