Steady State Hi/Low
06-27-2007, 03:17 PM
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Steady State Hi/Low Can someone explain "steady state" and exactly what's happening?
What are the differences between steady state hi and low?
In HP Tuners under dynamic airflow there's "High RPM Disable" set at 4000 rpms. I understand that's the point where maf solely controls fueling. Under steady state there are hi/low rpm and map thresholds set at 2600 and 84 respectively. What are these thresholds?
Do they tie into the high rpm disable?
What are the differences between steady state hi and low?
In HP Tuners under dynamic airflow there's "High RPM Disable" set at 4000 rpms. I understand that's the point where maf solely controls fueling. Under steady state there are hi/low rpm and map thresholds set at 2600 and 84 respectively. What are these thresholds?
Do they tie into the high rpm disable?
06-27-2007, 03:34 PM
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I think Chris posted this on HPT's forum several years ago:
Plus, from HPT's help: "This RPM threshold determines if High or Low steady state determination will be used. If MAP is greater than Hi/Lo MAP Threshold or RPM is greater than Hi/Lo RPM Threshold the High mode settings are used otherwise Low mode settings are used. "
Code:
RPM > 4000 ---------- *trust MAF completely and ignore SD calcs (apart from MAF sanity checking purposes) RPM < 4000 ---------- if RPM > 2400 and MAP < 84 kPa then Steady MAP threshold = 0.0 kPa else Steady MAP threshold = 0.8 kPa If (SteadyMAP) then Calculate MAFAirmass/SDAirmass ratio (used for Unsteady MAP operation) Correction Airmass = MAF Airmass (filtered) else Correction Airmass = SD Airmass x MAF/SD Airmass Ratio (calculated during Steady MAP conditions) Transient Corrected Airmass = previous Final Airmass + proportion of Correction Airmass Final Airmass = fn(MAF Airflow, previous MAF Airflow, prev 3 MAP readings, prev 3 TPS readings, Transient Corrected Airmass)
06-27-2007, 04:23 PM
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Originally Posted by John-SDPC
I think Chris posted this on HPT's forum several years ago:
Plus, from HPT's help: "This RPM threshold determines if High or Low steady state determination will be used. If MAP is greater than Hi/Lo MAP Threshold or RPM is greater than Hi/Lo RPM Threshold the High mode settings are used otherwise Low mode settings are used. "
Code:
RPM > 4000 ---------- *trust MAF completely and ignore SD calcs (apart from MAF sanity checking purposes) RPM < 4000 ---------- if RPM > 2400 and MAP < 84 kPa then Steady MAP threshold = 0.0 kPa else Steady MAP threshold = 0.8 kPa If (SteadyMAP) then Calculate MAFAirmass/SDAirmass ratio (used for Unsteady MAP operation) Correction Airmass = MAF Airmass (filtered) else Correction Airmass = SD Airmass x MAF/SD Airmass Ratio (calculated during Steady MAP conditions) Transient Corrected Airmass = previous Final Airmass + proportion of Correction Airmass Final Airmass = fn(MAF Airflow, previous MAF Airflow, prev 3 MAP readings, prev 3 TPS readings, Transient Corrected Airmass)
Here's an example from one of my logs:
rpm__tps_map_maf hz_dynamic airflow g/sec_maf g/sec_com.a/f_act.a/f
2568_20__74__6250___66.30______________66.25_____1 4.63___15.83
in my tune at 6250 hz the value is 68.95
Thanks for the help.
