TWIN TURBO
Expert
Sometimes you just have to learn the hard way. About 6 months ago I updated my Superflow Dyno to the tune of about $4000.00 with new software that allowed me to reconfigure a couple of channels so I could install Wideband Lambda and add another way to measure AF Ratio's when it was not possible to install my mechanical air and fuel counters ie. in chassie snowmobile engine testing. To my disappointment when I was able to use both systems testing automotive big and small blocks this summer I found in "some" cases big differences in mechanical systems verses Wideband and had to ask Why?
"Oxygen Sensors do not measure AF Ratio's! They never have and never will. They can however, be used to control AF Ratio's which is something else entirely"
The only thing Oxygen Sensors can measure is the partial pressure ratio of oxygen inside the pipe as compared to the outside air. Automotive computors use this info to adjust the mixture of the engine not as the only info however. Putting aside pump gas, as nobody knows what we got their, Racing Gasoline can vary with the amount of oxygenates and the stoic values ranging from 14.0 to 15.3. The general accepted balanced is 14.7 pounds of air to 1 pound of fuel. This affects what we are seeing on our meters. Another killer is misfires, this will give the indication of a lean condition as you are putting unburned air and fuel in the pipe.
Stoichiometry aside Oxygen sensors can be compromised with other gases such as Hydrogen, which will cause a lean shift, and hydrocarbons (isooctane, aromatics etc.) which will cause a rich shift. And then we abuse them with high HEAT and LEAD which doesn't stop them from working immediately but stops their ability to give accurate info.
So, where we at? I'm not ready to throw away my mechanical counters thats for sure, and I'm wondering how much FAITH I'm putting into my Innovate Wideband on my Apex.
Comments?
"Oxygen Sensors do not measure AF Ratio's! They never have and never will. They can however, be used to control AF Ratio's which is something else entirely"
The only thing Oxygen Sensors can measure is the partial pressure ratio of oxygen inside the pipe as compared to the outside air. Automotive computors use this info to adjust the mixture of the engine not as the only info however. Putting aside pump gas, as nobody knows what we got their, Racing Gasoline can vary with the amount of oxygenates and the stoic values ranging from 14.0 to 15.3. The general accepted balanced is 14.7 pounds of air to 1 pound of fuel. This affects what we are seeing on our meters. Another killer is misfires, this will give the indication of a lean condition as you are putting unburned air and fuel in the pipe.
Stoichiometry aside Oxygen sensors can be compromised with other gases such as Hydrogen, which will cause a lean shift, and hydrocarbons (isooctane, aromatics etc.) which will cause a rich shift. And then we abuse them with high HEAT and LEAD which doesn't stop them from working immediately but stops their ability to give accurate info.
So, where we at? I'm not ready to throw away my mechanical counters thats for sure, and I'm wondering how much FAITH I'm putting into my Innovate Wideband on my Apex.
Comments?
tinker1735
Newbie
ineed help tunning sled 06apex mpi supercharger 10lbs specificaly with 02 sensor #,s are irratic
dynotechjim
Veteran
I'm having the same issues with my wideband on my SuperFlow as well. If you look at the dyno data on Art's MPI sc Attak on my website the LAMAF1 is the innovate readout, the A/F A-B is mechanical. I upgraded just like you did after I saw the plumbers nightmare with the sleds with return fuel systems.
But comparing both it looks like it takes 15-20 seconds for the wideband to catch up to the mechanical meters. So what I think I'm seeing on the innovate is from about 15-20 seconds ago, surely yesterday's news if youre trying to tune with that.
I'll stick with the 20 year old mechanical meters whenever possible.
The good part of the new software is the live graph of the dyno test as it happens, surely has saved a good size pile of pistons/ cylinders so far.
But comparing both it looks like it takes 15-20 seconds for the wideband to catch up to the mechanical meters. So what I think I'm seeing on the innovate is from about 15-20 seconds ago, surely yesterday's news if youre trying to tune with that.
I'll stick with the 20 year old mechanical meters whenever possible.
The good part of the new software is the live graph of the dyno test as it happens, surely has saved a good size pile of pistons/ cylinders so far.
Neither system is ideal.
I've used both mechanical and sensors for many many years (on dyno's and as an OEM automotive calibration engineer.. plus as a special contractor for the EPA). After using each I tend to lean toward the sensor based systems as it's more indicative of what happened during a combustion event.
I've been able to easily fool mechanical and sensor based systems into reading whatever I want even though it wasn't the true A/F.
Response time of current day sensor is in the ms range.
