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Are Wide Band O2 Sensors Affected By 100LL

Vans101

Well Known Member
I am interested in installing a wide band O2 sensor to read air fuel ratio. If I run 100 LL will the lead foul the sensor?
 
I just received one from PLX Devices to complete the (not running yet) EFII System 32 installation.
Not installed, and had not considered the 100LL v.s. unleaded fuel aspect.


If as Ross says its life would be 10%, I will reconsider drilling a hole in the beautiful Trombone Vetterman exhaust...


BTW, PLX Devices mentions to install the O2 sensor at least 2 feet from the cylinder head. I presume to prevent exessive heat.That would mean after the muffler in the (short) end tail pipe.

Does anyone know how that would affect its readings, IF I choose to install??
 
According to Theory...

Lead deposits are most likely when "cool" temps are permitted in the cylinders (and exhaust in the case of the O2 sensor). Robert at EFII recommends placing the sensor bung up close to the flame-front as it comes out the exhaust valve, thus keeping the temperatures up and the formation of lead deposits down. Though I cannot verify by personal experience, he says the sensor should last a very long time in that environment.
My sensor is down the pipe a bit and failed after about 50 hours. With the new system 32 installation, I am thinking of moving the bung up as Robert suggested and see how that works.
Needless to say, once you weld the bung in place, the mounting flanges will never come off the pipe... OR, put another way... you had better make sure the mounting flange is in place before you weld the bung - you'll not get it on if you don't!
 
We've seen the Bosch 4.9 LSU sensors last as little as 2 hours and as long as 300 using 100LL. Location doesn't seem to make much difference. There is some evidence that a long boss holding just the very tip (.100) into the exhaust stream may extend life slightly. Normal lifespan in auto use is 2500-4000 hours.

The biggest concerns are thermal shock, powering the sensor heater up at the same time as engine start (the auto OEMs don't do this) and condensation hitting the sensor on warmup (hence cautions about orientation in the pipe to help mitigate this).

Also, be sure to have the sensor mounted at least 12 inches from atmosphere to avoid dilution during valve overlap and reversion in the pipe.
 
According to Robert Paisley installing it much closer to the cylinder will keep the lead deposit off the sensor:
https://vansairforce.com/community/showthread.php?t=173975&page=2

That assumes that lead deposits are what kill them. Also possible that the lead present in the exh before it's deposit onto something is damaging when it comes into contact with the precious metal inside the senor. I know little about this, but know enough to be suspicious of a theory to only relies on deposits as the cause. Many of these metallic elements have unique reactions with gaseous elements. Just consider how a catalytic convertor performs it's function. Wouldn't be surprised that the opposite occurs as well. That certain gaseous elements change the make up of the precious metal.

Larry
 
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My first sensor lasted about 10 hours on my EFII system. I was running the engine rich for break-in. I now run aggressive lean of peak and the aircraft has a 100 hours on the replacement sensor.
 
In the oxygen sensor, the concentration of oxygen in exhaust is compared to the concentration in the surrounding atmosphere by an electrochemical cell. The sensor is often made up to two platinum electrodes separated by a porous solid electrolyte. The platinum catalyzes the breakdown of diatomic oxygen molecules to oxygen ions. The diatomic oxygen takes up electrons as it dissociates into oxygen ions. The ions are transported across the electrolyte to the exhaust side by the differential concentration. The rate of oxygen transport is proportional to the differing partial pressures of oxygen on each side of the cell. On the atmospheric side of the cell (with oxygen content typically ~21%), the gain of electrons is compensated by the loss of electrons on the exhaust side (where diatomic oxygen is reassembled and released), which causes an electrical potential (voltage) to develop across the sensor. This voltage is then converted to an oxygen concentration by knowing the reference oxygen concentration (21%) and the particulars of the electrochemical cell.

The presence of lead (in various compounds) vapor in the exhaust poisons the platinum catalyst, causing it to fail to cause oxygen dissociation, damaging the sensor over time, and reducing its response to oxygen differential concentration.

In this link it is suggested that position in the exhaust stream and contact temperature can affect the rate of poisoning damage done to exhaust catalytic converters (also containing platinum and other precious metal catalysts), which may imply that similar parameters play a role in the life and effectiveness of catalytic oxygen sensors.
 
No smart guy here.

