Enabling Flex Fuel on EcoBoost

Has anyone experimented with enabling the built-in "flex fuel" capability for EcoBoost? On my actual FFV N/A 3.5L V6, it uses inferred stoich to determine the setpoint for stoich. There's even a PID within VCM Scanner for inferred stoich AFR. However on EcoBoost, this PID is missing. I believe the mechanics are the same as my N/A engine has a wideband o2 system same as EcoBoost. I've experimented with setting stoich for the E85 content I was using versus just keeping it at 14.08 and filling up with E85 to see the LTFT compensate accordingly.

I'm just wondering if anyone has played around with enabling the flex fuel logic on EcoBoost and whether it was worth it.

i haven't done it myself as there's none to be had unless I drive a ways to get it but Ive seen it in several tunes on here.

I wanted to report back on this... I enabled the logic on my 2.7L EcoBoost and it works. In the past I'd just dump E85 into the tank and watch the LTFT increase to compensate. With the logic enabled, I just poured in like 10 gallons of E85 into a tank filled with about 8 gallons of ~E30, and the LTFT is at 0.8% idle, which normally doesn't happen with the use of E85.

With this E50-E60 mixture, and an ambient temp of 90F and my charge air temp going as high as 199F, there was almost zero spark reduction at WOT. This engine just loves E85. Gas mileage is down about 3 mpg but during highway cruising it isn't that bad.

I just don't see a PID to show inferred stoich or anything of that nature. I've only got LTFT to look at, as well as injector duty cycle and HPFP fuel pressure. The stock 2.7 HPFP and stock 2.7 injectors seem to have more than enough capacity for maxed out turbos and over E50.

Here's the strange thing about mine: My ECM 21320 table has 8 lines, but the Inferred Stoich values are all 14.6 except for the top line, which is 9.0. I was expecting the values to be more......gradual, from like 9.0 to 14.7 or something, if you see what I mean.

Instead, I have:

9.0
14.6
14.6
14.6
14.6
14.6
14.6
14.6

....and then of course I can enter the ethanol % off to the right of each value. I have 9.0 set at 100%, but I can't set reasonable ethanol values for the intervening (between 9.0 and 14.7) since the very next line is using Inferred Stoich of 14.7. Which makes no sense because it's not like you'd ever run anything that has a higher AFR than 14.7, so I'm not sure why those two values are so close together. What does your table look like?

It does the linear regression automatically. Just populate 100% for 9.0 and you should be good to go. It's looking for the stoich with 100% ethanol and 0% ethanol (straight gas).

Well, i make testing on my mustang 2.3 eco 2018, working fine, at e30 on the dash i see ~13afrAttachment 111197

On my 2014 SHO, when I ran E30 without enabling the flex fuel logic, I could see the LTFT going very positive to compensate to add fuel if I kept stoich at 14.08 (E10). When I changed stoich to match what is about E30, the LTFT would get close to 0%. On my 2017 Fusion Sport, with the flex fuel logic enabled, I see LTFT is close to 0% even with E60+ so I believe it is working. I don't see any PIDs for inferred stoich or anything like that unfortunately, and since the Fusion Sport isn't a flex fuel vehicle I don't believe they enabled the inferred alcohol content PID either.

Attachment 111198

It's not available for the Fusion Sport

I'm pulling Ethanol% with Torque Pro on my Fusion Sport, but I can't get it to spit out the actual PID (probably because they don't want you entering it into a competitor). I can't guarantee it's accurate or is reading what they say it's reading, but I'm definitely getting back data from the Ethanol PID on Torque Pro.

I hope it's okay to say that on an HP Tuners forum, but I only mention it because it means there's a PID out there that should work (as long as that's actually returning valid data).

It definitely works. I was running about E60 until the tank was almost gone. I filled up completely with E85, and based on my hand calculations (well actually an Excel spreadsheet I made), it would have been around E73 with stoich around 10.5

Today after 6 minutes of driving, the Alcohol Percentage and Inferred Stoich updated in VCM Scanner, showing 73.7-75% alcohol and 10.4-10.5 stoich. Very cool. I was also able to hit my maxed out air mass flow I typically see, and there was no indication fueling was an issue. Injector Duty Cycle was still peaking around 36% with fuel pressure holding at 2100 psi. I will be doing more WOT testing and keeping an eye on things. But overall I suspected that the 2.7 won't need a HPFP upgrade to run full E85 unless you are running some bigger turbos like the MKZ 3.0 turbo swap.

I am not seeing a huge dip in fuel economy versus E60 though, I'm averaging 18-18.5 mpg with 75% same as 60%, where I normally can average 23-25 mpg with E10. I am also not seeing any increase in spark advancing or decrease with 73% versus 60%. Theoretically anything over E50 has diminishing returns, but I kept hearing from other tuners that running full E85 offers better performance on longer duration romps like 1/4 mile runs or some spirited driving in Mexico.

Overall this is a pretty bad ass feature. Sure beats having to retrofit an alcohol sensor or constantly fiddling with the stoich.

Hey @metroplex what does your ECM-11525 look like?

Mine looks like this:

|0|0|0|0|0|20|65 |
|0|0|0|0|0| 0|100|

So basically zeroed out all the way up to 20, then at 65 if jumps to 100. So I'm assuming that means infer between 20% and 65%. I just wasn't sure if that was right or not. I guess so, especially since "E85" is actually not legally allowed to be 85%, but wanted to get your opinion since you've done a lot with the Flex stuff.

Yes that's what mine looks like. And E85 isn't legally not allowed to be 85%, it's that they relaxed the requirements so you can get as low as 68% ethanol in "E85". Sometimes they have tested 90% or greater content in E85 in the Midwest. Theoretically speaking anything above E47 or 50% really doesn't provide significant gains for effective octane with GTDI, but others have varying results.

You did remind me to look at other FFV base configs as some of my FFV/Flex tables were 0'd. I used a 2016 F-150 5.0 and a 2018 F-150 5.0 to copy some of their blend curves. The O2 bias tables are iffy though. Mine were zero'd out and I think that's why it was running richer than normal as my STFT was negative. I copied my base bias tables over as a baseline to start as the stock settings are negative (lean).

I did a WOT test and saw injector duty cycle go as high as 40% and the cooler denser air allowed me to start seeing some of my normal turbo numbers. No misfires either for Cylinder 6 and I didn't see any oil spray out of the weep hole. My garage now smells like cheap booze during cold starts. I'll keep an eye on everything as I test.

Quote:

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Originally Posted by metroplex

I am not seeing a huge dip in fuel economy versus E60 though, I'm averaging 18-18.5 mpg with 75% same as 60%, where I normally can average 23-25 mpg with E10. I am also not seeing any increase in spark advancing or decrease with 73% versus 60%. Theoretically anything over E50 has diminishing returns, but I kept hearing from other tuners that running full E85 offers better performance on longer duration romps like 1/4 mile runs or some spirited driving in Mexico.

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I wonder if what you're seeing is happening because our 11525 table maxes out at 65. If so, it sounds logical that it can't infer past the end-of-scale, so ethanol values above 65% would be off-scale high and I would expect truncation. Am I barking up the right tree there?

No , it's a matter of physics.