Flex Fuel Tuning

[Hpindy]

I'd never even try on Pirellis. The 555RIIs were doing their best but the sun had gone down and it was getting damp.

Ya don't bother on the pirellis. It's just stupid and I need a slap up side the head for trying it . New rear tires are already on order for next season .

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[fubar569]

The ol cosmo muchomacho 85 dollar ebay tires aren't too bad with warm pavement...but they absolutely wheel hop like a bastard even with full AAD, DIRS/Race, pinion side lockout, etc. When its cold...

I need to get the cradle locked out and finish the rear side of the diff lockout.

 

[16GoManGoHC2]

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Car seems to be calculating E% better. Been mixing in 99% E and it’s reacted pretty appropriately with each addition.
Was at 77% added 5 gal of 99 to 13 gallons and went to 80%. Added 5 gallons again last night which took it right up into the filler neck and now reading 84%. Garage party tonight at my buddies Dyno shop, pretty much the same timing map as prior run, I’d be happy if she made 925 HP again and 800 tq this time with more E. Hell, I’ll be happy to just drive her home afterwards!! 🤞
We shall see

 

[Hpindy]

Good luck ! Keep us posted

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[Speedy!]

Quick question to those running flex fuel. When running ethanol fuel are your fuel trims positive? On mine with the flex fuel tune installed when I run 93 my fuel trims are within +/- like 3-5% give or take. As ethanol is added the fuel trims start to go positive and the alcohol content in the log rises. On full E85 the trims are like +25(ish)%. Ya'lls work the same?

I'm assuming that's how the car knows how much ethanol is in the fuel, as the trims go positive it increases fueling through the alcohol multi tables the proper amount, but the trims remain positive since there isn't a separate injector scale table for ethanol.

 

[Hpindy]

Quick question to those running flex fuel. When running ethanol fuel are your fuel trims positive? On mine with the flex fuel tune installed when I run 93 my fuel trims are within +/- like 3-5% give or take. As ethanol is added the fuel trims start to go positive and the alcohol content in the log rises. On full E85 the trims are like +25(ish)%. Ya'lls work the same?

I'm assuming that's how the car knows how much ethanol is in the fuel, as the trims go positive it increases fueling through the alcohol multi tables the proper amount, but the trims remain positive since there isn't a separate injector scale table for ethanol.

Where at in your rpm/aircharge range?
Idle and cruise mine settles around +/_ 3% but WOT it will go up to 20-30% . Positive . I ran out of time to fine tune it .

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[Speedy!]

I hadn't reloaded a gasoline only tune in many weeks and my logs cruising around showed +10ish % STFT and +6%ish LTFT. WOT was almost +30% STFT and 0% LTFT.

Must be working as expected. I thought maybe my trims were off.

 

[16GoManGoHC2]

Quick question to those running flex fuel. When running ethanol fuel are your fuel trims positive? On mine with the flex fuel tune installed when I run 93 my fuel trims are within +/- like 3-5% give or take. As ethanol is added the fuel trims start to go positive and the alcohol content in the log rises. On full E85 the trims are like +25(ish)%. Ya'lls work the same?

I'm assuming that's how the car knows how much ethanol is in the fuel, as the trims go positive it increases fueling through the alcohol multi tables the proper amount, but the trims remain positive since there isn't a separate injector scale table for ethanol.

Except during a full reset, going to a 93 tune to set E% back to zero to which start up trims on a tank full of 80%E my trims go to 30% for a short time but as sensed E% starts going up in minutes the trims fall and fall to they get around 2-3%. They then are most always around +/- 2-3% no matter the E% or 93. Like there’s a table or multiplier based on E% what the fueling should be?

 

[Hpindy]

Except during a full reset, going to a 93 tune to set E% back to zero to which start up trims on a tank full of 80%E my trims go to 30% for a short time but as sensed E% starts going up in minutes the trims fall and fall to they get around 2-3%. They then are most always around +/- 2-3% no matter the E% or 93. Like there’s a table or multiplier based on E% what the fueling should be?

Mine is very similar that it will adjust the fuel on ethonal to about 3% +/- then it stop calculating there . But that's for idle and cruise only . There is a table in the tune that says at 3% you are good . I'm just not sure where that table is ......... Yet . . But in reality 3% +/- is pretty darn good in my opinion. WOT is different. I'm still working on that . Too bad I ran out of time .

