Mustang Turbo FMEM

So I've been playing around with my own tune here for some time now and have been pretty happy with it, but now I'm going up in with more load and hit Turbo FMEM on Driver Demand and Torque Airlimit... And I can't figure out why.

Turbo airflow "actual" and desired track pretty close up to about 4800 RPM, where desired starts to climb... Then it starts to bounce off Turbo FMEM (you can see the see-saw action in the desired airload).
The thing is, is turbo airflow limits for overspeed are well over the 37-40LB/min that the log is showing, so what's causing it?

It's controlling the boost normally, MCTs are reasonable enough, TIP does go pretty high (44PSI), but throttle closes and then it stabilizes... It's always done that, even with the stock tune (well, not 44PSI, throttle closure followed the same pattern though).

Is it compressor outlet temp that it thinks it's going over? I don't have time right now to test that, but I will when I get a chance.
Pretty sure there isn't a log PID for compressor outlet temp, so I have no idea where it thinks that's at anyway.

Is there a table axis that might be causing a limit? TIP Min vs Turbo airflow is the only table that once that I see that maxes at 40LB/min, other tables it's already well past their axis upper end.

If I can get this figured out, I think I'll be pretty happy with the setup, at least until a bigger turbo can be fitted.

Hope you find the issue and someone chimes in with help. The ecoboost mustang is my eleanor I chase my tail on them. It’s good then I get overboost condition on long pulls. Can’t find a way to lower boost I’d like to cap it at 23-24 max and at times it will hit 24-25 on stock turbo. Still has stock intercooler and cac pipes. Jlt cold air, 93 octane, ngk plugs 1 step colder gapped .028, mbrp car bad, stock turbo and down pipe, turbo blow off valve (older design) vacuum operated.

Quote:

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Originally Posted by Bill88stang

Hope you find the issue and someone chimes in with help. The ecoboost mustang is my eleanor I chase my tail on them. It’s good then I get overboost condition on long pulls. Can’t find a way to lower boost I’d like to cap it at 23-24 max and at times it will hit 24-25 on stock turbo. Still has stock intercooler and cac pipes. Jlt cold air, 93 octane, ngk plugs 1 step colder gapped .028, mbrp car bad, stock turbo and down pipe, turbo blow off valve (older design) vacuum operated.

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Shouldn't be too hard to drop the boost down to those levels with the canister pressure table... Logs the PIDs on the axes and see where it's at in the table and adjust from there.
Should also be able to limit pressure with the turbo outlet pressure parameter (7925).

As a check, I did a KAM reset. So I need to wait for my octane modifier to find it's way back to where it was (hopefully a full -1.0 this time), in the mean time I've prepped a tune with a few suspect air flow axis extended out...
I doubt it will do anything, I really hope someone can point me in a better direction.
I really hate just taking a blind stab at it, because if that still doesn't work... I REALLY don't know where to go from there. lol

Just going over the log again and a few past logs... Apparently I didn't realize that the MAP sensor is 2.5 bar, but apparently the TIP sensor is 3 bar?
Can anyone confirm that?
The calibration uses the same slope/offset for both MAP and TIP, I always just assumed they were both 3 bar.

I don't think this is the issue though, since MAP is maxed out through the whole pull and on other pulls in other logs in previous versions.

Edit:
Ok, is there something weird about my MAP sensor reading?
Looking at some Focus RS logs, their MAP has no problems going over 2.5 bar... They also run the same sensor as the Mustang 2.3.
Am I logging the wrong MAP PID?

Edit again:
Yeah, ok, looks like I've been logging the wrong MAP PID.

Something I noticed in the log, Eq Ratio Commanded SAE and it's telling you 11.75 afr at .80 lambda, but your tune file has 14.08 afr as stoich, so in reality, your not at 11.75 afr at .80 lambda (14.7 * .80), your at 11.26 afr (14.08 * .80). Just something to look out for.

Yeah, no worries... I don't usually look at it by AFR, always lambda. Well, except for when I glance at the gauge cluster.
Is there anything that actually references AFR other than the gauge cluster? Everything else is by lambda, right?

