Actual AFR differences from what is in Primary Fuel Table

roybfr · 07-06-2006, 10:17 PM

I am seeing differences in my actual AFR complared to what is in the Primary table for some RPM/Load cells. For example from 4400 to 7000 in the last load cell I have 11.40 going down to 10.88 but am seeing things that are around +/- .5 off of those values. Am I correct in thinking that I need to make some adjustments in my Intake calibration in the MAF voltage areas (3.9-4.5) that are happening during these times, or should I just be editing the Primary fuel table. Logically I think the the former but I am no expert.

WolfPlayer · 07-07-2006, 04:52 AM

This has been covered numerous times. Please try a search to get the most detail. However, in short, the differences are from car-to-car variances and the octane of the gas. I was originally seeing values that were as much as 1.2 AFR points off.

If you want to get those values spot on then yes, you want to adjust the MAF calibration. Some individuals posit that slightly tweaking the injector scalar and latency values will help out a tad bit and THEN you tweak the MAF table.

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roybfr · 07-07-2006, 09:38 AM

I know that injector scaler is good, installed them prior to the rotated kit and my AFR's were with in ~.01-.02 when I got the right value in there. I need to go back an look at the data to see if the differnece is consistant based on load/MAF voltage/RPM ect. I called Cobb and got a few ideas. Plus I realized I was not taking into account the trim values when comparing actual to the map value.

07-06-2006, 10:17 PM	#1
roybfr Junior STI Driver Location: Iowa Posts: 88 Join Date: Oct 2004 Trader Rating: (0)	Actual AFR differences from what is in Primary Fuel Table I am seeing differences in my actual AFR complared to what is in the Primary table for some RPM/Load cells. For example from 4400 to 7000 in the last load cell I have 11.40 going down to 10.88 but am seeing things that are around +/- .5 off of those values. Am I correct in thinking that I need to make some adjustments in my Intake calibration in the MAF voltage areas (3.9-4.5) that are happening during these times, or should I just be editing the Primary fuel table. Logically I think the the former but I am no expert. This ad is not endorsed by this member. Please register or login to hide this ad.

07-07-2006, 09:38 AM	#3
roybfr Junior STI Driver Location: Iowa Posts: 88 Join Date: Oct 2004 Trader Rating: (0)	I know that injector scaler is good, installed them prior to the rotated kit and my AFR's were with in ~.01-.02 when I got the right value in there. I need to go back an look at the data to see if the differnece is consistant based on load/MAF voltage/RPM ect. I called Cobb and got a few ideas. Plus I realized I was not taking into account the trim values when comparing actual to the map value. This ad is not endorsed by this member. Please register or login to hide this ad.

07-07-2006, 04:52 AM	#2
WolfPlayer Moderator & ECU Tech Car: 05 CGM STI Fav Mod: mo boostaz Location: Fredneck, MD Posts: 3,696 Join Date: Jun 2004 Trader Rating: (6)	This has been covered numerous times. Please try a search to get the most detail. However, in short, the differences are from car-to-car variances and the octane of the gas. I was originally seeing values that were as much as 1.2 AFR points off. If you want to get those values spot on then yes, you want to adjust the MAF calibration. Some individuals posit that slightly tweaking the injector scalar and latency values will help out a tad bit and THEN you tweak the MAF table. t