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CALCULATE STOICH FUEL RATIO

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I WAS WONDERING IF SOME ONE MAY HAVE A SPREED SHEET

THAT I CAN WORK OUT THE STOICH RATIO OF DIFFERENT BLEEDS OF

ETHANOL BLEEDS

E10 E15 TO E100

THANKS

I made one for equal part Avgas and Ethanol, so E50 so to speak. there is also one on the interweeb somewhere. I used molar mass instead of just going by volume so my stoic is a little different. never used stoic anyway because of lambda sensor doesn't care what fuel you run.

https://docs.google.com/spreadsheets/d/1r4clMH-o9fGd7sLgMMUVvYlkzSFUbtNX5tsE2m9YtPs/edit?usp=sharing

http://jcsautomation.com/temp/Stoich%20Calculator%20For%20E85%20Blends.xls

We do include the calculation in our Ethanol and Flex Fuel tuning course which You'll have access to as a VIP member Nigel. I would argue that the stoichiometric AFR is perhaps not as relevant as you may think. If you're using flex fuel in a VE based ECU then stoich is important but then the ECU will be constantly recalculating this based off the current E%. If you're worried about it from a tuning perspective then as always, I'd suggest you simply use lambda and forget about it. Even those who use AFR units and regularly tune ethanol blends almost invariably stick to a stoich setting of 14.7:1 and just tune for a fixed AFR target irrespective of the fuel blend. This is not an accurate way of tuning but has become the norm.

Qoting you Andre" If you're using flex fuel in a VE based ECU then stoich is important but then the ECU will be constantly recalculating this based off the current E%. If you're worried about it from a tuning perspective then as always, I'd suggest you simply use lambda and forget about it. Even those who use AFR units and regularly tune ethanol blends almost invariably stick to a stoich setting of 14.7:1 and just tune for a fixed AFR target irrespective of the fuel blend. This is not an accurate way of tuning but has become the norm." Quote.

I have AEM 30-334 controller using analog MPVI2 Prolink input. I want to use this for WB EQ err channel (lambda) in HP TUNERS to adjust part throttle VE and MAF calibration to have an "accurate way of turning " but qas told NEVER tune part throttle using a wideband. I will install UEGO o2 sensor after cat. I also have a vette with cat deleted. What is needed to have quality data? Run open loop all the time? I was going to use ECT to force open loop. Does the ECU eq ratio channel and the MPVI2 eq err channel compile my graph histogram data in open loop part throttle? I have only used a tailpipe innovate clamp for WOT MAF calibration and would like to do a better accurate job of part throttle tuning.

Thank you Andre for your response.

There's a couple of ways of dealing with the part throttle tuning. You can use a wideband (which is the most accurate in my opinion) but this requires forcing the ECM into open loop mode otherwise the closed loop trims will have the measured AFR sitting on the commanded anyway. Alternatively you can use the STFT + LTFT to tune the closed loop portion of the tables. There's a predefined math channel that combines the trims for you. The way I see it though is that you're going to need a wideband to tune the PE areas of the tables so why not just use it to tune everything?

Andre, I agree! the wideband is a tool producing the best accurate tune why not USE it. BUT, here is some hypothetical scenarios and really need help digesting this please.

I have a flex fuel (keep this in mind) L59 5.3L GM Suburban with a factory GM crate motor replacement I am working on. It shows 22% in alcohol % PID. It did not come with a sensor fitted only calculated %. Let's stick with the closed loop portion using MATHs histogram to adjust the table, and we have E20 in the tank, and at 40kPa I am 6% lean. Would it be 6% lean in my table regardless of fuel blend? Example, if I put a K&N filter in a stock truck I have seen about 10-20% fuel added calibrating VE table. How does the flex fuel ECU calculate fuel trim is X%+/- due to an Ethanol blend rather than to a mechanical change requiring extra fuel like this efficient filter example. Is there a way to reset the Alcohol % like LTFT reset? We do not use E85.

Thanks for the help.

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