Flex Fuel final afr adjustment questions

I'm just trying to get my bearings together here and have a fueling adjustment question I cant find by searching. I am specifically asking about E38's.

I have a good handle of getting the flex fuel turned on and working with truck settings, the spark side of things seem to always work exactly as planned as well.

I use the stoich table from the flex truck too and make minor tweaks to make sure my fuel trims are in line at idle and part throttle
(this table seems to have the most impact on that?)

So here is my main question: When the trims are in line in part throttle, when i got WOT i never seem to have a direct change to PE AFR when on flex. Meaning its usually much leaner than expected. I have spent the time getting it is close as possible on 93 prior and the AFR/lamda follows suit pretty close to commanded (1.280 - boosted engine). With no other changes and 1.280 in the alcohol PE table, it ends up much leaner right off the bat, like high 12's! Its like there is no direct fuel multiplier for PE when flex is active?

Through experimentation the only way I seem to get it in line is to either rape the alchohol PE table and or sometimes go back and whack the MAF or VE table in those operation regions to get it right.

If I have to hit the MAF or VE tables to get my PE right on ethanol, will this in turn screw up the 93 fuel as a result too?

Is there some multiplier setting I'm missing for this so I don't have to skew things to make it work?

TIA.

The stoich table should never change after it's been first setup. If the vehicle is running a real alcohol sensor it would make changes on the fly for you based on the alcohol content in the tank.

If power enrichment/boost enrichment was calibrated on gas it should be rather close when you run E85 or whatever mix in between.

Do you have logs or the tune file of how it's setup?

Attached is a CTS-V file that is a bolt on car with the DSX sensor kit. I don't have any logs but this car was around 74% content at the time of tuning. This is one I ended up playing with the MAF table to get the AFR in line for PE on flex fuel. Trims were damn near perfect cruising around with the stoich table as it is here.

I am not sure what i'm missing in the setup to get this to be linear for PE on flex fuel, just like it is in closed loop.

Quote:

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Originally Posted by BAD LS1

Attached is a CTS-V file that is a bolt on car with the DSX sensor kit. I don't have any logs but this car was around 74% content at the time of tuning. This is one I ended up playing with the MAF table to get the AFR in line for PE on flex fuel. Trims were damn near perfect cruising around with the stoich table as it is here.

I am not sure what i'm missing in the setup to get this to be linear for PE on flex fuel, just like it is in closed loop.

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Your tune would be more helpful especially since the CTS V uses a E67 not a E38.