How does IAT Compensation Apply values

scootarida1 · 10-13-2012, 07:28 PM

I was wondering if anyone knows how the IAT compensation values are applied to the fueling correction.

For example if my air intake temp is between two of the parameters that I change does it apply the values linearly based on the intake air temp? I currently have a blow through setup and I trying to dial this table it. Surprisingly, the car runs very different based on the temperature.

I am also wondering if I should change the temperature ranges since the temperature now is read after the intercooler and I'm wondering if the temp range values I have now are to large and maybe the actual correction would start linearly and then change more dramatically as temp increases and decreases.

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the suicidal eggroll · 10-13-2012, 07:31 PM

The IAT compensation values are linearly interpolated between cells, same as all other tables in the ECU.

I had to make massive changes in my IAT fueling compensation when I switched to blow through, mainly in the high temp (>100F) regions.

scootarida1 · 10-19-2012, 06:07 PM

Yah I remember back about the high temperatures. Unfortunately now here in PA I'm seeing even more significant changes to the IAT Comp table needed to be made now that I'm colder than the 68 degree column. When I was tuning my maf, I tried to make sure the IAT's were very close to 68 only taking data so that way I can really try to dial in the compensations as temperature varied.
Just wondering, have you had to make any changes based on cold weather as well? If I can remember back from the thread I started when you posted a screen shot of your IAT Comp table I don't remember seeing any changes to the cold side of the table.

the suicidal eggroll · 10-20-2012, 09:59 AM

I don't remember exactly, but if I did have to make any changes to the <68 F columns, they were very small adjustments...nothing significant.

scootarida1 · 10-20-2012, 10:15 AM

Okay, then that leads me to think I might have gotten a vacuum leak somewhere because it changed dramatically.

10-13-2012, 07:28 PM	#1
scootarida1 Scooby Newbie Member#: 154534 Join Date: Jul 2007 Chapter/Region: Tri-State Location: Wilkes-Barre, PA Vehicle: 2005 Forester XT Black	How does IAT Compensation Apply values I was wondering if anyone knows how the IAT compensation values are applied to the fueling correction. For example if my air intake temp is between two of the parameters that I change does it apply the values linearly based on the intake air temp? I currently have a blow through setup and I trying to dial this table it. Surprisingly, the car runs very different based on the temperature. I am also wondering if I should change the temperature ranges since the temperature now is read after the intercooler and I'm wondering if the temp range values I have now are to large and maybe the actual correction would start linearly and then change more dramatically as temp increases and decreases. * Registered users of the site do not see these ads.

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10-13-2012, 07:31 PM	#2
the suicidal eggroll NASIOC Supporter Member#: 51961 Join Date: Jan 2004 Chapter/Region: RMIC Location: Broomfield, CO Vehicle: 2005 STi 2012 WRX	The IAT compensation values are linearly interpolated between cells, same as all other tables in the ECU. I had to make massive changes in my IAT fueling compensation when I switched to blow through, mainly in the high temp (>100F) regions.

10-19-2012, 06:07 PM	#3
scootarida1 Scooby Newbie Member#: 154534 Join Date: Jul 2007 Chapter/Region: Tri-State Location: Wilkes-Barre, PA Vehicle: 2005 Forester XT Black	Yah I remember back about the high temperatures. Unfortunately now here in PA I'm seeing even more significant changes to the IAT Comp table needed to be made now that I'm colder than the 68 degree column. When I was tuning my maf, I tried to make sure the IAT's were very close to 68 only taking data so that way I can really try to dial in the compensations as temperature varied. Just wondering, have you had to make any changes based on cold weather as well? If I can remember back from the thread I started when you posted a screen shot of your IAT Comp table I don't remember seeing any changes to the cold side of the table.

10-20-2012, 09:59 AM	#4
the suicidal eggroll NASIOC Supporter Member#: 51961 Join Date: Jan 2004 Chapter/Region: RMIC Location: Broomfield, CO Vehicle: 2005 STi 2012 WRX	I don't remember exactly, but if I did have to make any changes to the <68 F columns, they were very small adjustments...nothing significant.

10-20-2012, 10:15 AM	#5
scootarida1 Scooby Newbie Member#: 154534 Join Date: Jul 2007 Chapter/Region: Tri-State Location: Wilkes-Barre, PA Vehicle: 2005 Forester XT Black	Okay, then that leads me to think I might have gotten a vacuum leak somewhere because it changed dramatically.