I did install an A/F ratio gauge on my O-360 while trying to run a TBI. I bought one on Amazon with the Bosch narrow band sensor and installed it as per the instructions. I had read that wide band sensors would not last with 100LL. Instructions said to mount the sensor at an angle in the pipe and a minimum distance from the head. The readings it shows appear to be the same now as when installed 400 hrs ago. I do lean aggressively on the ground and in the air. My mixture lever always ends up in the same position on the quadrant showing the same numbers (which bounce around, I guess since only 2 cyls are being monitored) on the A/F gauge, fuel flow, richness and power on the Dynon at my usual cruise settings.

We have someone on the field who uses a wideband sensor. It is connected to his Avspark electronic ignition (don't think it is made any longer). He has to clean the sensor every 10 or so hours or his EI doesn't work properly. Not sure how many sensors he has replaced.
 
...
I had read that wide band sensors would not last with 100LL. Instructions said to mount the sensor at an angle in the pipe and a minimum distance from the head. The readings it shows appear to be the same now as when installed 400 hrs ago. I do lean aggressively on the ground and in the air. My mixture lever always ends up in the same position on the quadrant showing the same numbers (which bounce around, I guess since only 2 cyls are being monitored) on the A/F gauge, fuel flow, richness and power on the Dynon at my usual cruise settings.

...

Your experience seems to go along with things I've read, including the link in my post above, about keeping the sensor close to the head, where the exhaust remains hot enough to minimize lead condensation, and the angle may prevent direct impingement of the exhaust on the sensor. Running LOP will keep the exhaust hot, and reduce the partial pressure of lead vapor, so maybe that helps keep it clean as well. I would bet that running rich of peak for significant amounts of time (beyond max power climbs, etc.) would increase the failure rate due to the higher lead concentration, soot from incomplete combustion, and possibly even the very low O2 concentration, which will leave nothing to compete with lead adsorbing on the catalyst.

One thing (among many) I don't know is how much of the failure mode relies on lead vapor condensing due to temperature (fouling), and how much the chemisorption of lead vapor on the catalyst contributes. I would imagine that both fouling due to soot and other condensates as well as chemisorption of lead on the sensor catalyst play significant roles, possibly in different operating regimes of the engine.

Additionally, I think others have noted that the way O2 sensors are powered up in aircraft applications is different than in automotives, where the sensor startup is delayed until after the engine is fired and the parts are heated enough to prevent water condensation That can contribute to short lifetimes for sensors.
 
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Additionally, I think others have noted that the way O2 sensors are powered up in aircraft applications is different than in automotives, where the sensor is allowed adequate time to heat up before the engine is fired. That can contribute to short lifetimes for sensors.

I've heard this but it doesn't make sense. In my race car I have dual FAST O2 sensors. I always turn the system on for a bit prior to cranking. However, this is a race car and represents probably 0.01% or less of the automobiles using O2 sensors. Most cars/trucks you open the door, sit down, & crank. The only time the vehicle knows it is being cranked is when the key is turned or button pressed and then an almost instant fire; unless it is a diesel. In my diesel truck I do turn on the key and make sure the glow plug light is out then fire. How do most cars heat the sensors prior to being fired if they don't know they are being fired until they are fired?

I am wiring up my O2 sensor soon in my plane, plan on putting it on a switch (like autopilot or EFIS) that gets powered prior to cranking to give it some time to heat.
 
I've heard this but it doesn't make sense. In my race car I have dual FAST O2 sensors. I always turn the system on for a bit prior to cranking. However, this is a race car and represents probably 0.01% or less of the automobiles using O2 sensors. Most cars/trucks you open the door, sit down, & crank. The only time the vehicle knows it is being cranked is when the key is turned or button pressed and then an almost instant fire; unless it is a diesel. In my diesel truck I do turn on the key and make sure the glow plug light is out then fire. How do most cars heat the sensors prior to being fired if they don't know they are being fired until they are fired?

I am wiring up my O2 sensor soon in my plane, plan on putting it on a switch (like autopilot or EFIS) that gets powered prior to cranking to give it some time to heat.

When modern engines are first cranked, they are operating in "open loop" mode, where there is no feedback from sensors and the engine is simply dumping X amount of fuel in to mix with Y amount of air. At some point steady engine operation and temperatures results in a change to "closed loop" mode where it starts paying attention to things like the oxygen sensor, catalytic temps, etc. For the first few minutes those are ignored.

The oxygen sensor, if it's hot prior to start, can get damaged by water vapor from the combustion chamber condensing on a cool valve/head/port/exhaust pipe and then droplets hit the hot ceramic sensor. For this reason most OEM's leave the sensor unpowered for the first 30 seconds to a minute after engine start, until the exhaust temperatures are well above the point that would allow for water condensation, and then power up the oxygen sensor. During this time period the engine is operating in open-loop mode.

