Subject: RX-8 Oil injection questions and thoughts
From: Rotary Engine
Date: 4/5/2011, 2:15 AM
To: AAA Put this in the To box


Question and thoughts about Oil injection.

Because the series 1 RX-8 engine is a bit short of oil injection as
Paul has
mentioned could or would an option be to add some sort of oil
injection into
the intake system to spray a fine mist into the intake system?

I think this would be rather like a 2-stroke oil injection system/s used
on Rotax engines and the like.

My thoughts were use the oil injection system that exists on the
Rotary but
add another injector into the intake system to spray 2-stroke oil using a
Richard Sohns adaptor.

Does anyone have any thoughts about this?

I'm just thinking out loud with ways to add lubrication oil for the Apex
seals, without requiring to premix it.

My thoughts about this is you don't need much oil at low RPM eg when
idling
on the ground, warm up, low rpm for descent and the like but you do need
more oil for high power settings to ensure that there is enough
lubrication
for the seals when they are under high power.  What do other think of
this
and if so what size spay nozzle/s would be needed?


Regards David (Australia)

The oil injection takes place when there is a vacuum in the intake
chamber.
The injector has a one way valve so atmospheric pressure does the
actual injection. The metering pump does just that. It meters the oil to
the injectors.

The metering pump controls a stepper motor by sending out pulses on
four wires. The cheapest and easiest way to modify the amount of
oil metered is to insert a low cost microcomputer in the wiring harness
that reads the pulses and modifies them in such a way that increases
the amount of oil metered.

http://www.imagesco.com/articles/picstepper/02.html

I recommend something like a BASIC stamp as a 3rd grade student can learn
to program it in BASIC. Here is the company I would go with as I have
extensive experience with their product and their $100 prototype board
is extremely easy to use.

The final product could cost under $20 for parts.
http://www.zbasic.net/

Paul Lamar


Re Oil injection,  With early two stroke ie 1970/80 Jap. motorcycles
especially Suzuki used a very simple system, a plunger pump driven via a
gear from the motor was used to inject oil onto the crankshaft and on
the thrust side of the piston/s, the stroke of which was varied by a
cable connected to the throttle. One set the initial setting to a index
mark and the pump did the rest, small amount at idle but still injected
oil on ove run at high speed, and lots more at wide open throttle, I
don't know how the Rotary oil injection works but could it not be rigged
to inject into the inlet manifold?
    John Burey.
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