Anyone make any head way on a Flex Fuel tune on a Hellcat?

[curt@injected]

Curt and Jay, I apologize for sounding dumb in all of this. I had to think pretty hard as to what you two were saying about the air fuel ratio, lambda, and the way Dodge does fueling. First off I am aware of the way the fueling is done with the Hemi's. The problem is the Stoich setting. I was under the impression that was used as a fueling target, rather than an actual stoich value. This came from Diablo. I was talking with one of the people there at one point. We were discussing setting a richer fuel target for closed loop fueling. They said to change that stoich value and that would do it. Problem is it never did work, but due to that I was always under the impression that was what the stoich value represented.

After thinking about what you were saying, and thinking about my past experience of how changing that value affects the fueling, I now realize that value is simply giving the computer a fuel/air value for the stoich set point, aka what fuel/air ratio equals a measured value of 1 lambda. This explains perfectly everything about why the Hellcat is showing 14.7:1 AFR on our dyno or a gauge but 13.8 on the dash. As you two stated it is just simply the calculation for the AFR based off the stoich value setpoint.

Just wanted to say thank you for pointing it out. It is something I guess I halfway understood, but due to some mis-information, did not completely understand. Now that I know what that value actually is doing, it explains so many things I could not seem to explain about some of the fueling issues I've run into, and why my calculations did not always work out the way I thought they should.

As for the E85 testing, I think the big thing to really make it work properly is to have a flex fuel sensor. I'm not sure that it would work, but I think for consistency it would be best. Either way I'm very interested in what you find Curt.

No reason to apologize. None of us just rolled out the womb understanding how all of this stuff works. I hope this at least cleared some stuff up for you. I stopped using AFR on the dyno some time ago. It just makes it simpler instead of recalibrating it for different fuels. That and it makes calculating your error much simpler than having to do it with AFR.

[curt@injected]

Ok by defined is it the area that calculates the alcohol percentage out that's the main issue now that it can be enabled?

I'm still waiting for stuff to be added. To be honest we don't know what all is going to be needed to make it work. For instance there is a multiplier for power enrich for FFV and cold start enrich. The stoich tables are also not complete in HPT now. That's just a start but I would assume, after doing a bunch of flex fuel on fords, that there is going to be more needed just to get the pcm to start inferring alcohol content. It would be cool to make it work though since we do a bunch of e85 stuff.

[Jay@HAP]

No reason to apologize. None of us just rolled out the whomb understanding how all of this stuff works. I hope this at least cleared some stuff up for you. I stopped using AFR on the dyno some time ago. It just makes it simpler instead of recalibrating it for different fuels. That and it makes calculating your error much simpler than having to do it with AFR.

X2 on that. I learn something new everyday.

[meatbag]

bump for info

[meatbag]

I am trying to do one right now but im just not seeing enough defined in HP to get the job done. Some of the table like the stoich have what im assuming is alcohol % on the axis but only one cell is available to fill out.

[JoshCP527]

get a hold of curt at injected he seems to have it figured out and has tested it. I am going to be testing his flex mapping soon. It is who i went to to get all of the flex stuff populated and added.

[Bill@HPTuners]

[curt@injected]

They're getting close. Bunch of stuff added thus far. A few things wrong a couple uneeded and a few still missing but they are making headway. Wish they had been this proactive back when I was trying to get the throttle to open or figure out why the stoich tables didn't work.

[Jay@HAP]

What is the Flex Fuel code modification patch? I don't know how long it's been there, I just saw it today.

[Steven@HPTuners]

What is the Flex Fuel code modification patch? I don't know how long it's been there, I just saw it today.

This patch modifies some tables to increase their sizes and populates some base data in certain tables.
Without it, you're stuck with table sizes fixed to 1 on some tables you may want to modify for flex fuel operation.

They're getting close. Bunch of stuff added thus far. A few things wrong a couple uneeded and a few still missing but they are making headway. Wish they had been this proactive back when I was trying to get the throttle to open or figure out why the stoich tables didn't work.

If you feel we're missing stuff or incorrect on things, feel free to let us know. We're happy to fix or add tables as we can. We try to be as pro-active as we can, but we're limited by available engineering resources. I used my own personal vacation time to map out a lot of this, off the clock, and we decided to add it as we can as I know there's desire for it.

Using what's there, I have a flex fuel calibration running on my own personal Hellcat, and inference of alcohol content with various different blends works great. Calibration will be the most difficult part for people wanting to tackle this, there's a lot to play with and get correct.

[meatbag]

nvm

[Jay@HAP]

Click on the OS button

[JoshCP527]

beta is fleshing out a lot....

[Jay@HAP]

beta is fleshing out a lot....

yeah there has been all sorts of stuff added recently

[DubstepShep]

Interested in how this might be used, if at all, on other dodge vehicles with other motors. I know a lot of the 5.7L hemis have the flex fuel tables in the tuning as well and it would be sweet to be able to add it.

[curt@injected]

Interested in how this might be used, if at all, on other dodge vehicles with other motors. I know a lot of the 5.7L hemis have the flex fuel tables in the tuning as well and it would be sweet to be able to add it.

Supposedly it will work on other dodge's although I have not tried it yet. Your airflow calculations would have to be very close as the hellcat is the only wideband equipped dodge