Did some more playing around, apparently it's not going to let me get my octane adjust up as high.
Seems to have topped off at -0.57 and doesn't want to go any further, which is another on going issue.
Something is causing it to just stop, no DTCs stopping it, the only thing I can think of is that I'm only writing the cal and it's causing some kind of misalignment with something that isn't written.
When I got it to -0.8ish, that was after I did a full write. Coincidence? Wish I could get a solid answer on that too.

Anyway, really at a loss for what's causing the FMEM.
Pull #1 (first snip), felt good, you can see it's holding a good number for the torque through the pull, but it hits Turbo FMEM and then comes out of it. I can't see anything that would be tripping it, I've tried extending some axis' that didn't do out to 40LB/min to see if that was it, but didn't do squat.
This version I've gone back to stock on a lot of tables, looked through some of my old versions and found one that produced a really good torque number and merged in some changed from that, seems to have done some good.

The other two pulls didn't hit FMEM, but it was dropping off load for some reason too, so I'm not sure what's up with that either.

I think I might have to do another full write and complete KAM/adaptations reset and see what happens after that, because there shouldn't be any reason I can't hit -1.0 OAR on 93 octane.

Maybe it's just this strategy I'm running, it's a fairly old one and original to the 2015 Mustang... Is there a safe way to update to a newer one? I'm pretty sure it'll cost credits to do it...

Another test tune, another log...

For whatever reason the ECU decided to finish learning the octane value, now it's a full -1.0. Whatever. :banghead:

Made some corrections to the wastegate canister table, bump boost up to hit a higher load target... Still quite a bit shy of the desired load, but that's ok, I'm pretty sure I don't want to hit a full 3.0 load anyway.
I don't think the poor stock turbo would do it anyway, it's already enough of a hot air gun at this point. lol

Weird thing is that it's not doing that weird oscillation that it was doing in the thread's original log snip, but it is still completely riding some kind of turbo FMEM.
Not setting a code, doesn't appear to be reducing load by any drastic amount. In the same full log file, I have a much longer pull at full pedal and it's not kicking out of boost for any reason.

I'd still really like an explanation for the turbo FMEM, but it would seem that no one here knows... But it also doesn't seem to be causing any issue right now either, so I guess I'm just going to roll with it.

mb its btr?Attachment 112710

You asking more then car can give you in this config.
If Correct your max air load and play with other parameters?
Attachment 112711

For example, mus 2.3 2019 load max 2.3 3.15 rear diff 0-100mph 4.5 96,8F intake air temp

Attachment 112712Attachment 112714Attachment 112715

I could give that a try, but I'm pretty sure it wouldn't help... Unless you've got an explanation for why those changes would?

My desired airload is much higher than actual, because driver demand is requesting that much.
I can push my actual airload higher with more boost from wastegate duty or putting less canister pressure in those areas, but I don't want to go too much higher than I am now because it will raise my boost too high (trying to keep less than 26PSI).

I've seen in other Mustang tunes where they are up in these loads and start getting turbo FMEM popping up like I am, but the one other thread about it never had any real answer either.

The weird thing I don't get is all the tuned Focus RS's that I've seen don't have these weird issues at all, they won't show any combustion stability in DD limit or popcorn in torque air limit, they also have a large difference in torque vs desired torque and actual load vs desired load, they'll run an entire pull nice and clean... But if I try to replicate the same conditions here, I get all these "limiter" flashing.
Granted the Focus RS does have a different intake tract and a *slightly* bigger turbo, but the hardware differences shouldn't that big right?

The Turbo FMEM seems to pop up when the requested/actual air mass flow exceeds the turbo model based on the conditions. I've run full E85 tunes before where the source for one or more PIDs read Turbo FMEM but there's full spark, full fuel, and full throttle opening (nothing seemed to be reducing torque at all). From what I have seen the only way to get these stock EcoBoost vehicles running fast is to push the stock turbos to the knife's edge in terms of flow.