I did it: E85 on a Supercharged T4R

[19963.4lsr5]

I guess a simpler way to say it is that if you have a proper stoichiometric mixture on E85, the actual AFR will be around 10 (9..8). But unless you've messed about with it, your AFR gauge will show 14.7, it will NOT show 10.

So with e85 what does the lamda value equal for 10:1af? Using gas as the lamda

I’ve seen monitors that you can program lamda for the fuel being burned. My brother and I use a WEGO that we can input a few sensors to it for logging purposes. MAP and TPS.


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[turbodudey2]

So with e85 what does the lambda value equal for 10:1 AFR? Using gas as the lambda

I’ve seen monitors that you can program lambda for the fuel being burned. My brother and I use a WEGO that we can input a few sensors to it for logging purposes. MAP and TPS.

The lambda reading is independent of the fuel type. Stoich is always at 1.

Because all gauges read in lambda (AFR is for display purposes only) it can be easier to tune with the native lambda value, then you don't have to worry about fuel type.

E85 stoich is right around 9.8:1 so a 10:1 AFR like your example question will read close to 1.

Since most gauges only have AFR curves programmed for gas, you won't see a 10:1 AFR displayed when running E85 - it'll still say 14.7. That's why, like mentioned before, it's important to remember the sensor and gauge are actually always reading lambda. The AFR displayed is just a calculated number.

 

[JohnMc]

So with e85 what does the lamda value equal for 10:1af? Using gas as the lamda

I’ve seen monitors that you can program lamda for the fuel being burned. My brother and I use a WEGO that we can input a few sensors to it for logging purposes. MAP and TPS.


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You may be thinking of it backwards. Lambda is the measure of the O2 left in the exhaust. It's independent of the fuel being used. It's what you can look at as an indication of a rich, lean, or stoich burn. You can't tell what the AFR was by looking at the lambda reading in the exhaust, all you can tell is rich, lean, or in between.

And FWIW, a WBO2 sensor puts out voltage between 0 and 5 volts. 5 being waaay lean, 0 being waaay rich. It's not a completely symmetrical curve between full lean and full rich, lambda of 1 (stoich burn) is often (it can vary dependingont he sensor) around 2.1 V.

So with gas or E85 or a mix in between, a stoich burn (10:1 E85, or 14.7:1 gas) will read as 1.0 lambda, around 2.1, 2.2 V from the WB O2 sensor.

The gauge looks at that voltage, and does some math internally to convert it to an AFR number. It can't tell from the WB sensor what fuel was burned. So someone has to have set it to do a conversion from a direct lambda sensor reading to a contrived/derived AFR number. Which assumes you are burning some particular type of fuel.

So there is no E85 or gas lambda, lambda is the same regardless of fuel. The gauge does math based on what it fuel it thinks you are using to calculate an AFR number. So if your gauge is set to gasoline, a 10:1 AFR is stinking rich, regardless of what fuel you are using. If your gauge is set to E85, 10:1 is stoich, regardless of what fuel you are using.

Generally, I'm not sure what the advantage of changing the gauge setting around would be. Because E85 isn't always E85 (at least not pump E85). So it won't necessarily be an accurate AFR number anyhow.

Just treat it as a rich/lean gauge, with 14.7 being right in the middle. Regardless of what fuel you use.

 

[19963.4lsr5]

The lambda reading is independent of the fuel type. Stoich is always at 1..

I’m my experience Stoich is always 1 based on the fuel type.

A person running strait methanol with an AF of around 6:1 AF which is a stoich of 1 for that fuel type is different than e85 or strait gasoline.

Using a AF monitor that reads stoich instead of a AF number what is the reading going to be with a gasoline calibration of 14.7:1 which equals a stoich of “1” when they are running e85?

I’m not trying to argue with you. Just trying to hammer out the variation between different AF monitors and what the optimum reading should be for those with a meter reading stoich instead of an actual AF ratio.

Leaner is meaner until one puts holes in their pistons. Been there too many times.


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[JohnMc]

Stoich will be 1 lambda, regardless of the fuel.
Stoich will be 2.1V from the WBO2 meter, regardless of the fuel.
What an AFR gauge reads based on that input, is all up to the gauge.

 

[19963.4lsr5]

Stoich will be 1 lambda, regardless of the fuel.
Stoich will be 2.1V from the WBO2 meter, regardless of the fuel.
What an AFR gauge reads based on that input, is all up to the gauge.

