E85 and WB 02 Lambda numbers.

[KevinB]

Whats the deal? I do not understand what a/f to look for. Even though E85's stoich number is around 9:1, I have heard that people still tune it to 11:1 (reading from the wb o2) or whatever their tune is on E85. How does that work?

 

[GNVYUS 1]

Lambda reads as the amount of air in relation to fuel. So 12:1 on E85 is the same as 12:1 on gas.

Tune the same way you have been with gas, dynoing the car might reveal that E85 likes it a touch fatter but your car will tell you on the dyno if that works or not.

 

[Pablo]

Lambda reads as the amount of air in relation to fuel. So 12:1 on E85 is the same as 12:1 on gas.

Tune the same way you have been with gas, dynoing the car might reveal that E85 likes it a touch fatter but your car will tell you on the dyno if that works or not.

This man is correct.
" So 12:1 on E85 is the same as 12:1 on gas. " as displayed on the wideband of course

 

[bsdlinux]

X3 on that. And yes to make max torque, E-85 will have to be richer @ wot

 

[KevinB]

Thanks guys!

So in theory, if I usually run 11.5:1, I would look for 11.0:1 on e85 using the same wb o2 sensor?

 

[Pablo]

Not necessarily unless that .5 is the touch fatter mix it has been suggested to add. Stoich will still be at 14.7:1 with both fuels as displayed by the wideband.

 

[GNVYUS 1]

11:0 is probably a tad too fat, I just got done making 8 more hp at the wheel on my turbo Talon by going 11.2 to 11.7 and I would have pulled 5% more if I had a pull left.

I would set up a day where you can get in 3 pulls on a Dynojet and start off at your 11:0 and just pull the WOT Translator knob 5% leaner after each pull and see what happens. My guess is the HP will go up but the torque might or might not.

 

[hotrodwrx]

Hi folks, my first post here but thought I would comment on this thread. For background I am the guy on the Subaru board NASIOC that did the E85 FAQ over there.

A wideband O2 as mentioned above only measures the lambda reading which is independent of the fuel you are burning. Lambda 1.0 is stoichiometric mixture on any fuel. Most widebands assume you are running gasoline and compute the AFR based on that assumption. For example a lambda 0.82 on gasoline is 0.82 x 14.7 = AFR 12.054. The true stochiometric mixture for E85 is about 9.7:1 AFR but on a gasoline calibrated wideband it will show up just like gasoline as an AFR of 14.7:1.

In practice people generally do one of two things. They get comfortable using lambda numbers only or they stick with the gasoline AFR's just because they are used to working with them. You will generally find E85 likes to run just a tad richer than best power AFR's you found on racing gasoline, until you get into the higher boost ranges than you will have to add even more fuel. (E85 has wider flammability limits than gasoline so will run as much as 40% rich of stoichiometric mixtures where gasoline generally will not go much beyond 25% rich of stoichiometric for best power)

In the turbo import cars, we tend to get best power at lambda 0.72 - 0.76 on most cars. That would be a gasoline calibrated AFR of 10.584 - 11.172. When I first converted my WRX to E85 it was a simple conversion where I just increased the fuel injector size by 30% and it was quite happy running at a gasoline calibrated AFR or 11.5 at wide open throttle.

Due to E85's high octane and high evaporative cooling you can run much leaner than max power mixtures at lower load, if your engine management system allows you to tune the full range of load values. On my car I run lambda 1 all the way up to about 5 psi boost at light throttle low load conditions (highway cruise just tipping into the throttle lightly to over take another car). At higher loads I have the car set up to run a mixture of lambda 0.76-0.78 (which gives me slightly better fuel economy). I only run richer than that if I am cranking up the boost above 14 psi, but I generally drive around town with the boost turned down.

Glad to see you guys are getting into E85 I think you will find it a very forgiving fuel and lots of fun if you want to go balls to the wall on your tune.

Larry

 

[bsdlinux]

Hi folks, my first post here but thought I would comment on this thread. For background I am the guy on the Subaru board NASIOC that did the E85 FAQ over there.