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[fubar569]

I can log trims and lambda and can tell based on behavior if learning has been triggered.

During this period the trims will cycle either to the positive or negative side for a predetermined amount of time and the pattern is very distinct.. instead of switching they'll "box out" opposite of each other for a little bit.. etc...and they'll be slightly excessively positive or negative...

I do not recall any time where after this has occurred and percentage is learned that my trims ever fell out of a "normal" range at either cruise or WOT on full E85. Sometimes depending on conditions they're well under 5%.

 

[fubar569]

Also...I'm on my way down to pump for winter storage.

From a tank of 42% E that sensed 50.5% according to the car I added 12.9 gallons of E10 93 from sheetz for a calculated 19.5% E and the car sensed 22%...so I'm pretty happy. Seems to be improving with driving.

We'll see how far off it is in the spring when I sit down to baseline it again

 

[Speedy!]

I've sent Mike an email to see if it's expected. Mine's done the + fuel trim thing for almost a year since we started working on flex.

I'm trying to think of how the car would know the ethanol content if the trims weren't positive. In my logs I see the closer it gets to 93 the less the trims are, the more ethanol in the fuel the more positive the trims are. It remains at this state after the calculation is complete. There are events that cause a recalc, one is adding fuel to the tank for sure. The other I think has to do with how long it's been since the car has been driven but I'm not 100% on that one, and there's one for when the fuel level gets low as well, presumably expecting a fillup.

 

[fubar569]

I went ahead and reviewed some logs I kept.

At various ethanol content levels the trims are indeed positive but as long as the car sensed ethanol at the high end of 10% the STFT at WOT didnt appear to get any worse than +8% give or take.

When the ethanol was within 5-8% the STFT were about the same. Usually less than 5 or 6%

On E85 only they were +/-3% STFT.

Too many screencaps to save & upload...but I'm not seeing anything super wild like you are.

 

[Speedy!]

Hmmm, I'll have to see what Mike says then. I reviewed a ton of data logs and my trims are almost always positive on ethanol. There are only a few tables that control fueling and mine calculate out correctly so maybe there one I don't know about that impacts the trims.

 

[16GoManGoHC2]

Hmmm, I'll have to see what Mike says then. I reviewed a ton of data logs and my trims are almost always positive on ethanol. There are only a few tables that control fueling and mine calculate out correctly so maybe there one I don't know about that impacts the trims.

Mine reads on the low side too much too often for my liking. How does one get it to read higher? It’s like 5-8% low at times. No biggie if it’s 85 in the tank and it reads 77 but now with ethanol dropping in my area to 75 if the car reads that as 65-68 it’s going to back off on timing too much for my liking.
There a table to adjust that??

 

[Speedy!]

In my testing it seemed the fuel trims affected ethanol content calcs more than anything, however anything above about E60 you're going to get a good amount of timing. I'd rather it read low than high personally. Even E60 is like 97+ octane.

 

[Mopar gummy]

Just got my corn-version (lol) Thursday, and its a beast 800rwhp before, and 900rwhp after. I chose to do tapped small pump with 1200cc FIC and fullest, no flex. Looking forward to hearing from your build

 

[16GoManGoHC2]

Here’s a dyno video from Thursday night, loaded a tune mod right before the party, car recalculated E% to a lower figure, didn’t develops full boost for some reason, was 2 lbs shy, aircharge low by 150 mg, only got to 17 degrees of timing instead of 19 but still put down 901, second pull was 910. 2 weeks prior on a milder tune put down 935. On the way home ran like never before, put down a 140.6 1/4 on cold pavement. Highway was dead, came to a dead stop on I81 and nailed it. That would have probably been 950+ on the dyno. I still haven’t figured out why the pulls just 2 hours prior where different?? That run according to the log made full boost, 17.8 psi, 1940 air charge and 19 degrees of timing. A 1/4 right after 4 more miles down the road netted 137.5 I LOVE corn!!

 

[16GoManGoHC2]

Look at the graph, was spinning in every gear including 4th at the1/8th mile lol. Every dip is a shift and spinning. I just put new Nitto 315 555 R2’s on the day prior. They hooked better then my bald NT05R’s finally

 

[Speedy!]

1940 aircharge...at what rpm? Thats.....a lot lol