Is appears I must revisit this.


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[FJ60GatewayDrug]

This album has the LTFT at various points. High idle / cold start, low idle / cold start, low idle / warm engine. Plus an engine run up to about 2000RPM.

LTFT E85 - Album on Imgur

I took a look and didn't see any obviously damaged/cracked hoses.

0.514 lb/min is 3.886 g/s, which you read at 704 RPM. I had 3.6 g/s at 756 RPM. Given the variation of intake temperature and elevation, it seems to all be matching up.

I'd run another couple tanks of 91 through it for comparison and to check my LTFT against E10 gasoline, but... I gotta save my pennies for a clutch ound:

 

[19963.4lsr5]

I know my TPS in the off idle to around 20% (10-20%) is worn some. It’s got 293k miles on it and I’ll catch the LTFT at 15-18% in a three to five percent zone and instantly drop back to around zero around 18%tps. I have some spare sensors but haven’t gotten around to changing it.


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[FJ60GatewayDrug]

Update

The ratio of ethanol and gasoline varies by season. In the winter, there's more gasoline. In summer, more ethanol. This is to help cold starting. Here in SoCal, the difference is pretty minor, but I have noticed that I haven't seem to set a "too lean" code in awhile. I'm also regularly mixing in 91 and not doing straight E85 unless I've got a long trip planned. (Remembering that idle seems to be where E85 "struggles" the most, causing the fuel injectors to go over +20% fuel trim) MPGs continue to be crap, albeit slightly more crap when it's a tank of mostly E85.

An oil analysis from Blackstone came back clean, with wear matching other 5VZ-FE samples. I'll do another analysis next oil change, too, and see if there's any changes.

Also, I did pull a spark plug out and checked out the #4 cylinder, because it was in the middle and represented a good blend of heat soak but not hottest coolant, exhausted into the bank where my aftermarket AFR gauge reads from, and was the easiest to reach. I took photos, but they're photos of a screen, since the cheapie unit I have doesn't capture pictures natively. No visible deposits, or the entire thing is coated and looks like a new protective layer has formed; either way, the pictures-of-the-screen pictures aren't great. I'll dig them up and post them if people really want to see what a 200k+ mile piston top looks like.

 

[JoeT4R]

The ratio of ethanol and gasoline varies by season. In the winter, there's more gasoline. In summer, more ethanol. This is to help cold starting. Here in SoCal, the difference is pretty minor, but I have noticed that I haven't seem to set a "too lean" code in awhile. I'm also regularly mixing in 91 and not doing straight E85 unless I've got a long trip planned. (Remembering that idle seems to be where E85 "struggles" the most, causing the fuel injectors to go over +20% fuel trim) MPGs continue to be crap, albeit slightly more crap when it's a tank of mostly E85.



An oil analysis from Blackstone came back clean, with wear matching other 5VZ-FE samples. I'll do another analysis next oil change, too, and see if there's any changes.



Also, I did pull a spark plug out and checked out the #4 cylinder, because it was in the middle and represented a good blend of heat soak but not hottest coolant, exhausted into the bank where my aftermarket AFR gauge reads from, and was the easiest to reach. I took photos, but they're photos of a screen, since the cheapie unit I have doesn't capture pictures natively. No visible deposits, or the entire thing is coated and looks like a new protective layer has formed; either way, the pictures-of-the-screen pictures aren't great. I'll dig them up and post them if people really want to see what a 200k+ mile piston top looks like.

Pics, please. I definitely want to see them!!!!

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[gamefreakgc]

Is carbon buildup a problem with ethanol fuels? I hadn't heard about having to think about deposits, although with the 5VZ-FE engine I don't think really care too much either way. These things are stout engines, probably more of a performance issue than reliability issue?

You are spot on about those idle trims though. That's the hardest thing for me to tune on my 4Runner. I'll have partial throttle perfect at almost 0's, full throttle with near perfect AFR's and then I'll pull up to a stoplight and see a -20% fuel trim. And then the next day it'll be near 0 at idle. What the heck Toyota.

 

[JohnMc]

I had my E85 turbo Volvo motor apart several times (ahem, part of why I eventually turbo LS swapped it, the Volvo motor was pretty stressed putting out 350 whp). And there was never any particularly noticeable carbon buildup. You'd mostly get that from running stupidly rich most of the time, or from burning oil. Nothing about the fuel itself would tend to make more carbon and buildups (that I know of).