E78 1.4T Ethanol conversion

[Spcbrn]

Hey folks,

I have a 2017 1.4 Turbo engine, E78 ECM and looking for some answers regarding tuning for E85 fuel.
I know the best course of action would be running a physical flex sensor but unfortunately I won't be able to do it until later this year.

So I was wondering, my local gas station show the ethanol composition at the pump (in summer it sits at a steady 75-78%) so is there anyway to force this number into the ECM?
It's definitely not a long-term solution since this number is going to change with colder weathers but by then I should have the sensor installed.

I was thinking I could manually calculate the stoich AFR I want and copy the value across the whole table and then do the same for all the blend factors/multipliers tables but I wouldn't mind some input about that.
Sorry if it's a dumb question but is there any need to edit the torque model tables? In my ECM I have two sets "Airmass based" and then "E85 Airmass based" etc. Same questions about the IVT gain zones, I guess I'll have to calculate these manually?

Thanks for the help

[07GTS]

without the sensor the blending/multipliers and torque and stoich dont change to suit the ethanol so just leave as is, easiest is to just look at a stoich table with the ethanol 0-100% values and put in the correct value for the 0% cell as thats all that is used until u get the sensor, to fine tune if u know ur fueling is say 2% rich then just adjust the stoich until its the same 2% rich for when u fill it until the sensor is fitted, until u get the sensor u only have to set the stoich table to suit the ethanol %

[RoninDusette]

Hey folks,

I have a 2017 1.4 Turbo engine, E78 ECM and looking for some answers regarding tuning for E85 fuel.
I know the best course of action would be running a physical flex sensor but unfortunately I won't be able to do it until later this year.

So I was wondering, my local gas station show the ethanol composition at the pump (in summer it sits at a steady 75-78%) so is there anyway to force this number into the ECM?
It's definitely not a long-term solution since this number is going to change with colder weathers but by then I should have the sensor installed.

I was thinking I could manually calculate the stoich AFR I want and copy the value across the whole table and then do the same for all the blend factors/multipliers tables but I wouldn't mind some input about that.
Sorry if it's a dumb question but is there any need to edit the torque model tables? In my ECM I have two sets "Airmass based" and then "E85 Airmass based" etc. Same questions about the IVT gain zones, I guess I'll have to calculate these manually?

Thanks for the help

What I did with the e78 running e85 at 79.99% ethanol and 60 lb injectors was leave pretty much everything stock when it comes to the fuel and spark tables for ethanol. Especially for startup. The hardest part is getting the correct data for your injectors well at least for mine. It took me quite a long time to find the right spreadsheet or right data for them and to calculate them and scale them properly. So I left all the fuel and spark tables as well as IVT and blend tables all across the board bone stock for 85 cuz it's already scaled properly for flex fuel at least my e78 was. The only thing that was different was the power enrichment table for alcohol and like one other table that were completely zeroed out. But the power enrichment table for alcohol if you look at the regular one not the alcohol table The regular PE table it set for percentage of alcohol in the rows and in the columns RPM vs EQ ratio. So considering you have to run about 30% richer than you usually would you would scale this to suit if yours wasn't already the same way. A lot of people would take the whole table and turn it into you know one EQ ratio across the board but then you lose the ability to have the flexibility in flex fuel. So once I got my power set in for 91 octane in the first row I would dial it in with a fresh tank of just e85 and then interpolate from there once I got the very last and the very first row doubt and where I wanted them to be at wide open throttle. That's kind of a good example of how well their ECUs are already set up for flex fuel where as long as you get that top end and your baseline done you can interpolate from top to bottom and get right about where you need to be depending on your fuel blend you should be right about there Obviously to get it right across the board you'd have to tune for each percentage of fuel which I think there's like five or six rows but I found interpolating to be fine. You can do the same thing for your tort tables as well because you do want to scale those properly so you would set your torque tables for 91 octane at the bottom row and at the top road pure e85 just the purest you can get and then you can interpolate between those two so you can set your peak power for the different blends of fuel. That being said once you get a flex fuel sensor which you can go buy one on eBay for like 25 bucks and the connectors for like five or maybe 10 bucks and some nylon hose and hook that up and wire it into the ECU then it just automatically logs in there with that PID because the tables are already set up there's already a pin in the ECU for alcohol or a flex fuel sensor and once you get that in there you'll be able to measure your alcohol percentage and see where that's at as well instead of just kind of guessing. I highly recommend doing that because it's a super easy job. You just have to buy some DuPont connectors for the X1 connector on the ECU because you need to use a common ground to the ECU and the signal wire goes into the ECU and you want to wire that into the stock wiring loom it sounds daunting but it's not hard. There's only three wires I believe for the flex fuel sensor is just signal ground from the computer and hot wire which you can just Hook up to a 12 volt switched lead. If you have any questions feel free to PM me I've actually worked extensively on the 1.4T with the e78 running flex fuel and different size injectors and stuff so I'm really familiar with it if you have any questions