Dave,
I make best power in the 13’s and
I’m usually in the 11’s under boost for take-off. Once in stable
climb I lean into the 12’s. I typically don’t run above 32”
in cruise so I lean until I’m comfortable with intake temps or my
targeted GPH. I only run water injection for take-off and initial climb.
Those are contradictory
points. For, what is it that allows more timing advance other than
prevention of detonation. I think you mean that water is better at
cooling, but alcohols make up for it by providing an apparent increase in fuel
octane as well as cooling. – Yes that’s a better explanation. More time advance without alcohol is
limited in producing extra HP?
what is the purpose of
cooling other than improving detonation Margin? - Experiments during WWII with nozzle placement”
supposedly” showed that pure water injected directly at the engine block
was better for controlling detonation than injecting further upstream. But I
have no idea where I read it. Somewhere while researching my system. Could be
BS or have something to do with where the liquid state change occurs. In the
cylinder or in the intake manifold. But it’s probably not relevant to our
systems anyway.
Not in Southern California. They
sell blue stuff but I cant find any rated below 20deg F (7%methanol). I
even found one, a deep blue color, going for $4/gal no less, that proudly
proclaimed in big letters: "Protects from freezing down to 32
degrees!" Move to Texas! The taxes are
lower and our blue stuff is still 80 proof.
But that is an expensive
sensor that I will probably burn out with 100LL. Have you had any
problems with 100LL? – I don’t
burn a lot of 100LL so can’t say how long it will last. Mark S. purchased
a different system and his failed very fast. Too fast in my opinion. My
understanding is the sensors take a long time to fail but the signal response
time becomes too slow for closed looped engine controllers to use. A slow
response time in our systems should not cause problems as long as the
controller didn’t flag it as an out of parameter condition and shutdown
the gauge. We need to test Mark’s to see if the sensor is actually
putting out the correct voltages or if the controller is just unhappy with the
response time. You might check with Ross at http://www.sdsefi.com/.
This is from his site.
Bosch
technical information states the useful service life of the sensor is 100,000
miles or 10 years. Leaded fuel is not recommended with any O2 sensor and will
severely shorten the life of the sensor, lead content of .6 g/l drops life to
around 10,000 miles. In real world use, it appears that sensor life is more in
the range of 50,000 miles with unleaded fuel.
For a chemical lead scavenger to extend the life of O2
sensors when using leaded fuels:
Website: www.decalinchemicals.com
So a minimum life span of 500-600 gallons of 100LL? I would
also call the manufacture and verify how they handle a degraded signal in their
software before purchasing any system. Let them know you will be running leaded
fuel.
Bobby
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of David Leonard
Sent: Monday, August 29, 2011 2:20
PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: How to
tune with ADI?
Thanks Bobby,
What number are you looking for for mixture?
On Mon, Aug 29, 2011 at 7:24 AM, Bobby J.
Hughes <bhughes@qnsi.net>
wrote:
David,
Where are you injecting the water?
I am injecting into the plenum just before the throttle body and after the
intercooler.
Here are the few facts I think
I know about water injections.
- Water is better for detonation
prevention than an alcohol mix.
- Alcohol mixture allows timing
advance and more HP.
Those are contradictory
points. For, what is it that allows more timing advance other than
prevention of detonation. I think you mean that water is better at cooling,
but alcohols make up for it by providing an apparent increase in fuel octane as
well as cooling.
- Injection in the intake some
distance before the engine block = more cooling.
- Injection at the block = better
detonation margin.
what is the purpose of
cooling other than improving detonation Margin?
- Windshield wiper fluid is a
good alternative to dealing with methanol. Usually about 40% alcohol.
Not in Southern California. They
sell blue stuff but I cant find any rated below 20deg F (7%methanol). I even
found one, a deep blue color, going for $4/gal no less, that proudly proclaimed
in big letters: "Protects from freezing down to 32 degrees!"
Also a good wideband is very useful. http://www.jdmpartswholesale.com/product/plx-dm-5-wideband-o2-52mm-display-sm-afr-combo-black
It’s my most used instrument.
I Guess I should break down and get a WBO2 like the one you
linked. But that is an expensive sensor that I will probably burn out
with 100LL. Have you had any problems with 100LL?
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net]
On Behalf Of David Leonard
Sent: Sunday, August 28, 2011
10:24 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] How
to tune with ADI?
Ok, So I
have the new ADI system installed and working.... I think?
Some of you smart
racing guys probably have experience with ADI.
Most of the
instructions that come with tuning it are directed toward car guys that have
computers and knock sensors. All they do is turn the system on and the
computer allows more advance because I is not sensing any knock. The only
real advise I have so for for me is that I should be running just less than the
amount of ADI that it takes to bog down the engine. My system is a fixed
flow so I don't have much choice but it seems to be about right. If I use
straight water (which I did for initial testing), the engine bogs after about
10-15 seconds of ruining the ADI system. But when I uses a 50/50 mix of
water and denatured alcohol (too hard to find methanol around here, but close
enough) the engine does not bog.
So assuming my
amount of ADI injected is about right, now I am supposed to be able to lean to
better power and advance the timing a little. But how much? For the
last testing flight I was using EGT for lack of a better guide. When the
ADI comes on, my EGT drops by about 30 deg C, and there is a hint of roughness
to the engine. I can then lean a little and the roughness clears
up. For my test flight I leaned until my EFT came back up to where I
normally limit it (890 deg C). But if I then add 5 more inches of MAP,
there is still a hint of roughness even at 890 deg and I get the sense that it
wants to be leaned a little more. But I am afraid to do that... We are
talking 45" MAP and 7300 RPM here (185 KTS indicated (Vne) and
climbing at 500 fpm).
So here are my
questions:
Is EGT a useful
tool here, and does leaning to get the EGT back to 890 make any sense?
Since Methanol
will do such a good job at preventing detonation, is it safe to lean further
toward best power (peak EGT)? (note, that will be hard on the turbo... I
need to remember to bring the spare one to Reno)
How much advance
do you think i can add? I was previously ruining 5 deg ahead of
Tracy's
recommended initial set up. Can't give a number because the EC2
retards the timing with higher MAP's. How much, I have not heard. I
can easily add one deg at a time using Ed's EFI monitor. But without a
knock sensor am really in the blind.
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net