True flex fuel M156 ecu

[Mrboost05]

Planning on installing larger injectors and heading to the dyno this spring for a e85 tune but wondering if a dedicated e85 tune is the only option or has someone successfully got a flex fuel sensor working with the factory ecu/hp tuners. does the (2014 c63) have the capability ? Just wondering my options I don't have any interest in the current kits that are not really a true solution.

[chevota]

Someone said they did, but I'm pretty sure it was a M157 or M278, not an M156. I remember it because we chatted about the ethanol % sensor he added. Could've been on the MBWorld forum. I'm all but certain it was NOT done with HP.
I did notice in the latest version of HP there was an option to turn "Flex Fuel Monitoring" On in an M157 and M278, but not on an M156. It doesn't mean the option isn't in your ECU, it just means HP doesn't see it. Plus I have no clue if checking that box and adding an Eth sensor is all you need to do. I'd imagine user outlaw_50 would know? He seems to pop in once or twice a week. There are some other pro tuners here too, so I'm sure someone knows and we'll both find out.

I've been playing with Ethanol in my M278, but no special tune for it, or sensor. Mine appears to be limited by the lift pump in the tank, which peters out ~54% Eth, but varies with boost and A/F ratio of course. If oem boost and A/F then I bet $ I could run E100.

If you don't mind, I have some questions: I was wondering if your injectors could flow E85 as-is? I guess not, but I was curious why? I assume you need ~50% more flow, so how far will the stock ones go? And what is the drawback of bumping fuel pressure to get the extra flow you need? Seems like an easy solution but I don't hear about it, I only hear about bigger injectors.
What kinda gains do people get using E85 in that engine? Mine had a nice gain but I discovered it was mostly because it was pulling power on gas because the octane was too low. If I retarded the spark to work with gas, it stopped pulling power and I ended up with virtually the same gains. So ultimately I was kinda disappointed by the gains of 50% Eth vs gas.
Would Meth injection be as good or better in your eng? Seems reasonable, plus easier and cheaper. Any thoughts?

[outlaw_50]

It would be possible if you could add custom code and attach an external flex fuel sensor. I only saw one tuner who did that on MED17.7.2 A45.

M156 options is to add bigger injectors, remove some mm's from fuel rail thickness, and run dual racing fuel pumps but dont know exactly how much Ethanol it could handle.
M278 and M157 stock LPFP seems to run best on 20-25% Ethanol Blend.