03 Tahoe flex fuel tune

can you guy take a look at these two tunes and recommend any changes to the engine side of things? i have the trans set where it feels pretty good but feel free to make any recommendations. i am running the mod 2 tune during the data log and run flex fuel pretty much 100% of the time. the torque seems pretty flat but maybe its on the low side of things? i have not touched the ve table yet as im waiting on my wideband to be delivered.
appreciate your time in advance!

-cheers

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For sure it's pretty fat on fueling. Even without a wideband you can command 12.0 to 12.5 and still be pretty such you will be close.

Having no dyno makes knowing the best timing hard but a stock cam/heads doesn't need 30-32 degrees of timing at full throttle. Very possible it's making less power there than at 25 degrees. I know the factory timing curve isn't as high and it has the flex fuel timing adders that you may not be aware of, so it is adding in more timing than you likely need.

im going to try and pull some timing. but the fuel is set as it comes from factory on e85, with 91 it would run anywhere from 11.7-12.5 but stoich is 9.0 with e85 the truck wouldnt even run with 75% alky if i commanded 12.5 at wot. also im at almost 8000ft above sea level here in colorado.

You can still think of PE with a standard stoich though. You'd still plug in 1.170-1.180 to get the low 12's commanded on the gas scale. The number is always greater than 1.000.

14.7/1.175=12.5 gas
9/1.175=7.65 e85
1/1.175=.851

because the effect of the multiplier is based on the magnitude of the scale, all fuel ratios including lambda can use the same multiplier since the scales have different magnitudes at their stoich reference.
on most 0-5v widebands 1.25 volts is typically 12.5 afr/ .854 lambda / 7.68 afr e85 so you can see the multiplier works for all scales
which is why when you change fuel stoich, you dont have to change pe ratio to maintain the same enrichment factor.

On my data log it has a chart for my old aem which was logged through the egr sensor. Since there is no wideband on this Tahoe nor egr the aem chart is pegged rich. That data is not being used and means nothing. So please ignore it.

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Originally Posted by 5FDP

For sure it's pretty fat on fueling. Even without a wideband you can command 12.0 to 12.5 and still be pretty such you will be close.

Having no dyno makes knowing the best timing hard but a stock cam/heads doesn't need 30-32 degrees of timing at full throttle. Very possible it's making less power there than at 25 degrees. I know the factory timing curve isn't as high and it has the flex fuel timing adders that you may not be aware of, so it is adding in more timing than you likely need.

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On my '01 5.3 running pump E85 (80%) I left the timing tables stock and the cam and heads are stock as well. I am seeing 35+ degrees timing after the AFR multipliers and everything like that is added from the stock tables. There is no knock but I sure wonder if I could make more power with less timing. I had to make it richer because it has a huge intake and exhaust and was running lean on the stock tune. But the timing tables are STOCK, and it runs a lot better now that it has the needed fuel added (I am using wideband)

:confused: