Bri Bro

Lots of posts out there that I have looked at but here is my bottom line After running E85.

Before using your Wide band sensor to tune E85, set it on lamba display.

Why? AFR is the lamda divide by the fuel stoich value . All the WB sensors that are displaying AFR are assuming a certain fuel is being used. Most of the time it is gas. E85 is a blend of gases so that make AFR hard use.

BTW: You also need need about a 30% increase in injector flow rate for E85.

More to follow.

m73m95

Dude, you're late to the party MEGA e85 thread.

And, you don't need to touch your wideband. When your gauge reads 14.7:1 on e85, there is a physical difference in the air/fuel ratio than when seeing 14.7:1 on gas. All your wideband knows is stoichiometric mixtures.

I'm still not an e85 expert... But, there are those among us who are

m73m95

Wow.... 9:28, and 9:51 lol

Bri Bro

Back on subject:

John started a very good thread on e85, but the thing I want to bring forward is that tuning with E85 needs to have the WB set on Lamda rather then on AFR. This makes all the difference in getting the proper tune, If you read through all the threats, it get all mixed up in AFR for different fuels. My take on the subject after all is said an done is I have gone to Lamda and this works.

E85 is a blend of fuels that changes with the seasons so using the WB sensor in a gas may not be the best solution to the problem..

Bri Bro

Here is a list of common fuels and the ratio of air to fuel for Stoich. It is intersesting to note that ethanol has a lower ratio to fuel to air. The issue is that the BTU content of the fuel is lower then gas. One thing about gas, it gives more BTU then most fuels.


"Common fuels
When the composition of a fuel is known, this method can be used to derive the stoichiometric air-fuel ratio. For the most common fuels, this, however, is not necessary because the ratios are known:

Gasoline: 14.7
Natural gas: 17.2
Propane: 15.5
Ethanol: 9
Methanol: 6.4
Hydrogen: 34
Diesel: 14,6
You may find it interesting that methanol and ethanol both have a very low air-fuel ratio, while the carbon chain length is comparable to methane and ethane. The reason for that is alcohols like methanol and ethanol already carry oxygen themselves, which reduces the need for oxygen from the air.
Conclusion:
In order to be able to judge if an air-fuel mixture has the correct ratio of air to fuel, the stoichiometric air fuel ratio has to be known. If the composition of a fuel is known, this ratio can be calculated rather easily."

95ONE

DEAR SIR... >. you are getting it confused.. Just read the AFR like it was reg fuel. it will read 14.7 but it will truly be 9.7 (E-85 not pure ethanol) SOOOOOOo no need to make it more confusing. install wideband and tune for 11.8 at full boost.. its that simple. You're making it more complicated. yes, yes.. it will say 11.8 but it will actually be in the 8's. but why make it more confusing? keep it as is. and just know when it says 14.7 its stoich.. when its 11.8, it's right where it needs to be at full boost.. that easy.

Bri Bro

I agree, at Lamda =1 all is equal as 1 divided by any number is 1. But to get AFR, the fuel is divided by the lamda. The problem is the mix of the fuels, it changes all the time. The Lamda will reflect the changes with greater accuracy. Why is this more complicated? I just flip a switch and the WB goes to Lamba display.


Here is a table. The same lamba number applies across all fuel or fuel blends since it is fuel independent:

95ONE

Put down the chart.. lol What are you doing up? Soooo.. do you see that it makes no difference what fuel you tell the wideband its reading? It ALWAYS reads Lambda.. not afr. Sooo.. If you are familiar with tuning gas and not E-85. Keep it on the Gas AFR's. if it reads 11.8 set for gas, it is STILL at .8 lamda exactly what you want for ethanol. BUT if you're not used to reading e-85 ratios and have no idea and need to refer to a chart all the time, then don't bother. keep it on the gas ratios. I do. and it tunes E-85 great, but with fuel AFR ratio numbers I'm familiar with.

Bri Bro

I am getting ready for the next weekend and will be running E85 for the first time at speed, so I am setting up some datalogging. I am convinced that setting the WB to lamda is the right step...other may differ. Why? the division of a number is linear but decreases the accuracy and makes for all type of confusion. Why display AFR for gas when running E85? Lamda is fuel independent.

BTW: My hat is off to you for all the work you have done on getting E85 out into the mainstream.

