2019 Mustang Flex Tune MBT Lambda corrections

[hsteel]

Just gone through the process of copying the flex fuel tables from the 2018 F-150 repo file to my 2019 Mustang GT file.

One thing I wasn't sure of changing was the Spark->Advance->MBT Corrections->Lambda table. Are people leaving the Mustang one as is or copying across the F-150 data?

The Borderline Correction adjustments also have me a little nervous, due to the axis difference. I copied over the columns that matched, then interpolated the lower values. If someone would be willing to check over the changes I ported across, it would be greatly appreciated.

Car is stock.
StockFile-9-13-23.hpt
Flex-9-29-23.hpt

[engineermike]

Good questions.

There are a few ways to deal with flex borderline timing. One would be to leave the table all 0s and let the knock advance find the new, higher limit. This is the ultra safe way. Another way is to just populate the table with something in the 4-8 range. This is the least safe, but will work fine if you follow fords instructions for flex fueling. Then theres the in between way that the f-150 does it. They only add borderline at low speeds and loads and phase it out up top. My theory is it basically gets you the timing sooner at low rpm which allows knock advance to bring in the timing up top.

On mbt, it actually reduces timing on e85. This is probably technically accurate but most seem to agree that fords mbt is too low to begin with. For sure, if you leave it alone you wont be seeing those 30-32 deg numbers you hear about. However, you do at least need to copy the low load/speed numbers over because it affects anything requiring torque control, like idle, shift torque modulation, etc. what you could do is copy the f150 values at .8 and below load, and add a couple degrees above that. That said, make sure youve adjusted the cylinder pressure limit table or youll hit that before you ever reach mbt.

[hsteel]

Good questions.

There are a few ways to deal with flex borderline timing. One would be to leave the table all 0s and let the knock advance find the new, higher limit. This is the ultra safe way. Another way is to just populate the table with something in the 4-8 range. This is the least safe, but will work fine if you follow fords instructions for flex fueling. Then theres the in between way that the f-150 does it. They only add borderline at low speeds and loads and phase it out up top. My theory is it basically gets you the timing sooner at low rpm which allows knock advance to bring in the timing up top.

On mbt, it actually reduces timing on e85. This is probably technically accurate but most seem to agree that fords mbt is too low to begin with. For sure, if you leave it alone you wont be seeing those 30-32 deg numbers you hear about. However, you do at least need to copy the low load/speed numbers over because it affects anything requiring torque control, like idle, shift torque modulation, etc. what you could do is copy the f150 values at .8 and below load, and add a couple degrees above that. That said, make sure youve adjusted the cylinder pressure limit table or youll hit that before you ever reach mbt.

Thanks for the great advice. I am going to revisit my timing tables when I have a little more time. It was late when I pulled the MBT one over and have never thought about E lowering the advance for MBT. I also didn't pull across the cylinder pressure table, but after pulling it up now, the Mustang table has for the most part higher values. I am unsure how to interrupt these tables though.

Mustang Table
VCM_Editor_72f86z9j6S.png
F-150 table
VCM_Editor_6H7vd8vJWB.png
Comparison after matching the columns to the F-150 file and the moving the columns around
VCM_Editor_n7T52UF1x4.png

[engineermike]

Most would just raise cylinder pressure up out of the way like all 55’s.

[hsteel]

Should I be pulling tables across from the "Torque Model" tab? The only thing I have changed right now is the "Ethanol Efficiency" table.

[engineermike]

I don’t believe anything from the torque model needs changing except the ethanol efficiency.

[Thatwhite5.0]

Using the F150 is a good starting point to figure out how FF works, it's just that they have complete different BLK and MBT tables.. You'll end up doing what Mike said and maxing out the cylinder pressure and targeting more spark advance.
I'd zero out the BLK/MBT lambda spark modifiers. I'd zero out most of the spark modifiers in your file. With what you're trying to do, I'd set these tables two tables up like the following. This will get you 28-30*.

FF-mods-and-limiters.PNG

[hsteel]

Using the F150 is a good starting point to figure out how FF works, it's just that they have complete different BLK and MBT tables.. You'll end up doing what Mike said and maxing out the cylinder pressure and targeting more spark advance.
I'd zero out the BLK/MBT lambda spark modifiers. I'd zero out most of the spark modifiers in your file. With what you're trying to do, I'd set these tables two tables up like the following. This will get you 28-30*.

FF-mods-and-limiters.PNG

Thanks for the tips. Won't adjusting those pre-ignition and cylinder pressure tables up the safety ceiling for gasoline based fuels too? It looks like the F150 file does the "Modifier FFV Mult" table for both of those. Although it if it acts on the "Modifier FFV" table it isn't going to do anything!

[hsteel]

Looking over this again, would it be safer to make the limit adjustments in the "Modifier FFV" tables and then let the "Modifier FFV Mult" do the work? That way gasoline limits are left alone and E85 limits are adjusted. I want to run this as close to a flex tune as I can.

[engineermike]

Yes, that’s how I do it.