Stock 2019 Mustang GT, file and log.

[engineermike]

You're right, there are a million papers on this and tough to tell how good.

This one looks useful. Bottom of page 52 specifically mentions 60 ATDC (300 BTDCf) as optimum DI SOI for maximizing MEP, which exactly matches Ford's 300 deg commanded SOI on the stock Mustang except at high rpm. I can only assume Ford pushed SOI up to 330 at high rpm for extra window. What's interesting is that the 2018 stock Coyote cal uses 300 for SOI all the time; it wasn't until 2019 that they started moving it as a function of speed and load. Page 53 points out that DI injection too early loses some of the charge cooling effect due to piston impingement. It seems as though the only real reason to inject before 300 would be if you ran out of time on the EOI side. Elsewhere in the article it notes that improved VE from GDI is due to the improved charge cooling (p.16 and 46).

https://core.ac.uk/download/pdf/4433861.pdf

I haven't been able to digest this extensive study yet, but it seems to be packed with info we could find useful:

https://www.osti.gov/servlets/purl/1253890

It does state that "Other than needing to be at 1450 psi and above, FRP [fuel rail pressure] was surprisingly not an important variable."

It would seem as though moving SOI to 300 at all times WOT, then lowering GDI pressure to push EOI back to ~90 BTDC could potentially net benefits in both VE and KLSA.

[murfie]

From your log, this is a plot of the mystery SOI limit vs rpm:Attachment 109316

That looks like 6* per 1000 RPM. =.006*. That value gets you 1 millisecond per 1000 RPM being subtracted or moved elsewhere. There's a split table with 1.2ms in it, but I disabled LSHP mode an it didn't change. Maybe it applys enabled or disabled?

Im going to try to 0 this table out when I get home.

min seperation.PNG

Didnt work, nothing does.

If you don't command in that area it doesnt move.

SOI override345.PNG

SOI override355.PNG

No change in pulse mode.

Pulsemode.PNG

[engineermike]

Thanks, at least I know I’m not crazy now. The same limit at the same rpm seems to exist on the 3.5 eb.

[engineermike]

I’m now injecting all the way to an eoi of 65 deg btdc. I wonder how far back/late is safe....

[engineermike]

Here are a couple of oddities that I can't seem to nail down:

EOI clip vs rail pressure - I read somewhere that this is the GDI high pressure rail it's using, and looking at the break-points it will most certainly almost always be using the "high pressure" EOI clip. I have found after dozens of tests that the actual EOI clip is related to this number, but offset by some amount and possibly also rpm-related. For instance, I've found that an EOI clip setting of 60 actually clips it in the upper 90's. A clip of 49 actually clips it in the upper 80's. And a clip of 20 actually clips it in the low 60's. The logged clip is roughly 40 deg higher than the clip setting, but it seems to move slowly earlier/higher as rpm rises.

Max Injector Angle - One might assume based on the description that this angle is the maximum SOI - EOI that it will command. I tried using 40 deg to test this and determine if I could get an accurate handle on control in light of the above "fuzziness". Well, to my surprise, a max injector angle of 40 actually cuts off the injection angle around 31 at 3000 rpm, sloping down to 20-25 at 5000 rpm, and as low as 10 by 5500. So 40 does not equal 40.

SOI Maximum - This is the one we covered earlier, that appears to be a firmware SOI limit of sorts that prevents SOI from happening before a certain crank angle, and it linearly moves later/lower as rpm rises. I do not believe this one to be time-related because it's a constant slope limit, not a 1/x curve.

Any guesses as to what is going on with these GDI limits???

The only thing that "is what it is" and follows commands 1-for-1 seems to be the 1-Shot Intake SOI and maybe DI/PI Blend.

[ghostofnyc]

Great thread

[engineermike]

Soi mystery limit solved?

https://forum.hptuners.com/showthrea...orer-ST-OS-Mod

[cptuning]

hello guys looking for a manual or a explanation how to tune the fuel model on a 2019 mustang

[junits15]

I'm glad this got bumped this was a great read