When I installed the SDS system on my 9A this spring, I put an electronic timer circuit in place to be triggered by the starter solenoid current and wait 30 seconds before applying power to my oxygen sensor.
 
When modern engines are first cranked, they are operating in "open loop" mode, where there is no feedback from sensors and the engine is simply dumping X amount of fuel in to mix with Y amount of air. At some point steady engine operation and temperatures results in a change to "closed loop" mode where it starts paying attention to things like the oxygen sensor, catalytic temps, etc. For the first few minutes those are ignored.

The oxygen sensor, if it's hot prior to start, can get damaged by water vapor from the combustion chamber condensing on a cool valve/head/port/exhaust pipe and then droplets hit the hot ceramic sensor. For this reason most OEM's leave the sensor unpowered for the first 30 seconds to a minute after engine start, until the exhaust temperatures are well above the point that would allow for water condensation, and then power up the oxygen sensor. During this time period the engine is operating in open-loop mode.

When I installed the SDS system on my 9A this spring, I put an electronic timer circuit in place to be triggered by the starter solenoid current and wait 30 seconds before applying power to my oxygen sensor.


So don't heat them up prior to cranking, rethinking how I am going to wire mine now. Maybe this is why some many of them fail in our applications. Understand the open loop/closed loop/lookup tables. I had heard they need to be heated prior to cranking in order to prevent damage, didn't know how this was possible.
 
When I installed the SDS system on my 9A this spring, I put an electronic timer circuit in place to be triggered by the starter solenoid current and wait 30 seconds before applying power to my oxygen sensor.

Greg - Can you please post details on your delay timer circuit? I have a Ballenger AFR gauge with NTK wideband sensor in my plane, but it is wired to come on with the master. I'd like to change to your approach of delaying the sensor start.

Thanks!
 
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When modern engines are first cranked, they are operating in "open loop" mode, where there is no feedback from sensors and the engine is simply dumping X amount of fuel in to mix with Y amount of air. At some point steady engine operation and temperatures results in a change to "closed loop" mode where it starts paying attention to things like the oxygen sensor, catalytic temps, etc. For the first few minutes those are ignored.

The oxygen sensor, if it's hot prior to start, can get damaged by water vapor from the combustion chamber condensing on a cool valve/head/port/exhaust pipe and then droplets hit the hot ceramic sensor. For this reason most OEM's leave the sensor unpowered for the first 30 seconds to a minute after engine start, until the exhaust temperatures are well above the point that would allow for water condensation, and then power up the oxygen sensor. During this time period the engine is operating in open-loop mode.

When I installed the SDS system on my 9A this spring, I put an electronic timer circuit in place to be triggered by the starter solenoid current and wait 30 seconds before applying power to my oxygen sensor.

Has this approach worked for you in extending the sensor life, compared to the numbers Ross is suggesting?
 
Has this approach worked for you in extending the sensor life, compared to the numbers Ross is suggesting?

I can't speak to the extension of the sensor life because I've only been running it 122 hours with this set up since installation in March of this year - but I've had zero problems with the oxygen sensor setup for those 122 hours and 6 months so far.

Greg - Can you please post details on your delay timer circuit? I have a Ballenger AFR gauge with NTK wideband sensor in my plane, but it is wired to come on with the master. I'd like to change to your approach of delaying the sensor start.

Thanks!

Here is the device I purchased for this purpose - it weighs only a few grams, can be programmed literally hundreds of ways, and can handle the electrical load of the AFR sensor. I have mine drawing power off the same switch that energizes my SDS computer, and then it looks at the starter solenoid for voltage (from cranking the engine), then waits 30 seconds (you can set whatever delay you like) and then applies power to the AFR sensor. They have 5 amp and 10 amp versions to fit your needs.

https://www.amazon.com/Miniature-cy...8468709&redirect=true&s=merchant-items&sr=1-1
 
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AOPA Article

This article quotes Klaus Savier (Lightspeed founder), as saying:
"I thought about installing a lambda gauge in my airplane many years ago, but I was told they wouldn’t work with leaded avgas, so I didn’t question it, and I didn’t try. Finally, I decided to see for myself. I’ve been flying with lambda gauges in my two airplanes now for a combined 800 hours. I only had one probe go bad and that happened early, when there was a lot of rich operation."

