Our new oil pump body and dual pickup tube are built, tested and work
great. We get 20-21 gal/mn at 6000 shaft RPM and 5-6 bar (70-85 psi),
with no cavitation and no air mixed in the oil, just a little louder
noise than with the stock pump and stock pickup tube (which gives 9.5
gal/mn at the same RPM).

In a few words, we use standard rotors and shaft, but our new pump body
and dual pickup tube replicate the modification brought by Mazda in its
1993-95 oil pump (side channel feeding oil to the rear rotor) WHILE
BEEING DIRECTLY AND WITHOUT MODIFICATION ADAPTABLE ONTO A 1986-92 IRON.
Anyone interested by this mod out there?

Results: double the flow and more pressure than the stock pump, some
more noise... the pump obviously works harder (we measured 2-2.5kW)...
we are going to test its endurance. We are also concerned with the
resistance of the drive chain. Calculations show that we are getting
close to the chain's specs. We'll keep an eye on this and will consider
changing the chain for a heavier-duty one.

We have also learned in the process that, at these high flows, every
sharp corner that the oil flow must go around costs a 10-20% flow
reduction if not properly radiused... every detail counts... some more
than others of course. The stock pickup tube screen alone costs 40% in
flow reduction... at least if it rests on or very close to the sump's
bottom.

We are seriously considering installing an air-oil separator plate in
the sump. What do you think of the idea of cutting a number of holes
with the proper total surface and at the proper locations, and covering
the whole plate with a steel mesh? We would thereby achieve the dual
purpose of separating air from oil and preventing any debris from being
sucked into the pump, without inducing the headloss on the suction side
that the stock oil screen induces.... it might even be easier to
manufacture.

The only little problem I see is the turbo oil return line which would
be below the plate. If the turbo bearing gives up the ghost and debris
find their way into the oil return line, than there would be no
protection for them to be ingested in the oil pump. How likely a
problem is it?

Next step for us is to install the pump in the Arrow and see if it
solves the cooling problem as we think it should. I'll keep you
informed.

Francois Badoux

      Sounds interesting Francois. Any idea what it would cost?


     Kelly Troyer

The Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2004 All world wide rights reserved.