Not sure why your seeing 15-20 sec delay.. unless your sensor is a very large distance away from the exhaust ports (transport delay can cause lag errors.. it takes a given amount of time for an exh gas slug to leave a port and travel to the sensor). Or there is just somethign wrong with it.
On a typical car.. putting the sensor in the tailpipe vs near the head causes a ~400 RPM shift in your readings. So if using tailpipe sensor.. what you see at ~5500 RPM actually happened at ~5100 RPM inside the engine.
You DO need to let the sensor get to operating temp before you make your pull. I can put a heatsink on some of the aftermarket sensors and get them to read .5 to .75 A/F different that what they should.
Heat and pressure will skew the sensor readings. A sensor in an NA engine running LBT will show a different A/F ratio of one on a turbocharged engine running the same fueling.. unless the electronics measure the pressure in the exhaust. Some do, some don't. Each time you use the sensor it should be calibrated. Lead does slow the reponse time down and eventually it will stop working.
Most of the cheaper aftermarket systems use some sort of free air calibration.. which is fine (I've designed a few dufferent ones.. from cheap to very expensive myself).
What we do is use test gases and a 6 point polynomial tranfer function for teh sensor each and every time we used them.
Not all sensors measure the oxygen content of the atmosphere as the reference O2 level (I think the Innovate one does.. I can call them and ask as I developed some hardware for them and know them well). Some sensors generate thier own O2 reference (these are usually more expensive). On the cheaper ones.. lengthen the wiring harness, you just shot yourself in the foot.
Mechanical systems work good if the fuel flow measured actually made it into the engine.. it doesn't always. Plus you have to correct for fuel pressure at the point where the fuel is entering the intake manifold. If your running 100 lb/min of airmass flow and 100 lb/min of fuel flow and your injector duty cycle is 50%, you have X A/F ratio. Now up (or lower) the fuel pressure. Same air, fuel and duty cycle, but your A/F is now Y.
Injected systems with a sticky injectors can totally foul up the mechanical readings. Plain pumping losses on the fuel only side of a return style system also need to be accounted for. It's also not as simple as X - Y = fuel delivered where X is measured fuel going into the engine, Y = measured fuel returning. Fuel timing plays a big role in that. On injected engines if your firing well into the overlap period, some part of that fuel is doing no useful work.. but the mechanical systems will measure it and it will show up in the BSFC and A/F readings. Meachincal systems also do not account for the fuel mass puddle. Not all that fuel injected through the pintle goes into the cylinder. As the fuel impacts the manifold wall, there is always a puddle of fuel that grows/shrinks. Most all modern day vehicles (cars/trucks) have special modeling software in them to keep track of the fuel puddle. Very complicated stuff.
As you said, returnless systems are a major pain to connect.
I used to catch alot of automotive engineers on a simple test...
What will the UEGO read on cylinder #4 if we're running at LBT and I pull the spark plug wire off. Amazing how many get that wrong.
My main focus is on injected engines.. carb'd engines are an entirely different animal.
The rules of thumb like beast power = 13.X A/F are just that.. rules of thumb. The engine will tell you what it wants and each and every engine is different. Take 2 identical engines, one makes best power at 13.2 and another at 12.8. Same everything (in theory). They aren't.
Our race motor makes about 2500 HP and for it to do that, it HAS to run at a measured A/F ratio of 10.2 (measure it how you want). Should be a blubbering pig but due to the camshaft design, chamber design, etc.. that is what IT likes to run. Run it at 11.2, it loses power and eventually eats itself up.
Speaking of Superflow... sometimes it's just the software that is the issue.
We've had them out a few times to go over our systems and THEY don't even know how to figure out thier own software.
The absolutel best way is to collect everything that comes out of the pipes and measure all of the constituants. Then you can know the true A/F at a given point in time.
I've used both mechanical and sensors for many many years (on dyno's and as an OEM automotive calibration engineer.. plus as a special contractor for the EPA). After using each I tend to lean toward the sensor based systems as it's more indicative of what happened during a combustion event.
I've been able to easily fool mechanical and sensor based systems into reading whatever I want even though it wasn't the true A/F.
Response time of current day sensor is in the ms range.
Not sure why your seeing 15-20 sec delay.. unless your sensor is a very large distance away from the exhaust ports (transport delay can cause lag errors.. it takes a given amount of time for an exh gas slug to leave a port and travel to the sensor). Or there is just somethign wrong with it.