The article goes on to say:
the lead fouling caused his first lambda probe to fail. But that problem hasn’t recurred, primarily because the information the gauge provides allows him to run his engine far leaner—and that keeps lead deposits from building up.


https://www.aopa.org/news-and-media/all-news/2018/february/pilot/pe-lean-on-me
 
I edited my post above to reflect the fact that my understanding of the O2 sensor/engine startup sequence was originally incorrect. Hopefully that will prevent confusion in the future. Thanks for the correct info!
 
Additional info from Ballenger AFRv500v2 manual on sensor care

This is from the manual for the Ballenger AFR gauge that I have in my plane. I'm using the NTK sensor. The manual is available here:https://www.bmotorsports.com/download/products/o2/AFR500v2_Manual.pdf

I've bolded some portions for emphasis.

The AFR500v2 is widely fuel compatible. Many are listed below:
Gasoline / Petrol (leaded or unleaded)
Alcohol (Methanol)
Ethanol
Compressed Natural Gas (CNG)
Liquefied Petroleum Gas (LPG)
Propane
Many other combustible fuels

Top causes for an error:
1. Bad Sensor due to rich misfiring or backfiring (tuning far too
rich and/or raw fuel hitting the sensor possibly leading to a
cracked ceramic or contaminated ceramic element).
2. Bad Sensor due to having the sensor in the exhaust stream
with no control and no heating which almost immediately foul
a sensor
.
3. Bad Sensor due to bad manufacturing or damage in transit or
improper installation (sensor is at the bottom of the pipe, etc).
4. Bad Sensor due to mechanical damage (dropped or hit).
5. Sensor not reading within range due to being too hot or cold
(ie right next to the port or far down the exhaust stream)
.

How to maximize sensor life
1. Get a baseline tune before installing a sensor. You don’t need the sensor in most cases to get your baseline timing and fuel settings.
2. NEVER leave a sensor in an exhaust unheated (disconnected).
3. Don’t leave the sensor in continuously, only use for tuning and specific monitoring periods.
4. Limit your use of the sensor with leaded, race, or oil mixed fuels. NTK sensors are significantly more durable than Bosch sensors in such environments.
5. Limit time in water cooled exhausts and avoid this where possible.
6. Handle the sensor with extreme care. The sensing element is a delicate ceramic. Rough handling or drops may destroy the sensor.
7. Never exceed 1700F (930C) EGT at the sensor. In high EGT environments, extended bungs such as SNSR-01064/SNSR- 01054 or Heat Sink Bung Extenders such as SNSR-01065 are strongly recommended.

Sensor Installation
Oxygen sensors are sensitive to temperature, pressure and contaminants. A non-ideal sensor installation may dramatically reduce your sensor life.

Ensure that there are no leaks in the exhaust system as this will falsely indicate lean or high air fuel ratio values. The sensor should be installed upstream of any air-injection equipment.

The sensor should not be installed in a pressurized environment and therefore should be installed downstream of any turbochargers or similar systems causing exhaust pressure.

The sensor should be installed upstream of any emissions systems and catalytic converters.

Typically, the oxygen sensor should be installed 1ft to 4ft from the exhaust ports. A sensor that is too close will receive frequent thermal variations, leading to a reduced sensor life. A sensor that is too far away may run too cold and risk condensate leading to reduced sensor life.

The sensor should be installed at least 10˚ above horizontal to avoid condensation and water pooling in the sensing element. Ideally the sensor is installed off vertical between the 10 and 2 clock positions (see Fig 4).
 
Exchange?

NTK sensors are significantly more durable than Bosch sensors in such environments

Anyone know if the NTK and Bosch (PLX) sensors are directly interchangeable? My question focuses on the cable connector the PLX units have.

I'd hate to have to rewire my system to change over to the NTK...
 
Anyone know if the NTK and Bosch (PLX) sensors are directly interchangeable? My question focuses on the cable connector the PLX units have.

From info in the Ballenger manual & on their website, it appears that the cable connector is likely the same, since they list on only one type of cable.

However, you should verify that the device that the sensor is connected to is compatible with both types of sensors. For the Ballenger gauge, there is a jumper setting to change sensors. The NTK & LSU 4.2 use the same setting, but the LSU 4.9 requires a different setting.

The first option is Bosch LSU 4.9 sensor capability. As shipped (unless otherwise specified), this is set for the Bosch LSU 4.2 & NTK Sensors. You must install a red jumper to enable LSU 4.9 ONLY mode.
 
