What about E85 fuel

Will it be posibble to use the Nano EFI with E85 or is this something in the future? I am starting to worry that my supercharged 720cc (44 ci) side valve BSA M21 will run too hot.

I’m interested, but I haven’t done anything with E85 yet. I probably won’t be able fit in the research necessary to start sizing up an approach/implementation until after Beta. Unless it’s requested a lot as a release feature.

You know you want to.

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Perhaps this is a naive view, but my understanding is that E85 is a map scaling and injector sizing situation. As in, you need something like 30% more fuel (to account for the lower energy in alchohol) and that’s about it.
Beyond that there can be some material concerns (older seals can be eaten by alcohol) but most modern components should haven’t any issue with that. Potentially a fuel injector may need to be validated to have proper material in it’s internal seals, but i haven’t seen such concerns raised in quite some time with automotive components, at least.
You may have to make some allowances for extra water (e85, having much more alcohol will absorb more atmospheric moisture in the same conditions than std gasohol mixtures) such as more variability in fuel trim allowance, but usually that just results in cleaner parts.
I’d be willing to test this on my equipment (like a +50% sized injector and a similarly scaled fuel map).

While i can’t see most people trying to run alcohol as a primary, it would be nice to be able to use it when it was available and reasonably cost effective. If the difference is really just mapping, and we had a metering capable fuel system (which we may not) it would be nice if you could plug in how much of what fuel you put in, and let nanoEFI scale the fuel map appropriately for what should be in the tank as a result with the assumption that appropriate mixing is happening to homogenize whatever is in there. That’d allow you to run anything from straight gasoline to straight ethanol. A little bit of trim from the o2 sensor as is going to happen anyway, and it seems feasible from a mechanical perspective. It doesn’t seem (famous last words) that the programming for this would add much either {InjectorPulseWidth = GetMapValue(sTPS, sTPSTrend, sTach, sMAP,Displacement,VolumetricEffciency)*EthanolContentOffset *FuelTrim(sO2)}. Of course this is a bit of an oversimplification, but I can convince myself that it should be simple.

Anyway, i wouldn’t say “hold up BETA” to get this working, but i’d like to see it in a post-release update for sure.


From my limited knowledge of E85, yes, you will need to use 30% more fuel, but a better way to monitor it is the AFR, as it has a different burn characteristic.

E85 afr

The addition of a flex fuel sensor would be required, that way pretty much any blend can be used, but I don’t know how fuel tables would need to be trimmed, this is where the O2 sensor and some dyno time would probably be needed, for the guinea pig, then data uploaded, which could possibly be used as a base setting.
My wifes car is running the Holden (GM) LFX engine, which has a sticker on the inside of the fuel door, stating ‘upto E85’ can be used.
Some fuels sold locally here (South OZ), will vary in the E% mix.
I plan on adding one to my LS1 for E85 uasge, also E85 benefits from high compression ratios or forced induction.
E85 having an octane rating of around 105RON, so more boost, more timing = more fun.

flex sensor

Finding a small enough sensor might be a challenge, but something that can be added at a later date would open up even more possibilities.

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I’d think some level of auto-tune could also be used to figure it out without a sensor besides the oxygen sensor we’ll need already.

Run at idle for 30 seconds or so (maybe up to a minute) to calibrate fuel trim. The engine will already be at or very near running temp (unless you trailer it to the gas station), so the IAC can adjust the idle to normal, and adjust the fuel to proper stoich and make a darn close guess of what your fuel mix is, i would think.