Help With IAT And AFR Swings

[TAPyvehc93]

I was looking for some advise on how to keep my AFR's rock steady with temperature swings. Its a turbo 5.3 with a 2011 e38 running a 2BAR SD OS and the IAT sensor has been relocated to just behind the throttle body using a IAT breakout harness. I'm not sure which of the three tables would be appropriate for adjusting. Flow rate multiplier vs IAT, cylinder charge temp bias and filter tables or the VE charge temp multiplier table? This might be a stupid question but is charge temp measured from the IAT sensor?

[Poopsy]

Use the zr1 bias and filter tables for charge temperature if you relocated the IAT there.

Pretty sure it's zr1 that has iat in manifold by throttle body.

[TAPyvehc93]

Yeah, I am using the ZR1 bias table and the IFR vs IAT multiplier table but its still not enough. It still seems to be lean as IATS go up which is weird because I would think it would be opposite. I was seeing an average of 5-6% leaner going from 72*F to 88*F. Seems a little much. Pretty much from what I gather, the ZR1 bias tables makes it totally dependent on IAT and not on ECT which I think is fine in my case because my IAT sensor has been relocated to just behind the throttle body in the intake. What I was wondering though is can I use the VE vs Manifold air temp multiplier table instead of the IFR vs IAT multiplier table? I'm thinking the manifold air temp multiplier table would use a dedicated manifold air temp sensor mounted in the blowers like the CTS-V's and ZL1s. Which in my case wouldn't work because although i do technically have a manifold air temp sensor, its being being power by a IAT breakout harness which I think would only reference IATs and not MATs. Who know? I'm just trying to get consistent AFR's regardless of weather conditions.

[TAPyvehc93]

Little update after playing around with the IFR vs IAT temp modifier. As I said before, I notice my AFR's where going leaner as my IAT increased. I find that odd because I am using the ZR1 bias and filter tables which make everything IAT dependent(or so I believe) and I always thought hotter air required less fuel. Now I still do believe that but for whatever reason it appears to be backwards on here and I'm not sure why yet. I ended up doing a log just sitting in the driveway with the engine fully warned and with the hood open to avoid heat soak. I made a histogram to log AFR error vs IAT. Ambient tenp was about 68 or so and I started at 72*F and then shut my hood and let the temps increase to about 88*F. I then transferred the data I gathered to my IFR vs IAT table, flashed the truck and tried it out. For one, my hot start issue was almost completely gone. No super lean spike and then wanting to die out like I was having. Secondly, my AFR swing of about 5% going from 73*F to 88*F was brought down to .3%. Just thought someone might find this info useful. I think I may be finally making progress on my inconsistent AFR issues!