On a typical car.. putting the sensor in the tailpipe vs near the head causes a ~400 RPM shift in your readings. So if using tailpipe sensor.. what you see at ~5500 RPM actually happened at ~5100 RPM inside the engine.
You DO need to let the sensor get to operating temp before you make your pull. I can put a heatsink on some of the aftermarket sensors and get them to read .5 to .75 A/F different that what they should.
Heat and pressure will skew the sensor readings. A sensor in an NA engine running LBT will show a different A/F ratio of one on a turbocharged engine running the same fueling.. unless the electronics measure the pressure in the exhaust. Some do, some don't. Each time you use the sensor it should be calibrated. Lead does slow the reponse time down and eventually it will stop working.
Most of the cheaper aftermarket systems use some sort of free air calibration.. which is fine (I've designed a few dufferent ones.. from cheap to very expensive myself).
What we do is use test gases and a 6 point polynomial tranfer function for teh sensor each and every time we used them.
Not all sensors measure the oxygen content of the atmosphere as the reference O2 level (I think the Innovate one does.. I can call them and ask as I developed some hardware for them and know them well). Some sensors generate thier own O2 reference (these are usually more expensive). On the cheaper ones.. lengthen the wiring harness, you just shot yourself in the foot.
Mechanical systems work good if the fuel flow measured actually made it into the engine.. it doesn't always. Plus you have to correct for fuel pressure at the point where the fuel is entering the intake manifold. If your running 100 lb/min of airmass flow and 100 lb/min of fuel flow and your injector duty cycle is 50%, you have X A/F ratio. Now up (or lower) the fuel pressure. Same air, fuel and duty cycle, but your A/F is now Y.
Injected systems with a sticky injectors can totally foul up the mechanical readings. Plain pumping losses on the fuel only side of a return style system also need to be accounted for. It's also not as simple as X - Y = fuel delivered where X is measured fuel going into the engine, Y = measured fuel returning. Fuel timing plays a big role in that. On injected engines if your firing well into the overlap period, some part of that fuel is doing no useful work.. but the mechanical systems will measure it and it will show up in the BSFC and A/F readings. Meachincal systems also do not account for the fuel mass puddle. Not all that fuel injected through the pintle goes into the cylinder. As the fuel impacts the manifold wall, there is always a puddle of fuel that grows/shrinks. Most all modern day vehicles (cars/trucks) have special modeling software in them to keep track of the fuel puddle. Very complicated stuff.
As you said, returnless systems are a major pain to connect.
I used to catch alot of automotive engineers on a simple test...
What will the UEGO read on cylinder #4 if we're running at LBT and I pull the spark plug wire off. Amazing how many get that wrong.
My main focus is on injected engines.. carb'd engines are an entirely different animal.
The rules of thumb like beast power = 13.X A/F are just that.. rules of thumb. The engine will tell you what it wants and each and every engine is different. Take 2 identical engines, one makes best power at 13.2 and another at 12.8. Same everything (in theory). They aren't.
Our race motor makes about 2500 HP and for it to do that, it HAS to run at a measured A/F ratio of 10.2 (measure it how you want). Should be a blubbering pig but due to the camshaft design, chamber design, etc.. that is what IT likes to run. Run it at 11.2, it loses power and eventually eats itself up.
Speaking of Superflow... sometimes it's just the software that is the issue.
We've had them out a few times to go over our systems and THEY don't even know how to figure out thier own software.
The absolutel best way is to collect everything that comes out of the pipes and measure all of the constituants. Then you can know the true A/F at a given point in time.
I have the Innovate setup (never used leaded fuel) and it is ultra-sensitive to even the slightest throttle input change, almost to the point that it's difficult to read, continuously climbing and falling in sync with the most minute throttle inputs, once the throttle is held in a steady state for 1-2 seconds it stabilizes... I cannot confirm that it is accurate but it seems to instantly recognize changes occurring in throttle position... My question would be: Can I take my sled to an automotive repair shop with an exhaust gas analyzer and verify my readings or would this be a waste of time and money ???
Travis Moore
Expert
HAMMER said:
The auto repair shop reading might be slightly diffrent but should not be too far off.
Bottom line is that a 11/1 AF ratio is VERY safe on these sleds @WOT, regardless of fuel.
dynotechjim
Veteran
runninrx1 very excellent post, I have to go back and reread that another time to absorb that.
Someone needs to explain to us how O2 sensors work--I can understand leaner than 14.7/1 has extra O2 passing by, and if that's what the O2 sensor measures, how does an O2 sensor determine richer than 14.7/1 if the O2 is gone? There' no unused O2 at 14/1 and no unused O2 in 11/1 so what's the deal?