Greg - Can you please post details on your delay timer circuit? I have a Ballenger AFR gauge with NTK wideband sensor in my plane, but it is wired to come on with the master. I'd like to change to your approach of delaying the sensor start.

Thanks!

Hey David

The way I have mine wired in the Porsche 930 you saw this weekend with the Microsquirt is to have the ECU fuel pump trigger provide ground for the coil of a relay, which powers on the wideband conroller.

I'd do the same thing in the airplane, I'll bet the SDS has exactly that circuit for its use in autos. If not, then I'd use a Hobbes switch to provide a ground for the relay when your oil pressure comes up.
 
I'd do the same thing in the airplane, I'll bet the SDS has exactly that circuit for its use in autos. If not, then I'd use a Hobbes switch to provide a ground for the relay when your oil pressure comes up.

Either would work - I have mine looking for +12 volts on the starter solenoid to indicate cranking, then starting a timer for power.
 
I got interested in A/F monitoring for my plane a while ago, and installed a system that has been working flawlessly for a couple hundred hours now. Wrote an extensive article for KitPlanes on it:

https://www.kitplanes.com/adding-direct-air-fuel-ratio-monitoring/

The key to making this work without the sensor failing prematurely is the right sensor. The one I found is made by NGK and is specifically rated to tolerate some lead. I used the Ballenger system, and modified the display to make it compatible with my panel space.

There are two things to say about this, IMO:
1) After all the back and forth about short sensor life, it CAN be made to work with the right sensor.
2) Having flown with A/F for some time now, let me tell you, it makes setting mixture SO much easier. None of the back and forth with finding the peak EGT, etc. Just remember your two chosen A/F numbers: One for rich of peak operation, one for lean of peak operation, and set your mixture to the number. Glance at your EGT and/or fuel flow to make sure something hasn't gone nuts, and you are all set. It's so nice, I'm reconciled to the possible cost of sensor replacement if and when, but so far still going strong.

Reinhard Metz
N49EX
 
Thanks Reinhard

Your article inspired me to install the same setup in my plane, and I love it. Thanks also for answering my questions!
 
Either would work - I have mine looking for +12 volts on the starter solenoid to indicate cranking, then starting a timer for power.

Problem there is if you don't start on first crank the sensor could now be hot and get a thermal shock when you do start the engine.

Oil pressure comes up momentarily after starting but shouldn't trip the switch with just cranking.

Plus the hobbes is simpler (is it Hobbs or Hobbes? Ones a stuffed cat, can't remember which)
 
I got interested in A/F monitoring for my plane a while ago, and installed a system that has been working flawlessly for a couple hundred hours now. Wrote an extensive article for KitPlanes on it:

https://www.kitplanes.com/adding-direct-air-fuel-ratio-monitoring/

The key to making this work without the sensor failing prematurely is the right sensor. The one I found is made by NGK and is specifically rated to tolerate some lead. I used the Ballenger system, and modified the display to make it compatible with my panel space.

There are two things to say about this, IMO:
1) After all the back and forth about short sensor life, it CAN be made to work with the right sensor.
2) Having flown with A/F for some time now, let me tell you, it makes setting mixture SO much easier. None of the back and forth with finding the peak EGT, etc. Just remember your two chosen A/F numbers: One for rich of peak operation, one for lean of peak operation, and set your mixture to the number. Glance at your EGT and/or fuel flow to make sure something hasn't gone nuts, and you are all set. It's so nice, I'm reconciled to the possible cost of sensor replacement if and when, but so far still going strong.

Reinhard Metz
N49EX

SWEEEET!

After doing an extensive Porsche 930 mod over the last 3 years (its now SCARY fast definitely a Widow Maker) and having learned a TON, I've been thinking about doing a dual-Microsquirt setup with essentially a toggle switch (best power, best economy) with concomitant mixture and timing settings (essentially the switch changes between two ignition and mixture tables).

s/b very doable.

Then turbo normalization :) bwahahahahaha
 
Could you provide more details on the "external smaller and auto-dimming display"? I would really like that. Also how is it mounted? I don't see any screws in your panel near the display.

I got interested in A/F monitoring for my plane a while ago, and installed a system that has been working flawlessly for a couple hundred hours now. Wrote an extensive article for KitPlanes on it:

https://www.kitplanes.com/adding-direct-air-fuel-ratio-monitoring/

The key to making this work without the sensor failing prematurely is the right sensor. The one I found is made by NGK and is specifically rated to tolerate some lead. I used the Ballenger system, and modified the display to make it compatible with my panel space.

