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That sounds like a good solution, but it is not what I really want to make
sure of.
I already have one of Richard Sohns RX-8 oil adaptors and a meter adjuster
plate. This allows the oil injection system to vary oil rate injection
based on RPM, which means the electronics are no longer required.
What I want to ensure is whether adding an extra oil injector or injectors
into the intake system for 2-stroke oil injector would be a good option or
addition. If it is, then where is the best place to add them or it in the
intake system, the stock manifold is being used for this project.
I thought this might be a fairly elegant solution. The RPM of the engine
controls the flow of 2 stroke oil that is injected. I've attached the
adapter information that Richard provides the prices in are out of date
I think.
Regards David
That RX8 oil metering pump adjuster is a clever idea Richard.
The best place is inject it into the fuel on the low pressure
side of the fuel pump. Mount the oil storage container high and use a
needle valve to control the gravity flow into a T in the fuel line.
Probably a better idea is to use a venturi in the fuel line so
the oil flow is proportional to the speed or amount of the fuel flowing
through the fuel line.
Putting the oil in the fuel also means it lubes the housing better
as it is automatically distributed through out the housing.
BTW it is by no means certain that low apex oil injection caused the
problems
with the early RX8 engine apex seals. The current thinking is failure of one
or more ignition coils caused misses that washed away the apex seal oil with
too rich raw fuel.
If you mix the oil with the fuel this cannot happen.
Paul Lamar
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Looking at the picture are you suggesting it be gravity feed into the
fuel line?
Would it not be better to add it into the fuel line under a little
pressure from the Oil
Injection Pump System?
Wouldn't that be a better option it would also make sure it mixes more
accurately with
fuel as it is being used and vary the amount based on engine RPM.
I guess a one way valve would be need to be installed ensure no back
flow of fuel into
the oil system not an issue to install though, apart from that I think
it would work.
So it would have force feed oil into the line, yes?
Regards David
It at depends on the positions of the respective tanks.
It is easy to mock it up and see what happens.
Paul Lamar
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I note another person asked this question,
which was what I wondered about in the first place.
how about just injecting oil directly into the intake manifold very
close to one of the
intake ports for each rotor ? with the controller this surely would be
good option?
Regards David
Mazda spent a lot of money coming up with a chrome surface so
the apex seal oil would spread out. Called Micro Channel Pores Chrome
Plating.
http://www.rotaryeng.net/1984-recent-tech.pdf
That is because they intended to inject oil directly into
the rotor housing thorough one hole for emissions reasons. The RX8 is now up
to two holes per rotor housing.
Back in the old days of carburettors the oil went into the float
bowl. It worked well. I suggest going back to that method by
Injecting oil into the input side of the fuel pump. The high pressure
fuel pump will mix the oil thoroughly with the fuel. We know that
mixing oil with the fuel works well because if you mix too much it
survives the combustion cycle and winds up in the oil sump.
Obviously it is spreading through out all of the chambers.
As soon as I get this project done I am working on and I get
Mike Will's rotary powered RV4 flying again I will try out this idea.
Paul Lamar
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I have every intention of still using the original oil injection holes.
I did find this info on the racing beat website.
http://www.racingbeat.com/mazda/performance/rotary-tech-tips/oil-filters-mop.html
It is near the bottom of the page.
RX-8 - Race Tips:- While undertaking development work on the RX-8
Renesis engine for SCCA T2/T3 use, we decided to introduce extra oil
into the fuel to monitor the effect. To our surprise, this additional
oil increased power! Further dyno testing found that by adding 10 oz. of
Royal Purple 2-Stroke Oil to 6 gallons of fuel, we gained an average of
1.7 HP from 2000-9000 RPM, along with an increase in peak power of 4 HP.
We validated this increase by changing back to a "non-oiled" fuel - and
the power returned to the previous level. Later, we tried the same test
with another brand of synthetic oil with nearly the same results. For
racing applications, the addition of a high quality synthetic oil
increases power and most certainly decreases wear. The only negatives
are the cost of the oil and an increase in the tendency to foul the
spark plugs. (Note: We have not performed these tests on non-RX-8
engines yet, these results are unknown.)
I guess that injecting or premixing some additional 2-stroke oil into
the fuel is apparently a better option and as such worth doing although
not at the rate that racing beat suggest for high end racing
applications, however any improvement in power is a bonus, improvement
in lubrication obviously is the aim without causing plug fouling.
Also from the Racingbeat site:- The metering rates for stock engines
vary, so consult an appropriate shop manual for your carâ??s
specifications. In normally aspirated racing vehicles we use either a
setting of 5cc/5minutes (total flow - 2,000 RPM, warm engine, arm in the
"full throttle" position) on the metering oil pump or premix 3.5 oz of
good quality synthetic oil (preferably 2-stroke motorcycle "oil
injection" oil) to 5 gallons of fuel. The requirement for turbo engines
in racing is high enough that use of a metering oil pump is impractical.
Therefore, we premix up to 22 oz of oil to 5 gallons of fuel in a 600 HP
2-rotor. If you are not pressing your engine this hard, you can use
proportionally less oil.
From this and other past posts in the newsletter. It would appear that
somewhere between 100 ml and 200 ml per 20 liters (200:1 - 100:1) would
be about the optimum amount to inject for use in flying.
If the oil is injected both into the original oil nozzles and then using
another oil nozzle to push oil into the fuel system right before the
injection pumps that should be fairly elegant and would not require
premixing oil into fuel.
I'm in the process of doing my engine now within the next few months it
should be finished on a test stand and ready for running using Tracy's
Computer system and engine monitoring system,
At the moment the making the adaptor for the gearbox is in progress,
that will be finished shortly.
Then it's on to putting it all together and building the wiring system
etc for it.
Regards David.
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