Anyone lower the RPM Threshold for Airflow Calculation (MAF)
Dec 13, 2007 | 09:00 AM
#1
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From: Fort Worth - TX
Anyone lower the RPM Threshold for Airflow Calculation (MAF)
Has anyone lowered the RPM threshold for Airflow Calculation in there tune?
This is what EFI Live says about the parameter:
The reason why I ask is becuase I can only VE tune up to ~3200rpm, due to the 3.42 gears, so I have a little bit of a gap. The only time I am in the 3200+ range is when I am in PE anyways, so I figure that if I lower the threshold down to ~3400 I should be good. Currently I have the VE dialed in and the MAF, however the gap between ~3200-4000 is kinda noticeable. And before anyone askes, "Yes" I do have a Wideband.....
Anyone know of any ill effects if I lower the threshold?
This is what EFI Live says about the parameter:
If engine speed is less than this value, then the PCM uses a dynamically calculated airflow value to determine grams of air per cylinder.
While the airflow is in a "steady state", then a correction factor is updated based on the airflow difference between the MAF sensed airflow and the MAP calculated airflow.
During rapid changes in airflow, the correction factor is applied to the airflow calculations to compensate.
If engine speed is above this value, then the PCM will use the MAF sensor exclusively (if not disabled by DTCs) to calculate grams of air per cylinder.
No updates are made to the airflow correction factor.
While the airflow is in a "steady state", then a correction factor is updated based on the airflow difference between the MAF sensed airflow and the MAP calculated airflow.
During rapid changes in airflow, the correction factor is applied to the airflow calculations to compensate.
If engine speed is above this value, then the PCM will use the MAF sensor exclusively (if not disabled by DTCs) to calculate grams of air per cylinder.
No updates are made to the airflow correction factor.
Anyone know of any ill effects if I lower the threshold?
Dec 13, 2007 | 09:57 AM
#2
Nope. I was running on MAF exclusively for awhile. Much easier to tune the 1 dimensional MAF table than the 2 dimensional VE table. You shouldn't have any problems, just get your MAF table dialed in correctly and you'll be fine.
Dec 13, 2007 | 10:04 AM
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Thanks for the reply, Thanks I was also planning on setting the PE Delay RPM to the same as the MAF Threshold, that way my fueling will be more consistant.
Below 3200rpm the VE table and the MAF will be controling fuel (easy to dial in). Above 3200 rpm the MAF table will be tuned to my PE AFR table.
Sound like a good plan?
Below 3200rpm the VE table and the MAF will be controling fuel (easy to dial in). Above 3200 rpm the MAF table will be tuned to my PE AFR table.
Sound like a good plan?
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