There are two things to say about this, IMO:
1) After all the back and forth about short sensor life, it CAN be made to work with the right sensor.
2) Having flown with A/F for some time now, let me tell you, it makes setting mixture SO much easier. None of the back and forth with finding the peak EGT, etc. Just remember your two chosen A/F numbers: One for rich of peak operation, one for lean of peak operation, and set your mixture to the number. Glance at your EGT and/or fuel flow to make sure something hasn't gone nuts, and you are all set. It's so nice, I'm reconciled to the possible cost of sensor replacement if and when, but so far still going strong.

Reinhard Metz
N49EX
 
SWEEEET!

After doing an extensive Porsche 930 mod over the last 3 years (its now SCARY fast definitely a Widow Maker) and having learned a TON, I've been thinking about doing a dual-Microsquirt setup with essentially a toggle switch (best power, best economy) with concomitant mixture and timing settings (essentially the switch changes between two ignition and mixture tables).

s/b very doable.

Then turbo normalization :) bwahahahahaha

I'm rebuilding my RV3 and had two Elektromotive ECUs left over from a previous project. I've put both of them in the -3 now, however use one for the left tank (with left fuel pump, left return line, replacement of the left magneto), and one for the right side. Run both of them at the same time (for ignition on both sides) and switch the 12V source to the injectors to effectively switch between tanks.

I like your idea of using the ECU between best power and best economy, however wonder: Why build in that choice? Genuine questions: If running at 65% power, will there ever be a reason to run in "best power"- mode (i.e. rich of peak)? Why not run LOP by default at lower power settings and ROP at higher ones? Implementation would really just be a matter of introducing a step up in your fuel tables.

Only pitfall I could think of would be the interpolation that the ECU is doing when between two data points. Right around the step-up point, this could prove problematic, when it interpolates between LOP and ROP and thus ends up right at peak EGT.

Seems like I've answered my own question :eek:
 
If running at 65% power, will there ever be a reason to run in "best power"- mode (i.e. rich of peak)? Why not run LOP by default at lower power settings and ROP at higher ones?

Climb is a good example. MAP keeps falling due to altitude. When the MAP is 20", you need to find a different way to tell the computer whether you want performance or efficiency. Running away from Wx, at altitude, is another example.

Larry
 
Only pitfall I could think of would be the interpolation that the ECU is doing when between two data points. Right around the step-up point, this could prove problematic, when it interpolates between LOP and ROP and thus ends up right at peak EGT.

Hans, there is nothing wrong with peak EGT at some moderate power setting. It's Lycoming's economy cruise recommendation.
 
Could you provide more details on the "external smaller and auto-dimming display"? I would really like that. Also how is it mounted? I don't see any screws in your panel near the display.

Yes, the Ballenger display is rather big. I took mine apart and figured out the type of LEDs and how they were driving them (very straight forward) and tied into their circuitry with a cable that connects to my smaller 7 segment LED display. They are multiplexed in a way that I added a photoresistor that controls LED drive pulse width to do dimming. Works quite well. The assembly is press fit into the panel from the back. The display is one a circuit board, which I surrounded with a piece of black bent plastic strip, to create essentially a custom packaging. So - now, if you want to do the same thing, I will need to send you the schematic (sketches) for what I did, won't fit well in line here, so send me an email address if interested:
[email protected]
Reinhard
 
Yes, the Ballenger display is rather big. I took mine apart and figured out the type of LEDs and how they were driving them (very straight forward) and tied into their circuitry with a cable that connects to my smaller 7 segment LED display. They are multiplexed in a way that I added a photoresistor that controls LED drive pulse width to do dimming. Works quite well. The assembly is press fit into the panel from the back. The display is one a circuit board, which I surrounded with a piece of black bent plastic strip, to create essentially a custom packaging. So - now, if you want to do the same thing, I will need to send you the schematic (sketches) for what I did, won't fit well in line here, so send me an email address if interested:
[email protected]
Reinhard

Most of these units provide a 0-5 volt, analog linear output for data logging. Just connect that to a GP input on your Dynon/Garmin and calibrate accordingly. You then get AFR data on your EFIS/EMS (including logs) with no need to mount the display on the panel.

Larry
 
Most of these units provide a 0-5 volt, analog linear output for data logging. Just connect that to a GP input on your Dynon/Garmin and calibrate accordingly. You then get AFR data on your EFIS/EMS (including logs) with no need to mount the display on the panel.