On our Superflow mechanical meters with carbureted engines there surely is a lag time from meters measuring what's going into the carbs (as opposed to what's going up the needle jets). We have to do very slow acceleration tests to get accurate mechanical A/F readings. But I believe that with full pressure fuel going from EFI pump to rail with fuel flowmeter in between that is nearly instantaneous. How can it not be? However the airflow meter is a plastic fan blade that increases speed as airflow increases, but when we use a flowmeter designed for V8 chevys there surely is inertia from that large fanblade that can fool us on rapid acceleration tests. That's why we load the engines at WOT at low RPM until all of that stabilizes then accelerate the engines at about 100 rpm/ sec to let that big plastic fanblade keep up. Surely not practical with 2500 hp V8s but easy with tiny 200 hp sled engines.
And it's best use A/F ratio (mechanical) as our carb jetting guide--wild port timing can blow excessive unburned charge out the pipe (unused O2 blowing by O2 sensors thinking we're leaner than 14.7?) and the net fuel trapped with air in the engine will be lower than total, making high BSFC numbers but max HP is what matter most to racers. My opinion after 20 years on this dyno on mostly two strokes is that about 13/1 mechanical creates max HP for dragracing, 11/1 is where I run my trail sleds.
How about the design of the O2 sensor? My innovates use cheap Bosch VW units and other O2 sensors might cost 10x as much. Do they react more quickly?
Whoever created this internet thing should get a Nobel Peace prize.
Someone needs to explain to us how O2 sensors work--I can understand leaner than 14.7/1 has extra O2 passing by, and if that's what the O2 sensor measures, how does an O2 sensor determine richer than 14.7/1 if the O2 is gone? There' no unused O2 at 14/1 and no unused O2 in 11/1 so what's the deal?
On our Superflow mechanical meters with carbureted engines there surely is a lag time from meters measuring what's going into the carbs (as opposed to what's going up the needle jets). We have to do very slow acceleration tests to get accurate mechanical A/F readings. But I believe that with full pressure fuel going from EFI pump to rail with fuel flowmeter in between that is nearly instantaneous. How can it not be? However the airflow meter is a plastic fan blade that increases speed as airflow increases, but when we use a flowmeter designed for V8 chevys there surely is inertia from that large fanblade that can fool us on rapid acceleration tests. That's why we load the engines at WOT at low RPM until all of that stabilizes then accelerate the engines at about 100 rpm/ sec to let that big plastic fanblade keep up. Surely not practical with 2500 hp V8s but easy with tiny 200 hp sled engines.
And it's best use A/F ratio (mechanical) as our carb jetting guide--wild port timing can blow excessive unburned charge out the pipe (unused O2 blowing by O2 sensors thinking we're leaner than 14.7?) and the net fuel trapped with air in the engine will be lower than total, making high BSFC numbers but max HP is what matter most to racers. My opinion after 20 years on this dyno on mostly two strokes is that about 13/1 mechanical creates max HP for dragracing, 11/1 is where I run my trail sleds.
How about the design of the O2 sensor? My innovates use cheap Bosch VW units and other O2 sensors might cost 10x as much. Do they react more quickly?
Whoever created this internet thing should get a Nobel Peace prize.
The Bosch wideband (LSU4) is a good sensor. It's cheap sicne it's used in production vehicles (VW's, Cadillacs, etc..). Trying to not get TOO technical here....
The core of regular O2 sensors (like the narrow band ones found in most all cars/truck these days) work on a simple principle of oxygen ratios. Inside the sensor you have a oxygen measurement element. Usually made of Zirconium dioxide which has been doped with Yttria. This doping creates 'holes' or a lattice structure in the zirconium dioxide that allows oxygen ions to move through the element when the element is hot. On each side of the element you have palladium (usually) films. These are the electrodes.
Each electrode is positioned so it sees either the outside reference air or the exhaust gasses. When you have excess oxygen on one element, oxygen ions travel to the side that has the lower oxygen and creates a voltage potential kind of like a battery. This is all based on the Nernst equation. If your into chemestry.. google it. Pretty hairy stuff.
Now what the sensor manufactuers do is dope the Zirconium in such as way that they can center the sensors output voltage to about .46 volts when the exhaust gas ratio is 14.7:1. Outside air ratio is usually around 20:1. This 14.7:1 ratio is called the Stoicheometric point, which happens to be the chemically correct A/F ratio for complete combustion (theorectically.. there is alot more to 14.7 than meets the eye).
