An early side ported intake/peripheral exhaust ported engine is the
baseline. The early side ported engine converted to a periphery intake,
is an aberration, similar to the factory pure race engines. The
Renesis
engine with side intake and side exhaust ports with zero overlap and very
little exhaust dilution of the intake is a similar but very different engine
from other rotaries. Any of these with a turbocharger added
becomes yet again another animal. All of these have home built intakes and
home built exhaust systems. One of the results will be no two will produce
the same outcome in any parameter.
The object of the EGT gage is to be able to see the combustion process in
near real time. So, the probes should be about 3" out from the port face. If
there is a curve in the pipe the probe should be on the outside of that curve
where the probe will be bathed in the flow.
And still there is no guarantee of success only an improved
likelihood.
Reverse the connections at the gage face to see if the readings follow the
reversal. They should or the gage is faulty. Reverse the probes in the header to
see if one just reads higher all of the time. If all is well in the gage
system reverse two the injectors and see if the EGT reading follows the injector
switch.
It is two single rotor engines sharing a crank shaft. You may never get the
same EGTs on both housings.
Try for EGT below 1650 at wide open throttle full rich mixture at
cruise speed. Add fuel to reduce the EGT (fuel cooling the engine). Peripheral
exhaust ports using stock apex seals only I have no experience with side exhaust
ports. Best power will be the same as a piston engine, or about 50 degrees rich
of peak EGT. However, piston engine EGTs may only be 1550 or so, while rotary
peaks may be above 1900 degrees.
Very bad for stock apex seals. So we stay well rich of peak EGT or
lean of peak EGT to attain the same low number. Very easy with the reduced
fuel flow.
Aircraft engines have a much higher duty cycle than even a racing
engine. Using stock spark plugs in an aircraft engine is uninformed at best. The
racing plug gifted by Mazda to successful racers is the NGK R6725=115 Or
Resistor plug PN 6725 in the 11.5 heat range.
Colder than the coldest street plug the 10 heat range. This plug is a
retracted tip single side electrode and comes out of the box gapped at around
.017"
I reduce that gap to .010" and I run a MSD 6AL on both leading and
trailing.
Why?
Because we think in terms of the piston engine where the mixture is pressed
to the end of a tube with the plug in the center. Real handy for getting
consistent performance. In the rotary the mixture goes by the plugs at 100 miles
per hour carried by a long strange looking rotor face and being held
against a cold rotor housing while it turns back into droplets. Chances of this
working is low at best.
The car engine need only operate well below 4,000 RPM. Not useful for
aircraft.
If using the stock "Lost spark" system on the leading plugs remember that
the spark gaps are added as in series, and one plug always runs backwards
electrically. So you could run a conventional retracted tip ice cold
plug with a shorter gap and or switch the plug wires or the plugs from time
to time.
But I run on as usual..................
Lynn E. Hanover
In a message dated 2/9/2012 7:29:24 A.M. Eastern Standard Time,
wschertz@comcast.net writes:
EGT’s are thermocouples, (Type K), if you want to check the probes, hook
a millivolt reading DVM up to the leads, and raise them to a known temperature
(like boiling water). You can get the millivolts vs. temperature from a
handbook. My opinion, is that if the settings on the EM2 are identical, the a
difference in the EGT readings when the engine is running is probably
real.
Have you tried it with the new plugs? I have the experience that when my
plugs begin to go that I get a big spread in EGT readings, and the engine
doesn’t like full throttle/high rpm’s, put in new plugs and it smooths
out.
Bill
Schertz
KIS Cruiser #4045
N343BS
Phase one testing
Completed