Larry

But it should be noted that some of those units have a TWO-wire 0-5 analog output - so you need to tie the negative to EMS ground to be able to get a good stable positive output. RTFM.
 
Are Wide Band O2 Sensors Affected By 100 LL

While it can be integrated into the EFIS/EMS/MFD, I find that this a fairly primary piece of info and like it dedicated, rather than one more item on the display that looks like all the others and needs more mental focus to access. Also, the Garmin GDU470 I have makes decisions of how many items it has room to display, and that often makes for difficulty getting your GP I/O TO Display.
 
I like your idea of using the ECU between best power and best economy, however wonder: Why build in that choice? Genuine questions: If running at 65% power, will there ever be a reason to run in "best power"- mode (i.e. rich of peak)? Why not run LOP by default at lower power settings and ROP at higher ones? Implementation would really just be a matter of introducing a step up in your fuel tables.

Only pitfall I could think of would be the interpolation that the ECU is doing when between two data points. Right around the step-up point, this could prove problematic, when it interpolates between LOP and ROP and thus ends up right at peak EGT.

Seems like I've answered my own question :eek:

Sometimes I want to go fast as I can, e.g. fun, outrun some weather etc, or am doing formation and/or acro at lower than max power but lots of power changes and don't want any hesitation or issues. Executing a go around/missed would be a good example.

Other times I'm droning along and willing to sacrifice a few kts to save on gas or avoid a fuel stop.

A simple switch lets me change my fuel and ignition tables entirely on the fly.

There are probably ways to get around the interpolation issue, e.g. by having two rows in the mix/timing tables very close to each other, but its at best a kludgy work around. Why do it when there's a facility already built in that I can take advantage of.
 
I'm rebuilding my RV3 and had two Elektromotive ECUs left over from a previous project. I've put both of them in the -3 now, however use one for the left tank (with left fuel pump, left return line, replacement of the left magneto), and one for the right side. Run both of them at the same time (for ignition on both sides) and switch the 12V source to the injectors to effectively switch between tanks.

Interesting choice. My thought was running full EFI, both auto-style injectors on a rail and ignition. With dual sensors for everything I could have one run the top plugs and one run the bottom plugs, but only one could run the injectors at a time. So it would be easier to simply wire in parallel and have a change over switch in case either a sensor (crank position for ex) or an ECU failed.
 
Interesting choice. My thought was running full EFI, both auto-style injectors on a rail and ignition. With dual sensors for everything I could have one run the top plugs and one run the bottom plugs, but only one could run the injectors at a time. So it would be easier to simply wire in parallel and have a change over switch in case either a sensor (crank position for ex) or an ECU failed.

Makes sense as well.

I wanted to solve the return line dilemma at the same time. Plus this allows me to have in-tank fuel pumps, totally eliminating vapour lock issues. And it made it a lot easier to have two completely independent systems - battery, fuel pump, injectors, ignition all in a left and right version.

Downside: If one side fails, I lose access to half of my fuel. Even this could be mitigated with the use of transfer pumps, but I am not flying over large stretches of water or mountain ranges, so I don't bother.

Quite frankly, I hadn't thought of the option of programming one LOP and one ROP. Quite an interesting concept as well.

What you can do is pretty much as I am doing: Run them parallel to have two sources for ignition, and have 8 injectors, switching the 12V source between one bank of 4 injectors and the other (using two switches, eliminating another single point of failure).

Or you only have 4 injectors and use 4 relays to switch the source of the signal to the injectors between the one or the other ECU. This is what I did on the previous iteration of my Subaru powered Jodel (where I have the Elektromotive ECUs as a leftover from). Worked well.

This is fun stuff... :)
 
You guys are describing the SDS system, pretty much.

I have dual pumps in parallel with the Andair full-duplex valve so no danger of losing a tank full of fuel if I lose a pump. Two complete ECU's, one has all the sensors to tweak the engine and make it dance to my tune, while the other is set up for a stock slightly rich power setting to get me to a good airport if the primary fails without losing power. One set of injectors, either board can fire them with the flip of a switch. Each board fires one set of plugs so you don't lose ignition if you lose a board. There's a LOP button on the programmer that can both take you LOP on mixture and advance the timing curve at the same time, with one buttonpush - and it has the AFR displayed on the programmer already.
 
Steve told me about this thread, and I thought I'd provide some feedback from my experience.