So now we have a 'battery' that tells us when the oxygen content in the exhaust is 14.7:1. Now the sensors output is not linear, it's logarithmic. We do know that .46 volts = 14.7:1 but .8 volts could be 12.0 or 12.5 (which is why A/F gauges that use narrow band sensors are not all that accurate once you get to either side of stoich).
Actually.. as stated earlier.. the stoich point of fuels DOES change but it's usually right around there.
Also inside the sensor is a ceramic heating element that is used to keep the sensor hot to where they work best.
Ok, now on to your Bosch sensor. Inside this sensor we have the typical narrow band sensing element, but they add in a pump cell separated by a diffusion gap. This gap is a tiny chamber that is connected to the exhaust gasses. In here is where everything takes place. So on one side of the gap, you have your Nernst cell (the regular O2 sensor) and on the other you have the pump cell. The pump cell (based on a catalytic reaction) can either 'consume' oxygen or consume hydrocarbons (fuel) depending on which way current flows through it. Through the wideband electronics, what needs to be done control current flow so that the pump cell consumes the oxygen (or fuel) in the diffusion gap so that the ratio is 14.7 (the Nernst cell will produce .46 volts at this point). How much current (and which direction) was required to get to this equilibrium point is relative to the A/F ratio.
Hopefully that made sense.. if not I can try to simplify it more.
The sesnor itself should react very quickly to changes in the exh A/F ratio providing it's hot. Not instantaneous, but damn close to it.
Since your seeing lag times of 15+ seconds.. something is obviously wrong somewhere.
Some things to do with the sensors to keep them healthy...
Don't leave them powered up without the engine running for long periods.
Make sure the sensor is hot before making a pull (the electronics should indicate when the sensor is ready to use.. usually 15-20 seconds after powering up the sensor).
Don't mount them so that the sensor body is pointed straight down (water will collect in the sensor and crack the heater). Best location is 12 o'clock.
Don't run excessive amount of leaded fuel as this tends to slow the sensor reaction time since it 'poisions' the elements. If possible after running leaded race gas, run some regular unleaded as this will help to clean it up somewhat.
Don't overheat the sensors. Put them in a location in the exh pipe so that they don't see exh temps above 1400 deg F.
The core of regular O2 sensors (like the narrow band ones found in most all cars/truck these days) work on a simple principle of oxygen ratios. Inside the sensor you have a oxygen measurement element. Usually made of Zirconium dioxide which has been doped with Yttria. This doping creates 'holes' or a lattice structure in the zirconium dioxide that allows oxygen ions to move through the element when the element is hot. On each side of the element you have palladium (usually) films. These are the electrodes.
Each electrode is positioned so it sees either the outside reference air or the exhaust gasses. When you have excess oxygen on one element, oxygen ions travel to the side that has the lower oxygen and creates a voltage potential kind of like a battery. This is all based on the Nernst equation. If your into chemestry.. google it. Pretty hairy stuff.
Now what the sensor manufactuers do is dope the Zirconium in such as way that they can center the sensors output voltage to about .46 volts when the exhaust gas ratio is 14.7:1. Outside air ratio is usually around 20:1. This 14.7:1 ratio is called the Stoicheometric point, which happens to be the chemically correct A/F ratio for complete combustion (theorectically.. there is alot more to 14.7 than meets the eye).
So now we have a 'battery' that tells us when the oxygen content in the exhaust is 14.7:1. Now the sensors output is not linear, it's logarithmic. We do know that .46 volts = 14.7:1 but .8 volts could be 12.0 or 12.5 (which is why A/F gauges that use narrow band sensors are not all that accurate once you get to either side of stoich).
Actually.. as stated earlier.. the stoich point of fuels DOES change but it's usually right around there.
Also inside the sensor is a ceramic heating element that is used to keep the sensor hot to where they work best.
Ok, now on to your Bosch sensor. Inside this sensor we have the typical narrow band sensing element, but they add in a pump cell separated by a diffusion gap. This gap is a tiny chamber that is connected to the exhaust gasses. In here is where everything takes place. So on one side of the gap, you have your Nernst cell (the regular O2 sensor) and on the other you have the pump cell. The pump cell (based on a catalytic reaction) can either 'consume' oxygen or consume hydrocarbons (fuel) depending on which way current flows through it. Through the wideband electronics, what needs to be done control current flow so that the pump cell consumes the oxygen (or fuel) in the diffusion gap so that the ratio is 14.7 (the Nernst cell will produce .46 volts at this point). How much current (and which direction) was required to get to this equilibrium point is relative to the A/F ratio.
