N54 Stock DME Flex Fuel

jyamona

Lieutenant
Free Vendor
Nov 7, 2016
932
Philly
UPDATE: Check Threadmarks by page numbers for important information!

Hey guys,

The time has finally come to share some details on my secret N54 project. It's been under development for many months now, and had no shortage of both hardware and software (mainly software
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) obstacles to overcome. That said, a major milestone was reached this week so it's time to let you all in! Coming soon to a stock DME near you:

FlexFuelLogo.png



Yep, real Flex Fuel. It is a fully implemented flex fuel solution, running on the stock DME! Dial your car in on pump (91-93oct), then E85, set the blending / interpolation curve tables, and be on your way. The benefits here are never having to reflash when changing ethanol blends again (or even worry about mixing the correct blend). Go from straight 93oct to 100% E85 or E98 on the same flash
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This is up and running on a few IJE0S cars now and works flawlessly. There is still some more work to be done, and of course porting to the other ROM types will take a good bit of time. Some hardware details are in need of finalization as well. More to come on those items in the weeks to follow.

Some overall highlights and features of this accomplishment:

  • first DME integration with a 3rd party sensor
  • first large scale rewrite and modification of DME logic
  • direct logging of Ethanol Content % in MHD
  • separate blending / interpolation per table grouping
  • seamless blending between maps for any ethanol content
I'd also like to give a big thanks to @CKI for his help in testing and flashing my countless revisions at all hours of the day, and also to @[email protected] for assembly code and hex conversion help along the way! In case you haven't guessed, this will be a module available in MHD similar to M-Boost.

A thread is worthless without pics, right? This log was taken after a fill-up to a higher E content, and you can see the AFR target rising as E% goes up. 2017 is just getting started, and will definitely be the year of the stock DME ;)

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eca_fuel_test.png

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doublespaces

Administrator
Oct 18, 2016
7,237
AZ
This is such badass news! I can now go fill up with ethanol whenever I get a chance... Major props!

So I assume the process is the same even if you run a different blend, like E54 for example but the blending tables will be different?

Because I don't know if I can even get my hands on E85 in AZ anymore.
 

[email protected]

Specialist
Free Vendor
Nov 6, 2016
60
Sav
As always Phenomenal work Jake and Martial. It was well worth the 8+hrs of flashing in the past few days.
To add some notes. I have had an E sensor wired into my DME for over 6 months and i have played with many mixtures. The DME's response in adapting to mixture changes is incredible. 60% changes in mixture on the same fuel scalar during just cruise and the DME responds quickly. There was a lot of preliminary testing and it all passes unnoticed. So that coupled with an active fuel scalar will be even better.
 

Joe

Specialist
Nov 1, 2016
58
Arizona
So this is why Jake, Chris and Jake all laughed at my comment the other day. Beautiful work. Any chance this can be added to a gpio on my ems4? Or haltech for that matter?

I also assume that PI driven by AIC would have the same problem, but one harder to solve.
 

[email protected]

Specialist
Free Vendor
Nov 6, 2016
60
Sav
So this is why Jake, Chris and Jake all laughed at my comment the other day. Beautiful work. Any chance this can be added to a gpio on my ems4? Or haltech for that matter?

I also assume that PI driven by AIC would have the same problem, but one harder to solve.
Yeah it was tough to hold in sorry, Theres several ways of solving the PI issue. The main idea was making sure we could get the DME to do what we wanted before investing more time into some of the other things. Now that the DME is 100% happy and cooperative we can now go through with making it a 100% complete kit.
 
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Xshadows

Corporal
Nov 4, 2016
121
Sanford NC
When this is working correctly with PI I will be switching to this with a MOTIV Boost Box. Going to be a killer combo! I will miss the gauge hijacking of my JB4 but this will make life way easier...
 

[email protected]

Specialist
Free Vendor
Nov 6, 2016
60
Sav
In the datalog posted for simplicity reasons the pump gas map is set to 11.5:1 afr and the E85 table set to 12.5:1. The interpolation is the % favoring E85. So a interpolation of 0 is 100% pump and a interpole of 100 is 100% E85. So as you can see it targets 11.8-11.9:1 @ 48% interpolation and changes to 12.2-12.3:1 @ 62% interpolation. To understand how well it works i did a run while it was changing to my fresh higher mixture. Just remember interpolation vs Ethanol is not linear. So 60% ethanol does not equal 60% interpolation.

Also for the first time we can officially badge the 335 as a true flex fuel

flexfuel pic.jpg
 
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