I've used the Ballenger AFR500 in both my RV-S6 (IO-540, 1 mag, 1 Electroair) and the Glasair I owned and raced for 3 years (TIO-580, dual mag). Started with the AFR500V1 in the RV, then upgraded to the V2 for the RV and moved the V1 to the GIII when I bought that aircraft.

Installations were per the manual in both planes (with respect to position, angle, etc), and I used only the NTK production grade sensor.

As noted in post #24 here, the manual recommends not having the sensor in the exhaust stream unheated or disconnected. So in both my installations, the system goes on with the Batt Master, and I wait for the unit countdown prior to engine start. I hadn't heard of issues with turning the sensor on prior to engine start, which seems to go against that MFGR recommendation. I'd be interested in more data about that.

I've had excellent life with the NTK sensors in both applications. No failures to date (several years and several hundred hours in the RV). The RV unit has been great during all regimes of flight, as well as LOP cruising. It really has been a great way to adjust mixture in all regimes. The GIII unit did an admirable job as well, though that engine was relatively purpose built for racing, and I did not explore as large a variety of flying as with the RV, and it was primarily a way to ensure I didn't lean that motor towards detonation during racing.

I agree with Reinhard and Steve about the display size, and would also love to learn about the wiring for a remote display (will send an e-mail). Also wondering if the signal could be sent to a Simpson gauge, as they have a wide variety of readout capabilities.

Fun info, and great KitPlanes article too!

Cheers,
Bob

Could you provide more details on the "external smaller and auto-dimming display"? I would really like that. Also how is it mounted? I don't see any screws in your panel near the display.

Yes, the Ballenger display is rather big. I took mine apart and figured out the type of LEDs and how they were driving them (very straight forward) and tied into their circuitry with a cable that connects to my smaller 7 segment LED display. They are multiplexed in a way that I added a photoresistor that controls LED drive pulse width to do dimming. Works quite well. The assembly is press fit into the panel from the back. The display is one a circuit board, which I surrounded with a piece of black bent plastic strip, to create essentially a custom packaging. So - now, if you want to do the same thing, I will need to send you the schematic (sketches) for what I did, won't fit well in line here, so send me an email address if interested:
[email protected]
Reinhard

While it can be integrated into the EFIS/EMS/MFD, I find that this a fairly primary piece of info and like it dedicated, rather than one more item on the display that looks like all the others and needs more mental focus to access. Also, the Garmin GDU470 I have makes decisions of how many items it has room to display, and that often makes for difficulty getting your GP I/O TO Display.
 
Do you have a part# and what's distance from the cylinder?

AEM (30-4110) UEGO Air/Fuel Ratio Gauge

Bob, sorry for the delayed reply.

The above is the AEM system I bought on Amazon. Sensor is the Bosch 4.9. I was incorrect in my post saying it is a narrow band sensor when in fact it is a wide band...memory, second thing to go....

The instructions say to mount the sensor a minimum of 10 degrees above the horizontal and 18" from the exhaust port. I put mine at about 45 degrees.
 
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Here is an observation that possibly resolves the question of whether to pre-heat the probe (as described in the instructions for the Ballenger unit, discussed in posts #25 and #47) and other discussion about delaying the probe energizing until after the engine is running.

Remember that in cars, you are absolutely sure there is no lead. So no risk of lead condensate damaging a cold probe. There is, however, still the problem of condensed water droplets hitting the hot probe tip. So you would opt to energize the probe after engine start.

With 100LL fuel, (or a race car with special fuel?) you have to choose your poison. If you pre-heat the probe, you reduce the risk of lead poisoning, but increase the risk of water damage. If you delay the probe heating, you have greater chance of lead condensation, but less chance of water damage.

So that seems to be the trade-off. It occurs to me that if the welded mounting boss is tall enough that the probe tip is not directly in the straight exhaust flow, the risk of water impingement is fairly low, and it seems better to pre-heat the probe, as described in the Ballenger instructions.
 
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The Bosch 4.9 and NTK sensors are quite different and can't be lumped together.

Bob Mills and some others have had usefully longer life from their NTKs than most of my customers using Bosch 4.2 or 4.9 with 100LL

The Bosch wideband sensor was never designed with leaded fuel in mind to my knowledge and Bosch itself says life will be much shorter when using it. With the NTK, lifespan looks to be superior so far when running 100LL and that's encouraging.

We'll be starting to test an NTK on a local aircraft here shortly and hope to do a video on that soon.
 
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