A wideband O2 as mentioned above only measures the lambda reading which is independent of the fuel you are burning. Lambda 1.0 is stoichiometric mixture on any fuel. Most widebands assume you are running gasoline and compute the AFR based on that assumption. For example a lambda 0.82 on gasoline is 0.82 x 14.7 = AFR 12.054. The true stochiometric mixture for E85 is about 9.7:1 AFR but on a gasoline calibrated wideband it will show up just like gasoline as an AFR of 14.7:1.

In practice people generally do one of two things. They get comfortable using lambda numbers only or they stick with the gasoline AFR's just because they are used to working with them. You will generally find E85 likes to run just a tad richer than best power AFR's you found on racing gasoline, until you get into the higher boost ranges than you will have to add even more fuel. (E85 has wider flammability limits than gasoline so will run as much as 40% rich of stoichiometric mixtures where gasoline generally will not go much beyond 25% rich of stoichiometric for best power)

In the turbo import cars, we tend to get best power at lambda 0.72 - 0.76 on most cars. That would be a gasoline calibrated AFR of 10.584 - 11.172. When I first converted my WRX to E85 it was a simple conversion where I just increased the fuel injector size by 30% and it was quite happy running at a gasoline calibrated AFR or 11.5 at wide open throttle.

Due to E85's high octane and high evaporative cooling you can run much leaner than max power mixtures at lower load, if your engine management system allows you to tune the full range of load values. On my car I run lambda 1 all the way up to about 5 psi boost at light throttle low load conditions (highway cruise just tipping into the throttle lightly to over take another car). At higher loads I have the car set up to run a mixture of lambda 0.76-0.78 (which gives me slightly better fuel economy). I only run richer than that if I am cranking up the boost above 14 psi, but I generally drive around town with the boost turned down.

Glad to see you guys are getting into E85 I think you will find it a very forgiving fuel and lots of fun if you want to go balls to the wall on your tune.

Larry

Hotrod,

OFFTOPIC :
Welcome to our board. You know me as AustinTr on your forum. I joined TB.com years ago and I am stuck with the screen name you see here. They won't let me change it..LOL :biggrin:

I have pointed many people here in your direction via your forum. There is a wealth of information on your forum and it has really helped me understand alot of the dynamics that come into play when running E-85. I enjoy the fact that alot of your members are actually running E-85 and can supply imperical evidence of their findings. Unlike many that just sit around and arm-chair the theory of it or whatever.

I am also glad to see more TB guys running the E-85. There is of course alot of hesitation to run it for one reason or another, alot of people on the fence and so forth. Actually it reminds me of when the ALKY injection systems really starting getting popular. I was seeing all kinds of excuses, like it will blow your motor up, etc.. similar to what you we see now when discussing the E-85..LOL Now a few years later some of the same people that were doing what I just mentioned..swear by the ALKY injection systems..go figure. You know they say there are 2 kinds of people.....and I digress


ONTOPIC :
Most TB guys are still running the stock O2 and not a WB. I'm one of those but I will soon have WB correction. I believe the newer cars like the WRX have it better when it comes to tuning etc just because the techonology is better and already installed on the cars. I have too found that you can way leaner with E-85 and stay out of trouble and make decent power. But at this point it is really foolish for me to go any further with out a WB.

The new chip that one of the vendors and I are talking about it will have the WB WOT correction, which is what really gets boosted cars insto trouble if they don't have it. Changing temps, boost levels, etc.. all make it a PIA to tune with OUR cars in regards to WOT. Having said that I'm seriously thinking about getting a FAST and being done wit it. That way I can tune the whole fuel map and take advantage of some of the lean cruise aspects of E-85.

Anyway thanks again for your involvement and sharing your knowledge with us.

 

[ronbuick]

I have some LM-1 files I would like someone smarter than me to look at

OK, Just installed the LM-1 WB02 and have some files that I would like some one with a tad bit more knowledge than me to look at, I'm running E-85 with
83lb inj. and a TT chip for E85, if anyone is interested I can send them to you to help me out.
thanks

Ron

 

[RmvBfrFlght]

I'm thinking that I'll post on this subject once more and leave it at that. Based on this statement:

A wideband O2 as mentioned above only measures the lambda reading which is independent of the fuel you are burning.

This is false (I didn't qoute the posters name because I am not pointing out anyone).

Here is what the truth is about WB readings:

On the rich side (which is what we care about) a WB O2 sensor responds to the remnants of combustible products in the exhaust. These products differ according to the fuel used. In that regard the reported Lambda will also differ when a different fuel is used.

