Lower LOAD with anticipation logic On

[fido]

I have strange problem with LOAD value in speed density mode on supercharged 4.6V8
As first I tuned MAF, with anticipation logic switched off (also adaptation is off, forced open loop etc).
Calibration went very well and I ended up with nice curve within 2-3% error.
I reached maximum LOAD about 1.85-1.9 Then I filled LWFM tables with LOAD from histogram.
Then I switched anticipation logic On and what a surprise - since then I'm getting LOAD values way
lower than what I put into LWFM tables and it don't react on rising these values.
I'm getting 1.4-1.6 instead of 1.8-1.9 so everything depending on load (spark) is
completely off, AFR is lean and car runs like crap.

I've Cylair WOT multiplier = 1.99, Cylair max multiplier = 1.99
Is there anything else, what could limit or scale LOAD calculation in speed density?

Unfortunately, I cannot attach tune here, as customer had SCT tuner so I had to tune
with SCT. Anyway, all the values/tables I used for tuning are present in HP too.

[Eric@HPTuners]

I have strange problem with LOAD value in speed density mode on supercharged 4.6V8
As first I tuned MAF, with anticipation logic switched off (also adaptation is off, forced open loop etc).
Calibration went very well and I ended up with nice curve within 2-3% error.
I reached maximum LOAD about 1.85-1.9 Then I filled LWFM tables with LOAD from histogram.
Then I switched anticipation logic On and what a surprise - since then I'm getting LOAD values way
lower than what I put into LWFM tables and it don't react on rising these values.
I'm getting 1.4-1.6 instead of 1.8-1.9 so everything depending on load (spark) is
completely off, AFR is lean and car runs like crap.

I've Cylair WOT multiplier = 1.99, Cylair max multiplier = 1.99
Is there anything else, what could limit or scale LOAD calculation in speed density?

Unfortunately, I cannot attach tune here, as customer had SCT tuner so I had to tune
with SCT. Anyway, all the values/tables I used for tuning are present in HP too.

Once you enabled anticipation logic, was the fueling the same?

[fido]

Once you enabled anticipation logic, was the fueling the same?

No, it was much leaner. Especially at WOT stage it went to lambda >1.0, where I had 0.8 with anticipation off. So AFR quite copied the lower load.
I suspect, there is load from LWFM scaled/clamped down somehow.

[Eric@HPTuners]

No, it was much leaner. Especially at WOT stage it went to lambda >1.0, where I had 0.8 with anticipation off. So AFR quite copied the lower load.
I suspect, there is load from LWFM scaled/clamped down somehow.

What are the vehicle and the modifications?

[fido]

Mustang GT 4.6V8, MY2005/2006, stroked to 5.0, KenneBell throttle, GT500 MAF, dual fuel pump, 72lbs BOSCH injectors, VMP compressor with smaller pulley, cams etc. Lots of modification. Biggest problem came when they changed compressor pulley and boost has raised to 15psi. We changed MAF, as it was pegged and changed injectors as they were saturated.

Anyway, fuel pressure is fine and it keeps ±40psi whole WOT range. MAF is fine and at the maximum RPM it's at 4,3 volts and calibrated curve looks as usual. I guess the problem is connected just with speed density, because with anticipation switched off, it keeps measured lambda at the commanded level (±0.8). I thought there is not any limit in >=2005 ECM as it was before (airflow 64#/min), but it seems that I'm still missing something.

[Eric@HPTuners]

Mustang GT 4.6V8, MY2005/2006, stroked to 5.0, KenneBell throttle, GT500 MAF, dual fuel pump, 72lbs BOSCH injectors, VMP compressor with smaller pulley, cams etc. Lots of modification. Biggest problem came when they changed compressor pulley and boost has raised to 15psi. We changed MAF, as it was pegged and changed injectors as they were saturated.

Anyway, fuel pressure is fine and it keeps ±40psi whole WOT range. MAF is fine and at the maximum RPM it's at 4,3 volts and calibrated curve looks as usual. I guess the problem is connected just with speed density, because with anticipation switched off, it keeps measured lambda at the commanded level (±0.8). I thought there is not any limit in >=2005 ECM as it was before (airflow 64#/min), but it seems that I'm still missing something.

Air temp sensor relocated?

[fido]

Yes, it is relocated. Anyway, good point It's good to think about physical sensors, that are involved into speed density calculation. What about MAP? Couldn't it be limited?

[fido]

I have new suspect...the injectors. Bosch 72lbs are troubled ones and I probably don't have correct calibration for them. So the "error" is hidden in MAF calibration (as I begun with MAF calibration) now and that's why I have ridiculously high load in MAF mode (the top is above 2!) which do not copy speed density calculation. Anyway, I'm still curious about what factor are involved into final LOAD calculation, when it's not direct copy from LWFM tables. I found a lot of people struggling with speed density, that tried to zero! this table and the result didn't changed.

[fido]

Well it didn't help. Even with 48lbs Shelby injectors, correct calibration and re-tuning MAF. Load was fine (maximum about 1.84, that's corresponding with compressor). Anyway after switching anticipation on, LOAD become way lower *again*(1.5 versus 1.8) that caused everything was off (fuel, spark advance). Polluting LWFM tables with measured LOAD values didn't help. It must be scaled/clamped somehow inside speed density calculation. I found the same issue all over tuner forums and no one solved that, except running the car without anticipation. That harm driveability a little. So either it's well kept tuners secret, or there is not way how to force 4.6V8 ECM to work correctly in forced induction configurations.

[Eric@HPTuners]

Well it didn't help. Even with 48lbs Shelby injectors, correct calibration and re-tuning MAF. Load was fine (maximum about 1.84, that's corresponding with compressor). Anyway after switching anticipation on, LOAD become way lower *again*(1.5 versus 1.8) that caused everything was off (fuel, spark advance). Polluting LWFM tables with measured LOAD values didn't help. It must be scaled/clamped somehow inside speed density calculation. I found the same issue all over tuner forums and no one solved that, except running the car without anticipation. That harm driveability a little. So either it's well kept tuners secret, or there is not way how to force 4.6V8 ECM to work correctly in forced induction configurations.

Did you change the Max Load and Calc MAP Max values in the Speed Density section?

[fido]

Did you change the Max Load and Calc MAP Max values in the Speed Density section?

Max load - yes, calc MAP Max - no. Thank you for pointing it out! I'll check it.