Weather Temperature compensation question

[mn_vette]

I've been chasing my tail trying to get proper temperature compensation for weather shifts. I'm running a base corvette LS3 with an ECS supercharger on it. Speed Density tune with 2Bar OS using injector data from the manufacturer. I've been messing with the Cylinder Charge Temp biases and that has gotten me nowhere. The injector duty cycle changes appear to be inline with the manifold air temp changes that I'm seeing. But I still seem to be going a 3-5% leaner when it is hot out (80F afternoon vs 60F morning). Looking at my MAF readings it seems that at certain parts of my VE table I am pulling in more air mass at HOT than at COLD given the same RPM and MAP reading. If I back calculate my cylinder air mass based on calculated value and AFR Error, I also come up with more air mass at HOT than COLD. I'm concentrating this on my cruising areas to try to get things dialed in and I'm kind of at a loss right now. Does anybody have any ideas what is going on?


Here is my latest tune with some funny stuff in the Cylinder Charge Temp table to experiment with things. And my two latest log files for the different air temps.
24_05_12_IdlemaxCCT.hpt

ColdCruise.hpl

WarmCruise.hpl

[ns158sl]

Is it in open loop? If yes, Why? lol

Where is the IAT sensor located? You could also try to play with the main VE charge temp multiplier.

[mn_vette]

Is it in open loop? If yes, Why? lol

Where is the IAT sensor located? You could also try to play with the main VE charge temp multiplier.

Yes, it is in open loop. I'm trying to get everything dialed in before relying on the closed loop to take over. The IAT sensor is located in the MAF in the stock location about a foot in front of the throttle body. I put a thermocouple in the intake close to the IAT sensor and appears to be reading within a degree or two.

My big concern is that if my MAF is reading correctly I'm somehow getting more air at hot cruise than at cold cruise. I'm not sure that I can do anything to compensate for that in a SD tune. I'm not sure how that is even possible unless there is something odd going on with my supercharger setup at certain RPM levels.

[07GTS]

turn desoot mode off
turn COT off
inj flow rate v flow set to all 1.0
set the charge temp bias back to stock if maf is used in intake, if ur PD boosted then u need IAT in the manifold after the blower, see if any of that helps

[hjtrbo]

You need to know the air temp and pressure after the supercharger to get a better idea. Moving your IAT sensor to the intake manifold should help your issue. However, you'll still be fighting the internal charge temp model. 3-5% floating on the richer side of 0 is close enough bro.

Edit: Was writing at the same time 07GTS posted.

[Alvin]

3-5% are very tight already.

It will never be 0%.

This is a very dynamic thing.. The humidity can change.. we have no compensation for that.. the temp of the fuel and therefore the volumetric density of the fuel changes..which changes how much mass the fuel injector fires.. I mean.. this is real world. it will never be 0-0

[smokeshow]

3-5% are very tight already.

It will never be 0%.

This is a very dynamic thing.. The humidity can change.. we have no compensation for that.. the temp of the fuel and therefore the volumetric density of the fuel changes..which changes how much mass the fuel injector fires.. I mean.. this is real world. it will never be 0-0

My V was like 16-17% stfts at idle. Bone stock. Lot of these guys need to step back away from the computer a little bit ..the data will look better lol. Too much under 5% is split hairs.

[Alvin]

yes..

Also people should realize there is a fairly wide window of fueling that makes the exact same power.. A NA setup will make almost identical (less than 5 rwhp if that) between 12.5-13.0

Or if any of you had the HORROR of watching 8 widebands on a engine dyno. The richest cylinder might be 11.5 and the leanest might be 13.8. The average will be 12.8... And the next pull the rich and lean cylinders all do a swaparoo.. no pattern. Just wildly off from each other in random orders.

[mn_vette]

turn desoot mode off
turn COT off
inj flow rate v flow set to all 1.0
set the charge temp bias back to stock if maf is used in intake, if ur PD boosted then u need IAT in the manifold after the blower, see if any of that helps

I will try those cal changes. The INJ flow rate vs flow is a stock table for my vehicle, but I can try changing it. The supercharger is a centri, not a PD, so the IAT reading is after the blower and intercooler.

I'm not too worried about getting things dialed in for an exact AFR, I'm more concerned that my IAT compensation is very out of whack. The car seems to be running fine, I'm just trying to learn and understand all the nuances of the ECM.