This is why when running alcohol you will find that a richer then expected lambda makes the best power. And an 'expected' lambda melts the pistons.

The simple fact is that a WB O2 sensor reports what it sees. And what it sees varies according to the fuel used. Don't believe everything you read in magazine's. No matter what WB selling company they came from.

RemoveBeforeFlight

 

[hotrodwrx]

The simple fact is that a WB O2 sensor reports what it sees. And what it sees varies according to the fuel used.

The lambda reading of a wide band is completely fuel independent. It is simply a measure of the free oxygen concentration in the combustion gases. The sensor neither knows or cares what you are burning all it is measureing is the unburned oxygen concentration.

A lambda 1.0 on gasoline and a lambda 1.0 on kerosene, and a lambda 1.0 on ethanol represent exactly the same unburned oxygen concentration.

You can get a false lean reading due to misfire, where there is unburned oxygen in the exhaust gasses, due to the failure to fire however.

This is why when running alcohol you will find that a richer then expected lambda makes the best power.

The reason a much richer lambda gives max power on ethanol/E85 has nothing to do with what the O2 sensor sees, it is due to the thermodynamics of the fuel. E85 has wider flammability limits than gasoline. It can run as much as 40% rich of stoicheometric where gasoline usually will not go much more than 25% rich of stochiometric (AFR 11.76) and produces max power at about 15% rich of stochiometric (AFR 12.8) if detonation is not a problem.

At those very rich mixtures E85 is burning much more fuel for a given amount of air and releasing more energy than gasoline could on the same amount of combustion air.

Wikipedia has a good article on wide band O2 sensors which covers their operation.

The sensors do change with age, and exposure to chemicals in very rich mixtures, but that is simply solved by recalibrating the sensor. In the case of exposure to lead of course the sensor slowly degrades and begins to read slow (another good reason not to mix leaded racing fuels with Ethanol).

The Bosch sensors used in the LM-1 for example are accurate to about 0.1 AFR (gasoline) between 0.8 and 1.0 Lambda, (accuracy equivalent is ~0.007 Lambda.)

Outside that range they are less accurate, but quite frankly we don't need more than about 0.3 +/1 accuracy on AFR for most tuning. On gasoline your max power will only change about 1-2% from about 11.8 -13.2:1 AFR as long as detonation is not an issue.


Larry

 

[RmvBfrFlght]

The lambda reading of a wide band is completely fuel independent. It is simply a measure of the free oxygen concentration in the combustion gases. The sensor neither knows or cares what you are burning all it is measureing is the unburned oxygen concentration. Larry

And what free oxygen is there is a fuel rich exhaust? None.

The issue as I see it is that you do not understand what a wide band O2 sensor is responding to.

The problem with Wikipedia is that ANYONE can post there, you, me, or the turnip truck driver.

On the rich side of stoich a WB O2 sensor measures the percentage of unburned combustionable products. There is NO free oxygen. Note the 'combustionable' products. Which include carbon & hydrogen.

And, if you do a little reseach you will find that different fuels have different ratios of these compounds in them. Thereby, a wide band O2 sensor will report a different percentage of remaining combustionable products for different fuels.

And if this isn't true, then why do the 'real' WB systems ($5,000 to $8,000 cost units) have setable C & H ratios on the front panel?

RemoveBeforeFlight

 

[ronbuick]

I installed the LM-1 WB02 a couple of weeks ago,running E85 with newly installed 83lb'ers and a TT chip for the E85, I could not get the boost below 25lbs, but at 25lbs I had zero knock on my Caspers gauge, I recorder several runs on the WB and down loaded them and played them back, talk about crapping my pants when I played back those runs it was so far off of the lean scale I did not know what to do, now I could not get boost levels below 25lbs so I bypassed everything and went straight from actuator to compressor with my hose, went out last Sunday the roads were dry made a couple of runs with my DS hooked up and the WB also, boost down to about 18-19lbs, did some recording with the WB and the same type of readings off the scale on the lean side, before I had my plugs gaqpped at .032, regapped to .028, thought that might help also, I'm starting to wonder if I just threw away 300.00 plus dollars on this peice of equipment or either I'm reading something wrong into this, I have a hood mounted feul pressure gauge and at 40lbs crusing and at 25lb boost 65-66 psi so that seems to be telling me my pump is putting out enought fuel, I'm going to run out the E85 and go back to gas and turn on the alky kit and see what kind of readings I get, I have recalibrated the sensor a couple of times to where it reads 20.9% and reinstalled it, I'm lost as to why this thing is going off of the scale on the lean side, anyone have any ideas or what to try. duty cycle of inj. at the 18-19lbs boost was about 70-72%. Do I need more fuel, less fuel or a different fuel? If there is something I missed please let me know.

