Flex Fuel Timing...2015 L83

[Closer_2001]

'15 Sierra, didn't come with Flex Option.

Installed Sensor and Enabled.

I'm currently using stock timing tables across the board but would like to optimize for 93 as well as flex.

Two questions:

Why all the peaks and valleys in the stock Alcohol Multipliers?
What is a safe upper range when running over 70% ethanol - 28* Total?

Screen shot of log vs. tune.

[schpenxel]

Dips are probably torque management during shifts or decel or something like that. You aren't logging pretty much anything regarding timing so hard to tell what's pulling it

[Closer_2001]

Dips are probably torque management during shifts or decel or something like that.

Sorry I was referring to the stock timing tables in the tune at WOT.

[tpawlish]

I converted mine to e85 a little while ago hereis something that will help change the fuel type faster
Also I've attached a Stock Truck 5.3 E85 for comparison

Delay.JPG


Stock FlexE85.hpt

[HeavyChevy305]

How much ethanol percentage is your sensor picking up?

[tpawlish]

I highest I've seen has been 83%

[HeavyChevy305]

I highest I've seen has been 83%

Lucky you. Mine won't go higher than 75%.

When I manually check my local gas stations e85 with a holley test tube it checks out to 85% ethanol. Normally I wouldn't care, but with these new Gen V's if it doesn't see at least 80% it won't reference the flex fuel tables 100%.

[Ben Charles]

Lucky you. Mine won't go higher than 75%.

When I manually check my local gas stations e85 with a holley test tube it checks out to 85% ethanol. Normally I wouldn't care, but with these new Gen V's if it doesn't see at least 80% it won't reference the flex fuel tables 100%.

That's not entirely true, you can setup the ethanol tables to read what ever you want... my setup has all timing in at E65

[tpawlish]

That's not entirely true, you can setup the ethanol tables to read what ever you want... my setup has all timing in at E65

he's right on my Race tune anything above E50 gets all the timing

[HeavyChevy305]

What tables do you specifically alter? I haven't messed with any of the flex fuel tables because i'm afraid it will mess with the factory algorithms. From what I understand, most of the tables reference each other, so messing with one will create a domino effect.

[schpenxel]

Specifically to do what?

[HeavyChevy305]

To take 100% advantage of the Flex Fuel Spark and Max Torque Timing modifier tables. They don't default to the multiple cell of 1.00 till the sensor sees 80%. I also noticed that the Injection Timing SOI base tables also multiply as alcohol content increases. From my understanding, SOI base and spark timing go hand in hand with these DI motors.

[Ben Charles]

Right click and edit axis...
Probably half the axis in my calibration are modified

[HeavyChevy305]

Damn! You learn something new every day lol.

Thanks Ben.

These 2017 5.3's come with some conservative Flex Fuel Spark tables. Pushing 20/22* max at WOT while logging. My Flex Fuel spark modifier table is different than the O.P.'s