Hopefully that made sense.. if not I can try to simplify it more.
The sesnor itself should react very quickly to changes in the exh A/F ratio providing it's hot. Not instantaneous, but damn close to it.
Since your seeing lag times of 15+ seconds.. something is obviously wrong somewhere.
Some things to do with the sensors to keep them healthy...
Don't leave them powered up without the engine running for long periods.
Make sure the sensor is hot before making a pull (the electronics should indicate when the sensor is ready to use.. usually 15-20 seconds after powering up the sensor).
Don't mount them so that the sensor body is pointed straight down (water will collect in the sensor and crack the heater). Best location is 12 o'clock.
Don't run excessive amount of leaded fuel as this tends to slow the sensor reaction time since it 'poisions' the elements. If possible after running leaded race gas, run some regular unleaded as this will help to clean it up somewhat.
Don't overheat the sensors. Put them in a location in the exh pipe so that they don't see exh temps above 1400 deg F.
SPEED
TY 4 Stroke Junkie
With the Innovate set-up ,there is a period of 15 to 20 seconds heat -up time required (which is indicated on the gauge before actual readings ). If we are making that dyno run before it is completed do you think that would contribute to the lag time??
The sensor on my particular sled located about 30 inches back from motor and apprx.2 oclock.
The sensor on my particular sled located about 30 inches back from motor and apprx.2 oclock.
Obsolutely.
If the sensor is not hot, you won't get much (or accurate) info from it.
Since how the sensor measures oxygen percentage changes based upon the sensors temperature, they drive the internal heater to get it up to operating temp (or turn it off if the sensor is too hot). By reading the resistance of the heating element, you can infer tip temperature. Careful temp control is crutial in getting accurate readings.
I haven't actually looked at the power setup on the RX-1/Apex to see if there is some place where VBAT is constantly available when key is in the run position or not. Couple weeks ago I plugged a cell phone charger into a GT's 12V plug.. it didn't work until I fired the sled up.. so that's not a good choice on where to power your sensor.. unless you want to wait a bit after the engine starts in order to see A/F readings.
If the sensor is not hot, you won't get much (or accurate) info from it.
Since how the sensor measures oxygen percentage changes based upon the sensors temperature, they drive the internal heater to get it up to operating temp (or turn it off if the sensor is too hot). By reading the resistance of the heating element, you can infer tip temperature. Careful temp control is crutial in getting accurate readings.
I haven't actually looked at the power setup on the RX-1/Apex to see if there is some place where VBAT is constantly available when key is in the run position or not. Couple weeks ago I plugged a cell phone charger into a GT's 12V plug.. it didn't work until I fired the sled up.. so that's not a good choice on where to power your sensor.. unless you want to wait a bit after the engine starts in order to see A/F readings.
Attachments
I have a small Red LED connected to my Dynotune Innovative wideband and it blinks for approx 20 sec. until the sensor is warmed up. My guage will read all 0's until warmed up also.
Like Hammer stated; my guage will change readings immediately upon any change in throttle position.
Like Hammer stated; my guage will change readings immediately upon any change in throttle position.
snowy1
TY 4 Stroke Guru
I just got mine on and it changes as soon as you change throttle position as well, seems to react very quickly.
dynotechjim
Veteran
I used to power up the LM1 from in ignition switch on the dyno, let it warm up to turn itself on, but the large electric started would suck the battery voltage down enough to reset the LM1 so we'd have to wait with engine running for 20 seconds until we got our readings again. So I bought the innovate 110v-12v adaptor, and leave it on continuously during dyno testing, meaning the O2 sensor stays hot all the time, even between runs. So there may be fairly long periods of time where sensor is hot, but engine not running. Plus we do run lots of leaded gas (though on this sesion we were using Arts O2 sensor which I think was new or close to it, with leaded gas).
Does anyone know how I might post a jpeg file of a graph of the A/F ratio?
Does anyone know how I might post a jpeg file of a graph of the A/F ratio?
dynotechjim
Veteran
SPEED
TY 4 Stroke Junkie
Jim, a/f is brand new , fuel mix was 50% premium unleaded 50% vp leaded. I don't believe that sensor should have been compromised on the amount we ran it.
Should also note that sensor is powered from independant 15 amp circuit direcctly fed from battery acitvated by ignition
Should also note that sensor is powered from independant 15 amp circuit direcctly fed from battery acitvated by ignition