Lemming

Dividing by a constant does not change the accuracy, it just makes it a different number.

blown 944

Brian, I'm sorry but IMO you are really making it more complicated than it is. If you want to use lambda it truly doesn't make a difference. If you just think about it you are only utilizing a multiplier, there is no other variable. So the reality is when you tune for 11.8 like Bruce said what you are doing is just using the gasoline multiplier but just adding more fuel to get to that ratio.

It doesn't really matter though if you are more comfortable with lambda. If you ever post reagardibg tuning all we have to do is add in the multiplier (or honestly it's pretty easy to deal with lambda too)

Good luck with running the fuel and I'm sure you're seeing sone of the benefits.

schip43

Brain I understand the point your are trying to make, I was making the same arguments on Tercelonline but the guys that have "been there done that" also said to just sit the WB for gas.

I'm not running E85 yet but I notice if I'm at PT at 14.7 it dithers from there if I set it to Lambda it dithers back and forth from 1, seems to ge the same.

If you get it wrong, it's gonna be bad news...just saying.

95ONE

Ok.. I'm up and around. Brian, Sid said what I was going to say after sleeping on it. I'm usually still in "MY BOX" that late. If it is what YOU are comfortable with. Asolutely.. Do that. And just like Sid says. LAMDA is actually pretty easy. .8-1.0. How easy is that? Honestly though. For a street car, under light load cruising, I like to use 1.15 lambda or 17.0AFR. It raises the NOx emmisions, but gives you nice fuel economy. It mimics a "European" stock factory map.

Heres another chart..

Lamda E85 Gas
0.780 7.613 11.466
0.790 7.710 11.613
0.800 7.808 11.760
0.810 7.906 11.907
0.820 8.003 12.054
0.830 8.101 12.201
0.840 8.198 12.348
0.850 8.296 12.495
0.860 8.394 12.642
0.870 8.491 12.789
0.880 8.589 12.936
0.890 8.686 13.083
0.900 8.784 13.230
0.910 8.882 13.377
0.920 8.979 13.524
0.930 9.077 13.671
0.940 9.174 13.818
0.950 9.272 13.965
0.960 9.370 14.112
0.970 9.467 14.259
0.980 9.565 14.406
0.990 9.662 14.553
1.000 9.760 14.700
1.010 9.858 14.847
1.020 9.955 14.994
1.030 10.053 15.141
1.040 10.150 15.288
1.050 10.248 15.435
1.060 10.346 15.582
1.070 10.443 15.729
1.080 10.541 15.876
1.090 10.638 16.023
1.100 10.736 16.170
1.110 10.834 16.317
1.120 10.931 16.464
1.130 11.029 16.611
1.140 11.126 16.758
1.150 11.224 16.905
1.160 11.322 17.052
1.170 11.419 17.199

BC

The usage of E85 allows a much wider range of AFR than does petrol. While "Stoich" for Ethanol is an actual 9.6 or 9.7 (or 14.7 on a petrol scale) when its E85, its important to understand that number is not going to be what is best for power.

In fact, unlike petrol, ethanol, when made richer, continues to add torque ALL THE WAY down to 6.75.

It IS a different fuel, and it does need to be treated differently.

What the OP is suggesting is technically true, as you need to start thinking in Lambda so there is no problems with "scales" and such. If you can practice divergent thinking, then, fine, but it can help some.

The turbo people in this forum can REALLY benefit. Since the volume and therefore mass of fuel is higher in the combustion process, ethanol has the possibility of spooling the turbos faster and earlier.

I believe more tuning and better tuning needs to be done because of this wider spectrum of possible AFR ratios in a normal car. Cruising can be tuned past stoich for better gas mileage on the lower-btu ethanol, and at part throttle increasing cruise, you can add more duty cycle to assist acceleration without so much throttle input. At BARN burning WOT, you would want to go full past rich to add that additional amount of torque.

The issues that arise when ethanol (or methanol) is burnt is that the amount of mass in the combustion process is past the task of many stock OEM ignition systems. Remember, that at the "nth degree" or in the extreme, methanol needs essentially a mig welder in the combustion chamber to ignite the mixture. So to a lesser degree, one must be aware of the amount of mass inside the combustion chamber that must be ignited for proper combustion and power.

Bri Bro

Thanks all. I am using Vflex and started out with +25%. After adding 5% I am getting numbers that look good. Idle at a little above 1 and on boost at around 8.1 - 8.2. It is kind of hard to get any real time data using second gear pulls so I will data log this weekend and see what I get.

The traqmate now can estimate HP so as I tweek the SM6 values I can see what happens. I can also look at distance vs time as a measure. The plan is to go down from 8.2 to say 7.8 since I don't want to do destructive testing.