thanks

Ron

 

[ronbuick]

Regarding the above thread are these LM-1 WB02, are these plug and play or are we to program these before use, I have been doing some reading on the instructions downloaded on my computer and I get the impression there has to be some programing involved before use or am I wrong,,, and it is a plug and play unit or not??
thanks

Ron

 

[hotrodwrx]

And what free oxygen is there is a fuel rich exhaust? None.

The issue as I see it is that you do not understand what a wide band O2 sensor is responding to.

The wide band sensor is basically a chemical battery that measures the partial pressure of O2 in the exhaust gas. In the case of rich mixtures it measures the amount of oxygen it must pump through the sensor cell to reach the stoichiometric reading.

then why do the 'real' WB systems ($5,000 to $8,000 cost units) have setable C & H ratios on the front panel?

Because unlike affordable widebands, they do not assume what fuel you are using and must know the C & H ratio to compute the true AFR from the indicated lambda reading.

The Innovate site has lots of good technical info on the WBO2 sensors including information directly from Bosch.

Since Bosch developed the O2 sensor, they are the "source" for information.

Bosch Automotive Handbook 6th Edition Pg 133-134
"Oxygen-concentration sensor (lambda oxygen sensor)
The fuel-metering system employs the exhaust-gas residual-oxygen content as measured by the lambda oxygen sensor to very precisely regulate the air/fuel mixture for combustion to the value (lambda)=1 (stoichiometric combustion P. 605)

The sensor is a solid-state electrolyte made of ZrO ceramic material. At high temperatures this electrolyte becomes conductive and generates a characteristic galvanic charge a the sensor connections;this voltage is an index of the gas oxygen content The Maximum variation occurs at lambda=1.

Electrically heated sensors are especially well-suited for measurements in the lean range, and already come into operation in the warm up phase.

For the wide band range, flat and smaller "wafer sensors of multilayer ceramic design (broadband lambda oxygen sensors) are used; these sensors can also be used in diesel engines. A sensor of this type is essentially a combination of a conventional concentration sensor which acts as a galvanic cell (Nernst sensor) and a limit current or "pump cell". A voltage is applied from an external source to the pump cell, which is the same design as the conventional concentration cell. If the voltage is high enough, a "limit current" sets in which is proportional to the difference in oxygen concentration at both ends of the sensor. Oxygen atoms are transported - depending on polarity - with the current. An electronic control loop causes the pump cell to supply the concentration sensor permanently through a very narrow diffusion gap with precisely enough oxygen from the exhaust gas to maintain a status of lambda=1 at the sensor. In other words, oxygen is pumped away in the event of excess air in the exhaust gas (lean range); in the event of a low residual-oxygen content in the exhaust gas (rich range), oxygen is pumped in by reversing the pump voltage. The relevant pump current forms the output signal.

when I played back those runs it was so far off of the lean scale I did not know what to do

Did you calibrate the sensor in free air before you did your runs?
(you only have to do this on install and periodically after to check for calibration drift - like every 6 months or so if you are anal about being exactly accurate. If you are not using leaded fuels the calibration should hold for a pretty long time)

If the calibration is off it will give you goofy readings. Also check for air leaks in the exhaust ahead of the sensor. If you are having a serious missfire (one cylinder not firing at all) it can sometimes give a false lean reading because the free oxygen in the exhaust gas from the unburned cylinder mixture is seen as a lean mixture. Same could be true if you are blowing a lot of mixture through the cylinder on valve overlap. Innovate has a good question and answer forum on their web site that should help you figure out what to look at next. On E85 I ignore the fuel air mixture and only pay attention to the lambda reading. On my car lambda 0.72 -0.76 at WOT is a good number. At light throttle cruise I see lambda 1.02 (AFR of 15:1) under light load light throttle that is no problem at all. My car cuts over to richer mixtures above 6 psi boost on E85, below that even on very lean mixtures it cannot detonate.

when I played back those runs it was so far off of the lean scale I did not know what to do

Just the calibration task as mentioned above on mine.


Larry

 

[ronbuick]

WRX, I have recalibrated this thing a couple of times and comes to 20.9%, install it took her out for a couple of runs at 18-19lbs boost vs. the 25lbs I was running earlier and the same thing off the scale on the lean side, if you like I can send you the first 7 sessions as I have them on this computer
here at work, the other 2 runs are on my laptop in my car and they were at18-19lbs vs the 25 lbs on the first 7 runs, they look scary, but maybe there is a misfire, if so I do not feel it what so ever, car runs out strong, let me know. Maybe I will install my other plugs which have just a few hundred miles on them and see what happens, Just love changin plugs in these cars, I think
I an do it in my sleep, lol

Ron

 

[RmvBfrFlght]

The wide band sensor is basically a chemical battery that measures the partial pressure of O2 in the exhaust gas. In the case of rich mixtures it measures the amount of oxygen it must pump through the sensor cell to reach the stoichiometric reading.

So on the rich side is it reading the excess O2 in the exhaust or isn't it? Last time you posted it measured the excess O2, now it is doing something else? What is this oxygen being used for? You already stated that it measured the excess oxygen in the exhaust even when rich of stoich.

I'll again answer with the correct information: in a fuel rich exhaust the WB O2 sensor is responding to the unburned combustionable matter. IOW, left over fuel. The sensor will actually burn this matter and measure the volume of oxygen required to burn it.

Because unlike affordable widebands, they do not assume what fuel you are using and must know the C & H ratio to compute the true AFR from the indicated lambda reading.

No, it is to have the correct calibration curve for the sensor based on the fuel being used. And by the way, the ratios are specified as oxygen to carbon (O/C) and hydrogen to carbon (H/C). This is why a WB O2 sensor responds to different fuels with a different curve. It has to do with how the carbon, hydrogen and oxygen atoms are strung together to form the molecules of the fuel.

The Innovate site has lots of good technical info on the WBO2 sensors including information directly from Bosch.

Since Bosch developed the O2 sensor, they are the "source" for information.

Larry

And again you post false information. NGK in concert with Honda developed the WB O2 sensor. It was derived from previous work that NGK & Honda did on a lean burn sensor. If you really want to know how a WB sensor works, read some NGK papers.

Bosch is very late in the WB O2 sensor game.

You remind me of people that have enough information to have them think they know what they are talking about. Yet barely know the subject.

RemoveBeforeFlight

 

[RmvBfrFlght]

WRX, I have recalibrated this thing a couple of times and comes to 20.9%, install it took her out for a couple of runs at 18-19lbs boost vs. the 25lbs I was running earlier and the same thing off the scale on the lean side, if you like I can send you the first 7 sessions as I have them on this computer
here at work, the other 2 runs are on my laptop in my car and they were at18-19lbs vs the 25 lbs on the first 7 runs, they look scary, but maybe there is a misfire, if so I do not feel it what so ever, car runs out strong, let me know. Maybe I will install my other plugs which have just a few hundred miles on them and see what happens, Just love changin plugs in these cars, I think
I an do it in my sleep, lol

Ron

Ron, there are some others factors that will affect the WB reading. The most obvious and one of the more difficult to find are exhaust leaks. Any leaking prior to the sensor and several feet past the sensor will skew the reading.

Others are exhaust back pressure and the exhaust temperature. Where abouts in the exhaust was the sensor installed?

A simple sanity check can be made if your tune runs in closed loop. Drive at a steady speed (within the speed limit ) and data log the WB. When you look at the log the WB O2 reading should be slightly oscillating at about stoich.

RemoveBeforeFlight

 

[ronbuick]

Remove, I installed the bung at the 1300hr. position and about 14" down on my THDP, I will try the steady cruise and data log it and see what she reads, that will happen this week end,the weather will be cold but sunny and
dry, at least that is what they are saying now, will keep you informed, I think
also I will re-install the denso iridium plugs just for the heck of it also, right now I'm using Brisk silver racing plug that is a couple of steps colder.

Ron